GB1580555A

GB1580555A - Sheet fed perfector type offset duplicator

Info

Publication number: GB1580555A
Application number: GB4078677A
Authority: GB
Original assignee: Hamada Printing Press Co Ltd
Current assignee: Hamada Printing Press Co Ltd
Priority date: 1976-10-22
Filing date: 1977-09-30
Publication date: 1980-12-03
Also published as: DE2744577A1; JPS5353409A; DE2744577C2; FR2368367B1; CS222253B2; FR2368367A1

Description

(54) A SHEET-FED PERFECTOR TYPE OFFSET DUPLICATOR (71) We, HAMADA PRINTING PRESS MFG. Co., LTD., a Joint Stock Company duly organized and existing under the laws of Japan, of 15-28, Mitejima, 2-chome, Nishiyodogawa-ku, Osaka, Japan do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a small sheet-fed perfector type offset duplicator for printing both sides of sheets at the same time.

Some conventional offset duplicators, for example such a type comprising two identical devices disposed in series or a type comprising two sets of a plate cylinder, a blanket cylinder, and an impression cylinder for successively passing sheets between the two sets of a blanket cylinder and an impression cylinder, may be mentioned as the ones to perform a printing on both sides of sheets.

However, none of them has achieved a simultaneous printing on both sides of sheets.

There is a perfector type press for printing both sides of sheets at the same time for example the sheet-fed press described in the U.S. Patent No. 3 690 253, comprising a blanket cylinder for offset printing and a cylinder two times as large as said blanket cylinder, wherein said latter cylinder is provided with an original plate for offset printing for transferring the image onto said blanket cylinder on the one semicylindrical surface thereof and a blanket on which the image is transferred from the other plate cylinder on the other semicylindrical surface thereof.

With this type of pressing machine, it is possible to perform an offset printing on both sides, however, the printing speed is low due to the fact that the delivery interval of sheets must be at least as long as the longitudinal length of a sheet and besides the whole machine ought to be large-sized owing to the use of a double-sized cylinder, which further is disadvantageous from the operational point of view.

Furthermore, it is extremely difficult to house two sets of a printing mechanism required for Perfecting within a bodv of one pressing machine, that is, even if a plate supplying mechanism could be connected with a plate cylinder, a plate discharging mechanism (disposed separately from the plate supplying mechanism in conventional pressing machines) to be disposed opposite to the plate cylinder can hardly be detachably disposed and in addition, the plate supplying mechanism and a blanket cleaner constitute an obstacle in the way of repair and adjustment work in the body of the pressing machine.

The inventor of the present invention has solved said problems by providing an offset duplicator having symmetrically disposed two sets of mechanisms required for the printing, and two blanket cylinders opposed to each other so that one may act as an impression cylinder for the other and adapted to pass sheets therebetween.

Meanwhile, a symmetrical disposition of the two sets of mechanisms required for the printing is disclosed in the U.S. Patent Nos.

348644 and 3486448. However, these inventions are related to the press for printing both sides of web, and not applied to the press for sheets. In the case of the sheet-fed press, a sheet must be supplied and discharged each time and the sheet supplying and discharging mechanism and the blanket mechanism are completely different from the press for web, even more complicated. It has been known that a symmetrical structure is very effective to be applied to the perfector type press, but it thus has been difficult to be applied to the sheet-fed press.

According to the present invention, there is provided a sheet-fed perfector type offset duplicator comprising a frame, two blanket cylinders adjacent one another, two plate cylinders each of which is adapted to contact a respective blanket cylinder, two inking and dampening mechanisms for supplying ink and water onto the surface of a printing plate mounted on the respective plate cylinder, two blanket cleaners for cleaning the surface of the respective blankets after a printing run from one pair of printing plates, a sheet-feed mechanism for supplying sheets onto one of the blanket cylinders, a sheet delivery mechanism for transferring printed sheets from the blanket cylinders to a sheet delivery position, a driving mechanism for driving one of the plate cylinders and a drive connection between, on the one hand, said one plate cylinder and, on the other hand, the other plate cylinder, the inking and dampening mechanisms, the sheet-feed mechanism, and said sheet delivery mechanism, wherein the two sets of blanket cylinders, plate cylinders, inking and dampening mechanisms, and plate cleaners are symmetrically disposed to a vertical plane in the body frame; wherein the two blanket cylinders are opposed to each other through a sheet path and each have a blanket fixing mechanism disposed in the inside of a groove thereof so as to hold both ends of a blanket under tension, wherein a gripper for receiving sheets from the sheet feed mechanism and passing them over to the sheet delivery mechanism is detachably mounted in the groove of one blanket cylinder; wherein two sets of plate supplying and discharging mechanisms are respectively mounted at the periphery of the plate cylinders in a detachable manner with respect to the frame for supplying a printing plate to the plate cylinder and discharging the printing plate from the plate cylinder after a printing run from that plate is over; wherein said two sets of blanket cleaners are respectively mounted at the periphery of the two blanket cylinders in a detachable manner with respect to the frame; and wherein a sheet trailing end guide means is provided for guiding the sheets fed by the blanket cylinder for pressing their trailing ends towards a blanket while a cleaning roll of the respective blanket cleaner is separated from that blanket and printing is being carried out.

The invention will be further described with reference to the accompanying drawings, in which: Fig. 1 is a schematic illustration of a sheetfed perfector type offset duplicator of the present invention shown in its entirety; Fig. 2 is an elevational explanatory view showing internal structure of a plate supplying and discharging mechanism of the offset duplicator according to the present invention; Fig. 3 is a developed plan view of the structure shown in Fig. 2; Fig. 4 is an explanatory view showing an open-and-close mechanism of the plate supplying and discharging mechanism; Fig. 5(A) is an explanatory view showing a main portion of a clutch mechanism of the plate supplying and discharging mechanism; Fig. 5(B) is an explanatory view showing a phase lock mechanism of the plate supplying and discharging mechanism in its entirety; Fig. 5(C) is a perspective view of a main portion of the phase lock mechanism shown in Fig. 5(B); Fig. 6 is a plan view of a blanket mechanism; Fig. 7 is a cross-sectional view seen along the line VII-VII of Fig. 6; Fig. 8 is a cross-sectional view seen along the line VIII-VIII of Fig. 6; Fig. 9 is an explanatory plan view showing the outer surface of one blanket cleaner and the internal structure of the other; Fig. 10 is a developed explanatory view showing internal structure of one of the blanket cleaners; Fig. 11 is a timing diagram showing the relationship between the plate snapping and plate discharging motions of the plate cylinder; Fig. 12 is a time chart showing the plate supplying and discharging motions.

Fig. 1 shows a sheet-fed perfector type offset duplicator of the present invention in its entirety, which comprises a blanket cylinder 300, a plate cylinder 351 adapted to contact said blanket cylinder, an inking and dampening mechanism 10 for supplying ink and moisture to the surface of a printing plate on the plate cylinder, a plate supplying and discharging mechanism 100 for supplying a fresh printing plate to said plate cylinder and discharging the used printing plate from the plate cylinder, a paper sheet feed mechanism 20 for feeding sheets (paper or the like suitable material) onto said blanket cylinder, a blanket cleaner 400 for cleaning the surface of the blanket cylinder, a paper (sheet) delivery mechanism 30 for transferring printed sheets from the blanket cylinder to a predetermined delivery position, and a driving mechanism comprising a roller 40 for driving the plate cylinder 35, to which the inking and dampening mechanism 10, plate supplying and discharging mechanism 100, paper feed mechanism 20, and paper delivery mechanism 30, are all drivingly connected. Another printing set consisting of blanket cylinder, plate cylinder, inking and dampening mechanism, plate supplying and discharging mechanism, and blanket cleaner is symmetrically disposed with respect to the first set of these components. As for the paper feed mechanism 20, the paper delivery mechanism 30, and the driving mechanism 40, only one set per offset duplicator is required and thus one driving mechanism 40 drives all the mechanisms. The two sets of mechanisms, except the blanket cylinder, are substantially of the same structure.

Said blanket cylinder 300, plate cylinder 35, inking and dampening mechanism 10, paper delivery mechanism 30, and drive mechanism 40 are disposed in a frame 3 of the body, while said plate supplying and discharging mechanism 100 and blanket cleaner are detachably mounted on the frame 3 of the body. Numeral 2 indicates a route of sheets between two sets of blanket mechanism 300.

Descriptions as to said inking and dampening mechanism 10, paper feed mechanism 20, paper delivery mechanism 30, drive mechanism 40, and the plate cylinder of said plate cylinder mechanism 350 will be omitted here as they are substantially of the same structure as those employed in conventional sheet-fed single-side presses.

The offset duplicator 1 does not require the plate supplying and discharging mechanism and the blanket cleaner in the case that the plate supplying and discharging and the cleaning of the blanket are manually operated, while these may be selectively mounted on the body frame for performing said operations automatically.

The etching mechanism in the offset duplicator 1 according to the present invention is disposed within a frame supporting the plate supplying and discharging mechanism and is adapted to insert the printing plate after etching directly into the plate supplying and discharging mechanism, while this etching mechanism may be eliminated and an etched printing plate may be inserted into the plate supplying and discharging mechanism instead.

In Figs. 2 and 3, the plate supplying and discharging mechanism 100, the blanket mechanism 300, and the plate cylinder 351 altogether forming a main portion of an offset duplicator 1 are shown.

The plate supplying and discharging mechanism 100 comprises a plate supplying mechanism and a plate discharging mechanism combined together, and mounted in a frame 101 detachably mounted on the body frame 3 of the offset duplicator 1. By providing the mechanism 100 detachably from the body frame, repair and maintenance work within the body and the mechanism is facilitated.

The plate supplying and discharging mechanism 100 is broadly divided into a frame 101, a transfer wheel 102, a stopper means 103, a detecting means 118, a feed roll means 120, an open-and-close mechanism 150, a clutch mechanism 180, and a plate discharging and conveyance mechanism 250, and it further includes a phase lock mechanism 210 for locking the phase of the transfer wheel and the plate cylinder at the time the plate supplying and discharging mechanism is disconnected from the body frame.

The transfer wheel has an appropriate diameter (for example one half of that of the plate cylinder), and is adapted to make two revolutions per one revolution of the plate cylinder, and comprises a shaft 104 pivotally mounted on the frame 101, plurality of disks 105 mounted on the shaft, and a gnpper 106 supported by the disks and comprising an anvil 106a, a pawl 106b, and a pawl shaft 106C, etc.

The fresh printing plate is conveyed through a table 107 into the mechanism 100, and is temporarily halted at an end (where the detection of the original plate is carried out) of the table 107 by a stopper 108 of the stopper means 103. The hook-shaped stopper 108 is mounted on a shaft 109 interlocking with a shaft 110 rotatably supported by the frame 101 together with the shaft 109 through links 111, 112, and 113, and a further link 114 is connected with a solenoid 116 through a link 115, thereby constituting the stopper means 103 for the plate. This stopper means is adapted to be released by the working of the solenoid 116 and normally keeps the plate under a halted condition by a spring 117 connected to an end portion of the link 114 with which the link 115 is not connected.

Said table 107 is a guide member having a groove-like track, and a working member 119 contacting the upper surface thereof is mounted on a limit switch (not shown) for detecting if the original plate is placed at the predetermined position (original plate detecting position) on the table or not, wherein said working member 119 and limit switch constitute the detecting means 118.

The original plate is conveyed with its plate surface facing down on the table 107 and is halted with its leading end portion held by rolls 121 and 122 by the stopper 108.

The rolls 121 and 122 constitute a feed roll means 120 for feeding the plate to the transfer wheel 102 upon instructions (to be detailed hereinafter) for the plate supplying, wherein the roll 121 has a gear 123 mounted on the shaft 104 of the transfer wheel 102 and a gear 126 to which driving force is delivered through idle gears 124 and 125, on the other hand the roll 122 is provided with a gear 127 engaging with the gear 126. The rolls 121 an22 rotate at the same speed toward an opposite direction to each other.

The rolls 121,122 are conventional rubber rolls and the driving roll 121 is stationarily arranged so that it contacts an end of the original plate occupying its detecting position, while the driven roll 122 is contacted with a sponge 131 of an etching mechanism 130 located below and further contacted with a throttling roll 132.

The roll 122 and the throttling roll 132 are rotatably supported by a supporting member 140 which is pivotally supported at one end thereof by a supporting shaft 141 fastened on the frame 101 and is engaged at the other end thereof with one end of a spring 142 which is secured at the other end thereof on the frame 101, wherein said other end of the supporting member is always tensed upwardly.

Said shaft 110 is provided on each end portion thereof with a cam 143 which is contacted with the upper surface of the supporting member 140 on the other end side thereof. When the stopper 108 is so located as to stop the original plate, said cam 143 pushes down the other end of the supporting member 140 against the spring 142 thereby positioning the roll 122 apart from and below the roll 121. The shaft 110 and the cam 143 are rotated with the rotation of the link 114 when the stopper means 103 is released, whereby the other end of the supporting member 140 is tensed and upwardly rotate by the spring 142 and the roll 122 comes in contact with the roll 121 thereby enabling the feeding of the original plate. Thus constituted is a feed roll means 120 by said pair of rolls 121 and 122, the gears 124, 125, 126, and 127 for rotating said pair of rolls, the supporting member 140, and the cam 143, etc.

In Fig. 2, the gripper 106 of the transfer wheel 102 is so positioned as to transfer the original plate to the plate cylinder 351 of the plate cylinder mechanism 350, while it stands by at the position 129 shown by the imaginary line during the printing. The original plate fed by the rolls 121, 122 of the feed roll means 120 is held at the end thereof by the gripper 106 on stand-by.

The etching mechanism 130 is arranged below the roll 122 of the feed roll means 120, and comprises an base-frame 137 secured on the frame 101, a frame body 133 laced on the base-frame 137, a reservoir 134 containing the etching liquid and formed in the frame body, a sponge 131 to be soaked in the etching liquid and disposed in said frame body and protected from slipping off on both sides thereof by a fixing member 136 and contacted with the roll 122 of the feed roll means 120, and a screw 135 for securing the frame body 133 onto the base-frame 137.

By disposing said etching mechanism 130 under the roll 122, etching process can be carried out simultaneously with the supply of the original plate after printing between the rollers 121 and 122. In the present invention, however, it is not always necessary to provide this etching mechanism in the plate supplying and discharging mechanism, and an etched original plate may be fed to the plate supplying and discharging mechanism instead.

nFigs. 3 and 4, the numeral 150 indicates an open-and-close mechanism of the gripper 106 of the transfer wheel 102. The gripper 106 must be opened and closed four times respectively, that is, (i) when it receives the original plate fed through the rolls 121 and 122. (ii) when the original plate is supplied to a gripper of the plate cylinder 351, (iii) when it receives the original plate discharged from the plate cylinder 351, and (iv) when it discharges the original plate.

The gripper 106 comprises an anvil 106a secured on said disk 10 , four pawls 106b to snap the original plate in cooperation with the anvil, a pawl shaft 106c having each pawl mounted thereon and rotatably supported on the disk 105, an arm 152 supported at the substantially middle portion thereof by the pawl shaft and having rolls 151a and 151b on both ends thereof, and a spring 153 fitted with the pawl shaft for pressing the pawl 106b against the anvil 106a.

The gripper of the plate cylinder to be detailed hereinafter has the same structure as that of the gripper 106.

The first cam 155 is used (i) when receiving the original plate and mounted on the frame 101 and contacted with the roller 151 a of the gripper 106. The second cam 156 is used (ii) when supplying the plate, the third cam 157 is used (iii) when discharging the plate, wherein the second cam and the third cam are mounted on or integrally formed with a cam member 158 and contacted with a roller 151b.

Said cam member 158 is cylindrical and engaged with the shaft 104 and provided with two V-shaped grooves 159 on the outer circumferential surface thereof. Numeral 160 designates a plate spring having V-shaped projections adaptable to the V-shaped grooves 159 and mounted at both ends thereof on the disk 105 through pins, wherein the spring action of this plate spring rotates the cam member 158 together with the shaft 104.

The fourth cam 161 is used (iv) when deliverying the original plate and mounted on the frame 101 similarly to the first cam 155 and contacted with the roller 151a.

The opening and the closing of the gripper 106 is carried out by four cams as aforementioned, but the gripper does not open and close four times responding to each revolution of the transfer wheel 102. A printing time intervenes between (ii) the plate supplying time and (iii) the plate discharging time.

At the instructions for the plate supplying, the first cam 155 and the second cam 156 are actuated to supply the plate and after the printing the plate discharge is carried out by the third cam 157 and the fourth cam 161 at the instructions for the plate discharging.

Thus, the transfer wheel 1 2 is rotated synchronously with the plate cylinder 351 only at the time of the plate supplying and plate discharging, while it must be prevented from rotation and the gear 123 only should be rotated during the printing.

In order to satisfy these requirements, the second cam 156 and the third cam 157 in the offset duplicator according to the present invention are formed so that they can be shifted.

Numeral 165 designates a plate for shifting the cams, which is mounted on the side of the cam member 158 and provided with a recess 166 for supplying the plate and a recess 167 for discharging the plate at two portions on the outer circumferential surface thereof.

A stopping member 170 is disposed out beyond the plate 165. This stopping member 170 is mounted on the frame 101 through a pin 171 with which a spring 172 is loosely fitted to insert a stop projection 170a at the end of the stopping member 170 into said recess 166 or 167 of the plate 165.

In response to the rotation of the disk 105, the cam member 158 and the plate 165 are rotated by the action of the plate spring 160, while the rotation of the cam member and the plate is prevented against the spring action of the plate spring 160 when the stop projection 1 70a of estopping member 170 is inserted in the recess 166 or 167 of the plate 165 by the action of the spring 172.

Therefore, only the disk 105 continues to rotate to enable the contact of the roller 15 ib of the gripper 106 with the second cam and the third cam.

The plate is transferred and received between the transfer wheel 102 and the plate cylinder 351 substantially at the point of contact of the two, therefore the second cam 156 and the third cam 157 are brought to a halt substantially at the same position by the action of the stopping member 170. However, the gripper merely disengages the original plate at the time of plate supplying, while the original plate must be snapped by the gripper at the time of plate discharging. This fact accounts for the cams slightly different to each other in shape as shown in Fig. 4. The projection 174 shown in Fig. 3 and Fig. 4 is provided on the side of the stopping member 170 and adapted to be kicked by a release member 175 provided on the side of one of the disks 105. To be specific, it is necessary that the stop projection 1 70a of the stopping member 170 comes to be engaged with the recess 166 for supplying the plate thereby actuating the second cam 156 to open and close (plate supplying movement) the gripper 106, and thereafter the third cam 157 comes to be properly located for discharging the plate after printing. For this purpose, immediately after the roller 151b is brought in contact with the second cam 156, the projection 174 is kicked by the release member 175 and the stopping member 170 is rotated against the spring 172 thereby disengaging the stop projection 170a from the recess 166.

During the printing, the transfer wheel 102 is not rotated as detailed hereinafter, but on stand-by in the state shown in Fig. 4. At the instructions for the plate discharging, the transfer wheel 102 starts to rotate, the stop projection 170a comes to be engaged with the recess 167 for discharging the plate, and the third cam 157 is brought to the proper location to prepare for the plate discharge.

The transfer wheel 102 is rotated only at the time of plate supplying and discharging, as aforementioned, and must not be rotated at the time of printing. The transfer wheel 102 is driven through the gear 123 by the plate cylinder, and the plate is transferred before being supplied by the roll 121 driven by the rotational power conveyed from the gear 123. On this account, a clutch mechanism 180 is provided to effect switching over of the supply of the driving power between the shaft 104 and the gear 123 and synchron ization of the g gripper of the plate cvlinder with the gripper plate transfer The clutch mechanism 180 is shown in Figs. 2,3, and 5. This mechanism is turned on by a solenoid 181 excited at the electric instructions for supplying and discharging the plate. The solenoid 181 is mounted on the body frame 3 and connected with a bar 184 through links 182 and 183 and adapted to move the bar 184 in the direction shown by an arrow 186 against the spring 185 when it is excited.

Numeral 187 designates a bell crank type pawl member rotatably supported by the body frame 3 through a pin 178, and said bar 184 is adapted to press a pin 187b provided on one end of the pawl member 187 thereby rotating the pawl member against a spring 187c. A pawl portion 187a is formed on the other end of the pawl member 187. A supporting member 188 keyed on the end portion ot the shaft 104 is provided with a hook 190 through a pin 189, and the hook 190 is provided with a pawl portion 1 90a engagable with said pawl portion 1 87a on one end thereof and a projection 190b on the other end thereof.

Numeral 200 designates a wheel having a gear 123 mounted thereon and rotatably mounted on the shaft 104 and provided with one recess 201 formed in the outer circumferential surface thereof. This recess is adapted to engage with said projection 190b of the hook 190 by a spring (not shown) or according to the disengagement from the pawl member 187. Owing to this engagement, the rotation of the gear 123 is transferred to the shaft 104 through the wheel 200, the hook 190 and the supporting member 188 to drive the transfer wheel 102. The projection 190b and the recess 201 are engaged with each other at one portion thereof, therefore the phase of the gear 123 with respect to the shaft 104 is constantly the same and the gripper of the plate cylinder and the gripper of the transfer wheel are synchronously rotated opposing to each other at the position of transference of the original plate.

When said solenoid 181 is de-energized, the pawl member 187 is rotated in the counterclockwise direction as indicated in Fig. 5 by the action of the spring 187c, and with the rotation of the hook 190 of the transfer wheel the pawl portion 190a comes to be engaged with the pawl portion 187a and the recess 201 of the wheel 200 comes to be disengaged from the projection 190b of the hook 190 whereby the supply of the driving power from the gear 123 to the shaft 104 is suspended.

The plate discharging and conveyance mechanism 250 is disposed below the transfer wheel 102 as shown in Fig. 2 and adapted to deliver the original plate onto a pan 251 after passing the original plate from the plate cylinder 351 to the transfer wheel.

Numeral 252 designates a roll for carrying and feeding out the discharged original plate in cooperation with the disk 105 of the transfer wheel 102, and a shaft 253 having this roll mounted thereon is supported by an eccentric member 254 rotatably supported at both ends thereof by the frame 101 through a bearing and adapted to adjust the parallelism between the transfer wheel 102 and the shaft 253.

The gripper 106 of the transfer wheel 102 is opened and closed by the action of the third cam 157 and receives the original plate passed from the gripper of the plate cylinder wherein the end of the original plate is held by the disk 105 and the roll 252, then said gripper 106 is opened by the fourth cam 161 thereby releasing the onginal plate. Thereafter, the original plate is conveyed by the disk and the roll, then shook down from the disk 105 by an upper guide member 257 and caught by a lower guide member 258, and then conveyed to between the rolls 260 and 261.

Driving power for the upper roll 260 is transmitted from the gear 123 of the transfer wheel through the idle gear 262, with which the gear 263 of the upper roll 260 is engaged and it is further engaged with the gear 264 of the lower roll 261, whereby the upper roll 260 and the lower roll 261 are synchronously rotated. The upper roll 260 and the gear 263 are mounted on the shaft 265 and the lower roll 261 and the gear 264 are mounted on the shaft 266, while the both shafts are pivotally mounted on the frame 101. The rolls 252, 260, and 261 are respectively mounted on each shaft in such a manner that they allow the adjustment of the direction and the location of each shaft. While two rolls are provided on each shaft, more rolls may be employed.

The plate is forcibly conveyed by said rolls 260 and 261, then guided by the upper and the lower guide members, and discharged onto the pan 251. The pan 251 is mounted on the frame 101 through bolts.

The disk 105 of the transfer wheel is formed in such a manner that about one half of the outer circumference thereof fronting to the gripper has a diameter smaller than that of the other half for reducing to a minimum the defilement of the surface of the disk invited by the discharged dirty plate after printing.

Now the phase lock mechanism 210 will be explained with reference to Figs. 5(A) - (C).

When the plate supplying and discharging mechanism 100 is disengaged from the body frame 3 for repair and adjustment work in the inside of the offset duplicator, in particular the plate cylinder mechanism 350, or the transfer wheel, the phases of the transfer wheel and the gear 123 with respect to the frame 101 are locked by this phase lock mechanism 210, and the plate supplying and discharging mechanism can be easily mounted simply by adjusting the phase of the gear of the plate cylinder mechanism thanks to the phase lock mechanism. The cardinal point for the determination of the phase of the sha groove 202, respectively.

Said latch 215 is constantly in a rotatable condition during the printing, and if the latch would be rotated the supporting member 188, the wheel 200, and accordingly the shaft 104 and the gear 123 should be locked with the phase determination member 212, however, the latch 215 is not actually rotated during the printing.

The latch 215 is pressed at the first stop projection 215a thereof by the inner circumferential surface 212b of the phase determination member 212 and thereby rotated by the phase determination member 212 subjected to the spring 213 and rotated around the pin 211.

The body frame 3 is provided with a pin 217 with which an outer circumferential surface 212c of the phase determination member 212 is contacted when the plate supplying and discharging mechanism is mounted on the body frame, as indicated by the full line in Fig. 5(B), however, the phase determination member 212 is disengaged from the pin 217 when the plate supplying and discharging mechanism is disconnected while the latch 215 is in a rotatable condition and the phase determination member is rotated until it takes the position shown by the imaginary line in Fig. 5 (B) thereby rotating thelatch 215.

The gear 123 of the transfer wheel has a cam plate 220 having a convex portion 220a formed in a portion thereof. The gear 359 of the plate cylinder 351 also has a cam plate 221 having two concave portions 221a engageable with said convex portion 220a and disposed in an angle of 1800 to each other. Said two cam plates 220, 221 constitute a gear phase control means for controlling the engagement of the gear of the transfer wheel and the gear of the plate cylinder.

The convex portion 220a of said cam plate 220 is disposed at a certain angle with respect to the stop groove 202 of the wheel 200, and it is preferable that the convex portion 220a is located on a line connecting the shaft 104 and the axis of the plate cylinder as shown in Fig. 5(B) when the stop groove is located to engage with the latch. The convex portion 220a is engaged with the concave portion 221a by the rotation of the plate cylinder 351.

The phase lock mechanism 210 of said structure will be sufficient for repair and adjustment work for the mechanism in the inside of the body of the offset duplicator, for example the plate cylinder mechanism, however, when the necessity for repair and adjustment of the plate supplying and discharging mechanism arises, the transfer wheel may be unlocked and rotated. If the plate supplying and discharging mechanism is mounted on the body frame with its phase shifted by the rotation of the transfer wheel, the printing becomes impossible. Therefore, a means preventive of incorrect mounting is provided.

The means 225 preventive of mismounting shown in Figs. 5(A) and 5(B) is loosely fitted with a pin 226 fixed in the body frame 3, and comprises a blocking member 228 prevented from the rotation in one direction by a pin 227 fixed in the body frame, and a slide bar 231 rotatably supported at one end thereof by said phase determination member 212 through a pin 229 and adapted at the other end thereof to be slidable in a longitudinal direction by a guide member 230 (shown in Fig. 5(A)) mounted on the frame 101, wherein the end of the slide bar 213 at the position 231a is moved as far as the position 231b as the phase determination member is rotated until it takes the position indicated by the imaginary line in Fig. 5(B).

The blocking member 228 is provided with a projection 228a which is brought into contact with the end of the slide bar 231 when it takes the position 231a.

When the transfer wheel, the gear, and the phase determination member have their phases different to one another and the phase determination member 212 is in a condition shown by the solid line in Fig. 5(B), the end portion of the slide bar 231 comes in contact with the projection 228a of the blocking member 228 which, rotatable as it is, allows the supplying and discharging mechanism to be disconnected from the body frame 3, on the other hand, when the end portion of the slide bar 231 is situated at the position 231a and contacted with the projection of the blocking member at the upper side thereof the blocking member which is prevented from the rotation by the pin 227 does not allow the plate supplying and discharging mechanism to be mounted on the body frame 3. Therefore, it is necessary for mounting the plate supplying and discharging mechanism to put the transfer wheel, the gear, and the phase determination member in an accorded phase and shift the end portion of the slide bar to the position 23 1b by rotating the phase determination member. In other words, their phases are accorded with one another when the plate supplying and discharging mechanism are mounted.

Now the engaging and the disengaging operations of the plate supplying and discharging mechanism 100 performed by said phase lock mechanism 210 will be briefly explained.

The projection 190b of the hook 190 is engaged with the recess of the wheel 200 and the supportion member 188 are rotated with the gear 123 during the printing, and at the instructions for terminating the printing the solenoid 181 is de-energized and the clutch mechanism 180 is stopped, whereby the hook 190 is disconnected from the wheel 200 by the pawl member 187 for preventing the transmission of the rotation of the gear 123 to the shaft 104.

The pawl portion 187a of the pawl member 187 is engaged with the pawl portion 190a of the hook invariably at the same position, and in this engaged condition, the second stop projection 21 Sb of the latch supported by the supporting member is faced with the groove 21 2a of the phase determination member 212.

In the next place, the gear 123 is a little rotated to make the stop groove 202 of the wheel 200 face with the third stop projection 215c of the latch. Disconnecting the plate supplying and discharging mechanism 100 from the body frame 3 in this condition, the phase determination member is disengaged from the pin 217 and rotated, while the supporting member 188 and the wheel 200 are locked to the phase determination member 212 by the latch.

When the phase of the transfer wheel 102 is not deviated, that is, when the latch is locked, the concave portion 221a of the cam plate 221 of the plate cylinder is adjusted to face with the convex portion 220a of the cam plate 220 of the transfer wheel and then the plate supplying and discharging mechanism Is mounted on the body frame 3.

When the phase of the transfer wheel 102 is deviated, the plate supplying and discharging mechanism is mounted after the latch is brought in a locked condition by the rotation of the transfer wheel. In the case that the phase of the gear 123 instead of the transfer wheel is deviated, the same procedures are to be followed too.

It is preferable that the plate supplying and discharging mechanism is disconnected only in such a condition that the pawl member 187 is engaged with the hook and the supporting member 188 is stopped.

The plate cylinder 351 of the plate cylinder mechanism 350 is provided with a gripper 352 and an open-and-close mechanism 367 for opening and closing this gripper 352 at the time of the plate discharging. Now the open-and-close mechanism 367 will be explained referring to Fig. 2 and Fig. 3.

A cylinder shaft 353 of the plate cylinder 351 is fitted on one end thereof with a circular cam member 354 rotating in coordinate with the plate cylinder and having a cam 355 for the plate supplying and a cam 356 for the plate discharging mounted thereon. Said plate cylinder 351 and the cam member 354 are in a relationship similar to that of the disk 105 of the transfer wheel and the cam member 158, and rotated in coordination by the engagement of the plate spring with the V-shaped groove. The cam member 354 is provided on the outer circumferential surface thereof with two concave portions 357 and 358.

Numeral 360 designates a pawl member rotatably mounted on the side of the body frame 3 through a pin 361. This pawl member is provided on one end thereof a pawl portion 360a engageable with said concave portions 357 and 358, and on the other end thereof with a pin 362, wherein a spring 364 loosely fitted with the pin 361 is adapted to press the pawl portion 360a toward the cam member 354.

Said concave portion 357 is for supplying the plate and is engaged with the pawl portion 360a of the pawl member 360 to stop the cam member 354 thereby leaving the plate cylinder 351 rotating alone, wherein the cam 355 for the plate supplying is disposed at the position the gripper 352 carries out the open-and-close motion (as shown in Fig. 2) for snapping the original plate passed from the transfer wheel 102 and a roller 352e of an arm 352b mounted on a shaft 352a of the gripper is contacted with the cam 355.

On the other hand, said concave portion 358 is for the plate discharging and is engaged with the pawl portion 360a to locate the cam 356 for the plate discharging at a predetermined position required for the plate discharging thereby making the gripper 352 perform the open-and-close motion for the plate discharging.

Said cams 355 and 356, similarly to the second cam 156 and the third cam 157 of the transfer wheel, are shifted at the time of plate supplying and discharging, wherein the pawl member 360 for providing a place for each cam must be engaged with different concave portion for the switching over of the cam.

Further, when the cam member 354 is stopped during the printing, the gripper holding the original plate are opened to interrupt the printing, therefore a mechanism to disengage the pawl member 360 is provided.

Numeral 370 designates a disengaging cam provided on the plate cylinder which comes in contact with the pin 362 of the pawl member to rotate the pawl member against the spring 364. Numeral 371 designates a disengaging arm secured on the shaft of the link 183 of the clutch mechanism 180, and this disengaging arm constitutes a portion of the clutch mechanism. The free end of the disengaging arm is contacted with the pawl member at the end thereof having the pin 362, and although not having a sufficient pressing force to rotate the pawl member when the pawl portion 360a thereof is engaged with the concave portion, can support the pawl member in a disengaged condition. Thus, the pawl portion 360a is disengaged from the concave portion only by the disengaging cam 370, and the disengaging arm 37 is provided for maintaining the disengaged condition of the pawl member.

When the solenoid 181 is excited at the time of the plate supplying, the pawl portion 360a of the pawl member 360 is engaged with the concave 357 for the plate supplying in a rotating condition, and locate the cam 355 at a predetermined position. When the plate supplying is finished and after or before the solenoid 181 is de-energized the pawl member 360 which has stopped the cam member 354 is disengaged therefrom by the disengaging cam 370, and owing to the deenergization of the solenoid the disengaging arm 371 maintains the pawl member in the disengaged condition.

At the time of the plate discharging, similarly to the time of the plate supplying, the solenoid 181 is excited and de-energized, whereupon the pawl portion of the pawl member 360 is engaged with the concave portion 358 for the plate discharging to locate the cam 356 at a predetermined position.

After the plate supplying, the pawl member 360 is disengaged by the disengaging cam 370 alone, therefore the concave 357 remains in the same situation with respect to the disengaging cam 370, and when the pawl portion 360a of the pawl member 360 meets the concave portion 357 for the plate supplying at first their engagement is prevented by the action of the disengaging cam 370 owing to the excitation of the solenoid at the time of the plate discharging, whereupon it comes to be engaged with the concave portion 358 for the plate discharging without fail.

Similarly, when the plate is supplied after the plate discharging, the disengaging cam 370 is so located as to prevent the engagement of the concave portion 358 for the plate discharging with the pawl portion 360a, which therefore is engaged with the concave portion 357 for the plate supplying alone.

The cam 355 for the plate supplying is different in shape from the cam 356 for the plate discharging, because the pawl of the gripper 352 at first open is closed at the time of plate supplying and takes the position as shown in Fig. 2 at the point of contact with the gripper 106, while the pawl of the gripper 352 starts to open from the point of contact at the time of the plate discharging.

Further, said pawl member 3 60 is adapted to be rotated by the solenoid 181 of the clutch mechanism 180 of the plate supplying and discharging mechanism 100, so the solenoid 181 is provided on the body frame 3 and the bar 184 is detachably contacted with the pawl member 187 in order to transmit the driving power of the solenoid to the pawl member 187, while if another solenoid is provided for driving the pawl member 360, the solenoid 181 may be mounted on the frame 101 and the whole plate supplying and discharging mechanism may be mounted on the frame 101.

Now the effects produced from said plate supplying and discharging mechanism, the phase lock mechanism, and the plate cylinder mechanism, etc. will be explained.

By using a single transfer wheel, the plate supplying and discharging can be performed on one side of the plate cylinder, and the etched original plate, as is once held bv the gripper of the transfer wheel which has been on stand-by, can be securely passed to the gripper of the plate cylinder.

Every operation from the detection of the plate to the plate discharging is automatically carried out by the provision of the stopper means, the detecting means, the feed roll means, and the plate discharging and conveyance mechanism.

Further, by providing the phase lock mechanism between the frame of the plate supplying and discharging mechanism and the body frame of the offset duplicator, the plate supplying and discharging mechanism can be very easily mounted on the offset duplicator and the phases of the plate cylinder and the transfer cylinder are securely accorded.

In Figs. 6-8, illustrated is a blanket mechanism 300 comprising a blanket cylinder 302 provided on one end thereof with a gear 301 for obtaining the driving power from the driving mechanism 40 of the offset duplicator, a blanket 303 covering the outer circumferential surface of the blanket cylinder, a fixing mechanism for fixing the blanket 303 by holding both ends thereof onto the outer circumferential surface of the blanket cylinder, and a gripper means 305 for gripping the leading edge of each sheet during pnntlng. The blanket mechanism shown in Figs. 6-8 is the one located nearer to the paper feed mechanism, while the other blanket mechanism is not supplied with paper and therefore does not need a gripper means.

The latter blanket mechanism obtains the driving power from the former.

The blanket cylinder 302 is supported through a bearing by a shaft 310 supported by the body frame 3 of the offset duplicator, wherein an elongated groove 311 leading to an inside cavity 302a is formed in the longitudinal direction for housing the blanket fixing mechanism 304 and the grippes means 305. The gear 301 is secured to the end portion of the blanket cylinder through bolts.

Conventional known rubber blanket is employed for the blanket 303, which is provided on both ends thereof a stop plate 312 and a fixing plate 313 for securing the end portion of the blanket to the stop plate through bolts.

Numeral 314 designates a stop member mounted on a shaft 315 supported at both ends thereof by the blanket cylinder 302.

The stop member 314 is substantially U-shaped and has a short end portion 314a and a long end portion 314b. Numeral 316 designates a supporting plate mounted on the blanket cylinder 302 and disposed in parallel with a plane including the axis of the blanket cylinder. An adjusting screw 317 is threadably engaged with this supporting plate for each stop member 314, and the end of the adjusting screw 317 is contacted with the long end portion 314b of the stop member.

Said stop plate 312 is provided with a bore 312a opposed to the short end portion 314a of each stop member 314, and the short end portion 314a is insertedly engaged with the bore 312a.

The blanket fixing mechanism 304 comprises said stop plate 312, the fixing plate 313, the stop member 314, the shaft 315, the supporting plate 316, and the adjusting screw 317, etc., and each set of this fixing mechanism is provided on each end portion of the blanket 303, wherein the stop member 314 is rotated by turning the adjusting screw 317 and the tension of the blanket 303 is adjusted through the stop plate 312. The blanket 303 is replaced by the engagement of the stop plate wlth the short end portion or the disengagement therebetween.

Numeral 318 designates a pin for stopping one end of the spring (not shown) fitted with the shaft 315, and the spring stopped by the pin 318 is adapted to rotate the stop member 314 in a direction that the long end portion 314b presses the adjusting screw 317, whereby the disengagement of the bore 31 2a of the stop plate 312 from the short end Portion 314a for displacing the blanket is facilitated.

The gripper means 305 is adapted to hold the ends of the fed sheets and release them after the image on the blanket 303 of the blanket mechanism is transferred thereon.

The gripper means 305 comprises an anvil 322, plurality of pawls 321 supporting the ends of the sheets between said anvil and themselves, a shaft 320 on which each pawl is mounted, an arm 323 mounted on one end of the shaft 320 for releasing said pawls 321 from the anvil 322 and having a roller 326 on the free end thereof, a spring 324 fitted with the shaft for elastically pressing said pawls against the anvil, a stop bar 327 stopping one end of the spring and disposed in parallel with said shaft 320, a pair of supporting members 329 supporting respective ends of the shaft and the stop bar and detachably mounted on the blanket cylinder through bolts and a fastener 319, and a connecting rod 328 supported at both ends thereof by the supporting member 329 and disposed to form a triangle with said anvil and stop bar.

The roller 326 of said arm 323 is contacted with a cam (not shown) mounted on the body frame 3 to open and close the gripper means, wherein said cam and gripper means perform open-and-close movements similarly to conventional ones, while said gripper means 305 differs from the conventional one in its structure that the anvil, the stop bar, and the connecting rod disposed triangularly constitute in cooperation with the supporting member a gripper means as an independent construction and that it can be disconnected from the blanket cylinder by disengaging the bolts and the fastener securing the supporting member.

Thus the blanket is fixed on the outer circumferential surface of the blanket cylinder 302 by the fixing mechanism 304 provided on each end portion thereof, wherein the tension of the blanket 303 is adjustable and due to the fact that the blanket is fixed by stopping the stop plate 312 provided on the end portion of the blanket by means of the stop member 314 the interval between both end portions of the blanket, i.e. the width of the elongated groove 311 can be narrowed and whereby the effective circumferential length [(the circumference of the blanket cylinder) (the width of the elongated groove) of the blanket cylinder can be enlarge thereby making the pressing area of the blanket cylinder larger than that of the conventional one having the same diameter.

In addition, the blanket can be easily fixed as the gripper means 305 is detachable from the blanket cylinder.

Figs. 9 and 10 show a blanket cleaner 400 which cleans the image remaining on the outer circumferential surface of the blanket 303 of the blanket cylinder 302 of the blan ket mechanism 300 after a printing with one plate is finished for eliminating the remaining image and preparing for the next print inQ.

ing; speaking, the blanket cleaner 400 comprises a cleaning mechanism 401 for supplying the cleaning liquid onto the surface of the blanket of the blanket mechanism 300, and a control mechanism 402 for actuating the cleaning mechanism only after the printing. Each of these mechanisms is disposed within a frame 409 which is detachably mounted on the body frame 3 of the offset duplicator 1 through bolts, whereby the blanket cleaner 400 becomes detachable with respect to the offset duplicator 1.

The cleaning mechanism 401 has two rolls 403 and 404, the former of which is a clean ing roll which can be contacted with the blanket 303 of the blanket cylinder, while the latter is a rubber roll contacted with said cleaning roll 403. This rubber roll 404 is contacted with a sponge 406 of a reservoir means 405 for the cleaning liquid to absorb the cleaning liquid from the sponge 406 and supply it to the cleaning roll 403. The reser voir means 405 for the cleaning liquid is pro vided with a stop member 410 for holding the sponge 406 in a case 407 and a tank 411 containing the cleaning liquid to be sucked by the sponge 406, wherein said case 407 is placed within an accepting stand 412 which is mounted on a frame 409 of the blanket cleaner 400 and securing a case 407 on the accepting stand through a screw 415 threadably engaged therewith.

Said cleaning roll 403 and rubber roll 404 are rotatably mounted on roll shafts 417 and 418 respectively, and the roll shaft 417 of the cleaning roll is supported by a rotating plate 420 of the control mechanism 402 while the rotating plate is rotatably supported by the roll shaft 418 of the rubber roll supported by the frame 409. Said roll shaft 417 is supported by the rotating plate 420 through an eccentric member 419, and by rotating this eccentric member 419 with respect to the rotating plate the contact pressure against and the parallelism with respect to the rubber roll 404 or the blanket cylinder 302 can be adjusted.

Numeral 422 designates a throttle means constituting a portion of the control mechanism 402, and this throttle means controls the quantity of the cleaning liquid to be supplied to the cleaning roll and it further controls the rubber roll 404 for preventing the dispersion of the cleaning liquid after the cleaning roll 403 is taken off from the blanket.

The throttle means 422 comprises a throttle roll 423 rotatably supported by the rotating plate 420 and contacted with the rubber roll 404, a brake plate 425 guided by a slit 424 of the rotating plate and contacted with the throttle roll 423, and a pair of pressing members 427 supported by the rotating plate and pressing the brake plate 425 against the throttle roll 423 through the action of the spring 426.

The control mechanism 402 is adapted to rotate the rotating plate 420 for driving the cleaning roll 403 to and from the cleaning position of the blanket, and driven by a solenoid 430.

The solenoid 430 is adapted to rotate the shaft 432 supported by the frame 409 through a link 431, and said solenoid 430 and link 431 are shown on the side of another blanket cylinder disposed symmetrically.

The shaft 432 is provided with a link 433 connected with a link 435 provided on a shaft 434. Numeral 437 designates a spring provided between a shaft 438 secured on the frame 409 and a shaft 439 secured on the rotating plate. This spring 437 is adapted to rotate the rotating plate 420 in a clockwise direction in Fig. 9 for taking the cleaning roll 403 off from the blanket 303.

When said solenoid 430 is excited, it rotates the link 433 in a clockwise direction, whereby the rotating plate is rotated in a counterclockwise direction (in Fig. 9), i.e., the direction opposing the force of the sprinf! 437, thereby contacting the cleaning ron 403 against the blanket.

As the working extent of said solenoid 430 is fixed, the cleaning roll 403 is moved in a limited travel, while the shaft 434 is mounted on the rotating plate 420 through an eccentric member 440 which is rotated for adjusting the location of the axis of the shaft 434 with respect to the rotating plate, whereby the phase of the rotating plate with respect to the shaft 418 is changed and the contact pressure of the cleaning roll 403 against the blanket 303 can be adjusted.

Numeral 445 in Figs. 9 and 10 designates a sheet-back end guide means comprising a bell crank 446 rotatably supported by the frame 409, a link 447 connected between one end of the bell crank and the rotating plate 420, and a presser shaft 448 provided on the other end of the bell crank, wherein the bell crank 446 is rotated with the rotation of the rotating plate 420 in the opposite direction to the latter and the presser shaft 448 guides the paper sheets fed by the blanket cylinder pressing their back ends toward the blanket cylinder while the cleaning roll 403 is out of contact with the blanket and the printing is carried out.

Numeral 450 designates an air-blow means provided for drying the surface of the blanket 303 after cleaning. The surface of the blanket after cleaning is wet with the cleaning liquid, therefore it may stain the paper if the following printing is immediately performed. For this reason, paper for absorbing the cleaning liquid has been inserted in the conventional printing machine. As this is uneconomical, the present invention provides an air-blow method for drying the surface of the blanket after cleaning.

Numeral 451 designates a nozzle body disposed in parallel with the blanket cylinder 302 and having a nozzle on the blanket side.

The nozzle bod 451 is connected with a vacuum pump of the paper feed mechanism 20. In the air-blow means 450, the nozzle body 451 is adapted to jet the air which was obtained by suction at the time paper was attracted under vacuum in the paper feed mechanism.

As the blanket cleaner 400 thus formed is detachable from the offset duplicator 1, repair work in the inside of the offset duplicator is facilitated, the blanket can be cleaned after each kind of printing, and the contact pressure of the cleaning roll against the rubber roll or the blanket cylinder is adjustable, whereby the most preferred cleaning is attained. Further, drying after cleaning is performed by the air-blow against the blanket effecting a continuous printing.

Numeral 460 designates a paper-detecting means constituting a portion of the paper feed mechanism 20. This paper-detecting means is disposed within the body frame 3, and of substantially the same structure as those employed in conventional presses, however, comprises an electric means such as a photoelectric tube for detecting the sheets stopped at the paper-detecting position by a stop finger 461. The detected sheets are delivered to between the two blanket cylinders 302 impressed at the paper-detecting signal.

The instructions for the plate supplying or discharging for actuating the solenoids 116 and 181 of said plate supplying and discharging mechanism 100 are sent out when two magnet switches MS disposed on the plate cylinder mechanism 350 are actuated by two pulse switches PS (not shown in the plate cylinder) provided on the outer circumference of the plate cylinder and informative of the angle and position thereof.

Fig. 11 shows a relationship between the plate supplying and the discharging of the plate cylinder carried out by actuating the magnet switch by said pulse switch, and Fig.

12 shows a time chart of the offset duplicator in its entirety. With reference to both Fig. 11 and Fig. 12, the whole work of the offset duplicator 1 from its starting up to the plate supplying, printing, plate discharging, and the cleaning of the blanket will be explained.

As the present offset duplicator is a perfecting type, it comprises two sets of the blanket cylinder, plate cylinder, inking and dampening mechanism, and blanket cleaner and each set performs substantially the same work.

When the starting button of the offset duplicator 1 is pressed for the motor starting MM, the plate cylinder 351 of the plate cylinder mechanism 350 is rotated by the driving mechanism 40, wherein a pulse signal PS1 and a pulse signal PS2 are sent out respectively from a signal tions.

When the single lever SL is turned to the second stage position SL2, the paper feed and counting are started. The paper fed into the offset duplicator is detected by the paper detecting means 460, wherein the finger of the paper detecting means is actuated by the passage of the paper and at the signal of this actuation of the finger the blanket cylinder 302 is actuated so as to impress voltage to the blanket cylinders opposed to each other, whereupon the required sheets are printed.

When the printing is finished, a count-up signal is sent out from the counter to stop the paper supplying, and the blanket cylinder is released from the impressing condition, and the single lever is returned to its original position SLo through the first stage position SL1, whereupon the paper supplying mechanism and the inking and dampening mechanism are stopped.

When the single lever SL is turned to the position SLo, the magnet switch MS1 is in a condition possible to be turned ON, and is turned ON by the pulse signal PSl whereby the solenoid 181 is actuated to start the plate discharging motion MSl2. By the action of the solenoid 181, the clutch mechanism 180 is put on, and after the cam for the gripper 352 of the plate cylinder and the cam for the gripper 106 of the transfer wheel are respectively changed over to those for the plate discharging, the original plate is transferred from the gripper 352 to the gripper 106.

Thereafter, the plate is delivered to the pan 251 by the plate discharging and conveyance mechanism 250. The plate discharging is terminated at the pulse signal PS2, similarly to the plate supplying.

The action BL of the blanket cleaner 400 is carried out in such a manner that the solenoid 430 is actuated as soon as said magnet switch MS1 is turned ON and the cleaning of the blanket is continued until the time set on the timer T2 runs out. This blanket cleaner is stopped when the timer T2 is put out, or when the plate is located at the original plate detecting position in the plate supplying and discharging mechanism, or otherwise it may be operated by a separate switch.

After cleaning the blanket, the air-blow means 450 (AR) is actuated by the deenergization of the solenoid 430, and the drying by the air-blow is continued until the first pulse signal PS2 after the expiration of the set time on the timer T2 is sent out.

Stopping the offset duplicator 1 is carried out in such a manner that at the timing at each portion on the right end in Fig. 12, if the detecting signal PD is OFF, the stop button STP and the pulse signal PS1 are turned on thereby putting OFF the motor starting MM.

When the detecting signal PD is ON, the offset duplicator 1 continuously repeats the operation.

In the above-mentioned offset duplicator according to the present invention, it is possible to carry out offset printing on both sides of sheets at the same time, and as the plate supplying and discharging mechanism and the blanket cleaner are detachable from the frame body, maintenance and inspection in the inside of the body frame of the offset duplicator can be easily carried out, in addition, by providing the etching mechanism and the paper-back end guide means, the original plate is swiftly etched and the transference of the print is beautifully done.

WHAT WE CLAIM IS: 1. A sheet-fed perfector type offset duplicator comprising a frame, two blanket cylinders adjacent one another, two plate cylinders each of which is adapted to contact a respective blanket cylinder, two inking and dampening mechanisms for supplying ink and water onto the surface of a printing plate mounted on the respective plate cylinder, two blanket cleaners for cleaning the surface of the respective blankets after a printing run from one pair of printing plates, a sheet-feed mechanism for supplying sheets onto one of the blanket cylinders, a sheet delivery mechanism for transferring printed sheets from the blanket cylinders to a sheet delivery position, a driving mechanism for driving one of the plate cylinders and a drive connection between, on the one hand, said one plate cylinder and, on the other hand, the other plate cylinder, the inking and dampening mechanisms, the sheet-feed mechanism, and said sheet delivery mechanism, wherein the two sets of blanket cylinders, plate cylinders, inking and dampening mechanisms, and plate cleaners are symmetrically disposed to a vertical plane in the body frame; wherein the two blanket cylinders are opposed to each other through a sheet path and each have a blanket fixing mechanism disposed in the inside of a groove thereof so as to hold both ends of a blanket under tension, wherein a gripper for receiving sheets from the sheet feed mechanism and passing them over to the sheet delivery mechanism is detachably mounted in the groove of one blanket cylinder; wherein two sets of plate supplying and discharging mechanisms are respectively mounted at the periphery of the plate cylinders in a detachable manner with respect to the frame for supplying a printing plate to the plate cylinder and discharging the printing plate from the plate cylinder after a printing run from that plate is over; wherein said two sets of blanket cleaners are respectively mounted at the periphery of the two blanket cylinders in a detachable manner with respect to the frame; and wherein a sheet trailing end guide means is provided for guiding the sheets fed by the blanket cylinder for pressing their trailing ends towards a blanket while a cleaning roll of the respective

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. tions. When the single lever SL is turned to the second stage position SL2, the paper feed and counting are started. The paper fed into the offset duplicator is detected by the paper detecting means 460, wherein the finger of the paper detecting means is actuated by the passage of the paper and at the signal of this actuation of the finger the blanket cylinder 302 is actuated so as to impress voltage to the blanket cylinders opposed to each other, whereupon the required sheets are printed. When the printing is finished, a count-up signal is sent out from the counter to stop the paper supplying, and the blanket cylinder is released from the impressing condition, and the single lever is returned to its original position SLo through the first stage position SL1, whereupon the paper supplying mechanism and the inking and dampening mechanism are stopped. When the single lever SL is turned to the position SLo, the magnet switch MS1 is in a condition possible to be turned ON, and is turned ON by the pulse signal PSl whereby the solenoid 181 is actuated to start the plate discharging motion MSl2. By the action of the solenoid 181, the clutch mechanism 180 is put on, and after the cam for the gripper 352 of the plate cylinder and the cam for the gripper 106 of the transfer wheel are respectively changed over to those for the plate discharging, the original plate is transferred from the gripper 352 to the gripper 106. Thereafter, the plate is delivered to the pan 251 by the plate discharging and conveyance mechanism 250. The plate discharging is terminated at the pulse signal PS2, similarly to the plate supplying. The action BL of the blanket cleaner 400 is carried out in such a manner that the solenoid 430 is actuated as soon as said magnet switch MS1 is turned ON and the cleaning of the blanket is continued until the time set on the timer T2 runs out. This blanket cleaner is stopped when the timer T2 is put out, or when the plate is located at the original plate detecting position in the plate supplying and discharging mechanism, or otherwise it may be operated by a separate switch. After cleaning the blanket, the air-blow means 450 (AR) is actuated by the deenergization of the solenoid 430, and the drying by the air-blow is continued until the first pulse signal PS2 after the expiration of the set time on the timer T2 is sent out. Stopping the offset duplicator 1 is carried out in such a manner that at the timing at each portion on the right end in Fig. 12, if the detecting signal PD is OFF, the stop button STP and the pulse signal PS1 are turned on thereby putting OFF the motor starting MM. When the detecting signal PD is ON, the offset duplicator 1 continuously repeats the operation. In the above-mentioned offset duplicator according to the present invention, it is possible to carry out offset printing on both sides of sheets at the same time, and as the plate supplying and discharging mechanism and the blanket cleaner are detachable from the frame body, maintenance and inspection in the inside of the body frame of the offset duplicator can be easily carried out, in addition, by providing the etching mechanism and the paper-back end guide means, the original plate is swiftly etched and the transference of the print is beautifully done. WHAT WE CLAIM IS:

1. A sheet-fed perfector type offset duplicator comprising a frame, two blanket cylinders adjacent one another, two plate cylinders each of which is adapted to contact a respective blanket cylinder, two inking and dampening mechanisms for supplying ink and water onto the surface of a printing plate mounted on the respective plate cylinder, two blanket cleaners for cleaning the surface of the respective blankets after a printing run from one pair of printing plates, a sheet-feed mechanism for supplying sheets onto one of the blanket cylinders, a sheet delivery mechanism for transferring printed sheets from the blanket cylinders to a sheet delivery position, a driving mechanism for driving one of the plate cylinders and a drive connection between, on the one hand, said one plate cylinder and, on the other hand, the other plate cylinder, the inking and dampening mechanisms, the sheet-feed mechanism, and said sheet delivery mechanism, wherein the two sets of blanket cylinders, plate cylinders, inking and dampening mechanisms, and plate cleaners are symmetrically disposed to a vertical plane in the body frame; wherein the two blanket cylinders are opposed to each other through a sheet path and each have a blanket fixing mechanism disposed in the inside of a groove thereof so as to hold both ends of a blanket under tension, wherein a gripper for receiving sheets from the sheet feed mechanism and passing them over to the sheet delivery mechanism is detachably mounted in the groove of one blanket cylinder; wherein two sets of plate supplying and discharging mechanisms are respectively mounted at the periphery of the plate cylinders in a detachable manner with respect to the frame for supplying a printing plate to the plate cylinder and discharging the printing plate from the plate cylinder after a printing run from that plate is over; wherein said two sets of blanket cleaners are respectively mounted at the periphery of the two blanket cylinders in a detachable manner with respect to the frame; and wherein a sheet trailing end guide means is provided for guiding the sheets fed by the blanket cylinder for pressing their trailing ends towards a blanket while a cleaning roll of the respective

blanket cleaner is separated from that blanket and printing is being carried out.

2. A sheet-fed offset duplicator as claimed in claim 1, in which one of the two blanket cylinders has a gear through which driving power is delivered from the driving mechanism and a groove extending in an axial direction, a blanket attached on the outer circumferential surface of the blanket cylinder; a fixing mechanism disposed in the inside of the groove of the blanket cylinder and holding both ends of the blanket; and sheet gripper means mounted in the inside of the groove of said blanket cylinder and adapted to open and close for clamping the end of sheets; said fixing mechanism includin a stop plate secured to each end portion ofthe bLanket, a steady plate, a supporting plate mounted within the blanket cylinder, and a stop means having a stop member engaged at one end thereof with said stop plate and contacted at the other end thereof with an adjusting screw threadably engaged with the supporting plate; said stop member being rotatably supported by the blanket cylinder for moving the stop plate by screwing the adjusting screw in a direction for loosening the blanket, and said sheet gripper means being detachably mounted on the blanket cylinder.

3. A duplicator as claimed in claim 2, in which the stop plate has a bore with which one end of the stop member is engaged, and is mounted on an end portion of the blanket through the steady plate, and adapted to be movable in parallel with a plane including the center line of the groove and the axis of the blanket cylinder with respect to the blanket cylinder.

4. A duplicator as claimed in claim 2 or 3, in which the stop means comprises a substantially U-shaped stop member engaged with the stop plate and having one end shorter than the other end contacted with the adjusting screw, a shaft mounted on the blanket cylinder for rotatably supporting the stop member with respect to the blanket cylinder, and a spring fitted with the shaft and urges said other end of the stop member against the adjusting screw.

5. A duplicator as claimed in claims 2, 3, or 4, in which the sheet gripper means comprises an anvil, pawls holding the ends of sheets between the anvil and themselves, a shaft on which each pawl is mounted, an arm mounted on one end of the shaft for releasing said pawls from the anvil and having a roller on the free end thereof, a spring fitted to the shaft for resiliently pressing said pawl against the anvil, a stop bar by which one end of the spring is stopped and which stop bar is disposed in parallel with said shaft, a pair of supporting members supporting respective ends of said anvil, shaft, and stop bar and detachably mounted on the blanket cylinder, and a connecting rod supported at both ends thereof by this supporting member and constituting a triangle in cooperation with the anvil and the stop bar.

6. A duplicator as claimed in claim 5, in which each plate supplying and discharging mechanism comprises a frame detachably mounted on the body frame; a gripper mounted on the plate cylinder for holding the end of the original plate; a transfer wheel having a gripper for holding the end of the printing plate and rotated by the plate cylinder for rotating this gripper synchronously with the rotation of the gripper of the plate cylinder; an open-and-close mechanism for the transfer wheel for opening and closing the gripper of the transfer wheel when the printing plate is supplied, when the plate held by the gripper of the plate cylinder is passed, when the plate is received from the gripper of the plate cylinder, and when the received plate is released; an open-and-close mechanism for the plate cylinder for opening and closing the gripper of the plate cylinder when the printing plate is received from the transfer wheel and when the plate is passed to the transfer wheel; and a clutch mechanism actuated at the instructions for the plate supplying thereby rotating the transfer wheel as well as actuating the open-and-close mechanism of each gripper so as to pass the printing plate held by the transfer wheel over to the plate cylinder and further actuated in response to a signal for plate discharging thereby rotating the transfer wheel as well as actuating the openand-close mechanism of each gripper so as to release the plate held by the plate cylinder through the transfer wheel.

7. A duplicator as claimed in claim 6, in which the open-and-close mechanism for the plate cylinder comprises a cam member having two concave portions on the outer circumferential surface thereof and mounted on one end of the cylinder shaft; a cam for the plate supplying mounted on said cam member and adapted to open and close the gripper when the printing plate is passed from the gripper of the transfer wheel; a cam for the plate discharging mounted on said cam member and adapted to oPen and close the gripper when the printing plate is passed to the gripper of the transfer wheel after the printing; a pawl member rotatably mounted on the body frame and having a pawl portion engageable with the concave portion of said cam member; a disengaging cam mounted on the plate cylinder and adapted to disengage said pawl member from the concave portion of the cam member; said cam for the plate supplying is so located as to open and close the gripper at the time that said pawl member is engaged with one concave portion of the cam member and the cam for the plate discharging is so located as to open and close the gripper at the time that said pawl member is engaged with the other concave portion, and further said pawl member is adapted to become engageable with the cam member by the action of the clutch mechanism.

8. A duplicator as claimed in claims 6 or 7, in which the transfer wheel comprises a shaft, plural disks mounted on this shaft, a gripper supported by these plural disks at the outer circumferential portion thereof, and a gear mounted on said shaft, substantially one half of the circumference of said each disk which follows the gripper in the rotation being larger in diameter than the other half portion thereof.

9. A duplicator as claimed in claims 6, 7 or 8, in which the plate discharging and conveyance mechanism comprises a roll rotated in contact with the transfer wheel through the original plate held by the gripper of the transfer wheel, a guide member for guiding the end of the original plate having passed through between said roll and the transfer wheel, and a pair of rolls adapted to forcibly deliver the original plate guided by said guide member to the plate discharging position.

10. A duplicator as claimed in any one of claims 6-9, in which the open-and-close mechanism of the transfer wheel comprises a first cam for opening and closing the gripper in order to hold the original plate supplied to the transfer wheel a second cam for opening and closing the gripper in order to pass the plate from the transfer wheel to the plate cylinder; a third cam for opening and closing the gripper in order to convey the plate from the plate cylinder to the transfer wheel; a fourth cam for opening and closing the gripper in order to release the plate from the transfer wheel; a cam member fitted with the shaft of the transfer wheel, and contacted with the transfer wheel so that the both may be rotated together, and provided with said second cam and third cam disposed within the orbit of the gripper of the transfer wheel; a plate mounted on the side of this cam member and having a concave portion for the plate supplying and a concave portion for the plate discharging on the outer circumferential surface thereof; a rotatably supported stop member engageable at one end thereof with each concave portion of the plate; and a disengaging member mounted on the side of the transfer wheel and adapted to rotate and disengage the stop member having been engaged with the concave portion of the plate; said first cam and fourth cam being located outside the orbit of the gripper of the transfer wheel, the concave portion for the plate supplying and the second cam being so located as to open and close the gripper of the transfer wheel by the second cam for passing the original plate to the gripper of the plate cylinder when said stop member is engaged with the concave portion for the plate supplying, the concave portion for the plate discharging and the third cam being so located as to open and close the grippes of the transfer wheel by the third cam for receiving the original plate from the gripper of the plate cylinder when said stop member is engaged with the concave portion for the plate discharging, said disengaging member being located in the periphery of the concave portion which has been engaged with and is disengaged from the stop member.

11. A duplicator as claimed in any one of claims 6 to 10 in which the clutch mechanism comprises a wheel secured on the shaft of the transfer wheel and having a concave portion on the outer circumferential surface thereof, a hook rotatably supported by the gear of the transfer wheel and having a projection engageable with the concave portion of said wheel on one end thereof and a pawl portion on the other end thereof, a rotatable pawl member having at one end thereof a pawl portion engage able with the pawl portion of said hook, a solenoid for driving the pawl member for rotating the pawl member in order to engage and disengage the pawl portion, and an disengaging arm rotated by the action of this solenoid for actuating the open-and-close mechanism for the plate cylinder.

12. A sheet-fed offset duplicator as claimed in any one of claims 1 to 5, wherein each plate supplying and discharging mechanism is provided with a transfer wheel having a plate gripper for holding the end of the original plate and two sets of cams for opening and closing the plate gripper and provided with a clutch mechanism actuated in response to an electric signal for supplying and discharging the original plate, said two transfer wheels being symmetrically disposed with respect to the vertical plane.

13. A duplicator as claimed in any one of claims 1 to 5, in which the plate supplying and discharging mechanism comprises a frame detachably mounted on the body frame; a stopper means for stopping the fed original plate at the printing plate detecting position; a detecting means for detecting that the original plate is conveyed to the original plate detecting position; a gripper mounted on the plate cylinder for holding the end of the original plate; a transfer wheel having a gripper for holding the end of the printing plate and rotated by the plate cylinder so as to rotate said gripper thereof synchronously with the rotation of the gripper of the plate cylinder; a feed roll means actuated at the instructions for the plate supplying for conveying the printing plate from the printing plate detecting position to the gripper of the transfer wheel; an open-and-close mechanism for the transfer wheel for opening and closing the gripper of the transfer wheel when the original plate is supplied, when the held printing plate is passed to the gripper of the plate cylinder, when the printing plate is received from the gripper of the plate cylinder, and when the received printing plate is released; an open-and-close mechanism for the plate cylinder for opening and closing the gripper of the plate cylinder when the printing plate is received from the transfer wheel and when the printing plate is passed to the transfer wheel; a clutch mechanism actuated at the instructions for the plate supplying thereby rotating the transfer wheel as well as actuating the open-and-close mechanism of each gripper for passing the plate held by the transfer wheel to the plate cylinder and also actuated at the instructions for the plate discharging thereby rotating the transfer wheel as well as actuating the open-and-close mechanism of each gripper for releasing the plate held by the plate cylinder through the transfer wheel; a plate discharging and conveyance mechanism for sending the plate to the plate discharging position after the plate discharging is finished.

14. A duplicator as claimed in claim 13, in which the stopper means comprises a rotatable stopper to be contacted with the end of the original plate and a solenoid for rotating this stopper through plural links and shafts, and that a feed roll means comprises a driven roll adapted to be oscillated with a driving roll which is secured at the position it holds the end of the plate situated at the original plate detecting position, a supporting member supporting the driven roll and rotatably supported at one end thereof, and a cam mounted on the shaft of the stopper means having a link rotated by said solenoid and contacted with the free end of the supporting member, the supporting member being so oscillated by the rotation of the cam as to hold the plate between the driven roll and the driving roll when said stopper retreats from the stop position of the original plate.

15. A duplicator as claimed in claim 13 or 14 in which an etching mechanism having a sponge contacted with one of the feed roll means of the plate supplying and discharging mechanism and a reservoir containing the etching liquid to be supplied to the sponge is provided within the frame of the plate supplying and discharging mechanism for effecting an etching treatment on the surface of the original plate while the transference of the original plate by the feed roll means is taking place after the printing is over.

16. A duplicator as claimed in any one of claims 1 to 5, in which the plate supplying and discharging mechanism comprises a stopper means for stopping the fed original plate at the original plate detecting position; a detecting means for detecting that the original plate is conveyed to the original plate detecting position; a gripper mounted on the plate cylinder for holding the end of the original plate; a transfer wheel having a gripper for holding the end of the original plate and rotated by the plate cylinder for rotating said gripper thereof synchronously with the rotation of the gripper of the plate cylinder; a feed roll means actuated at the instructions for the plate supplying for conveying the original plate from the original plate detecting position to the gripper of the transfer wheel; an open-and-close mechanism for the transfer wheel for opening and closing the gripper of the transfer wheel when the original plate is supplied, when the held original plate is passed to the gripper of the plate cylinder, when the original plate is received from the gripper of the plate cylinder, and when the received original plate is released; an open-and-close mechanism for the plate cylinder for opening and closing the gripper of the plate cylinder when the original plate is received from the transfer wheel and when the original plate is passed to the transfer wheel; a clutch mechanism actuated at the instructions for the plate supplying thereby rotating the transfer wheel as well as actuating the open-and-close mechanism of each gripper for passing the original plate held by the transfer wheel to the plate cylinder and also actuated at the instructions for the plate discharging thereby rotating the transfer wheel as well as actuating the open-and-close mechanism of each gripper for releasing the original plate held by the plate cylinder through the transfer wheel; a plate discharing and conveyance mechanism for sending the original plate to the plate discharging position after the plate discharging is finished; a frame supporting said stopper means, detecting means, transfer wheel, feed roll means, open-and-close mechanism for the transfer wheel, and said plate discharging and conveyance mechanism respectively and detachably mounted on the body frame supporting the plate cylinder, the open-andclose mechanism for the plate cylinder, and the clutch mechanism; And a phase lock mechanism which is for locking the phase of the shaft of the transfer wheel with the phase of the gear with respect to the frame according to the movement of the transfer wheel from the position it has been adjoined to the plate cylinder and which is adapted to bring the gear of the late cylinder in a condition engageable with the gear of the transfer wheel in order to phase the gripper of the plate cylinder and the gripper of the transfer wheel to allow the passing of the original plate.

17. A duplicator as claimed in claim 16, in which the phase lock mechanism comprises a phase determination member supported by the frame of the plate supplying and discnarging mechanism; a lock means adapted to lock the shaft of the transfer wheel and a gear fitted with the shaft and adapted to convey the driving power therethrough to the shaft with said phase determination member maintaining the relative phases to one another taken during the printing; a phase control means for the gear for controlling the meshing of the gear of the transfer wheel with the gear of the plate cylinder; and a means preventive of mismounting for preventing the plate supplying and discharging mechanism from being mounted on the body frame supporting the plate cylinder mechanism under a condition that the phase determination member is not locked with the shaft and the gear of the transfer wheel by said lock means.

18. A duplicator as claimed in any one of the preceding claims, in which a blanket cleaner comprises a cleaning mechanism and a control mechanism; said cleaning mechanism having a frame detachably mounted on the body frame of the offset duplicator, a cleaning roll located above the blanket cylinder and adapted to be rotated in contact with the blanket cylinder, a rubber roll rotated in contact with the cleaning roll, and a reservoir means for the cleaning liquid for supplying the cleaning liquid to the rubber roll; said control mechanism having a rotating plate rotatably supported by the shaft of the rubber roll supported by said frame and supporting the roll shaft of the cleaning roll, an actuating means for rotating said rotating plate in order to move the cleaning roll to and from the position where it is brought in contact with the blanket cylinder, and a throttle means mounted on said rotating plate for adjusting the amount of the cleaning liquid on the rubber roll by means of pressing the throttle roll against the rubber roll.

19. A duplicator as claimed in claim 18, in which the reservoir means for the cleaning liquid has a sponge contacted with the rubber roll, a case stopping the sponge and forming a tank for containing the cleaning liquid, an accepting stand on which the case is placed, and a screw provided in the accepting stand for securing the case to the accepting stand.

20. A duplicator as claimed in claim 18 or 19, in which driving means comprises a shaft supported by the rotating plate through an eccentric member, a solenoid, plural links and shafts connecting the solenoid with said shaft for converting the rectilinear motion of the iron core of the solenoid to the rotary motion of said shaft, and a spring for rotating the rotating plate by tension in such a direction that the cleaning roll is separated from the blanket cylinder, said axis of said shaft with respect to the rotating plate being adjusted by rotating said eccentric member.

21. A duplicator as claimed in claim 18, 19 or 20 in which the throttle means comprises a throttle roll contacted with the rubber roll and rotatably supported by the rotating plate, a brake plate contacted with the throttle roll and supported by the rotating plate, and a pressing member resiliently pressing the brake plate against the throttle roll.

22. A duplicator as claimed in anv one of claims 18 to 21 in which the roll shaft of the cleaning roll of the cleaning mechanism is rotatably supported by the rotating plate through the eccentric member, and that said eccentric member is rotated for adjusting the location of the axis of the cleaning roll with respect to the rotating plate.

23. A duplicator as claimed in claim 22, in which the blanket cleaner comprises a cleaning mechanism having a frame detachably mounted on the body frame, a cleaning roll adapted to be rotatable contacting the blanket cylinder, a rubber roll rotated in contact with this cleaning roll, a reservoir means for supplying the cleaning liquid to the rubber roll, and a control mechanism having a rotating plate rotatably supported by the roll shaft of the rubber roll supported by said frame and supporting the roll shaft of the cleaning roll, an actuating means for rotating said rotating plate in order to move the cleaning roll to and from the position where it is brought in contact with the blanket cylinder, and a throttle means mounted on said rotating plate for adjusting the amount of the cleaning liquid on the rubber roll by means of pressing the throttle roll against the rubber roll; and in which the sheet-back end guide means comprises a bell crank rotatably supported on the frame of the blanket cleaner, a link connected between one end of the bell crank and the rotating plate, and a presser shaft provided on the other end of the bell crank, said presser shaft being adapted to be located at a position for guiding back ends of sheets only when the cleaning by said blanket cleaner is not taking place.

24. An offset duplicator constructed and arranged to operate substantially as hereinbefore described with reference to the accompanying drawings.