Printing apparatus
United States Patent [1 1 Ishikawa [541 PRINTING APPARATUS [75] Inventor: Chuji lshikawa, Kawasaki, Japan [73] Assignee: Ricoh Co., Ltd.. Tokyo, Japan [22] Filed: Aug. 28, 1973 [21] Appl. No; 392,130  
 [30] Foreign Application Priority Data Aug 30. 1972 Japan 47-86252 [52] US. Cl ll/93.18, 101/99, 101/95 [51] Int. Cl B4lj 7/36 {58] Field of Search 101/93 C, 95-97, 101/99, 110; 235/60 P [561 References Cited UNITED STATES PATENTS 3.307.676 3/1967 Hickerson 101/110 X 3.664.259 5/1972 Wcinkle 101/99 3.690.249 9/1972 Nihira ct a1. 101/95 3.690.251) 9/1972 Bremner ct a1. 101/95 3.731.812 5/1973 Bremner 101/99 3.738164 6/1973 Sobottka ct a1.. 101/110 3.756.147 9/1973 Gross ct a1 101/95 [57] ABSTRACT A printing apparatus for cash registers and the like wherein the set of type wheels are rotated through co- 1 Apr. 1, 1975 operating serrations by respective connection discs which are loosely mounted on an operating shaft that is reciprocally rotated by a suitable driving system. An arm member is secured to the operating shaft adjacent each disc for reciprocal rotation therewith and has a lock member formed on its free end which cooperates with a catch means formed on a lever member which is pivotally supported on the adjacent connection disc. A spring is connected between each lever member and the connection disc for urging the catch means into cooperative engagement with the lock member so as to rotate the connection discs with the operating shaft through the adjacent arm members. A selectively operated pawl is arranged adjacent each connection disc to stop the rotation of the connection disc at a predetermined position corresponding to the proper positioning of a digit on the cooperating type wheel, at which time the spring permits release of the cooperating engagement between the catch means and the lock member permitting the continued rotation of the operating shaft. Thus, the shaft may rotate until each of the connection discs has been stopped at a proper position and then the appropriate digits on the type wheels may be printed. Rotation of the shaft is then reversed and the connection wheels returned to their original positions by release of the pawls and reengagement of the catch means and lock members. Alternate forms of the driving system for rotation of the operating shaft are disclosed and a second set of type wheels may be included for cooperation with the connection discs to provide a second corresponding printout.  
 8 Claims, 4 Drawing Figures PATENTEDAPR 11915 1874286 SHEET 3 Bf 3 PRINTING APPARATUS BACKGROUND OF THE INVENTION This invention relates to printing apparatus. and more particularly to a printing apparatus of the type used with cash registers and the like.  
  In one type of such printing apparatus known in the art. a main shaft under the influence of a spring is rotated against the biasing force of the spring to thereby rotate type wheels in meshing engagement with connection discs mounted on the main shaft. Printing is carried out while the connection discs and the type wheels remain stationary in predetermined positions and the main shaft continues to rotate. The main shaft. connection discs and type wheels are then rotated in the reverse direction, after printing. by the biasing force of the spring andreturned to their initial position. This type of apparatus has disadvantages in that. for example. a force of comparatively large magnitude is required to rotate the connection discs against the biasing force of the spring; the load is not uniform because it relies on the degree of expansion of the spring; and a considerable shock is produced when the moving parts return to their original positions.  
  In another type of such printing apparatus known in the art. the connection discs are mounted on the main shaft. arranged in side-by side relationship. and connected to one another through plate springs. Owing to inertia or some force unexpectedly exerted on the apparatus at the time the main shaft starts rotating. some of the connection discs may be kept from rotating in synchronism with the main shaft, with the result that pawls for stopping the respective connection discs will not be brought into engagement with teeth in correct positions.  
  The object of this invention is to obviate the aforementioned disadvantages of the prior art.  
 SUMMARY OF THE INVENTION The present invention provides a printing apparatus for cash registers and the like having wheels and a rotatable main shaft and including: means for rotating the main shaft in opposite directions comprising a first gear secured to the main shaft. :1 second gear in meshing engagement with the first gear. and a member for moving the second gear in swinging motion in opposite directions; operation units each comprising a pivotal arm secured to the main shaft and formed at its forward end with a lock. a connection disc loosely mounted on the main shaft and maintained in meshing engagement with the type wheel. and a lever pivotally supported by the connection disc and formed therein with a catch adapted to engage the lock. the number of such units being equal to the number of digit positions of a numeral to be printed; and means for stopping each connection disc in a position corresponding to the digit set for which the connection disc functions.  
 BRIEF DESCRIPTION OF THE DRAWINGS Other and additional objects and features of the invention will become evident from the description set forth hereinafter when considered in conjunction with the accompanying drawings. in which:  
  FIG. I is a view of the printing apparatus comprising one embodiment of the present invention, shown in its standby position;  
  FIG. 2 is a view of the printing apparatus of FIG. 1 shown in its operative or printing position; and  
  FIG. 3 shows a modification ofthe printing apparatus according to the invention.  
 FIG. 4 shows a modified cam and follower arrangement.  
 DETAILED DESCRIPTION OF THE INVENTION IN FIG. I and FIG. 2, a cam l is adapted to rotate. for example. in response to a function key being dcpressed following the setting of the cash register at a certain number. Rotation of the cam I causes a segmental gear 2. through a roller 3 in engagement with the cam I. to move in swinging motion about a shaft 4 in opposite directions. A return spring 5 acting on the segmental gear 2 maintains the roller 3 and cam I in engagement with each other. The segmental gear 2 has a serration 2A which is in meshing engagement with gear 7 that is secured to a main shaft 6 to which a pivotal arm 8 (for one unit) is secured and on which a connection disc 9 (for one unit) is loosely mounted.  
  The connection disc 9 is formed on its outer periphery with an involute serration portion 9A and a ratchet serration portion 98 of the same pitch. A coupling lever 10 which is pivotally connected at II to the connection disc 9 is normally urged to move clockwise in FIG. I and FIG. 2 about its pivot I I by the biasing force of a tension spring 12 connected at one end to the connection disc 9 and at the other end to the coupling lever III. The pivotal arm 8 has planted at its forward end a pin I3 adapted to be engaged in a recess 10A formed in the coupling lever II). The action ofthe spring I2 ensures that the pin 13 is engaged by the edges of the recess 10A.  
  A type wheel 14 which is formed with a serration 14A in meshing engagement with the involute serration portion 9A ofthe connection disk 9 has inscribed on its outer periphery characters and digits in any necessary number (fifteen in this embodiment) which is equal to the number of teeth of the serration MA. A paper web 24 and a ribbon 25 move between the type wheel 14 and a platen 15 so that printing is carried out by the type characters on the outer periphery of the type wheel 14. The pivotal arm 8, connection plate 9., coupling lever I0 and type wheel I4 are provided in any number which is equal to the number of digit positions in a numeral or the number of symbols to be printed. and arranged in side by side relation on main shaft 6.  
  Disposed adjacent the ratchet serration portion 9B of each connection disc 9 is a pawl 16 which is urged by the biasing force of a spring 17 into engagement with the ratchet serration 9B. The pawl 16 is controlled by a solenoid I9 through a trigger lever I8 adapted to engage in a recess 16A formed in the pawl 16. The requisite numbcr of trigger levers I8, all of which are mounted on a common shaft 20. each have one arm 18A which is aligned with similar arms 18A on the rest of the trigger levers 18 for engaging recesses I6A. However. since the various solenoids 19 are disposed in three different positions in which they are displaced from one another for compactness. other arms 188 provided on the trigger levers I8 are displaced from one another as shown. Each trigger lever 18 is normally urged by the biasing force of a spring 2] into engagement in the recess 16A in the respective pawl I6. A stopper 22 is provided for aligning connection discs 9 and consequently type wheels 14. A release member 23. adapted to rotate in synchronism with the cam l, releases the pawl 16 from engagement with the ratchet serration portion of the connection disc 9.  
  Operation of the printing apparatus constructed as aforementioned will now be described. If the cam l is rotated by depressing the function key when the printing apparatus is in its standby position shown in FIG. 1, then the segmental gear 2 is pivoted clockwise about the support shaft 4 through the roller 3. This causes the main shaft 6 to rotate counter clockwise through the engagement of the serration 2A of the segmental gear 2 with the gear 7 secured to the main shaft 6.  
  Each pivotal arm 8 secured to the main shaft 6 pivots counter clockwise and causes each connection disc 9 to rotate through the coupling lever 10 by virtue of the engagement of the pin l3 in the recess 10A. This causes each type wheel 14. which is in engagement with the serration 9A of the connection disc 9 through the serration 14A, to rotate clockwise.  
  Attached to the ratchet serration portion of each connection disc 9 is known tooth number detector (not shown) which produces a signal to the respective solenoid l9 during the rotation of the connection disc 9 when the number of teeth detected by the detector co incides with the digit set by depressing a number setting key. Upon receipt of the signal, the solenoid 19 is energized and releases the trigger lever 18 from engagement in the recess 16A formed in the pawl 16. This results in the pawl 16 being brought into meshing engagement with the ratchet serration portion 98 of the connection disc 9 by the biasing force of the spring 17 to thereby interrupt the rotation of connection disc 9. The pin 13 engages the recess MA. as long as the connection disc 9 is rotated by the pivotal arm 8 through the coupling lever 10. However when the rotation of connection disc 9 is interrupted by the pawl l6 then the pin 13 is released from engagement in the recess 10A by overcoming the biasing force of spring l2 through rotation with main shaft 6 and pivotal arm 8. When this is the case, the main shaft 6 continues to rotate and eventually stops after continuing its movement upon reaching a predetermined angular position following the interruption of rotation of connection disc 9. Thus, each connection disc 9 and consequently each type wheel [4 stops in a position consistent with the digit set by depressing a number setting key. Upon completion of the rotation of main shaft 6 the stopper 22 is brought into engagement with the involute serrations 9A so as to align all connection discs 9 and consequently the type wheels 14 in position to thereby permit printing to be carried out by the platen 15. The printing apparatus is shown in the operative or printing position in FIG. 2.  
  After printing. the stopper 22 is restored to its original position. and the rotating release member 23 moves the pawl l6 downwardly against the biasing force of spring 17. Thus. the pawl 16 is released from engagement with the ratchet serration portion 9B and locked by the trigger 18 as the latter is brought into engagement in the recess 16A formed in the pawl [6. The scg mental gear 2 swings counterclockwise under the influence of the return spring 5, and the main shaft 6 and pivotal arm 8 move clockwise. At this time. the pin 13 on the pivotal arm 8 again engages in the recess ltlA formed in the coupling lever 10, so that the connection disc 9 is restored to its original position shown in FIGv I through the coupling lever 10.  
  The cam I may be in the form of a groove cam l formed therein with a groove for receiving therein the roller 3&#39; on the segmental gear 2, so that the cam 1&#39; can control the back and forth swinging motion of the segmental gear in its entire range. This arrangement would permit the return spring 5 to be eliminated because the segmental gear 2 can be controlled positively by the cam i. This arrangement is shown in FIG. 4.  
  FIG. 3 shows a modification of the printing apparatus according to the invention. As shown. another type wheel 14&#39; formed with a serration l4&#39;A is employed in addition to the type wheel 14 formed with the serration 14A. The type wheel 14&#39; has a platen l5 cooperating therewith, with a paper web 24&#39; and a ribbon 25&#39; being interposed between them This arrangement permits two receipts, one for the customer and the other for filing purposes. to be prepared. In this case, each connection disc 9 is made ready to carry out printing with the type wheel l4 after finishing printing with the type wheel l4. so that the same printing operation can be performed twice.  
  From the foregoing description, it will be appreciated that the printing apparatus according to the invention permits each connection disc 9 to be rotated positively when the main shaft 6 rotates by virtue of the engagement ofthe pin 13 in the recess 10A. This arrangement permits the connection disc 9 to be rotated positively by the main shaft 6, even if the load is great in magnitude as in the case with the embodiment shown in FIG. 3. Since no spring is used to return each connection disc to its original position. the need to rotate the main shaft against the biasing force of the spring is elimininated and variations in load occuring during the rotation of the main shaft are very small.  
 What is claimed is:  
  l. A printing apparatus for cash registers and the like comprising:  
 a. a rotatable type wheel having a first serrated portion thereon;  
 b. a rotatable connection disc having a second serrated portion thereon cooperating with said first serrated portion to rotate said type wheel in response to rotation of said connection disc;  
 c. a rotatable main shaft having said connection disc loosely mounted thereon;  
 d. gear means secured to said main shaft for rotation therewith;  
 e. means for rotating said gear means in opposite directions about the axis of said main shaft;  
 f. an arm member secured at one end to said main shaft for rotation therewith and formed on its opposite end with a lock member;  
 g. a lever member pivotally supported on said connection disc and having:  
 I. catch means formed thereon for cooperatively engaging said lock member;  
 2. means connected between said lever member and said connection disc for urging said catch means into cooperative engagement with said lock member so as to rotate said connection disc with said main shaft through said arm member and for releasing said cooperative engagement upon the stopping of connection disc rotation; and  
 h. means for stopping said connection disc during rotation at a predetermined position corresponding to a desired position for said type wheel.  
  2. Apparatus as in claim 1 wherein said means connected between said lever member and said connection disc is a biasing spring.  
  3. Apparatus as in claim I wherein said means for rotating said gear means comprises:  
 I. a pivoted segmental gear for meshing with said gear means and having a cam follower thereon; and  
 2. a rotating cam means for moving said cam follower in back and forth motion to pivot said segmental gear in opposite directions.  
  4. Apparatus as in claim 3 further comprising a biasing spring connected to said segmental gear for maintaining engagement between said cam means and said cam follower.  
  5. Apparatus as in claim 3 wherein said cam means is a groove cam having a groove therein and said cam follower is a roller riding in said groove.  
  6. Apparatus as in claim 3 wherein said stopping means comprises:  
 l. a third serrated portion on said connection disc; 2. pawl means pivotally mounted for engagement with said third serrated portion; and 3. means for pivoting said pawl means into engagement with said third serrated portion at said predetermined position. 7. Apparatus as in claim 6 wherein said means for pivoting said pawl means comprises:  
 1 a biasing spring for urging said pawl means toward engagement with said third serrated portion; 2. trigger means for engaging and holding said pawl means against the urging of said biasing spring; and 3. means for releasing the engagement between said trigger means and said pawl means. 8. Apparatus as in claim 1 further comprising a second rotatable type wheel having a third serrated portion thereon for cooperating with a fourth serrated portion on said connection disc.