US3468244A - Variable character printing apparatus - Google Patents

Description

Sept. 23, 1969 YOW-JIUN HU 3,468,244

VARIABLE CHARACTER PRINTING APPARATUS Fild Oct. 13, 1966 6 Sheets-Sheet 1 nvwswraz YOW J/U/V HU Sept. 23, 1969 vowu 3,468,244

VARIABLE CHARACTER PRINTING APPARATUS Filed Oct. 13, 1966 6 Sheets-Sheet 2 m N a u no v 3%- g, n rl q? to Sept. 23, 1969 YOW-JIUN HU 3,468,244

VARIABLE CHARACTER PRINTING APPARATUS Filed Oct. 13, 1966 6 Sheets-Sheet Z5 Sept. 23, 1969 YOW-JIUN HU VARIABLE CHARACTER PRINTING APPARATUS 6 Sheets-Sheet 4 Filed Oct. 13. 1966 Sept. 23, 1969 YOW-J|UN I-IU VARIABLE CHARACTER PRINTING APPARATUS 6 Sheets-Sheet 5 Filed Oct. 13, 1966 m 6ft I .v v NN n m d v QN n C J\ 8 u mN l a u S 6 u m l 5 -520 L mm lluullllhmulxmml I I I I i I I l I |||1 Se t. 23, 1969 YOW-JIUN HU VARIABLE CHARACTER PRINTING APPARATUS 6 Sheets-Sheet 6 Filed Oct. 13, 1966 3,468,244 VARIABLE CHARACTER PRINTING APPARATUS Yow-Jiun Hu, Alexandria, Va, assignor to Farrington Business Machines Corporation, Springfieid, Va., a corporation of Massachusetts Continuation-impart of application Ser. No. 401,273, Oct. 2, 1964, now Patent No. 3,280,739, dated Oct. 25, 1966. This application Oct. 13, 1966, Ser. No. 586,421

Int. Cl. B41f 3/20, 3/04, 1/04 U.S. Cl. 10199 13 Claims ABSTRACT OF THE DISCLOSURE An apparatus in a printing machine comprising a tray or printing bed which is movable into printing and nonprinting positions relative to a printing path traversed by a platen mounted on the printing machine. The movable tray includes type bars which are selectively positionable through a printing station on the tray. The tray in the nonprinting position is loaded with a printing plate and document and the individual type bars are selectively positioned according to the particular transaction being accomplished. An alignment mechanism for the type bars comes into play when the tray is moved in the printing position. The tray is locked in the printing position until an imprint is made and then the tray is released for return to the nonprinting position. One of several further features provides for an arrangement to automatically return the type bars to a reference datum position on the tray when the tray itself is returned to the non-printing position.

This invention relates to a device for printing indicia such as variable positioning data on sales slips, documents or the like wherein the data is printed from individual printing devices positionable within the machine from the exterior thereof.

The present application is a continuation-in-part of my earlier copending application Ser. No. 401,273 filed Oct. 2, 1964, the improvement comprising the combination of a movable printing station apparatus comprising the selective positioning of variable data arranged on the type bars.

The objects of this invention are to provide a printing device which is simple and economical in construction, which produces a clean cut and uniform printing with inexpensive plates, which operates conveniently and with little effort, which is durable and reliable in use, and which will print various types of fixed and variable intermittently changed information.

Briefly, the device has a movable printing bed or tray to receive sales slips or the like, with selectively positionable longitudinally extending type bars and one or more seats for printing plates which in the present embodiment is shown in combination with a carriage assembly comprising a curved platen selectively cut-out for printing only one transverse line of data across the type bars. The tray is so arranged as to enable the machine to operate automatically for a single imprint cycle at a time, and allow a tray upon which the printing bed is located to be movably disposed relative to the carriage assembly for further convenience. Further improvements provide for allowing the type bars on the tray to be aligned accurately when the tray is moved into a printing position and provide automatic reset of the type bars when the tray is returned to an initial start position.

Although the variable positionable character mechanism employed on a moving tray is shown in the illustrated embodiment to be utilized in combination with the curved platen assembly shown herein, it is understood, of course,

atent O "ice that other types of manual or powered platen assemblies might be employed in combination therewith.

For the purpose of illustration, a typical embodiment of the invention is shown in the accompanying drawings in which FIGURE 1 is an isometric view of the printing machine.

FIGURE 2 illustrates a section of the machine taken on the line 2-2 of FIGURE 1 with the tray 51 having been pushed inwardly.

FIGURE 3 is a section of the machine taken on the line 3-3 of FIGURE 2 with the carriage assembly 31 having been rocked into a position slightly displaced from the printing bed.

FIGURE 4 shows a cut-away fragmentary view disclosing the type bar assembly in greater detail and also illustrating the lowering of guide means 45 and rotation of carriage assembly 31.

FIGURE 5 is a bottom view of FIGURE 2.

FIGURE 6 illustrates a section of the printing machine taken on the line 66 of FIGURE 2.

FIGURE 7 shows a top view of FIGURE 2 with the motor 24 removed.

FIGURE 8 is a schematic diagram relating to the movement of the carriage assembly 31.

FIGURE 9 shows a section of the type bar assembly taken on the line 99 of FIGURE 5.

FIGURE 10 is an isometric enlarged view of the actuator arm 149 partially shown in FIGURES 1, 5 and 9.

The embodiment herein shown for the purpose of illustration comprises a printing machine having a base 21, see FIGURES l and 2, with an upstanding wall member 22 to which a rigid plate 23 is secured for mounting a power unit generally indicated at 24, which power unit may be of the electric or pneumatic type. The drive shaft 25 of the power unit is directly connected to an eccentric shaft 26 supported at one end by wall member 22 and at its other end by a wall member 27 which is spaced parallel with and attached to wall member 22 by way of wall separators 28 and 29.

A carriage assembly generally referred to as 31, comprises a rocker arm 32 and a bushing 33 having been force fitted within a circular opening in the rocker arm 32, whereby the opening defined by the bushing 33 is adapted to be loosely fitted about the eccentric shaft 26, for easy rotation of the arm thereabout. Spacers 34 are provided to prevent the rocker arm from lateral movement along the eccentric shaft. A platen 35 is snugly mounted on the bottom of rocker arm 32 by providing guide grooves 36 in the arm to be compatible with an extension 37 of the platen, thus allowing the platen to be easily replaced. The platen could be of metal, plastic or of some porous material impregnated with ink such as the platen disclosed in U.S. Patent No. 2,620,730, and if desired the printing surface of the platen could be partially relieved as shown in FIGURE 4 forming an extension finger 38' so that any unwanted information on a printing plate or else where in the printing field, would not be recorded. The printing surface 38 of the platen 35 has a curved configuration to be hereinafter disclosed in more detail.

In a preferred embodiment of the present invention, a bearing 39 (see FIGURES 2-4) integral with a plate member 41 is attached above the surface of platen by screw means 42 to a recessed portion 43 of the carriage assembly for limited movement in a vertical slot 44 formed by a guide member 45, which guide member is attached to a screw 47 and secured to an identation 4 6 in wall member 27 by the frictional coaction of screw 47 and guide member 45 with the wall 27 when the screw is tightened thereto. Upon loosening of screw 47, the screw and attached guide member 45 may be lowered toward the base 21 by way of elongated slot 48 as illustrated in 3 FIGURE 4, thereby freeing the carriage assembly 31, when displaced at substantially its furthermost position from a printing bed, from the guide slot 48, thus allowing the carriage assembly 31 to be manually rotated by facilitating maintenance of the machine in replacement or cleaning of the platen member 35. If desired, the ends of the platen may be additionally secured to the rocker 32 by way of a flathead screw 49.

Beneath the carriage assembly 31 and mounted on base 21 is tray 51, wherein there is positioned an anvil 52 defining a portion of a printing bed disposed to receive an embossed customer identification token or printing plate 53. There is also provided adjacent anvil 52, a printing plate 54 for afiixing thereto station identification information such as the station address, assigned number for recording purposes, etc. whereby both, the identification token 53 on anvil 52 and printing plate 54, are employed to support a document or sales slip 55 upon which an imprint is to be made. The identification token 53 may be of the construction shown in Patents 2,620,729 or 3,034,- 430, being formed with raised characters. To one side of printing plate 54 there is located a variable numbering wheel 56 for recording of additional information such as the date of a transaction. The rim portions 57 and 58 of tray 51 are utilized for properly positioning the sales slip 55 within the tray, whereas on either side of anvil 52, the yieldable biased members 59 and rim 61 are employed for properly locating the identification token 53. The far side 62 of anvil 52 is indented allowing the identification token to be readily tipped for convenient removal from the printing machine. It is noted that the left band edge 57 of tray 51 may be extended outwardly from the tray by way of extensible rods 63, as shown in FIGURE 1, for accommodating large size sales slips.

As disclosed in FIGURE 3, tray 51 is movable with respect to the carriage assembly 31 of the imprinting ma chine via a pair of parallel guide tracks 64 in base 21 receiving the protracted portions 65 of tray 51. The rear of the imprinting machine, as illustrated in FIGURES 2 and 7, is provided with a compression spring 66 wound about a holder 67 mounted on the tray 51 by angle support 68, the spring being guided in an indentation 69 of the base 21 and the free edge of the spring being fixed to the base by screw 71. The spring 66 is biased in the direction shown by the arrow to force the tray 51 outwardly in a document receiving or removal position. To limit the outward movement of the tray a recess 72 is terminated at point 73 in the tray 51 to engage the cap of screw 71 as shown in FIGURE 5. In tray 51 and complimentary with the angled underside of anvil 52 is a wedge 74 having a width which is substantially narrower than that of anvil 52, which anvil occupies the full width of the cut-out in tray 21 within which it is seated. Abutting the front end of wedge 74 there is shown in FIGURE an anvil support screw 75 threadedly transferable through passageway 76 in a stair-like member 77 which is pivotable about the screw 78 fixed to tray 51. It is readily observed that by adjusting the anvil support screw 75 abutting wedge 74, anvil 52 may be raised or lowered to regulate the distance of the identification token 53 from the platen 35 to achieve a proper print quality on the document 55.

It is additionally noted that if, for some reason, the carriage assembly 31 becomes jammed during printing, the operator by rotation of the stair-like member 77 about the pivotable screw 76 to the position 77 (as shown in FIGURE 1), may disengage the anvil support screw 75 from the wedge 74 allowing anvil 52 to be lowered for relieving the jam. The stair-like member 77 is held in its normal position by frictional engagement with wedge 74.

The motor 24 is connected to a normally open snapaction switch 79, as illustrated in FIGURE 1, which switch circuit is closed to activate motor 24 when biased pin 81 is forced inwardly as shown in FIGURE 7, the snap-action switch being electrically connected to a further switch 82, thence to a voltage source by way of leads 83, Pin 81 of snap-action switch 79 is situated so as to be forced inwardly by the action against spring 86 of the angle support 68 on tray 51 when the tray is pushed inwardly towards the carriage assembly 31. The apparatus which locks the tray 51 after it has been pushed forward for an imprinting function and also releases the tray thereafter for removal of the printing plate 53 and document 55, is shown in FIGURES 2 and 6, comprising a pear-shaped cam 84 fixed to the eccentric shaft 26 to be rotatable therewith as the carriage assembly is rocked about the eccentric shaft 26, whereby the top portion of pear-shaped cam 84 will be at its further-most position from the printing bed. A slide 85 slidable up and the side of wall member 22 by way of an elongated slot 86 is guided through the rigid plate 23. The top of the slide 85 has a rod 87 protruding therefrom to coact with the pear-shaped cam 84 for vertical up and down movement of the slide whereas the bottom of slide 85 is integral with a latch 88 adapted to coact with a catch 89 when dropped as cam 84 rotates, for locking the tray 51 after having been pushed forward in a ready for imprint position as illustrated in FIGURE 2. The catch 89 is adjustable within a cut-out 91 in the tray 51 by means of a screw 92, so that while the tray 51 is locked it will, via angle support 68, maintain the depression of pin 81 of snap-action switch 79 through spring 80, to continuously activate motor 24 and thus the rocking of carriage assembly 31 for accomplishing an imprint from identification token 53, printing plate 54 and date wheel 56 onto document 55. It is noted that cam 84 is so shaped that, in one position after a complete revolution of eccentric shaft 26 or a complete imprinting cycle of carriage assembly 31, it will act upon rod 87 to lift slide 85 and therefore lift latch 88 releasing the tray 51 when the platen carriage 31 has been rocked about eccentric shaft 26 to be in its uppermost position relative to the printing bed. Upon lifting latch 88 from engagement with catch 89, the rewinding of biased spring 66 will force tray 51 outwardly, thus deactivating motor 24 until the tray is again pushed inwardly.

The rocking motion of the carriage assembly 31 as it is driven about the eccentric shaft 26 via drive shaft 25, is clearly shown in the schematic drawing of FIGURE 8 wherein the eccentric shaft is replaced by an equivalent crank, whereby the particle 93 represents the center of the drive shaft 25, particle 94 represents the center of the offset portion of eccentric shaft 26 which portion is driven about drive shaft 25 in a circle denoted by the dashed circle 95, and particle 96 represents the center of the hearing 39 which is fixed to the carriage assembly 31 and guided for vertical sliding movement in the guide member 45 as the carriage assembly 31 is rocked. The particles are connected by linkage members, which when driven around one complete revolution of circle will denote the various positions of the platen 35 relative to a printing bed 97. It will be observed that in the present embodiment only one quarter of a complete revolution of eccentric shaft 26 is employed for performing an imprint whereby the platen 35 contacts the document and identification token on printing bed 97. It has been found in practice that it is desirable to achieve as true a rolling action as possible, and thus fixed bearing 39 may be easily positioned to achieve such an effect.

Situated on the right hand side of the tray, as illustrated in FIGURES 1 and 4, are a series of type heads 121, 122, 123, 124 and 125 each having type element 0 through 9 thereon. The type heads are respectively mounted on a series of selectively settable type bars 126, 127, 128, 129 and 130, each of which bars is longitudinally slideable in a direction parallel to the tray movement, and at least slideable for selectively positioning any one of the several type elements within an area adjacent that of anvil 52. The type bars are individually movable through one each of a plurality of tabulator knobs 131 secured thereto by way of oiIset extension arms 132.

The type bars ride on the upper surface of tray 51 and are separated from one another, adjacent opposite ends, by spacers 132', preferably of nylon, which spacers are protruded from a fixed body within the tray and which spacers additionally assist in guiding the type bars Within each of a plurality of well defined paths. Located at each of the opposite ends of the tray is one of a pair of brackets 133 enclosing all of the type bars and holding them together for more accurate positioning, and further preventing the type bars from substantial movement in the vertical direction. Rollers 134 are mounted on a shaft 135 at the top of the brackets 133 to provide an enhanced sliding movement of the type bars When handled by an operator.

As may be observed from FIGURE 9 the bottom exterior surface of each type bar is formed with a plurality of notches 136 having a selected relationship relative to a corresponding type element positioned on the upper surface of the corresponding type bar. Below the type bars are a plurality of detents 137 each having right angle configuration and all mounted to be pivotable about a common shaft 138. As illustrated in FIGURE 9 a plurality of leaf springs 139 separately but lightly bias in an upward direction each detent 137 in a clockwise direction about the pivot shaft 138 to bring the detent end into engagement with a notch 136. By way of such a resilient detent action each type bar is selectively and correctly positioned or registered. As may be seen in FIGURE 9, to visually ascertain where the printing field for the type elements lies relative to platen element 38, a locator member 141 having a cut-out window 142 is provided. The locator member may have written data thereon for denoting cents and dollars or any other type of similar information which might aid the opeartor.

Referring back to FIGURES 5 and 9 there is shown a separate rod 143 extending downwardly from each of the type bars at their forward ends. The bottom portion of each rod 143 is tied to the rearward end of the tray by one of a plurality of tension springs 144. Running beneath all of the detents 137 in a transverse direction, is a single alignment bar 145 adapted for movement in the vertical direction, and being loosely held within a groove 146 in tray 51 by way of the springs 144, which springs pass through a series of openings 147 formed within the alignment bar, a separate opening being formed for each of the longitudinally extending springs 144. The tension on springs 144 is such that should a detent 137 be engaged with a notch 136, it will not be able to overcome the force of leaf spring 139 acting up to maintain such engagement.

Situated directly above detents 137 and also running in a transverse direction thereto, is a reset lever 148 in the shape of a cylinder bisected in its longitudinal axis as illustrated in FIGURE 10. The reset lever is extended to the side of the tray 51 through a circular slot 150 where it is secured to a vertical movable oblong shaped actuator arm 149 mounted at a right angle relative to reset lever 148 as may also be seen from FIGURE 4. Pivotably mounted slightly in from one end of the actuator arm is a finger 151 extending downwardly beneath the lower exterior surface of actuator arm 149 and biased by spring 152 toward that same end of the actuator arm to abut an outward protruding wall 153 of actuator arm 149, yet finger 151 is no positioned that the finger may be rotated against the spring tension about forty to ninety degrees in the direction 17 indicated by the arrow M. In operation, should actuator arm 149 be moved upwardly, it will in turn rotate the reset lever 148 in the P direction to collectively force the detents 137 downwardly against springs 139 and away from engagement with the notches 136 in the type bars allowing the force on the forward end type bars from springs 144 to be dominant and reset the type bars.

As may be observed from FIGURE 4, a raised platform 154 having angular shaped edges 155 is seated on the base 21 at an area over which is to be traversed by the traveling tray 51. More specifically, when the tray has been completely pushed into printing position on the base, the platform 154 will lie under that area occupied by the alignment bar 145, and due to its positioning will cause the alignment bar to be raised by engagement therewith into contact with all of the detents 137 forcing the same into engagement with notches 136 to lock the type bars and prevent vertical movement of the type bars while the tray remains in the printing position.

On the side of the base 21, adjacent the type bar area and dlrectly in line with the travel of the actuator arm 149 is a trip bar 156. The height of the trip bar from the base 21 is such that while the tray is initially pushed forward, it Will cause the finger 151 to be rotated in the M direction (see FIGURE 10), however, the trip bar will not contact the actuator arm spaced therefrom and thus will not cause :he same to be moved at that stage of the machine opera- In operation of the above described device, an identification token will be inserted on anvil 52 and thereafter a document 55 will be placed upon the tray surface while the tray is in an open position as disclosed in FIGURES 1 and 4. It will be assumed that the tabulator knobs 131 have been reset to their reference position as shown in FIGURES 1 and 4 as reflected by the window 142. The machine operator will then individually position the type bars to selected settings in accordance with a specific transaction, which combined settings would be visuallynndicated by the setting window 142. During this operat1on the detents will be forced in and out of the notches 136 due to the action of leaf springs 139 to cause a clicking l1ke sound which will audibly assure the operator of having accurately positioned the type setting. Due to the vibrations transferred by way of the snapping detents, the operator will additionally feel when a detent 137 has been forced into notch 136. Then, the tray 51 will be pushed inwardly against wound spring 66 until the tray 1s forced against spring to depress pin 81 thus activating the motor 24 which drives the eccentric shaft 26. As the tray is pushed inwardly finger 151 will contact trip bar 156 and be pivoted in the M direction while the actuator arm 149 remains stationary relative to tray 51. Further inward movement of the tray into printing position will cause the alignment bar to be raised vertically as it rides up the raised platform 154. In such a raised position the top of the alignment bar 145 will contact all of the detents 137 and align and lock then from vertical movement into engagement within the notches which they were previously set to by the operator. As the eccentric shaft 26 is rotated, pear-shaped cam 84 will be displaced from its position shown in FIGURE 6, thereby allowing latch 88 to be dropped for engagement with catch 89, as illustrated in FIGURE 2, to hold the tray 51 inwardly against motor activating pin 81 and simultaneously maintaining the printing bed in alignment for imprinting upon document 55 by carriage assembly 31. As the carriage assembly is directed in the clockwise direction, platen 35 is brought into a rocking type contact with the sales slip 55 on the printing bed and platen element 38 and 38' will only contact that portion of the sales slip overlying the type numerals located at the window 142 and the identification token to produce an optimum quality imprint transfer onto the sales slip 55 from identification token 53 and the selected type numerals. Upon completion of one revolution of the eccentric shaft 26 and after the accomplishment of an imprint, the pear-shaped cam 84 will raise latch 88 as shown in FIGURE 6 allowing the force of wound spring 66 to force the tray 51 outwardly for document removal and deactivation of motor 24.

As the tray moves outwardly the locking bar 145 will slide off the raised platform 154 and therefore lower the alignment bar from locking engagement With the detents 137 and the type bars. Further outward movement of the tray will cause the finger 151 to contact the trip bar 156 and since the finger will become locked into its lower position by abutting action with wall 153 (see FIGURE 10) the entire actuator arm 149 will be raised due to its positioning and thus rotate reset lever 148 in the P direction to force the detents 137 against springs 139 and out of contact with notches 136 in the type bars. Simultaneously, the tensioned springs 144 will draw the type bars back into their reference position, for subsequent settings during the next printing operation to be accomplished.

In a further feature, while tray 51 is in its document receiving position and motor 24 is deactivated, the guide member 45 may be loosened by means of screw 47 and thus lowered away from hearing 39. Thereby, due to the unique construction and arrangement, one may manually rotate the carriage assembly 31 about eccentric shaft 26, as shown in FIGURE 4, for easy and quick cleaning or replacement of the platen 35.

Although the above printing mechanism is shown to be utilized with a power unit 24, it may be readily operated manually by simply providing an operating handle 98 for attachment to the bolt terminal end of the eccentric shaft 26 as shown in FIGURE 4.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention, it is desired therefore, that only such limitations be placed on the invention as are imposed by the prior art and as set forth in the appended claims.

It is claimed:

1. A printing apparatus comprising a stationary base, a tray having a printing station adapted to support a portable printing plate thereat, a head assembly fixedly supported on said base and including a printing head having a platen adapted for movement through a printing path relative to the base, a plurality of type bars mounted in adjacent relation on said tray, selector means connected to said type bars for individually moving each of said type bars to bring any one of a plurality of type characters to be printed into position at the printing station, means for moving said tray along the base into stable printing and non-printing positions, said printing station adapted to lie adjacent said printing path when the tray is in the printing position enabling the platen to print data at the printing station on a form interposed between the tray and the head assembly, and said printing station adapted to be spaced from the printing path when the tray is in the non-printing position.

2. Apparatus according to claim 1 including aligning means adapted for movement into engagement with said type bars for accurately aligning the type characters on the type bars with one another prior to imprinting, said aligning means normally disengaged from said type bars when the tray is in the non-printing position, and actuating means for moving said aligning means into aligning engagement with said type bars when the tray is moved into the printing position.

3. Apparatus according to claim 1 including separate detent means adapted for yielding engagement with each type bar providing proper printing registration of each type character prior to imprinting the character, aligning means adapted for movement into engagement with said detent means to provide a positive engagement with the type bars for accurately aligning the type characters on the type bars, said aligning means normally disengaged from said detent means, and actuating means for moving said alignment means into engagement with the detent means when the tray is moved into the printing position.

4. Apparatus according to claim 1 including means for releasably locking the tray against movement in the printing position until the platen has traversed the printing station, and means for biasing the tray into the nonprinting position after the platen has traversed the printing station.

5. A printing apparatus comprising a base, a tray having a printing station, a head assembly supported on said base and including a printing head having a platen adapted for movement over a printing path relative to the base, a plurality of type bars mounted in adjacent relation on said tray, selector means connected to said type bars for individually moving each of said type bars to bring any one of a plurality of type characters to be printed into position at the printing station, means for moving said tray relative to the base into printing and nonprinting positions, said printing station adapted to lie adjacent said printing path when the tray is in the printing position enabling the platen to print data at the printing station on a form interposed between the tray and the head assembly, said printing station adapted to be spaced from the printing path when the tray is in the non-printing position, aligning means adapted for movement into engagement with said type bars for accurately aligning the type characters on the type bars with one another prior to imprinting, said aligning means normally disengaged from said type bars, actuating means for moving said aligning means into aligning engagement with said type bars while the tray is in the printing position, and means for releasably locking said tray against movement in the printing position until the platen has traversed the printing path.

6. Apparatus according to claim 5 including means for normally biasing said tray into the non-printing position, means for releasing said tray from said locked position when a printing operation is completed allowing said tray to be urged into the non-printing position.

7. A printing apparatus comprising a base, a tray having a printing station, a head assembly supported on said base and including a printing head having a platen adapted for movement over a printing path relative to the base, a plurality of type bars mounted in adjacent relation on said tray, selector means connected to said type bars for individually moving each of said type bars to bring any one of a plurality of type characters to be printed into position at the printing station, means for moving said tray relative to the base into printing and non-printing positions, said printing station adapted to lie adjacent said printing path when the tray is in the printing position enabling the platen to print data at the printing station on a form inter-posed between the tray and the head assembly, said printing station adapted to be spaced from the printing path when the tray is in the non-printing position, separate detent means adapted for yielding engagement with each type bar providing proper printing registration of each type character prior to imprinting the character, the indicia marked control panel on said tray alongside the area where said type bars are slidable, said selector means having a reference datum position relative to said control panel, and means for automatically returning said selector means from a pre-set condition to their reference datum position when the tray is moved from its printing position to its nonprinting position.

8. Apparatus according to claim 7 wherein said automatic return means comprises spring means for acting on said type bars to normally bias the selector means to the reference datum position said spring means being efiective only when the detent means does not engage the type bars.

9. Apparatus according to claim 8 including trip means adapted to disengage said detent means from the type bars when the tray is moved from the printing position to the non-printing position.

10. Apparatus according to claim 8 wherein said spring means is further adapted to provide a uni-directional resilient mount for the aligning means.

11. A printing apparatus comprising a base, a tray having a printing station, a head assembly supported on said base and including a printing head having a platen adapted for movement over a printing path relative to the base, a plurality of type bars mounted in adjacent relation on said tray, selector means connected to said type bars for individually moving each of said type bars to bring any one of a plurality of type characters to be printed into position at the printing station, means for moving said tray relative to the base into printing and non-printing positions, separate positioning means for yielding engagement with each type bar providing proper printing registration of each type character prior to imprinting, aligning means adapted to provide positive engagement of said positioning means with said type bar for accurately aligning the type characters on the type bars with one another prior to imprinting, said aligning means normally disengaged from the type bars, actuating means for moving said aligning means into positive engagement with the positioning means when the tray is moved into the printing position, means for releasably locking the tray against movement in the printing position until the platen has traversed the printing path, means for normally biasing said tray into the non-printing position, and means for releasing said locking means after the platen has traversed the printing path allowing the tray to be urged by the biasing means into the non-printing position.

12. Apparatus according to claim 11 including a reference datum position for said selector means, means for returning said selector means from a pre-set condition to their reference datum position comprising spring means acting on said type bars adapted to normally bias the selector means to the reference datum position when the positioning means does not engage the type bars, and trip means for disengaging the positioning means from the type bars when the tray is moved from the printing position to the non-printing position.

13. Apparatus according to claim 12 wherein only one type character on each type bar can be moved to be placed at the printing station at any one time, and said platen has a selected configuration adapted to cause an imprint on a document interposed between the type bars and the head assembly only at the printing station.

References Cited UNITED STATES PATENTS 1,305,778 6/1919 Cushing et a1. 101-269 2,344,675 3/1944 Burts 346-58 3,058,416 10/1962 Grant et al 101-269 3,138,091 6/1964 Maul 101-269 X 3,170,390 2/1965 Wagner 101-90 X 3,279,369 10/1966 Wight 101-269 3,280,739 10/1966 Hu 101-297 WILLIAM B. PENN, Primary Examiner US. Cl. X. R. 101-45, 269, 297, 407

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