Abstract:
A bottom-weighted, free-standing, self-contained, self-supported printer in which the printer is provided with two vertical hoppers in spaced-apart adjacency, with the first hopper to house a supply of cut paper and with the second hopper for paper retrieval in a first in/first out (FIFO) sequence, in which the printer has an exceedingly small footprint so that it may be utilized adjacent the display for a personal computer. Various features include an L-shaped structure to house various size printing assemblies; bottom weighting for stability; electronics carried between the hoppers; an optional front opening for paper retrieval from the front of the printer; a combination of a bidirectional motor and unidirectional clutches for driving picker and exit rollers as well as the platen; a specialized paper guide; an alternative paper path for cut or continuous paper sheets to provide a &#34;limp mode&#34; operation; a paper leading and trailing edge sensor; and swing way sides for easy access to hoppers and printing apparatus.

Description:
This is a continuation of application Ser. No. 754,068, filed July 11, 1985, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to printers and more particularly to a free-standing printer for use with computers or other like devices in which the printer is free-standing and occupies a minimum amount of space while accommodating both relatively inexpensive precut paper as well as continuous form paper is desired. 
     BACKGROUND OF THE INVENTION 
     Current personal computers include some sort of keyboard entry device, a central processing and disc drive unit and a monitor usually involving the use of a cathode ray tube (CRT). In the case of word processing, printed text or material is presented on the CRT screen, is edited and is then printed by a printer which in general is a horizontally-oriented device which takes up a considerable amount of space and which utilizes fan-folded or sprocket-fed continuous sheets of paper which require physical room for input and output stocks. There is also great paper waste for leading and trailing paper leaders. Moreover, it is only with great difficulty that these printers can be made to utilize low cost bond and copier paper, and cut sheet jam ups in such a machine require virtually disassembling the entire unit in order to clear the jam. The horizontal printing units resemble flat typewriters without a keyboard and are exceptionally heavy and unweildly such that they must be placed on an adjacent table, or the work station must be significantly enlarged in order to accommodate the printer. More often than not the printer is located away from the typing work station which makes viewing of the print out inconvenient for the operator in that the operator must move from the typing station to the printout station, especially if pre-cut sheets of paper are utilized. 
     By way of further background, one type of apparatus for feeding sheets of paper from a magazine into a printing office machine is shown in U.S. Pat. No. 4,248,415 in which detachable angled paper magazines are utilized with a separate already existing printer. This patent is thus directed to a printer add-on and not to a stand-alone self-contained printer. In this patent the counter rotation of a printer platen squares paper when paper is fed from a magazine into a platen by virtue of a picker roller. It will be appreciated that in this patent vertical hoppers are not used and that there is no specification of how the paper is withdrawn from the collection bin. Moreover, the utilization of paper magazines introduces a level of complexity and additional parts which in general result in a more expensive machine. Thirdly should there be a machine jam-up or in time &#34;wearout&#34;, there is no alternative paper for path feeding paper into the printing mechanism should the picker mechanism malfunction. Thus there is no so called &#34;limp mode&#34; operation. Also, the platen and picker rollers are belt driven which suffers from belt stretch and breakage. Finally, the provision of electronics between hoppers is neither shown nor taught in this patent and bottom weighting of the device to provide a small-footprint, free-standing, self-contained printer is not discussed. Other feeding devices for printers, but none constituting a stand-alone printer, include U.S. Pat. Nos. 2,366,206; 3,776,545 and 4,089,402. It will be noted that each of these devices is made for attachment to an already existing device and mainly relate to sheet feeding as opposed to a stand-alone printer configuration. 
     SUMMARY OF THE INVENTION 
     In the subject invention rather than providing a horizontally-oriented printer, or even one with angled magazines, a vertically-oriented self-contained, stand-alone printer is utilized which is bottom-weighted by the printing apparatus and has a small footprint particularly in the width direction, so that it may be used directly beside the monitor or CRT utilized for a personal computer. Note. it is the width dimension of conventional printers that results in the need for a wider table. The subject printer is free-standing and stable and has, in one embodiment, a toaster-like configuration in that vertically oriented and spaced-apart input and exit hoppers are utilized. The input and exit slots of the respective hoppers are at the top of the unit and resemble the openings of the conventional toaster. In one embodiment the exit slot is opened at the front of the unit facing the operator to provide a forward facing slot from which to remove printed sheets. This front access permits the printer to be located on a shelf with a shelf immediately above. 
     In operation, paper is loaded into the printer through the input slot where it is stored within the printer in the input hopper. In order to facilitate paper loading in one embodiment this side of the hopper is outwardly swingable to permit loading of cut paper. In another embodiment paper loading occurs from the top so that space need not be allocated to a swing away side. The printer is provided with a picker roller driven by a one way clutch and a bidirectional motor. The picker roller picks a sheet of stored paper and moves it downwardly, where it is curved by a guide into the nip between a cylindrical platen and a mating pinch roller or rollers. In one embodiment the platen is driven by the bidirectional stepping motor through a one way clutch so that the platen only moves in the drive direction. In another embodiment reversing motion of this platen is prevented which presents a non-moving nip between the platen and a mating pinch roller when the motor drives the picker roller. This permits paper squaring against the nip between the platen and pinch roller. 
     When the paper reaches the platen and has been squared, the bidirectional motor is reversed, thus driving the unidirectional clutches for the exit roller and the platen. In summary, the same motor drives the platen, the exit roller and the pick roller. Thus the bidirectional motor may be actuated to drive the platen so that it permits printing which is accomplished either at the platen or between the platen and the bottom of the exit hopper. 
     Note that in one embodiment for bulky printing apparatus, all the printing apparatus is located in the rightwardly extending L portion at the base of the unit to give it stability during printing. This provides a free standing operation with a minimum lateral area being occupied by the printer. Alternatively for some print heads the unit need not extend to the right to provide an &#34;L&#34;. Moreover, since the unit can accommodate low cost bond copy paper, the paper is compatible with both personal computer type printing applications, copying type applications and the typewriter of a small business or home. 
     Because of the particular orientation of the printer, opening of the exit hopper side of the printer exposes the entire printing mechanism such that paper jams, should they occur, are easily cleared. Ribbon and print head change are also accomplished through this opening. 
     Additionally, the input hopper side of the case is optionally provided with a slot to permit insertion of either continuous paper or cut paper into the nip between the platen and the pinch roller to provide an alternative paper path which may also be utilized should the drive system for the input hopper be disabled or malfunctioning. This provides that paper can be fed into this slot and through the printer regardless of whether the input hopper and associated drive mechanism are operating properly. Thus the alternative paper path provides for a limp mode of operation. 
     In one embodiment, at least two one-way clutches are coupled to allow the drive motor to do both the job of picking paper and driving the exit roller. When the motor is driven in one direction power is applied to the picker shaft and the exit roller shaft overruns or slips. Hence one motor accomplishes at least two functions. If the platen is also to be driven by this one motor, in one embodiment, a one way clutch mechanism is inserted between the platen drive shaft and the motor drive shaft so that one motor provides three functions. 
     As mentioned before, in order to be sure that the platen picks up the paper reliably, the paper is overdriven into a curved shape by the picker roller. This curved shape results in the paper attempting to spring into the platen. When the platen begins to rotate in the drive direction the spring force paper urges the paper in the drive direction, thereby assisting the pickup action that occurs between the platen and the pressure rollers. 
     Any one of a number of printheads or printing assemblies may be utilized in conjunction with this particular unit including impact printers, ink jet printers, thermal printhead printers and electrostatic printers, should such be desired. 
     Further, one embodiment, the controller and input/output (I/O) electronics for the feeding and printing operation is carried on circuit boards positioned between the two hoppers, thereby eliminating the need for additional space for the electronics. Also since the electronics are relatively light, and are carried by light circuit boards, locating the circuit boards between the hoppers does not unbalance the vertical printer since the relatively heavy printing components and drive assemblies have been located at the bottom of the unit. 
     In summary, a free-standing, self-contained, vertical-hopper &#34;toaster&#34; configuration, self-supported printer is provided in which the printer has two adjacent spaced-apart vertical hoppers for cut paper feed and FIFO paper retrieval, with the paper retrieval hopper having a front as well as top slot in one embodiment. The electronics and boards are mounted between the hoppers, such that the printer is bottom weighted by the printing apparatus and thus has an exceedingly small footprint so that it may be utilized adjacent the display for a personal computer. Paper, in the form of cut sheets, is stored in one of the vertical hoppers and is picked a piece of a time and moved downwardly around a cylindrical platen and then upwardly towards the direction of the exit hopper, with the printing being accomplished either as the paper moves around the platen, or afterwards as the paper moves over a printhead which is positioned between the platen and the exit roller. The picker roller is utilized to move the paper from storage in the input hopper to a printing position, and is driven directly by a bidirectional motor and a specialized clutch assembly which in one mode drives the picker roller, with the platen braked and the exit roller running; whereas in the reverse direction the motor drives the platen and the exit roller during the printing operation. A curved guide is provided so that the downwardly moving paper enters into the nip between the platen and associated pressure roller or rollers with the curvature of the paper after the platen being maintained by the curved guide until the paper reaches the printhead position. A leading trailing edge paper sensor is utilized in one embodiment to sense the beginning and end of a cut sheet of paper so that the printhead may be actuated to print the paper. In this embodiment the paper sensor provides for an auto load and an auto unload capability, such that the forms need not be printed on costly fan-folded or sprocket-fed forms, with the paper sensor sensing the beginning and end of a cut sheet. The paper in the output hopper is in a first in/first out sequence. 
     In an alternative paper path embodiment the curved guide is provided with a curved lip adjacent to a slot in the side of the printer case for the feeding of continuous sprocket-fed or fan folded paper into the nip. Thus continuous paper feed may be provided, or alternatively cut sheets can be fed along this alternative paper path. 
     Because of the vertical orientation of the printer and its L shape, in one embodiment with the printing apparatus at the base of the unit, the printer is weighted at its base by the printing apparatus, motors and associated carriage drive units. The unit is therefore mechanically stable though free standing and has a small footprint. In one embodiment, the vertical free-standing configuration allows for jam removal by the swinging away of both the input hopper side and the exit hopper side of the printer which exposes all necessary parts for jam removal and printer part interchange. The swing away aspect is advantageous when non-specified or inferior paper is used which papers tends to cause jams. 
     The printing element may either be located adjacent to the platen to use it as an impact anvil, or the printing may be performed after the paper leaves the platen. Moreover, the bottom portion of the printer which forms the &#34;L&#34; may be made longer or shorter to accomodate different size printing systems without disturbing the feed or drive circuitry. Also the &#34;L&#34; shaped bottom permits access for ribbon change, daisy wheel change, or font change without access to other parts of the printer. Of course the right hand side of the upper part of the case can be extended to give a more box-like configuration, thus eliminating the necessity for the L-shaped configuration. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features of the subject invention will be better understood in conjucntion with the Detailed Description taken in conjunction with the drawings of which: 
     FIGS. 1A and 1B are isometric views of the subject stand-alone, vertically-oriented printer illustrating its relatively small footprint as it resides on top of a portion of a personal computer, as well as its optional swing away exit hopper side used to expose the printing apparatus contained therein; 
     FIG. 2 is a diagramatic and partial sectional view of the subject printer illustrating the optional swinging open of the input hopper side of the unit permit the insertion of paper into the input hopper; 
     FIG. 3 is a cross sectional and diagramatic view of the subject free-standing vertical printer illustrating the stacking of paper in the input hopper, along with the mechanical drive for the picker and exit rollers as well as the platen, in which the printing apparatus and platen drive are illustrated as being at the bottom of the unit to promote stability; 
     FIGS. 4A, 4B and 4C illustrate the movement of a cut sheet of paper from the input hopper down through the nip between the platen and the pinch roller and up past the exit roller where it is deposited in the exit hopper; 
     FIG. 5A and 5B illustrate an alternative paper path through the subject vertically-oriented printer, in which the paper enters from the left and proceeds to the nip between the platen and its associated pinch roller; and, 
     FIG. 6 is a side view of the subject printer showing a single drive motor and the use of three unidirectional clutches. 
    
    
     DETAILED DESCRIPTION 
     Referring now to FIG. 1A, a free-standing, vertically-oriented printer 10 is illustrated as having a vertically upstanding portion 12 and a rearwardly running portion 14 which defines the depth of the unit that runs from front to back at the right side of the printer to give the appearance of an L-shaped structure having a footprint illustrated by double-ended arrows 16 and 18 to be relatively small compared to the personal computer generally illustrated by dotted outline 20 to include a display 22 resting atop a dual disc drive unit 24. 
     As can be seen from this figure, the printer has an input slot 30 in its top surface 32 to permit the insertion of paper 34 therethrough and into the printer&#39;s input hopper as will be described hereinafter. Also as will be described hereinafter, a side portion (left side surface) generally indicated by reference character 36 and as illustrated in FIG. 2 is allowed in one embodiment to swing away from the main body of the unit, also to permit the insertion of cut sheets of paper. An alternative version allows insertion without opening of the input hopper. 
     Referring back to FIG. 1A, it can be seen that the cut sheets of paper may extend above the top surface 32 of the printer such that the length of paper utilized by the printer is not restricted to any given vertical length. Thus the printer can accommodate letter size and legal size paper with ease. A narrow finger slide (not shown) is provided in one embodiment to prevent input and output paper droop for long legal forms. 
     The printing is accomplished under the command of internal electronics driven by, for instance, the output of a personal computer or even a dedicated word processor. Controls for such printing are generally indicated by reference character 40 to be on the top surface 42 of the L-shaped portion of the printer which extends to the right. Alternatively these controls can be mounted at the front of the printer for easy access, should the shelf provided by the L be used for storage. Moreover, if the controls are push buttons 41 mounted on angled surface 43 of FIG. 2 of the front of the printer, pressing a button will not move the printer rearwardly. Referring back to FIG. 1A, a ledge 44 is provided such that discs for the disc drive or firmware manuals may be stored upstandingly along right side surface 46 of the printer. 
     The cut sheet or other printed material is collected in FIFO order in an exit hopper having an exit slot 50 in top surface 32 which, in one embodiment, is extended down front face 54 of printer 10 as exit slot 50&#39;. Thus the exit hopper is exposed through a slot which runs from the top surface and down the front side so that paper may be removed in the direction either of arrow 56 or arrow 58. The significance of the vertically running front slot 50&#39; is that paper may be removed in the direction of the operator so that the entire printer and/or associated machinery may be put on a shelf with a shelf immediately there above. The opening of the exit hopper towards the operator has the advantage of saving space, in that apparatus, books or the like may be placed on the shelf immediately above the printer without affecting the ability to remove printed materials therefrom. Note in FIG. 1B that side 46 may be hinged to the printer body and swung outwardly to the right as shown by arrow 59 so that it separates from the main body of the printer along line 59&#39; to expose the inner workings 60 of the printer for permitting change of printer parts and to facilitate jam removal. These inner workings may include a stationary ribbon cartridge 61 and a relatively heavy carriage and ribbon drive motor assembly 63 that contributes to the bottom weighting of the unit. 
     Referring now to FIG. 2 the swingable side portion 36 is shown to be hingedly attached to the printer. Side 36 has a channel or slot 62 adapted to accommodate cut sheets of paper which slot is also made up of a side wall 64 in the interior of printer 10 which will be as described hereinafter. 
     The input hopper constitutes the opposed sidewalls 63 and 64, along with interior side walls 66 and 66&#39; which exist at each end of slot 30 formed when swingable side 36 is moved to the right in a closed position. 
     Also shown in this figure is a spring loaded member 70 which is secured at a point 72 to frame 74 to which side 36 is attached. The configuration is such that as side 36 is closed, spring member 70 produces a pressure in the direction of arrow 76 so that any paper between spring member 70 and picker roller 80 is pressed to the picker roller. Also, paper which exists within the input hopper comes to rest against the bottom thereof which has two upstanding corner tabs 84 to retain the paper in the hopper until such time as the picker roller is actuated. 
     Referring now to FIG. 3, in which reference characters contained therein refer to like elements of FIGS. 1 and 2, printer 10 is seen to house cut sheets 86 between spring member 70 and picker roller 80 which are kept in place by tabs, as discussed herein. 
     As can be seen a curved guide member 90 is positioned beneath the hopper and a further guide 92 is provided so that a paper within the input hopper is directed into the nip 94 between a platen 96. An associated pinch roller 98 may have a braking mechanism generally indicated by reference character 100 which restricts free motion of the platen unless the platen is driven in the direction illustrated by arrow 102. Alternatively, a separate drive motor may be coupled to the platen which prevents platen movement until this motor is actuated. In another embodiment there is enough inertia or friction in the mounting of the platen to keep it stationary unless driven. All of the above permit paper squaring in the nip between platen and associated roller. 
     Immediately above the platen is an exit roller 104 which, as will be seen, drives the printed material into the exit hopper after having been printed by a heavy, bottom weighting printing mechanism generally illustrated by apparatus 110 which may include a ribbon drive assembly 111 and a ribbon drive gear 113. In the illustrated embodiment an impact printer utilizes the platen as an anvil. Printer 110 is driven by printer and motor control electronics 112 housed between the input and exit hoppers, with the exit hopper being defined by side walls 114 and 116, with wall 116 forming an outer portion of the printer housing. The printer mechanism is generally housed in the L-shaped bottom portion of the printer as well as a motor 120 which, as illustrated in FIG. 6 can be seen positioned at the bottom of the free-standing vertically-oriented unit. In one embodiment motor 120 is a relatively heavy bidirectional stepper motor under the control of printer and motor control electronics 112, the weight of which contributes to the stability of the printer because of its location at the bottom of the unit. 
     It will be appreciated that the electronics for driving motor 120 and printer 110 are relatively light and therefore can be located relatively high with respect to the printer body without significantly affecting the center of gravity of the printer. With the printing mechanism motor being located at the bottom of the unit, exceptional stability is provided for the subject printer due to the bottom weighting provided. Note that heavier components may be located at the bottom of the circuit board to lower the center of gravity of the unit, whereas any transformers utilized may be mounted in the base of the printer for bottom-weighting purposes. 
     In one embodiment motor 120 drives picker roller 80 through a one way clutch 122 so that picker roller 80 is driven in the direction of arrow 124 for rotation of the shaft coupled to the clutch in the direction of arrow 124 for rotation of the shaft coupled to the clutch in the direction of arrow 126. Otherwise, for a counter rotation of motor 120, picker roller 80 is free wheeling. 
     A drive reversal unit 140 is attached to the motor of 120 such that when picker roller 80 is driven in the direction of arrow 123, exit roller 104 is free wheeling and the platen 96 is braked to a stop via the brake action on picker roller 98 or by friction or inertia. Reversal of motor 120 drives platen 96, via its associated one way clutch assembly 142 in the direction of arrow 102, whereas the same motor direction drives exit roller 104 in the direction of arrow 144 via a one way clutch 146. The three one way clutches utilized in one embodiment of this invention are more fully described in connection with FIG. 6. 
     For the printer and motor control electronics to operate properly a paper sensor 150 is located through guide 90 so that the beginning and end of cut paper passing around platen 96 may be sensed, with the printer 110 being actuated conventionally by electrics 112. Additionally, motor 120 upon the sensing of paper at sensor 150 may be driven in a different fashion to provide for appropriate printing via printer 110. 
     Referring now to FIGS. 4A through 4C, the paper path through the printer is now described. As can be seen, originally picker roller 80 is driven in the direction of arrow 124 such that sheet 150 buckles at a point 162 due to corner tab 84. This can be clearly seen in FIG. 4A. The purpose of the tab, as is conventional, is to assure that one and only one sheet is picked at a time. 
     Referring now to FIG. 4B the picked sheet 160 is driven to the nip 94 between platen 96 and pinch roller 98 so as to urge the paper in the direction of arrow 164, with roller 80 and guide 90 cooperating to drive the paper into the nip as indicated by the bulge of the paper at 166. 
     Since picker roller 80 is driven by a predetermined amount due to the delivery of a predetermined number of pulses to stepper motor 120, upon the stepping of a predetermined amount, bidirectional motor 120 is reversed, and as illustrated in FIG. 4C platen 96 turns in the direction of arrow 102 to drive paper 160 by the print head portion 170 of printer 110, with the printer having been actuated by virtue of passage of paper past sensor 150. It can be seen here that the paper is curved by the curvature of guide 90 and its cooperation with platen 96 such that it continues to curve upwardly where it meets with exit roller 104 such that it is driven into exit hopper 50 where other cut sheets 172 are already shown as residing within the hopper and standing upwardly on the bottom portion 174 of the exit hopper in a FIFO order. It will be noted that the pressure produced by brake 100 of FIG. 3 is not sufficient to affect the movement of roller 98 or platen 96 in the driven direction. 
     The purpose of the brake, if used, is to provide a stationary nip into which the paper can be driven so as to square up the paper. The braking mechanism also serves to stabilize the line position of the printing process. The stationary nip can also be provided by a separate motor and drive or by the inertia of a stationary plate itself. 
     It will be appreciated that while an impact printer is illustrated in this embodiment, any type of printing mechanism may be utilized including electrostatic printheads, thermal printheads and ink jet printheads which may be utilized either at platen 96 or between platen 96 and the exit hopper. 
     In one embodiment the side surface 46 of the unit is swingable which provides access not only to any paper jams which may occur but also access to the printer mechanism such that the printing font, daisy wheel, matrix, thermal print head, or ribbon may be changed at a convenient location to the operator. 
     Referring now to FIGS. 5A and 5B, an optional alternative paper path is illustrated by the path of paper 200 through s slot 202 in sidewall 203 of the printer body. Here a top guide 204 insures that the paper is guided towards nip 94 where it passes around platen 96 and is picked up by exit roller 104 and moved into exit hopper 50. It will be appreciated that this alternative paper path is useful when continuous sheets, either fan-folded or sprocket-driven, are to be utilized in the printing process. It is also possible to utilize this alternative paper path should there be a malfunction of the input hopper assembly such that printing can nonetheless occur regardless of such malfunction, a so called &#34;limp mode&#34; operation. 
     Referring now to FIG. 6, motor 120 is shown to be housed within the printer body with its output shaft directly driving unidirectional clutch 122 which is in turn coupled to a picker roller drive shaft 220 which drives an exit roller shaft 228 which cooperates with a drive gear 224 which is located on a shaft 226 coupled to unidirectional clutch 146 which drives an exit roller shaft 228 which exit roller 104 is fixedly attached. Gear 224 drives an idler gear 230 which in turn drives a drive gear 232 which is attached to the shaft 234 of unidirectional clutch 142 which drives the platen 96. As can be seen, pinch rollers 98 are located along a shaft 238. 
     A print head carriage generally indicated at 240 carries the conventional stationary ribbon cassette 242. A ribbon 245 from the cassette is pulled out and pushed back in by the print carriage drive motor 243 through carriage belt 244 and a gear train (not shown). All of the apparatus is typically heavy and is mounted at this base of the printer for stability. 
     As can be seen in this manner the single motor 120 operates as illustrated in FIG. 3 to drive the respective rollers and platen in the required directions. It will also be appreciated that other drive mechanisms may be utilized, including a separate drive motor for platen 96. 
     From the foregoing, it will be appreciated that the self-supporting, self-contained vertical printer hereof has an input hopper with laterally spaced, substantially vertically extending generally parallel walls 63 and 64 and an exit hopper having similar walls and which walls have a longitudinal extend in a direction front-to-back parallel to said walls sufficient to accommodate paper sheets having a predetermined width. The width dimension is the dimension transverse to the plane parallel to the hopper walls and against which faces of the sheets of paper rest when inserted into the hoppers. As can be seen in FIG. 3, the housing has a height dimension greater than its width dimension, with the width, dimension being the dimension transverse to a plane parallel to the hopper walls. It will also be observed from a review of FIG. 1A, as well as FIG. 2, that the width dimension is smaller than the width of the sheets of paper. It will also be seen from a review of FIG. 2 that the long direction of the rectilinear hoppers is in the generally vertical direction. 
     Having above indicated a preferred embodiment of the present invention, it will occur to those skilled in the art that modifications and alternatives can be practiced within the spirit of the invention. It is accordingly intended to define the scope of the invention only as indicated in the following claims.