US3318237A

US3318237A - Silk screen printing machine

Info

Publication number: US3318237A
Application number: US476246A
Authority: US
Inventors: Stancil I Ramsey
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-08-02
Filing date: 1965-08-02
Publication date: 1967-05-09
Anticipated expiration: 1984-05-09

Description

I. RAMSEY May 9, 1967 5,

SILK SCREEN PRINTING MACHINE 5 Sheets-Sheet 1 Filed Aug. 1965 IN EN TOR.

srA/vc/L 1. RAMSEY BY A nap/var y 9, 1967 EY 3,318,237

SILK SCREEN PRINTING MACHINE y 9, 6 s. I. RAMSEY 3,318,237

SILK SCREEN PRINTING MACHINE Filed Aug. 2, 1965 5 Sheets-Sheet 3 INVENTOR. STANC/Z 1. 84/1455) ATTOPNE'Y S. I. RAMSEY SILK SCREEN PRINTING MACHINE May 9, 1967 5 Sheets-Sheet 4 Filed Aug. 2, 1965 IQ I N INVENTOR. STANCIL I. DA M55) I. RAMSEY May 9, 1967 SILK SCREEN PRINTING MACHINE 5 Sheets-Sheet 5 Filed Aug.

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ll lllll y [11 mlnuuuum N INVENTOR.

STANCIL I. RAMSEY United States Patent 3,318,237 SILK SCREEN PRINTING MACHINE Stancil 1. Ramsey, 4009 Harvey Parkway Oklahoma City, Okla. 73118 Filed Aug. 2, 1965, Ser. No. 476,246 15 Ciaims. (Cl. 101124) This invention relates generally to an improved machine for use in the silk screen printing process. More particularly, but not by way of limitation, this invention relates to an improved silk screen printing machine wherein the screen or stencil is disposed in a generally horizontal position and the printing medium is applied to the underside of the screen.

For the most part, silk screen printing machines constructed in the past have had the silk screen disposed therein relatively above the roll carrying the paper stock to be printed and have had the ink or printing medium applied on the upper side of the screen. Such an arrangement results in poor control of the impression on the paper, such as blurred or fuzzy lines, due to the gravitational flow of the ink through the screen.

However, some machines have had the silk screen disposed relatively below the roll and have included means for applying the ink to the underside thereof thus avoiding the blurring of the impression. Many of these machines have been constructed so that the ink reservoir and inking apparatus forms a portion of the reciprocating bed or platen that carries the silk screen. When the ink reservoir is carried in reciprocating motion with the screen, it has been necessary to operate the printing machine at relatively low speeds due to the tendency of the machine to spill or splash the ink from the reservoir.

All of the printing machines previously constructed that have the silk screen disposed relatively below the roll have had the roll carrying the paper stock arranged for movement in a vertical direction relative to the stencil. Thus, such machines require synchronization of the vertical movement of the roll with the reciprocating movement of the silk screen. Difficulty has been encountered in the machines having the vertically moving roll in attempting to accurately synchronize the movements of the roll with the movement of the screen to obtain multicolor prints wherein a single sheet of paper stock to be printed must be passed through the printing machine for each different color to be applied thereto. The registration of the various colors on the paper stock has not been entirely satisfactory. Also, the machines incorporating a vertically moving roll are inherently more complex thereby increasing the difficulty of construction and, consequently, the cost of the printing machine.

This invention provides an improved silk screen printing machine that includes: a cylindrical roll for carrying the paper stock to be printed that is rotatably mounted; a stencil or silk screen mounted for horizontal reciprocating movement below the roll and relatively toward and away from the roll; a stationary ink reservoir mounted below the stencil; pump means disposed in the reservoir for delivering the printing medium from the reservoir to the underside of the stencil; a spreader blade mounted below the stencil and movable into engagement with the stencil to distribute the printing medium on the underside thereof; a squeegee blade mounted below the stencil, in vertical alignment with the roll, whereby the squeegee blade moves into engagement with the stencil forcing the stencil into engagement with the paper stock carried by the roll; and, means for moving the spreader blade and squeegee blade into engagement with the stencil in timed relationship with the reciprocating movement of the stencil.

3,318,237 Patented May 9, 1967 One object of the invention is to provide an improved printing machine that can be easily and economically manufactured.

Another object of the invention is to provide an improved ,silk screen printing machine wherein the printing medium is applied to the underside of the stencil.

A further object of the invention is to provide an improved printing machine for use with the silk screen printing process that can be operated at relatively high speeds.

Still another object of the invention is to provide an improved printing machine for use in the silk screen printing process having all parts thereof contacting the print: ing medium arranged to be quickly and easily changed.

One other object of the invention is to provide an improved silk screen printing machine incorporating means for removing the printing medium from the screen in the event that the machine must be shut down during the printing process.

Still another object of the invention is to provide an improved silk screen printing machine that provides accurate impressions and accurate registration for multicolor printing.

The foregoing and additional objects and advantages of the invention will become more apparent as the following detailed description is read in conjunction with the accompanying drawings wherein like reference characters denote like parts in all views and wherein:

.FIG. 1 is a perspective view of a silk screen printing machine constructed in accordance with the invention;

FIG. 2 is a schematic diagram illustrating a drive system used in the silk screen printing machine of FIG. 1;

FIG. 3 is an enlarged perspective view illustrating the inking system utilized in the silk screen printing machine of FIG. 1;

FIG. 4 is a schematic diagram illustrating the apparatus used for spraying solvent on the silk screen in the printing machine of FIG. 1;

FIG. 5 is a schematic diagram illustrating a portion of the apparatus used in the printing machine of FIG. 1 for applying and distributing ink on the silk screen;

FIG. 6 is a schematic diagram illustrating the apparatus used in the printing machine of FIG. 1 for actuating the squeegee;

FIG. 7 is a schematic diagram illustrating the apparatus used in the printing machine of FIG. 1 for moving the wiper blade into and out of engagement with the silk screen to remove ink from the silk screen;

FIG. 8 is a schematic diagram illustrating the drive system utilized in the printing machine of FIG. 1 for rotating the inking roller;

FIG. 9 is a schematic diagram illustrating the positions of the various components of the printing machine during the movement of the silk screen relatively toward the cylindrical roll and during the printing cycle; and,

FIG. 10 is a schematic view similar to FIG. 9, but illustrating the various parts of the printing machine during the movement of the silk screen relatively away from the cylindrical roll. I

Referring to the drawing and to FIG. 1 in particular shown therein, and generally designated by the reference character 10, is a printing machine constructed in accordance with the invention. The printing machine 10 includes a base 12 having a bed or platen 14 located thereon and arranged to 'be reciprocated relative to the base 12 and relative to a roll 16.

An angularly disposed platform 18 is mounted on the base 12 and has one edge in juxtaposition with the roll 16. The platform 18 is provided so that paper stock 19 may be placed thereon and fed to the roll 16 as will be described.

The roll 16 is journaled in the base 12 and includes a pair of spaced grippers 17 for holding one end of the paper stock 19 in engagement with the roll 16. The grippers 17 are moved into and out of engagement with the paper stock 19 by a pair of cams 21 mounted on the base 12. The construction of the roll 16 and the grip pers 17 is well known to those skilled in the printing industry.

As illustrated in FIG. 1, the machine also includes a plurality of belts 20 extending around a shaft 22 that is journaled in the base 12 and a shaft 24 that is journaled in a paper conveyor 26. The belts 20 are provided to move the paper stock 19 from the printing machine 10 to the paper conveyor 26 after the printing process has been completed.

A silk screen frame 28 is mounted on the platen 14 by a plurality of threaded fasteners 30 for reciprocating movement with the platen 14. A stencil or silk screen 32 is fastened to the frame 28. The stencil or silk screen 32 is of the usual construction, that is, it is fabricated from a porous material, such as silk, and has been prepared for use by closing a portion of the pores or interstices in thematerial to form the desired design thereon. The construction of silk screens is well known to those skilled in the art and will not be described further.

An ink or printing medium reservoir 34 is releasably secured to the base 12 by a plurality of brackets 35 and is located generally under the roll 16 and below the silk screen 32. The silk screen 32 is mounted so that .it passes between the reservoir 34 and the roll 16 but above the platen 14 for purposes that will become more apparent hereinafter.

The printing machine 10 is also provided with a manual brake (not shown). A brake pedal 37 is shown in FIG. 1 and is connected through appropriate linkages 39 and others not shown with the manual brake (not shown). The structure and arrangement of the manual brake is well known to those skilled in the art.

As shown schematically in FIG. 2, the printing machine 10 is driven by a motor 36 that is mounted on the base 12. The motor 36 includes an output shaft 38 having a flywheel 40 and a pair of gears 42 and 44 mounted thereon. The gear 42 meshes with a mating gear 46 that is connected for rotation with the roll 16.

The gear 44 meshes with a mating gear 48 that is mounted on a shaft 50 journaled in the base 12 by a pair of bearings 52.. The shaft 50 carries a gear 54 that is in mesh with a gear 56 on a drive shaft 58. The drive shaft 58 carries a second gear 60 that is alternately engageable with a rack gear 62 and a rack gear 64 each of which is mounted on the platen 14. While the drive shaft 58 is journaled in bearings 66, the gear 60 carried on the drive shaft 58 is movable into engagement alternately with either the .rack gear 62 or the rack gear 64 while maintaining the gear 56 in mesh with the gear 54. The aforedescribed construction of the drive shaft 58 is a well known and a commonly used means for imparting reciprocating motion to the platen 14.

The gear 48 carried on the shaft 50 is also in mesh with a gear 68 mounted on a cam shaft 70 that is journaled in the base 12 by a pair of bearings 72. The cam shaft -70 also has four

cams

74, 76, 78, and 80 mounted thereon. The cams are mounted exteriorly of the base 12 on the cam shaft 70'as is clearly shown in FIG. 1.

The gear arrangement described for driving the printing machine 10 is constructed so that the roll 16 makes one revolution during the movement of the platen 14 relatively toward the roll 16 and makes one additional revolution during the movement of the bed relatively away from the roll 16, that is, the roll 16 makes two revolutions for each reciprocating movement of the platen 14. The cam shaft 70 makes one revolution for each two revolutions of the roll 16, that is, the cam shaft 70 rotates once for each complete reciprocating movement of the platen 14.

FIG. 3 is an enlarged view showing the inking system utilized in the printing machine 10 in relation to the roll 16. The base 12 has been omitted for clarity of illustration. As shown in FIG. 3, three

shafts

82, 84 and 86 are disposed in spaced, generally parallel relationship relatively in front of the roll 16. Each of the

shafts

82, 84 and 86 is journaled at each end in brackets 88 that are attached to the base 12 (see FIG. 1).

A pair of spaced, lever arms 90 are rigidly attached to the shaft 82. The other end of each arm 90' is connected with one end of a respective linkage member 92. The other ends of the linkage members 92 are removably and pivotally connected with a four bar linkage 94 that is pivotally mounted on a bracket 96 attached to the reservoir 34.

The four bar linkage 94 has an elongated spreader blade 98 mounted thereon. The blade 98 extends transversely across the printing machine 10 below the stencil 32 and is movable into engagement with the underside of the stencil 32 as will be described.

The linkage 94 also carries an elongated inking blade 100 that extends across the printing machine 10 relatively below the stencil 32. One edge 102 on the inking blade 100 is disposed adjacent an inking roller 104 that is journaled in the frame 12. A second edge 105 on the blade 100 is disposed in spaced, parallel relationship to the stencil 32. The blade 100 is moved by the linkage 94 to a position wherein the edge 102 is in juxtaposition with the roller 104 and the edge 105 is in juxtaposition with the stencil 32 during the printing cycle.

As illustrated in the exploded portion of FIG. 3, the ends 111 of the inking roller 104 are removably journaled in the base 12 by an assembly comprising a bracket 106 that is rigidly mounted on the base 12. The bracket 106 has a recess 108 formed therein sized to receive a bearing 110. The bearing 110 is provided with an aperture 109 for receiving the end 111 of the inking roll 104. The bracket 106 is also provided with a hole 112 arranged to receive a pin 114 that extends from the lower side of a clamping member 116.

To mount the roller 104 in the base 12, the end 111 of the inking roller 104 is placed in the aperture 109 of the bearing 110. The bearing 110 is then positioned in the recess 108. The clamping member 116 is connected with the bracket 106 by inserting the pin 114 into the hole 112. After insertion of the pin 114 into the hole 112, a dog 118 that is pivotally mounted in the base 12 is rotated downwardly into a notch 120 provided in the upper surface of the clamping member 116 thereby locking the clamping member 116 in assembled relation with the bracket 106. A threaded thumb screw 122 that extends through the clamping bracket 116 is then tightened so that an end thereof (not shown) engages the bearing 110 to secure the bearing 110 in the bracket 106.

As is evident from the foregoing description, the inking roller 104 may be quickly and easily removed from the base 12 by reversing the foregoing assembly procedure. It is important that the inking roller 104 be easily removable so that it can be cleaned and/or replaced when multicolor prints are to be made by the printing machine 10.

Also shown in FIG. 3 is a spur gear 124 that is mounted on the end 111 of the inking roller 104. The gear 124 is in mesh with a spur gear 126 mounted on a stub shaft 128. The stub shaft 128 is journaled in the base 12 and carries a chain sprocket 130 thereon. The spur gears 124 and 126 and the chain sprocket 130 form part of the mechanism for rotating the inking roller 104. The mechanism for driving the inking roller 104 will be described more fully in connection with the description of FIG. 8.

The shaft 84 has a pair of levers 132 mounted thereon that are pivotally connected to one end of a respective one of a pair of linkage members 134. The other end of each of the linkage members 134 is pivotally and releasably connected with a lever 136. The lever 136 is pivotally mounted in the base 12 by a pin (not shown) inserted through the opening 138 provided in the lever 136.

A bracket 140 is mounted on the upper surface of the lever 136. The bracket 140 has a recess 142 therein adjacent the lever 136, thereby forming a slot with the upper surface of the lever 136 to receive a squeegee blade assembly 144.

The squeegee blade assembly 144 is attached to the lever 136 by an elongated threaded fastener 146 that extends therethrough into threaded engagement with the squeegee blade assembly 144. The threaded fastener 146 is elongated so that access may be had to release and attach the squeegee blade assembly 144 in the machine with greater facility.

The squeegee blade assembly 144 includes a mounting member 148 that is inserted in the slot formed by the recess 142 and threadedly receives the fastener 146. The mounting member 148 extends transversely across the machine 10 and has a downwardly extending flange 150 thereon.

A squeegee blade 152 that is preferably constructed from a material, such as resilient natural or synthetic rubber, is positioned adjacent the flange 150 and also extends across the machine 10. The squeegee blade 152 is assembled with the mounting member 148 by a mounting strip 154 and a plurality of threaded fasteners 156. The fasteners 156 extend through the squeegee blade 152 and strip 154 into threaded engagement with the flange 150.

The squeegee blade 152 is located below the stencil 32 in vertical alignment with the centerline or axis of the roll 16. The squeegee blade 152 is movable into and out of engagement with the stencil 32 as will be described in connection with FIG. 6.

A pair of levers 158 are mounted on the shaft 86. Each lever 158 is pivotally connected with one end of a respective one of a pair of linkage members 160. The other ends of each of the members 160 are pivotally and removably connected with a wiper blade 162.

The wiper blade 162 extends transversely across the machine 10 below the stencil 32. The wiper blade 162 is pivotally connected to the bracket 96 that is, as previously described, mounted in the ink reservoir 34. Due to the pivotal attachment of the wiper blade 162 to the bracket 96, the wiper blade 162 is movable into and out of engagement with the underside of the stencil 32. The means for imparting movement to the wiper blade 162 will be described more fully in connection with the description of FIG. 7.

- The system utilized for spraying solvent on the stencil 32 is shown schematically in FIG. 4. As shown therein, a cam follower 164 has one end pivotally attached to a bracket 166 mounted on the base 12 (see FIG. 1) and has the other end connected with an upwardly extending rod 168. The rod 168 extends upwardly through a bracket 170 that is also mounted on the base 12 as shown in FIG. 1.

The rod 168 and the connected cam follower 164 are biased relatively downwardly by a compression spring 172 that encircles the rod 168 and has its lower end in engagement with the rod168 and its upper end in engagement with the bracket 170. The upper end of the rod 168 is provided with a flange 174 that is engageable with the upper surface of a yoke 176 attached to a member 178.

The member 178 extends upwardly into engagement with an operating handle 180. The operating handle 180 is pivotally mounted on the base 12 and arranged, when positioned as shown in FIG. 4, to permit the cam follower 168 to engage the irregular surface of the cam 80. The operating handle 180 may be pivoted relative to the base 12 to a position (not shown) wherein the member 178 is lifted upwardly moving the yoke 176 upwardly and, by virtue of the engagement of the yoke 176 with the flange 174, also moving the rod 168 and the connected cam follower 164 upwardly and out of engagement with the cam 80.

Mounted on the base 12 is a switch 182 (also see FIG. 1) that is held in an open position by a spring 184. The switch 182 is mounted directly below the cam follower 164 so that the cam follower 164 engages the switch 182 during a portion of the rotation of the cam to close the switch 182 connecting a source of electrical energy, designated by the reference character 186, by a conductor 188 and a conductor 190 to a solenoidactuated valve 192. The electrical circuit is completed through a conductor 194 that is connected with the solenoid-actuated valve 192 and with the source of electrical energy 186.

The solenoid-actuated valve 192 is connected in a conduit 196 that has one end in fluid communication with a pump 198 and the other end in fluid communication with a plurality of nozzles 200 (see FIG. 1). The pump 198 is connected by a conduit 202 with a source of solvent (not shown).

As can be perceived from viewing FIG. 4, rotation of the cam shaft 70 and the attached cam 80 permits the cam follower 164 to move downwardly into engagement with the switch 182, closing the switch 182 and opening the solenoid-actuated valve 192.

With the valve 192 open, solvent flows from the pump 198 through the conduit 196 and the nozzles 200. The nozzles 200 are oriented to direct the solvent toward the upper surface of the stencil 32. The cam 80 is positioned on the cam shaft 70 so that the solvent spray occurs when the stencil 32 is disposed relatively below the nozzles 200.

The schematic diagram of FIG. 5 illustrates more completely the structure for moving the inking blade and the spreader blade 98 into the position wherein ink will be deposited on the underside of the stencil 32. As shown therein, a third lever 204 is mounted on the shaft 82 and is pivotally connected with one end of a linkage member 206. The other end of the linkage member 206 is pivotally connected with a cam follower 208.

The cam follower 208 is pivotally mounted in the bracket 166 and is in engagement with the cam 76 carried by the cam shaft 70. Attached to the cam follower 208 is an upwardly extending rod 210 that extends through the bracket 170. A compression spring 172 is disposed on the rod 210 and has one end in engagement with the rod 210 and the other end in engagement with the bracket to resiliently bias the cam follower 208 into engagement with the cam 76.

A lever 212 is pivotally mounted on the base 12 and has one end connected with the cam follower 208 by a member 214. The other end of the lever 212 is connected by a tension spring 216 with the base 12.

A foot-operated pedal 218 extends through an operators platform 220 mounted on the base 12. The lower end of the pedal 218 is pivotally connected with the lever 212 between the pivotal mounting point of the lever 212 and the end attached to the tension spring 216. As can be appreciated from viewing FIG. 4, depressing the pedal 218 pivots the lever 212 relatively against the tension spring 216, forcing the cam follower 208 out of engagement with the surface of the cam 76. As long as the pedal 218 is held depressed, the spreader blade 98 and inking blade 100 are held in a position relatively away from the stencil 32 wherein ink cannot be deposited on the stencil 32.

With the pedal 218 released, the cam follower 208 engages and follows the surface of the cam 76. It can be seen thaat the cam follower 208 moves relatively upwardly and downwardly depending on the particular portion of the cam 76 with which it is in engagement.

When the cam follower 208 is in the position shown,

that is, in a position relatively close to the cam shaft 70, the linkage member 206 transmits a force to the lever 204 that rotates the shaft 82 and the lever arms 90 pulling the linkage members 92 relatively toward the shaft 82 and, through the four bar linkage 94, raising the spreader blade 98 into juxtaposition with and the inking blade 100 into engagement with the underside of the stencil 32. With the

blades

98 and 100 in the position described, ink is transmitted from the inking roller to the inking blade 100 from which the ink is deposited on the underside of the stencil 32. The spreader blade 98 distributes the ink over the underside of the stencil 32 and removes excess ink therefrom.

When the cam 76 is rotated to a position wherein the cam follower 208 is raised upwardly, the shaft 82 is pivoted in the opposite direction to move the four bar linkage 94 relatively away from the shaft 82, moving the inking blade 100 and spreader blade 98 relatively away from the stencil 32.

FIG. 6 illustrates schematically, but more completely the structure for moving the squeegee blade 152 into engagement with the underside of the stencil 32. As shown therein, a cam follower 222 is pivotally connected to the bracket 166 and is in engagement with the irregular surface on the cam 78 mounted on the cam shaft 70. A linkage member 224 extends from the cam follower 222 and is pivotally connected with a third lever 226 that is mounted on the shaft 84.

An upwardly extending rod 228 connected at its lower end with the cam follower 222 extends through the bracket 170. A compression spring 230 that encircles the rod 228 has one end in engagement with the rod 228 and the other end in engagement with the bracket 170, whereby the cam follower 222 is resiliently biased into engagement with the surface of the cam 78.

A connecting member 232 pivotally connects the end of the cam follower 222 with the lever 212. The lever 212 and the various parts associated therewith function as described in the connection with FIG. to move the cam follower 222 out of engagement with the cam 78,

thereby holding the squeegee blade 152 out of engagement with the underside of the stencil 32 when the pedal 218 is depressed.

As illustrated in FIG. 6, the cam follower is in engagement with a low portion of the cam 78 so that cam follower 222 is moved relatively downwardly, pulling the lever 226 downwardly through the linkage member 224, pivoting the shaft 84 in a direction to lift the lever 132. The movement of the lever 132 lifts the lever 136 and the attached squeegee blade 152 into contact with the underside of the stencil 32.

The stencil 32, due to the engagement of the squeegee blade 152 therewith, is deformed upwardly into engagement with the paper stock 19 carried by the roll 16. The squeegee blade 152 forces the ink on the stencil 32 through the interstices therein depositing the ink on the surface of the paper stock 19.

When the cam shaft 70 and the attached cam 78 rotate until the cam follower 222 is riding on the relatively high portion of the cam '78, the linkage member 224 moves upwardly, pivoting the shaft 84 in the opposite direction, pivoting the lever 136 relatively downwardly and moving the attached squeegee blade 152 out of engagement with the stencil 32.

The schematic diagram of FIG. 7 illustrates the structure for moving the wiper blade 162 into and out of engagement with the stencil 32. As shown therein, the shaft 86 is provided with an additional lever 234 that is pivotally connected with one end of a linkage member 236. The other end of the linkage member 236 is piv-' otally connected with a cam follower 238. The cam follower 238 is arranged to engage the irregular surface of the cam 74 and has one end pivotally connected with the bracket 166 mounted on the base 12 as previously described.

A rod 240 is connected at its lower end with the cam follower 238 and extends upwardly therefrom through the bracket 170. A compression spring 242 encircles the rod 240 and has one end in engagement with the rod 240 and the other end in engagement with the bracket 170, thereby resiliently biasing the cam follower 238 downwardly into engagement with the cam 74.

It can be seen in FIG. 7 that the cam follower 238 moves either upwardly or downwardly relative to the cam shaft 70 depending upon the portion of the cam 74 engaged thereby. As the cam follower 238 moves relatively downwardly, the linkage member 236 moves the lever 234 downwardly pivoting the shaft 86 in a direction to raise the wiper blade 162 into contact with the lower surface of the stencil 32. When the cam follower 238 is in the relatively upward position as illustrated in FIG. 7, the shaft 86, through the linkage described, pivots in the opposite direction, moving the linkage members 1160 relatively downwardly and pivoting the wiper blade 16 2 relatively away from the lower surface of the stencil 32.

The

cams

74, 76, 78 and 80, as previously described, are mounted for rotation on the cam shaft 70 and, therefore, rotate at the same speed. While a single cam could be provided to replace the individual cams shown, it is prefered that the arrangement shown be used so that the cams can be synchronized relative to each other to actuate the various blades in timed sequence thereby performing the printing process in the most efficient manner. For example, the cams are arranged so that the squeegee blade 152 is moved into engagement with the stencil 32 slightly after the spreader blade 98 and the inking blade 100 are moved into juxtaposition with the stencil 32. Also, the cam 74 is positioned on the cam shaft 70 so that the wiper blade 162 is out of engagement with the stencil 32 during the travel of the stencil 32 relatively toward the roll 16 and is in engagement therewith as the stencil 32 travels relatively away from the roll 16. The eam 80 is positioned so that solvent is sprayed on the stencil 32 only when the stencil 32 is disposed thereunder.

FIG. 8 illustrates schematically the drive system utilized for rotating the inking roller 104. While the inking roller 104 may be driven by the motor 36 through an appropriate drive mechanism, it is preferred that the inking roller 104 be driven separately as illustrated.

It has been found that a different rotational speed of the inking roller 104 for different viscosities of printing mediums provides the most efficient movement of the ink from the roller 104 to the inking blade 100.

Therefore, the chain sprocket previously described, is connected by an endless chain 244 with a sprocket 246 mounted on an output shaft 247 of a variable speed device 248. The variable speed device 248 is arranged to be driven by an electric motor 250 mounted on the base 12 as illustrated in FIG. 1. The variable speed device 24 8 is conveniently provided with a handle 252 for adjusting the speed of the output shaft 247 and the sprocket 246. A variable speed motor may be utilized if desired in place of the motor 250 and the variable speed device 248.

Operation The printing machine 10 is placed in operation by starting the motor 36 and releasing the brake pedal 37. As described in connection with FIG. 2, the motor 36 reciprocates the platen 14 and causes the rotation of the cam shaft 70 and the roll 16. Also, the motor 250 is started to cause the rotation of the inking roller 104.

The paper stock 19 is fed from the platform 18 to the roll 16 where it is engaged by the grippers 17 so that the paper stock is disposed around the roll 16 substantially as illustrated in FIG. 9.

As the roll 16 rotates, carrying the paper stock 19 therewith, the platen 14 moves relatively towards the roll 16 due to the engagement of the gear 60 with the rack gear 64 (see FIG. 9). During the movement of the platen 14 toward the roll 16, the wiper blade 162 is held out of engagement with the underside of the stencil 32 as shown in FIGS. 7 and 9, since the cam follower 238 is on the raised portion of the surface of the cam 74. The spreader blade 98 and inking blade 100 are moved upwardly into juxtaposition with the underside of the stencil 32 since the cam follower 208 (see FIG. connected therewith is in engagement with the lower portion of the cam 76.

Ink or other printing medium contained in the reservoir 34 is picked up by the inking roller 104 and carried thereby onto the upper surface of the inking blade 100 from which it is placed on the underside of the stencil 32. As the platen 14 and stencil 32 move relatively toward the roll 16, the ink on the underside of the stencil 32 is distributed evenly on the stencil 32 by the spreader blade 98 that is in engagement with the underside of the stencil 32.

As the inked portion of the stencil 32 approaches the squeegee blade 152 the squeegee blade 152 is moved into engagement with the underside of the stencil 32 since the cam follower 222 (see FIG. 6) connected therewith is on the lower surface of the cam 78. The engagement of the squeegee blade 152 with the stencil 3-2 deforms the stencil 32 relatively upwardly into engagement with the paper stock 19 carried by the roll 16. The ink on the stencil 32 is forced through the interstices in the stencil 32 by the squeegee blade 152, thereby leaving an impression on the paper stock '19.

When the stencil 32 has completed its movement relatively toward the roll 16, the gear 60 moves downwardly out of engagement with the rack gear 64 and into engagement with the rack gear 62 (see FIG. 10), thereby reversing the direction of movement of the platen 14 and the attached stencil 32. As this occurs, the squeegee blade 152 is moved out of engagement with the stencil 32 since the cam follower 222 connected therewith is in engagement with the raised surface of the cam 78 (see FIG. 6).

Simultaneously, or shortly thereafter, the spreader blade 98 and inking blade 100 are moved downwardly away from the stencil 32 as the cam follower 208 connected therewith (see FIG. 5) engages the raised surface of the cam 76.

As shown in FIG. 10, the wiper blade 162 is moved upwardly into engagement with the underside of the stencil 32 as the cam follower 238 connected therewith engages the lower surface on the cam 74 (see FIG. 7). The wiper blade 162 removes ink from the stencil 32 as the stencil 32 moves relatively away from the roll 16.

As the first revolution of the roll 16 is completed, the grippers 117 are released from the paper stock 19 so that the paper stock 19 is fed off the roll 16 onto the belts 20, thus completing the printing cycle. It should be pointed out that the stencil 32 moves out of engagement with the roll 16 when the squeegee blade 152 moves to its lower position as illustrated in FIG. 10. The only blade in contact with the stencil 32 during the movement of the stencil 32 relatively away from the roll 16 is the wiper blade 162.

The reservoir 34 and the various blades are mounted in the machine 10 in a relatively stationary position, that is, they do not reciprocate. Therefore, the only reciprocating portion of the machine 10 is the platen 14 and the stencil 32 which permits very rapid operation of the machine 10 without the danger of splashing or spilling ink from the reservoir 34.

Also, the machine 10 operates relatively clean, that is, the squeegee blade 152 and spreader blade 98 function to remove excess ink from the stencil 32 as it moves relatively toward the roll 16 and the Wiper blade 162 removes ink therefrom during movement of the stencil 32 relatively away from the roll 16 to avoid the dripping of ink from the stencil 32 that is often present in the silk screen printing machines previously constructed.

If the machine is to be shut down for a period of time, the pedal 218 is depressed, moving the spreader blade 98, inking blade 100, and squeegee blade 152 out of engagement with the stencil 32 so that no ink can be deposited thereon. The reciprocation of the stencil 32 is continued with the operating handle 180 moved to a position wherein the cam follower 164 (see FIG. 4) is in engagement with the cam 80. In this position, the cam follower 164 engages the switch 182 to close the switch 182 during each reciprocating movement of the stencil 32.

When the switch 182 is closed, the solenoid valve 192 opens to permit solvent to be sprayed by the nozzles 200 on the stencil 32. The solvent spray removes ink from the stencil 32 to effectively prevent the ink from drying and closing the interstices in the stencil 32.

If a different type or color of printing medium is to be used in the machine 10, the

linkage members

92, 134 and 160 are removed from their respective blades. The ends 111 of the ink roller 104 are released from their mounting in the base 12 by removing the clamping member 116 as previously described. The reservoir 34, after the brackets 35 have been removed, is pulled from the machine 10 along with the attached

blades

98, and 162 for cleaning or replacement. Also, the squeegee blade 152 may be quickly and easily removed from the machine 10 'by loosening the threaded fasteners 146 that connect it to the lever 136. Thus, it can be seen that the machine 10 is arranged so that the portions thereof that are in contact with the ink or printing medium may be quickly and easily removed when multiple color prints are to be made or when the machine 10 is to be cleaned.

It should be understood that the embodiment described in detail hereinbefore is presented by way of example only and that many modifications and changes therein can be made Without departing from the spirit of the invention or from the scope of the annexed claims.

What I claim is:

1. In a machine for printing an impression on paper stock and the like, the improvement comprising:

a cylindrical roll rotatably mounted in said machine for carrying the stock to be printed;

a stencil mounted for horizontal reciprocating movement below said roll relatively toward and away from said roll;

a stationary ink reservoir mounted below said stencil;

ink pump means rotatably disposed in said reservoir for delivering ink from said reservoir to the underside of said stencil;

a spreader blade spaced from said ink pump means and mounted below and movable from a position out of engagement with said stencil to a position engaging said stencil at a point not in vertical alignment with said roll to distribute the ink on the underside of said stencil;

a squeegee blade mounted below said stencil and below and in vertical alignment with said roll and movable into engagement with said stencil to force the ink through said stencil onto the stock carried by said roll and movable away from said stencil; and,

means for moving said spreader blade and squeegee blade into engagement with said stencil in timed relationship with the reciprocating movement of said stencil.

2. The machine of claim 1 and also including:

a wiper blade movably mounted under said stencil, said wiper blade being engageable with said stencil to remove ink therefrom; and,

means for moving said wiper blade into and out of engagement with said stencil in timed relationship with the reciprocating movement of said stencil.

3. The machine of claim 1 wherein said means for moving said spreader blade and squeegee blade includes: a rotatable cam having an irregular cam surface for each of said blades and rotating in timed relationship with the reciprocating movement of said stencil; a cam following linkage for each of said blades in engagement With the surface of a respective one of said cams, said linkages being connected with said blades to move saidlblades into and out of engagement with said stencil as said cams rotate. 4. The machine of claim 1 wherein said ink pump means includes:

an elongated roller mounted for rotation and disposed in said ink reservoir with the roller in contact with the ink; an inking blade movably mounted below said stencil and having one edge disposed adjacent said roller whereby rotation of said roller deposits ink on said inking blade and having a second edge disposed adjacent said stencil whereby ink is deposited on said stencil by said inking blade; and means for moving said inking blade toward and away from said stencil and roller in timed relationship with the reciprocation of said stencil. 5. The machine of claim 4 wherein said means for movingsaid inking blade includes a linkage connecting said inking blade to said spreader blade for movement therewith.

6. The machine of claim 4 and also including: a variable speed motor having an output shaft; and, means rotatably connecting said output shaft with said roller whereby the rotational speed of said roller can be varied by varying the rotational speed of the variable speed motor. 7 7. In a machine for printing an impression on paper stock and the like, the improvement comprising:

a cylindrical roll rotatably mounted in said machine for carrying the stock to be printed; a stencil mounted for horizontal reciprocating movement below said roll; a stationary ink reservoir mounted below said stencil; an elongated roller mounted for rotation and disposed in said ink reservoir with the roller in contact with the ink in said reservoir; an inking blade movably mounted below said stencil and having one edge disposed adjacent said roller whereby rotation of said roller deposits ink on said inking blade and having a second edge disposed adjacent said stencil whereby ink is deposited on said stencil by said inking blade;

-a spreader blade mounted below and movable toward and away from said stencil to distribute the ink deposited on said stencil by said inking blade;

first linkage means for connecting said inking and spreader blades for movement together;

a first cam having an irregular surface thereon, said first cam being rotatable in timed relationship with the reciprocating movement of said stencil;

a second linkage including a cam follower engaging said irregular surface, said second linkage being connected with said inking and spreader blades whereby said inking and spreader blades are moved by said first cam in timed relationship with the reciprocating movement of said stencil;

a squeegee. blade mounted below said roll and stencil and movable into engagement with said stencil to force ink through said stencil onto the stock carried by said roll and movable away from said stencil;

a second cam having an irregular surface thereon, said second cam being rotatable in timed relationship with the reciprocating movement of said stencil;

' a third linkage including a cam follower engaging the irregular surface on said second cam, said third linkage being connected with said squeegee blade to move said squeegee blade into and out of engagement with said stencil in timed relationship with the reciprocating movement of said stencil;

a wiper blade mounted below said stencil and movable into and out of engagement with said stencil to remove ink therefrom;

a third cam having an irregular surface thereon, said third cam being movable in timed relationship with the reciprocating movement of said stencil; and,

a fourth linkage including a cam follower engaging the irregular surface on said third cam, said fourth linkage being connected with said Wiper blade to move said wiper blade into and out of engagement with said stencil in timed relationship with the reciprocating movement of said stencil.

8. The machine of claim 7 and also including:

a spray nozzle mounted on said machine and connected with a source of solvent suitable for dissolving the ink, said nozzle being oriented in a direction to spray said solvent on the upper surface of said stencil;

valve means operably connected with said nozzle for controlling the flow of solvent from said solvent source to said nozzles;

a fourth cam having an irregular surface thereon mounted for rotation in timed relationship with the reciprocating movement of said stencil; and,

means operably connected with said valve means engaging the irregular surface on said fourth cam whereby said valve means is opened by said fourth cam to permit solvent to spray on the upper surface of said stencil during a portion of the reciprocating movement of said stencil.

9. A printing machine comprising:

a frame; v

a cylindrical roll journaled in said frame for carrying paper stock and the like that is to be printed;

a horizontal bed mounted for reciprocating movement in a horizontal direction in said frame below said roll and relatively toward and away from said roll;

a stencil mounted on said bed for horizontal reciprocating movement below said roll;

means for reciprocating said bed and rotating said roll in timed relationship;

a stationary ink reservoir mounted on said frame below said stencil;

ink pump means journaled in said frame and disposed in said reservoir for delivering ink from said reservoir to the underside of said stencil;

means on said frame for driving said ink pump means;

a spreader blade mounted on said frame below said stencil and movable from a position out of engagement with said stencil to a position engaging said stencil to distribute the ink on the underside of said stencil;

a shaft journaled in said frame and rotatable in timed relationship with the reciprocating movement of said bed;

a first cam having an irregular surface mounted on said shaft;

first linkage means engaging the irregular surface on said first cam and connected with said spreader blade to move said spreader blade into engagement With said stencil when said stencil is moving relatively toward said roll and to move said spreader blade out of engagement with said stencil when said stencil is moving in the opposite direction;

a squeegee blade mounted on said frame below said stencil and directly below said roll and movable from a position out of engagement with said stencil to a position engaging said stencil and moving said stencil into engagement with the stock carried by said roll whereby the ink is driven through said stencil onto said stock;

a second cam having an irregular surface mounted on said shaft; and,

second linkage means engaging said irregular surface 13 on said second cam and connected with said squeegee blade to move said squeegee blade into engagement with said stencil when said stencil is moving relatively toward said roll and out of engagement with driving said ink pump means;

an elongated inking blade having generally parallel edges mounted on said frame below said stencil and adjacent said roller, said inking blade being movable eluding means for varying the rotational speed of said roller. 13. The printing machine of claim 12 and also including:

said stencil when said stencil is moving in the opa plurality of spray nozzles mounted on said frame posite direction. and connected with a source of solvent suitable for 10. The printing machine of claim 9 and also including: dissolving the ink, said nozzles being oriented in a a Wiper blade mounted on said frame below said stencil direction to spray said solvent on the upper surface and movable from .a position out of engagement of said stencil; with said stencil to a position engaging the under- 10 a valve operably connected with said nozzles for conside of said stencil to remove ink therefrom; trolling the flow of solvent from said source to said a third cam having an irregular surface mounted on nozzles; and

said shaft; and, means for actuating said valve in timed relationship third linkage means engaging the irregular surface on with the reciprocating movement of said bed wheresaid third cam and connected with said wiper blade by solvent is sprayed on said stencil during a portion to move said wiper blade into engagement with said of the reciprocating movement thereof. stencil when said stencil is moving relatively away 14. The printing machine of claim 13 wherein said from said .roll and out of engagement with said stenmeans for actuating said valve includes: l il wh aid'stencil is moving in the opposite dia fourth cam having an irregular surface thereon rection, mounted on said shaft; 11. The printing machine of claim 10 wherein said a Solenoid connected with said valve for moving said ink pump means includes: valve between open and closed positions;

an elongated roller journaled in said frame disposed switch means electrically connected with a source of in said ink reservoir with the roller in contact with electrical energy a i Said Solenoid, said Switch the ink and operably connected with the means for means being engageable With the irregular Surface on said fourth cam to actuate said solenoid opening said valve during when said stencil is in a position wherein said nozzles can spray solvent thereon.

15. The printing machine of claim 14 and also including means for holding said switch means out of engagement with said fourth cam whereby said valve remains closed during the reciprocating movement of said from a position wherein one edge is in juxtaposition with said roller whereby rotation of said roller deposits ink on said inking blade and the other edge is in juxtaposition with the underside of said stencil Stencilwhereby said inking blade deposits ink on said stencil to a position wherein said edges are relatively remote References Cited by the Exammer from said roller and stencil; and, UNITED STATES PATENTS fourth linkage means connecting said inking blade to 1 421 884 7/1922 Yohns said spreader blade whereby said inking blade moves 1541787 6/1925 codger'1e et a1 101 120 to the position depositing ink on said stencil when 1861610 6/1932 Respers 101 123 said spreader blade is in the position engaging said 40 2:492:052 12/1949 Martin 101 124 stencll- 2,613,596 10/1952 Meissner 101-124 12. The printing machine of claim 11 wherem sa1d 2,864,308 12/1958 Luppold 101 124 means for driving said ink pump means includes:

a motor mounted on said frame and having an output shaft; means connecting said output shaft with said roller in- 5 ROBERT E. PULFREY, Primary Examiner.

H. P. EWELL, Assistant Examiner.

Claims

1. IN A MACHINE FOR PRINTING AN IMPRESSION ON PAPER STOCK AND THE LIKE, THE IMPROVEMENT COMPRISING: A CYLINDRICAL ROLL ROTATABLY MOUNTED IN SAID MACHINE FOR CARRYING THE STOCK TO BE PRINTED; A STENCIL MOUNTED FOR HORIZONTAL RECIPROCATING MOVEMENT BELOW SAID ROLL RELATIVELY TOWARD AND AWAY FROM SAID ROLL; A STATIONARY INK RESERVOIR MOUNTED BELOW SAID STENCIL; INK PUMP MEANS ROTATABLY DISPOSED IN SAID RESERVOIR FOR DELIVERING INK FROM SAID RESERVOIR TO THE UNDERSIDE OF SAID STENCIL; A SPREADER BLADE SPACED FROM SAID INK PUMP MEANS AND MOUNTED BELOW AND MOVABLE FROM A POSITION OUT OF ENGAGEMENT WITH SAID STENCIL TO A POSITION ENGAGING SAID STENCIL AT A POINT NOT IN VERTICAL ALIGNMENT WITH SAID ROLL TO DISTRIBUTE THE INK ON THE UNDERSIDE OF SAID STENCIL; A SQUEEZE BLADE MOUNTED BELOW SAID STENCIL AND BELOW AND IN VERTICAL ALIGNMENT WITH SAID ROLL AND MOVABLE INTO ENGAGEMENT WITH SAID STENCIL TO FORCE THE INK THROUGH SAID STENCIL ONTO THE STOCK CARRIED BY SAID ROLL AND MOVABLE AWAY FROM SAID STENCIL; AND, MEANS FOR MOVING SAID SPREADER BLADE AND SQUEEGEE BLADE INTO ENGAGEMENT WITH SAID STENCIL IN TIMED RELATIONSHIP WITH THE RECIPROCATING MOVEMENT OF SAID STENCIL.