CA1096802A - Coded printing element and apparatus for use thereof - Google Patents

Abstract

U.S.833,274 ABSTRACT OF DISCLOSURE

A printing element comprising a plurality of print characters is coded so as to identify the nature and orientation of the printing element. A sensor senses the code and the output of the sensor is utilized to control spacing between the character elements and the force applied to the hammer which strikes the character elements. The printing element comprises a daisy-like array wherein the character elements are supported at the end of a plurality of radially extending beams so as to form a substantially circular array.
The coded area identifying the printing element and the orientation is displace from the circular array in a substantially arcuate pattern concentric with the circular array.

Description

1 ~ ~ 6 ~ ~ 2 - 1 Background of the Invention . 2 This invention relates to printin~ elements ~nd more 3 particularly, to printing elements of.the type utilized in 4 serlal impact printers.
The printin~ elements in serial impact printer8 6 comprise a plur~lity of characters which are sequentially 7 moved to the printing pos~tion on a copy mediumt The prlnt-8 ing element is forced into contact with a marki~g or inking 9 medium which in turn contaçts the copy medium by approprlate means such as a solenoid-actuated hammer. In many applica-11 tions, as for example typewriters, the printing elements re-12 gardless of ~heir form are interchangeable so as t~ permit 3 various fonts (e.g., ~onts for ~oreign languages) to be .
utilized in ~onnection with thç same apparatus. In addit~Qn 15 ~o;changing the printing elements, tho printing ap~ara~u~
16 may be appropriately ad~u~ted so as to chan~e the strike 17 forçe, commonly refçrred to as hammer stre~gth, as well as : 1~ the sp.a~ing between the various charae~ers. In addition, 9 t~è numb~er of characters on a character element may change ~equiring the printing apparatus to function differently ;. :21~ w~th differ~nt printing elementsr `22 ~ A daisy-type prin~ing element o the kln~ descr~bed ~ : :
23~: abov~:is~disclosed in U. S. patent 4,018,639. As shQwn 24 therein, the character elements are located at tbe ends of a $ plural~ty of radially extending beams which are centra.lly 26 suppor~ed at a bub- However, such print elements do not in-;27 : clude any code or indLcia which could be machi~e-sensed so as t~ automatically prepare the printing apparat~s to appro-priatçly respond to the par~icular printing elements. In-stea~, thq pFinting elements require the opera~or to appro-31 p~iately identify indicia in the printing element so that ~ 32 the opera~or may appropriately prepare the printing : - 2 -. ~. ', 10~ 2 apparatus for the particular printing element.
U. S. patent 3,498,439 does disclose coded disc for use in connection with a character element for automati-cally preparing the printing apparatus to perform in prede-termined modes. However, no code is carried by the char-acter element.
U. S. patent 3,949,853 discloses the use of mechan-ical keying to assure that the daisy-like printing element is mounted in a predetermined orientation with respect to the drive shaft. U. S. patent 3,651,916 - Becchi discloses a system for sensing a reference datum or home position.
S~mmary of the Invention It is an object of this invention to provide a printing element which includes a coded area which may be sensed by the printing apparatus.
It is a further object of this invention to pro-vide a printing apparatus which automatically responds to the coded area.
It is a further object of this invention to auto-matically adjust the spacing between printed characters inresponse to the coded area as sensed by the printing appara-tus.
It is also an object of this invention to auto-matically adjust the force with which the printing element strikes the inking medium prior to contact with a copy medi~m in response to the automatically sensed coded area of the printing element.
It is a still further object of this invention to identify when the printing element is in the proper orien-tation in response to the automatic sensing of the codedarea by the printing apparatus.

It is a still further object of this invention to 10~6~2 automatically sense the number of character elements on the printing element and control energization of the hammer means in the absence of characters.
It is yet another object of this invention to auto-matically sense character substitutions or replacements.
In a particularly preferred embodiment of this invention, the printing element comprises a character wheel including a hub and a plurality of beams extending radially outwardly from the hub. The character elements are located at and supported by the radial outer extremities of the beams in a substantially circular array so as to permit the character to be rotated through a circular path to and from the print position. The coded area may lie outside the circular path and preferably radially inwardly therefrom.
In the preferred embodiment of the invention, the encoded area comprises a series of open and closed spaces providing a binary codeO The first and second spaces are always open to establish a true home position. The third space is coded to indicate whether the printing element is special or regular. me fourth, fifth and sixth spaces be-yond the third space are coded to represent information for controlling spacing between character elements. The seventh space is coded to as to represent the number of characters and the eighth and ninth spaces are coded to represent the impact force applied by the hammer. A tenth space is closed and an eleventh space is always open to indicate a false home position or improper printing element orientation.
In accordance with a specific embodiment of the invention, a printing system comprises: a pxint element having support means, a plurality of print characters mounted on said support means in a character array adapted to be moved to and ~Q~6Ei~$2 from a print position, a coded area on said support means con-taining information for identifying operational characteristics of the particular print element: drive means coupled to said print element for moving said characters to and from said print position: sensor means associated with said print element for sensing said information contained in said coded area: and print control means including a first memory portion for stor-ing operational information for said printing system and further including code storage means coupled to said sensor means for storing said information contained in said coded area and for controlling said printing system in response to the combination of said information stored in said code storage means and said first memory portion.
Description of the Drawinqs Fig. 1 is a plan view of a daisy-type printing element embodying the invention~
Fig. 2 is an enlarged view of a portion of the printing element of Fig. 1, - 4a -10~

Fig. 3 is a block diagram of a section of a print-ing apparatus which reads and stores the data encoded on the printing element of Figs. 1 and 2, Fig. 4 is a block diagram of a section of a print-ing apparatus which controls the printing of the printing apparatus in response to the data encoded on the printing elements of Figs. 1 and 2, Fig. S is a detailed schematic diagram of the com-ponents of blocks shown in Fig 3, Fig. 6 is a detailed schematic diagram of the com-ponents of blocks shown in Fig. 4:
Fig. 7 is a flow chart for a microprocessor util-ized in reading and storing the data encoded on the printing elements of Figs. 1 and 2, and Figs. 8a and 8b are flow charts for a micropro-cessor for controlling the printing in response to the data -encoded on the printing elements of Figs. 1 and 2.
Detailed Description of Preferred Embodiments Referring to Fig. 1, a printing element comprises a daisy-like wheel 10 including a central hub 12 and a plur-ality of beams 14 extending radially outwardly from the hub 12. Each o~ the beams 14 is terminated in a character slug 16 having a character element raised thereon for use in serial impact printing.
In accordance with the descriptions contained in U. S. Patent No. 4,198,582 and Belgian Patent No. 868,402, the hub 12 comprises a plurality of discrete rotor elements 18 which are circumferentially spaced about the hub 12. The rotor elements 18 function in conjunction with the stator structure of a rotary stepper t~ 5 6g~æ

motor so as to drive the wheel 10 ~rom character position to character position during serial impact printing.
The wheel 10 includes a handle 20 extending radi-ally outwardly from the hub 12. In accordance with the description contained in Belgian Patent No. 870 ,432, the handle 20 includes a plurality of circumferentially spaced openings 22 which are maintained in the same relative relation-ship as the spaces 24 between the beams 14~ The openings 22 allow the position of the wheel 10 to be determined in all wheel orientations even when the handle 20 is juxtaposed to the app-ropriate sensor.
In accordance with this invention, the wheel 10 includes a coded area 26 comprising a series of open and closed spaces 28 which form a binary code. More particularly, the coded area 26 comprises a series of eleven open and closed spaces as best shown in ~ig. 2 which are located near the per-iphery of the hub 12 adjacent the handle 20.
The following table sets forth the code utilized in the coded area 26 at the various spaces 28:
20SPaCe Code Function i open home position ii open home position iii open or closed special or regular print wheel iv open or closed spacing between characters v open or closed spacing between characters vi open or closed dead characters present or absent vii open or closed number of characters 30viii open or closed hammer strength ix open or closed hammer strength x closed false home pGsition 10~6B~2 1 xi open false home position

2 From the foregoing table, it will be understood

3 that each of the spaces or positions i-xi includes binary

4 coded information in the form of an open or closed space which provides information to the printing apparatus for 6 control of that apparatus in response to the coded informa-7 tion. In a particularly preferred embodiment of the inven-8 tion, where an open space corresponds to a binary 0 and a 9 closed space corre~ponds to a binary l, the following code 10 is utilized:
11 SPace C _ Functio 12 iii O special print wheel 13 l regular print wheel 14 iv and v OO unused Ol 12 pitch wheel (12 char~cters per inch) 16 lO lO pitçh wheel (lO characters per inch) 17 ll proportional spaced wheel 18 vi O l~dead key" characters present on wheel 19 l no "dead key" characters on wbeel vii o 92 character wheel 21 1 98 character wheel 22 viii and ix OO increase strength two increments 23 Ol increase hammer strength one increment 24 lO use nominal hammer strength ll decrease hammer strength one increment 26 x ~ 0 homing error (e.g., wheel mounted back-27 wards) 28 l no homing error ~ :
2~ As an aid to visually identifying the coded infor-mation, operator readable indicia 30 corresponding with the 31 coded inform~tion at the ~rea 26 are provided on the wheel 32 lO. ~e indicia 30 which is located radially inwardly from 1046~3~2 the coded area 26 and the handle 20 may be in various forms including a hexadecimal number matching the binary word en-coded at the area 26. As shown in Figs. 1 and 2, the wheel 10 comprises a handle 20 and 92 character elements displaced from the handle and leaving a character void at the handle 20. In a 98 character wheel constructed in accordance with this invention, the handle 20 is eliminated and replaced by beams having character elements at the ends thereof.
Reference will now be made to Fig. 3 wherein cir-cuitry is shown in block form which performs the homing func-tion for the wheel 10 while storing the coded information on the wheel 10 which is located at the area 26. The system includes an on/off control 50 which automatically places the system in the homing state. When the system is placed in the homing state, pulses from a homing clock 52 are applied to a wheel advance circuit 54 which is coupled to the stator 56 of the motor which drives the wheel 10. ~s the wheel 10 - is stepped around, a wheel code sensor 58 optically scans the radial position of the wheel 10 in which the coded area 26 is located.
A code locator circuit 60 iq responsive to the output fro~. the wheel code sensor 58 to properly locate the coded area 26. Once the code area 26 has been properly lo-cated by the locator circuit 60, the binary information at each of the spaces iii-x are loaded into code storage in response to a code storage control circuit 64 such that out-puts III-X of the code storage 62 represents the information stored in the spaces iii-X.
The various outputs IV-IX of the code storage 62 are utilized to control the hammer strength and character spacing as shown in Fig. 4. More particularl~, a hammer control circuit 66 is responsive to outputs VII-IX of the ~q6~Z

code storage 62 and character information stored in a memory 68 which is accessed in response to character position infor-mation. Similarly, the space between the characters which will be governed by linear movement of a carriage for the wheel 10 is controlled in response to a space control cir-cuit 70 which is responsive to the code storage outputs IV-VI and character position information from the memory 68.
Output III is utilized to indicate that the machine can operate in its normal mode if a regular print wheel is indicated or that a special print wheel is present and the machine must be operated in a different mode to accommodate the special print wheel. Output X is utilized to indicate a homing or orientation error, i.e., the wheel 10 is in back-wards.
The homing operation performed by the circuitry shown in Fig. 3 will now be described in greater detail with reference to the specific components of the circuit as shown in Fig. 5.
The on~off control circuit 50 comprises a one-shot multivibrator 72, a flip-flop 74 and a delay circuit 76.
When the positive edge of an ON signal, which is initiated in response to the application of AC power, a cover closure or an off-on switch, is applied to the single shot 72, the flip-flop 74 is set in the home state. The output from the flip-flop 74 is then applied to the delay circuit 76 so as to initiate the homing se~uence after a slight settling de-lay. The output from the one-shot 72 also clears the coun-ters and registers of the wheel advance circuit 54, the code locator circuit 60 and the code storage control 64.
The output from the delay circuit 76 enables an A~D gate 78 o~ the clock circuit 52 so as to pass clock pulses from a source 80 to the wheel advance circuit 54, the _g_ lQ96~3C)2 1 code locator circuit 60 and the code storage circuit 62. As 2 the rotor formed by the whçel lO advances in a predetermined 3 direction (clockwise as viewed from Figs. l and 2) in re-4 sponse to the clock pulses supplied to the counter 82 of the wheel advance circuit 54, the output from the wheel code 6 sensor 58 is applied to a previously cleared shi~t register 7 84 of the code locator circuit 60, When eight filled spaces 8 have been sensed by the wheel code sensor 58 in a row and 9 the corresponding input has been applied to the register 84, an AND gate 86 is enabled which sets a fl~ip-flop 88 having 11 an output applied to an AND gate 90 of:the storage control 12 circuit 64. With the AN~ ga~e 90 enabled, the first open 13 ~ space detected by the wheel code sensor 58 will produce an .
: ~ 14 output:from the NOR gate 92 and enable the AND gate 90 at ; ls clock pulse ~ime. The detectLon of this open space enables 16~ tbe AND gate 90 80 as~ to apply pulses to the load counter 17 94 ofthe code storage co~trol 64.
18~: ; As the counter 94 is advanced in response to each 19~ ~subsequent c~lock pulse,~ the output of the counter 94 i9 de-:~ coded~at~a-~decoder 96 having outputs applLed to AND gates 1~ 98~which~are~sequentLally enabled:~ 60 as:to permit the se-;22~ quentLal~outputs~from~thè wheel code senfior 58 to be stored 3~ in D-type~flLp-flop:s lOO of~the~code storage circuLt 62 4~ a:fter~Lnvers~Lon~at~an Lnverter:102. The flip-flops lOO

5~ wh~ich~seore;:~the~states~or~spaces III-X are sequentially strobed~by ~h:e~code~storag:e control circuit 64 as the appro-7~ pria~te~spàces~pass~the point of optical communication with ~the~wheel~code sen~or 58.: Once the counter 94 reache~ a count of ten which is arrived at after space X has reached a~poLnt of optical communication with the wheel code sensor :: 31 :58, the counter resets the home state flip-10p 74 which 32 i~nhibits the clock 52 thereby locking in the states of the , ~

1096~2 flip-~lops 100 which represent the coded information at spaces III-X. N~ strobing by the decoder 96 occurs during the first two counts of the counter 94 when the spaces i and ii are in optical communication with the wheel code sensor 58.
With the homing sequence completed and the code information stored, the printing operation may begin unless a homing error has occurred. In this connection, it will be understood that if the wheel 10 is mounted backwards, the flip-flop 100 having the X output will be 0 since the tenth position which will be in optical communication with the sensor 58 will actually be the ii space which is open. Only when the wheel 10 is in the proper orientation, i.e~, for-wards, will the X output be 1 corresponding to the closed x space. If the X output is 1, the printing operation may now begin as will now be described in detail with reference to Fig. 6.
The memory 68 comprises a ROM 104 which is access-ed in response to a character position inputs. The output from the ROM 104 is used by the hammer control 66 and the space control 70. The ha~mer control circuit 66 comprises four AND gates 106 which are selectively enabled to achieve four levels of hammer strength or inhibited when a 92 char-acter wheel is utilized rather than a 98 character wheel.
The hammer strength for the individual characters as deter-mined by the R~M 104 is combined with the incremental hammer strength as determined by a digital multiplexer 108 which is responsive to outputs VIII and IX at an adder 110. ~he appropriate gate is then enabled to provide the desired hammer strength.
The gates 106 are inhibited in response to output VII of the appropriate flip-flop 100 in Fig. 5. In this 1C~96~3~)2 connection, the output VII is applied to an OR gate 112 hav--ing an output which remains high where the wheel 10 has been sensed as having 98 characters so as to continuously enable the AND gates 106. Where the output VII is low, a comparator 114 provides a high output to enable the gates 106 only as long as the character position applied to the comparator 114 corresponds to one of the 92 character elements on the 92 -character wheel 10.- When the character position corresponds to positions 93-98, the output of the comparator will go low so as to inhibit the han~ner when the wheel 10 is in these positions.
The space control circuit 70 as shown in Fig. 6 also comprises a plurality of AND gates 116 which are selec-tively enabled in response to the output from a digital mul-tiplexer 118 and outputs IV and V. Ihe outputs IV and V are capable of selecting proportional outputs for each character which is stored in the ROM 104 or a constant output corre-sponding to 12 pitch and 10 pitch print respectively. Out-put VI which is applied to a NAND gate 120 is capable of selectively inhibiting the linear movement of the wheel 10 so as to inhibit spacing when dead keys are struck. In this connection, a character position is compared with predeter-mined dead keys corresponding to, for example, the diacriti-cal marks "\ ", "/", "J " and " " at comparators 122. The outputs from the comparators 122 are applied to the M~D gate 120 through an OR gate 124. As long as the VI output remains low, the output of the ~ND gate 120 is necessarily high so as to enable the AND gates 116. However, when the VI output goes low and the wheel 10 is in a character position corre-sponding to a dead ~ey as determined by the comparators 122, the output from the N~D gate 120 goes low so as to inhibit spacing between character strikes.

lQ96~02 Although no circuitry utilizing the X output has been shown and descr bed, it will be understood that this output may be utilized to sound an alarm indicating that there is a homing error.
In the embodiments of Figs. 5 and 6, homing and printing has been controlled by discrete components. How-ever, it is possible to perform the same control utilizing a microprocessor. Reference will now be made to the flow chart of Figs. 7 and 8 for a description of a particular use of a microprocessor.
The initial wheel position is established as zero (200) and the count of closed spaces is also initially set at zero (2Q2). The print wheel 10 is then advanced (204) to determine if the space juxtaposed to the c~ptical sensor, i.e., wheel sense, (206) is open or closed. If the space is closed, loop 208 is entered and the closed count is supplemented by 1 (210). Counting of closed spaces con-tinues as provided by loop 208 until the count of closed spaces equals 8 (212). If, however, an open space is sensed in the wheel at any time (206) prior to the time that the count of consecutive closed spaces equals 8, loop 214 will reset the count of closed spaces to zero.
After a count of closed spaces equal to 8 (212) is achieved, the wheel continued to be advanced (216) search-ing for the first open space. This search for the first open space continues in loop 218 until such time as the first open space in the wheel corresponding to a bin~ry 1 is sensed (220). The index is then set at 1 corresponding to coded space I (222).
The wheel 10 is continually advanced (224) in loop 226 with the index increasing by one (228) as long as the index is less than 9 ~230). ~s the wheel is advanced in 1~6f~Z

1 loop 226, the wheel sense is input to storage. With the 2 coded information now in storage snd the wheel lO in tbe 3 home posltion, printing may proceed as will now be desc~ibed 4 with reference to the flow chart of Fig. 8a.
~uring printing, the selected characters input to

6 the hammer strength i~ first dqtermined by accessing ha~mer

7 s~trength for the particular charàcter o~ a hammer table and

8 ~emory (232). The stored state of Space VIII is then de~er-

9 mined (~34). If the state o spsce VIII is 0 and the s~ate ~f space IX is also 0, the hammer stren~th will be incre-1~ mented by 2 (238). If the state of space IX is not 0, 'the 12 hammer stren~th will be incremented by 1l(24C~. Si~ilarly, 3 if the state of space VIII is not 0, (234j, the hammer 14 $tr~n~th will be diminished by one increment or remain tbq 'sa~e depending ~Pon the 6tate of sRa¢e rx (24h~ .
, Wher~e ~ke particular character to be printed i8 7 not in a position greater than 92 (~46), tbe previously de-termined hammer strength is applied to the ham~er (~48~. If the character position i$ greater éhan i2 ~246),~the'state of space VII is~determined (2'S0). If ~he.s~ate o spac~ VII
?1;~ L8~0;~indLcating ~ 92 character wheel, ehe ha~mer strength'is set~ae~0 (Z5~ eo inhibit impact~wi.th the character eleme~t.
3::~ On~ehe~other hand,~if ehe sta~te.of space VII iB not 0 (~5~, 4~ ehe~previously det:ermined ham~er strength is output and ap-25:~ plied to the;ham~er (~48)- ~ ' 26:~ The spac~e ~etween characters is ~ow determined by 27~:~: conerolling the moeion of the w~eel lO rçlative'to the.print : point. Initially, the state of the space IV is determined (254). I~ the state is l, thq state of ~he spaçe V must : then be determined (256). If the st~te of the spac~ V is l~
31 the linear motion ~s proportional to t4e chara~ters'. If the : 3~ state af the space V i8 not ~, a ~otion output o~ 6 corre-' 1C)96~2 sponding to 12 characters per inch result (258).
If the state of position IV is not 1 and the state of the space V is determined to be 1 (260), a motion of 5 corresponding to 10 characters per inch (262) is output.
It is now necessary to determine if the particu-lar character is a dead key, i.e., no spacing or linear motion should be produced. Referring to Fig. 8b and begin- -ning with an index equal to 1 (264), if the dead keys index equals the particular character (266) then it must be deter-mined if the state of space VI is zero. If the state of space VI is 0 (268) indicating that the motion of the whe~l

10 is inhibited (270), there is no motion output for the wheel t272). On the other hand, if the state of the posi-tion of VI is not equal to 0, i.e., there are no dead keys, the previously determined motion is output.
If the dead keys initial index does not correspond to the character input (266), the index is successively in-creased by 1 (272) as long as the index is less than 4 (274) in a loop 276. When the index reaches 4 indicating that a particular character does not correspond to a dead key, the previously determined motion is utilized as the output.
The foregoing invention may be embodied in the serial impact printer described in U. Sr Patent ~o. 4,149,808 and Belgian Patent No. 868,402 9 both of which are assigned to the assignee of this invention. In addition, details concern-ing the manner in which the spaces I-XI may be sensed are set forth in Belgian Patent ~o. 870,432 which is also assigned to the assignee of this invention.
It will be understood that different codes may be 1~6~3~2 substitu~ed ~o achieve different o~ectives. For example, it is possible to eliminate hammer strçng~h coding It is 3 also possible to add coding which will indicate character 4 substitutions and/or relocations, as for example, commas S and periods as well as other characters on the wheel.
6 Although preerred embodiments of the inventiop have 7 been shown and described, it will be understood that other 8 embodiments which will appear t~ those of o~dinary skill 9 in the art do fal;L within the ~rue spirit and scope of the invention as set forth in the appended claims.

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Claims (10)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A printing system comprising:
a print element having support means, a plurality of print characters mounted on said support means in a char-acter array adapted to be moved to and from a print position, a coded area on said support means containing information for identifying operational characteristics of the particular print element; drive means coupled to said print element for moving said characters to and from said print position; sensor means associated with said print element for sensing said information contained in said coded area: and print control means including a first memory portion for storing operational information for said printing system and further including code storage means coupled to said sensor means for storing said information contained in said coded area and for controlling said printing system in response to the combination of said information stored in said code storage means and said first memory portion.

2. The system of claim 1 wherein said print element comprises a character wheel, said support means including a hub and a plurality of beams extending radially outwardly from said hub, said character elements being supported by the radial outer extremities of said beams in a substantially circular array so as to permit said character elements to be rotated through a circular path to and from said print position, said coded area having substantially fewer bits of information recorded thereon than the number of said print characters in said character array.

3. The system of claim 2 wherein said encoded information modifies information stored in said first memory portion.

4. The system of claim 2 wherein said encoded area lies radially inwardly from said circular path, said encoded area occupying an arcuate region less than 180°.

5. The system of claim 2 wherein said encoded area is located on said hub.

6. The system of claim 1 wherein said print system com-prises means for moving a copy medium relative to said print element, said print control means controlling the increment and movement of said copy medium relative to said print element in response to said information contained in the coded area sensed by the sensor means in combination with said opera-tional information stored in said first memory portion.

7. The system of claim 6 wherein said print control means inhibits said movement for selected characters of said print element in response to the coded area sensed by the sensor means.

8. The system of claim 1 wherein said print system com-prises impact means adapted to force said print character into contact with a copy medium, said print control means controll-ing said force in response to said combination of information stored in said code storage means and said first memory portion.

9. The system of claim 8 wherein said print control means inhibits said force in response to the coded area sensed by the sensor means for certain void positions in said array.

10. The print element of claim 2 wherein said encoded area comprises a series of closed and open spaces in said hub, said spaces comprising a first open space, a second open space, a third space, a fourth space coded to represent information for con-trolling the movement of the character element relative to the copy medium, a fifth space coded to represent information re-lating to the movement of the character element relative to the copy medium, a sixth space coded to represent information relating to the movement of the character element relative to the copy medium, a seventh space coded to represent the number of characters on the wheel, an eighth space coded to represent the impact force with which the character element is struck, a ninth space coded to represent the impact force with which the character is struck, a tenth space coded to represent proper homing, and an eleventh open space.