Abstract:
A hand-operable pad-type printing machine capable of one hand operation, thereby enabling the operator to handle the printing article by the other hand. In addition, the machine secures the printing precision which would be difficult to achieve under hand-operated pad-type printing machine.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a printing machine, and more particularly to a hand-operable pad-type printing machine adapted for printing designs or lettering on a relatively small amount of articles. 
     2. Description of Prior Art 
     The pad-press type printing machines are well known and widely used in printing designs or lettering on articles. This type of printing machine is provided with a pad for transferring ink from a printing surface to an article. In addition an inking plate and doctor blade are provided. For mass printing use the pad, the inking plate, and the doctor blade are automatically operated by means of an electric motor and a pneumatic cylinder. 
     For small printing use a hand-operable type is also known and used. This type of machine is provided with (1) a driving section whereby either of a pad or a carrier on which the printing surface and article are mounted is horizontally moved so as to enable the pad to locate above the printing surface and article, and (2) a press section whereby the pad is pressed to the printing surface and the article. The application of ink to the printing surface and the removal of superfluous ink therefrom are manually carried out. 
     There is another pad-type printing machine which is provided with a lever whereby the pad is circularly moved, in association with which the carrier holding the printing surface and article are reciprocally moved in a plane so that the pad and the printing surface are alternately pressed to the article. The application of ink to the printing surface and the removal of a superfluous ink are mechanically operated in association with the movement of the carrier. 
     The first-mentioned hand-operated pad-type printing machine is disadvantageous in that the operator must use his both hands to operate the driving section and the press section, and that the application of ink to the printing surface and the removal of superfluous ink must be also carried out by hand. This is labor- and time-consuming, and reflects in the cost. 
     The last-mentioned printing machine may have an increased efficiency because the operation of a single lever effects all the working steps, but the printing precision is sacrificed because of the circular movement of the pad which is likely to cause misalignment between the printing surface and the pad. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     The present invention aims at solving the problems pointed out with respect to the known hand-operable pad-type printing machines, and has for its object to provide a pad-type printing machine operable by a single hand without trading off the printing precision. 
     Other objects and advantages of the present invention will become more apparent from the following detailed description, when taken in conjunction with the accompaning drawings which show, for the purpose of illustration only, one embodiment in accordance with the present invention. 
     According to the present invention there is provided a hand-operable pad-type printing machine, which comprises; 
     a body structure; 
     an ink tray provided in a lower section of the body structure, the ink tray accommodating a printing plate; 
     a slider unit reciprocally movable in an upper section of the body structure; 
     a handle pivotally connected to the slider unit at one end thereof, thereby enabling the slider unit to move horizontally; 
     a pad unit having a pad for transferring inked patterns from the printing plate to the article, the pad unit carried on the slider unit so as to move horizontally in accordance with the movement of the slider unit, wherein the pad unit has a point at which it is engaged with the handle, thereby enabling the pad unit to move vertically when the handle is swung about the pivotal point to the slider unit; 
     an ink scraper and doctor blade unit carried on the slider unit so as to move horizontally in accordance with the movement of the slider unit, wherein the ink scraper and doctor blade are reciprocally moved in the ink tray; 
     a first cam mechanism for moving the ink scraper on coming in a state in which it is submerged in the ink in the ink tray so as to cover the printing plate with ink, and on going back in a state in which it is kept out of contact with the printing plate; and 
     a second cam mechanism for moving the doctor blade on coming in a state in which it is kept out of contact with the printing plate, and on going back in a state in which it is submerged in the ink so as to wipe superfluous ink on the printing plate. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view showing a printing machine embodying the present invention; 
     FIG. 2 is a cross-sectional plan view taken along the line II--II in FIG. 1; 
     FIG. 3 is a vertical cross-section taken along the line III--III in FIG. 1; 
     FIG. 4 is a vertical cross-section taken along the line IV--IV in FIG. 1; 
     FIGS. 5 (a) and (b) are diagrammatic views exemplifying the operation of the first cam mechanism viewed in the direction of arrows V--V shown in FIG. 4; 
     FIG. 6 is a vertical cross-section taken along the line VI--VI in FIG. 1; 
     FIGS. 7 (a) and (b) are diagrammatic views exemplifying the operation of the second cam mechanism viewed in the direction of arrows VI--VI shown in FIG. 6; 
     FIG. 8 is a front view particularly showing a printing unit provided in the printing machine; 
     FIG. 9 is a front view on an enlarged scale showing the printing unit of FIG. 8; 
     FIG. 10 is a cross-sectional view taken along the line III--III in FIG. 9; 
     FIG. 11 is an analytical perspective view showing the printing unit; and 
     FIG. 12 is a cross-sectional view showing a modified version of the printing unit. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 to 3 there is provided a printing machine 1 which includes a body structure 2 (hereinafter referred to as the body). The body 2 includes a raised floor 2a, a vertical wall 2c and a ceiling space 2d. An ink tray 4 is placed on the raised floor 2a, the ink tray 4 accommodating a printing plate 3. The body 2 has an extended portion 2b on which a supporter 5 is placed for holding a printing article X. The article in this specification includes all objects on which designs or lettering are printed whether it may be flat or cubic. The body 2 is provided with a slider unit 9 in the ceiling space 2d on which an ink-transfer pad 6, an ink scraper 7 and a doctor blade 8 are carried. 
     The slider unit 9 includes bearing sections 9a at opposite sides which are carried on guide bars 10 horizontally provided in the ceiling space 2d. Under this arrangement the slider unit 9 reciprocates between the positions I and II as shown by the arrows (a) and (b). The slider unit 9 is provided with a first guide member 9b extended downward, the guide member 9b having a pair of bars 12 slidably passing therethrough. The bars 12 supports the pad 6 through a first intermediate member 11. The slider unit 9 is additionally provided with a second guide member 9c which have two pairs of bars 15 and 16 slidably inserted therethrough, so as to support the ink scraper 7 and the doctor blade 8, respectively; that is, the supporting bar 15 is fixed to the ink scraper 7 through a second intermediate member 13, and the supporting bar 16 is fixed to the doctor blade 8 through a third intermediate member 14. The pad 6 is upwardly biased by means of a spring 17; normally it is maintained at the height shown in FIG. 1, whereas the ink scraper 7 and doctor blade 8 are downwardly biased by means of springs 18 and 19. The ink scraper 7 and doctor blade 8 are allowed to move between an upper limit and a lower limit, which are defined by a first and a second cam mechanisms 30 and 40. The operation of these cam mechanisms will be described hereinafter. 
     As the slider unit 9 reciprocates, the pad 6, the ink scraper 7 and the doctor blade 8 reciprocate between the positions I and II as shown in FIG. 1. wherein the pad 6 is above the printing plate 3 at the position I and is above the printing article X at the position II. The ink scraper 7 and the doctor blade 8 reciprocate within the ink tray 4. 
     The slider unit 9 is moved by a handle 20, which comprises a pair of levers pivotally connected to the slider unit 9 at one ends 20a, and a grip 20b which projects outside through the ceiling space 2d. Each lever has its middle portion 20c kept in contact with a roller 22 carried on a bracket. 
     It is essential for the pad 6 to descend only at the positions I and II; in order to secure it there are a roller 24 provided on an extension 23 of the handle 20, and an abutment board 25 fixed in the ceiling space 2d. The abutment board 25 has a bottom 25a and sloped sides 25b and 25c. If the pad 6 is not at the positions I and II the handle 20 is prevented from moving down with the roller 24 coming into abutment with the bottom 25a of the abutment board 25, whereas when it is at the positions I and II the roller 24 is guided along the sloped sides 25b and 25c, respectively, thereby allowing the handle 20 to lower. The length of the abutment board 25 is equal to the distance between the positions I and II. 
     As shown in FIGS. 4 to 7 the ceiling space 2d has walls 2d&#39; and 2d&#34; at opposite edges. The first cam mechanism 30 and second cam mechanism 40 are located inside the walls 2d&#39; and 2d&#34;, respectively. 
     Referring to FIGS. 4 and 5 the first cam mechanism 30 for the ink scraper 7 will be described: 
     This cam mechanism 30 includes a first planar cam 31 extending to cover the whole distance over which the ink scraper 7 moves, and a second planar cam 32 fixed to a rear portion of the first planar cam 31. wherein the second planar cam 32 terminates short of the length of the first plate 31 so that as shown in FIG. 5 a postion I lacks the second planar cam 32. The top surfaces of these plates 31 and 32 provide cam faces 31a and 32a, respectively. The first cam face 31a includes a lower portion 31 1 , an ascending slope 31 2  and a higher portion 31 3 . The second cam face 31b includes a higher portion 32 1  and a descending slope 32 2 . 
     The supporting bars 15 of the ink scraper 7 are fixed to a supporting member 33 which has a first follower 34 rolling on the cam face 31a and a second follower 36 rolling on the cam face 32a, which second follower 36 is carried on an arm 35 pivotally connected to the supporting member 33. The arm 35 is normally biased forward by a spring 37 so that the second follower 36 is placed in abutment with the rear face of the first follower 34 as best shown in FIG. 5(a). 
     Referring to FIGS. 6 and 7 the second cam mechanism 40 for the doctor blade 8 will be described: 
     This cam mechanism 40 includes a first planar cam 41, a second planar cam 42 and a third planar cam 43. As best shown in FIG. 7 the third planar cam 43 is fixed to a forward portion of the first planar cam 41 and a backward portion of the second planar cam 42. The top surface of each planar cam 41, 42 and 43 provides a cam face 41a, 42a and 43a at its top, respectively. The cam face 41a includes a higher portion 41 1  and a descending slope 41 2 . The cam face 42a includes a higher portion 42 1  and a descending slope 42 2 . The cam face 43a includes an ascending slope 43 1  and a higher portion 43 2 . 
     The supporting bars 16 of the doctor blade 8 are fixed to a supporting member 44, on which a first follower 45 is provided for rolling on the cam faces 41a and 42a. The supporting member 44 is additionally provided with a second follower 47 carried on an arm 46 pivotally connected thereto, the second follower 47 rolling on the cam face 43a. The arm 46 is normally biased rearward by a spring 48 so that the second follower 47 is placed in abutment with the front of the first follower 45 as best shown in FIG. 7. 
     In the illustrated embodiment the ink tray 4 is made of plastic panel, and as shown in FIGS. 1 and 3 it includes a first recess 4a for storing ink, and a second recess 4b for accommodating the printing plate 3, with a slope portion 4c interlocated therebetween for smoothly transferring the ink from the recess 4a to the recess 4b. The ink tray 4 is placed on a base plate 52 fixed to the raised floor 2a through a spacer 51. The printing plate 3 is also made of plastic panel, and secured to a metal block 53 by means of bolts 54 through press means 55. The spacer 51 houses magnets 56 whereby the metal block 53 is attracted to secure the printing plate 3 and the ink scraper 7. In this way the ink tray 4 is secured on the base plate 52. 
     In operation the handle 20 is rotated in the clockwise direction, with the slider unit 9 being at the position I (FIG. 1), thereby enabling the pad 6 to lower against the spring 17 and come into contact with the printing plate 3 in the ink tray 4. If the printing plate 3 is covered with ink with superfluous ink wiped therefrom, the inked patterns are transferred to the pad 6. Then the handle 20 is rotated in the counter-clockwise direction, that is, in an upward direction, and simultaneously the handle 20 is pulled out so as to enable the slider unit 9 to come to the position II, that is, in the direction of (a) in FIG. 1, where the handle 20 is again rotated in the clockwise direction. In this way the pad 6 is again desended and kept in contact with the article X so that the inked patterns the pad 6 are transferred thereto. When the pad 6 descends to the positions I and II the roller 24 on the extension 23 of the handle 20 is guided along the sloped sides 25b and 25c of the abutment board 25, thereby ensuring that the pad 6 is properly positioned against the printing plate 3 and the article X. Thus the patterns are printed exactly on desired places on the article. 
     When the slider unit 9 moves from the position I to the position II the first cam mechanism 30 is operated to cover the printing plate 3 with ink; more specifically as shown in FIG. 5 (a) at (A) (the position I) the first follower 34 is located on the lower portion 31 1  of the cam face 31a. At this stage the ink scraper 7 is submerged in the ink in the first recess 4a as shown in FIG. 1. Then the slider unit 9 moves in the direction of arrow (a) in FIG. 1, whereby the followers 34 and 36 are moved together in the direction of arrow (a) in FIG. 5. Immediately after they move the second follower 36 comes into abutment with the rear portion of the second planar cam 32, and rides on the cam face 32a of the second planar cam 32 against the spring 37 at (B). The first follower 34 moves to the position (C) (the position II). In accordance with the movement of the first follower 34 the ink scraper 7 moves in the ink tray 4 in the direction of arrow (A) in FIG. 1, and urges the ink in the recess 4a onto the printing plate 3 in the recess 4b. In this way the printing plate 3 is covered with the ink. At this stage the second cam mechanism 40 is also operated to ensure the following series of operation take place: 
     At the initial position I, that is, at (D) in FIG. 7 the first follower 45 is located on the higher portion 41 1  of the cam face 41a (first planar cam 41). However immediately after the followers 45 and 47 move in the direction of arrow (a) the second follower 47 rides on the higher portion 43a of the cam face 43a via the slope 43 1 , thereby maintaining its higher position regardless of the descending slope 41 1  of the first planar cam 41. Thus the doctor blade 8 is prevented from moving down, and kept at its raised position. However the higher portion 43 1  of the third planar cam 43 is slightly higher than the higher portion 41 1  of the first planar cam 41 as clearly shown in FIG. 7(a), thereby raising the doctor blade 8 by a distance corresponding to the difference between the higher portions 41 1  and 43 1 . At (F) (the position ii) the second follower 47 becomes separated from the third planar cam 43, and the first follower 45 rides onto a boundary between the higher portion 42 1  and the slope 42 1 . 
     In this way the pad 6 comes into contact with the article X at the position II. Then the pad 6 is caused to ascend and the slider unit 9 is moved in the direction of arrow (b) until it returns to the position I. In accordance with the return of the slider unit 9 the doctor blade 8 wipes superfluous ink on the printing plate 7. More specifically, when the first and second followers 45 and 47 move from the state at (F) in the direction of arrow (b), the second follower 47 comes into abutment with a front of the third planar cam 43, thereby riding on the cam face 43a of the third planar cam 43. The first follower 45 moves along the slope 42a of the cam face 42a. In accordance with the descent of the first follower 45 the doctor blade 8 lowers, and when the first follower 45 descends along the slope 42a the dotor blade 8 comes into abutment with the printing plate 3. The doctor blade 8 continues to move on the printing plate 3, thereby wiping superfluous ink from the non-printing area. When the doctor blade 8 moves beyond the printing plate 3 the first follower 45 rides on the higher portion 41 1  of the cam face 41a from the slope 41 1  thereof as shown at (H) in FIG. 7(b), thereby causing the doctor blade 8 to rise until it returns to the position I shown in FIG. 1, wherein the second follower 47 again comes into abutment with the front of the first follower 45. In this way the initial starting state is restored. When the slider unit 9 returns to its original position: that is, in the direction of arrow (b) the first cam mechanism 30 is operated as follows: 
     As shown in (I) and (J) in FIG. 5 (b) the first follower 34 is initially on the higher portion 31 1  of the cam face 31a, and then moves to the descending slope 31 1 . At this stage the second follower 36 rides on the higher portion 32 1  of the cam face 32a, thereby ensuring that the ink scraper 7 is maintained at its higher position. When the followers return to the position 1 as shown in (K) in FIG. 7 (b) the second follower 36 becomes separated from the second planar cam 32, and the first follower 34 rides on the lower portion 31 1  of the first planar cam 31. In this way the initial starting state is restored. 
     The article X is replaced every time when the printing is finished, and the handle 20 is repeatedly operated from the position 1 to the position II and vice versa. 
     Referring to FIGS. 8 to 12 the printing unit referred to above will be described in greater detail; 
     The printing machine has a body 101, which has a floor 102 on which a printing unit 120 is mounted. The printing unit 120 includes a pad 104, an ink scraper 105 and a doctor blade 106. The pad 104 is fixed to a supporting bar 107 slidably supported on the body 101. Likewise the ink scraper 105 and the doctor blade 106 are fixed to supporting bars 108 and 109, respectively, which are also slidably supported on the body 101. The body 101 has an extension 101a on which a article unit 110 is provided for containing article X. 
     These supporting bars 107, 108 and 109 are operated in the afore-mentioned manner. 
     As shown in FIGS. 9 to 12 the printing unit 120 also includes a base 122 fixed to the floor 102 by means of bolts 121, an ink tray 123 and a printer 124, which includes a metal block 125 of a rectangular shape and a printing plate 126 having ink-carrying hollows (not shown) on its surface. The printing plate 126 is secured to the metal block 125 by means of bolts 127 through press means 128. 
     Particularly referring to FIG. 11 the ink tray 123 is made of plastic by a vacuum forming method, wherein the plastic is not a type liable to chemical corrosion by a solvent present in the ink. As described above the ink tray 123 includes a first recess 123a for accommodating the printer unit 124, and a second recess 123b for storing ink, with an intermediate slope 123c interlocated therebetween. 
     The base 122 includes a spacer 130 and a sheet 129 on which the metal block 125 is placed. The spacer 130 and sheet 129 are jointed to each other by bolts 121. The spacers 130 are provided with two magnets 131 in holes 129b in such a manner that the top surfaces 131a of the magnets are flush with the top surface 129a of the sheet 129, and attracted to the undersurface 125a of the metal block 125, thereby securing the union of the metal block 125 and the base 122. 
     As shown in FIG. 12, magnets 131&#39; can be provided in the undersurface 125a&#39; of the metal block 125&#39;, wherein the base 122&#39; (the sheet 129&#39;) is made of magnetic material. In either case the number of the magnets is not limited to two but can be determined in accordance with the size of the metal block or the magnet per se.