METHOD FOR ERASING A MISTYPED CHARACTER

Abstract: A correction member moving system for a printer in which an error such as a mistyped character on a recorded member is erased by an error correction member comprises the steps of positioning a correction member at a first position, typing a type corresponding to the error through the error correction member on the recorded member to thereby erase the error, separating the error correction member from the recorded member, and automatically forwarding the error correction member by a predetermined distance. The preferred embodiment, further, comprises the steps of automatically backing the error correction member at the erased position, and positioning the error correction member at a second position.

Description: BACKGROUND OF THE INVENTION The present invention relates to an error correction method for a printer and, more particularly, to an error correction member moving method for an error correction device in a printer which detaches an error correction member from a recording paper after erasing an error such as a mistyped character. Various types of error correction devices have been developed for correcting errors such as mistyped characters. In GB-A-20 13 576 there is disclosed an error correction method of a character printed on a record medium by a typewriter, comprising the steps of shifting the whole carriage to a first erase position and to a second erase position, striking the type of the character to be erased against an erase medium or correction tape onto the record medium twice by means of the printing mechanism of the typewriter, the position of the second strike being slightly displaced from that of the first strike. For erasing the mistyped character the correction tape is lifted up to the printing position moved down after completion and moved forward by a predetermined distance. Document DE-A-31 35 309 discloses an error correction device operating as follows: First, a platen of a typewriter is moved forward by one character space. By pressing a correction key, a mechanism positions the printing point to the character to be erased and lifts up the correction tape to face the ink ribbon used for normal typing. By typing the character corresponding to the mistyped character the ink ribbon as well as the correction tape are lifted to the printing position and the chosen character hits first the ink ribbon and than the correction type thereby erasing the mistyped character. Afterwards both tapes are moved down and the correction tape is moved forward by one character space. Two types of error correction tapes are generally used for erasing the mistyped character. One type is a correction tape having an adhesive material on its surface. The erasing of the mistyped character is executed in such a manner that an ink, which prints the mistyped character, on the recording paper is removed from the recorded paper by typing the selected printing type corresponding to the mistyped character. Because the ink on the recorded paper has been adhered to the adhesive material of the error correction tape, the ink should be thus removed from the recorded paper to erase the mistyped character. Second type of them is an error correction tape having adhesive white pigments. The erasing of the mistyped character is executed in such a manner that the adhesive white pigments are attached to the typed ink on the recorded paper when pressing the recorded paper via the error correction tape by the selected printing type. In both of the above mentioned methods, the error correction tape is directly moved down from the correcting position to the normal position. Following the down movement of the error correction tape, a correct printing type corresponding to a desired character is selected and is typed, so that the correct character is typed through an ink ribbon on the position at which the mistyped character was present. The erasing operation of the error correction tape is thereby completed. Conventionally, as soon as the error correction tape is lifted up at the correcting position and the mistyped character is erased by typing the selected printing type through the error correction tape, the error correction tape is directly moved down. Accordingly, as shown in Fig. 1, a tape surface 2 of the error correction tape 1, which is depressed for erasing the mistyped character, may be rumpled. Tension rollers 3 and 4 are provided for tensing the error correction tape 1 in the horizontal direction. The ends of the error correction tape 1 are connected to a tape supply spool at the side of the tension roller 3 and a tape storing spool at the side of the tension roller 4. The reason why the error correction tape is rumpled is as follows: When the tape surface 2 carrying the adhesive material or the adhesive white pigments is in contact with the recorded paper by being hitted on the recorded paper with the selected printing type, the recording paper and the tape surface 2 are attached. In this condition, the error correction tape 1 is directly moved down and is forcibly removed from the recording paper. Therefore, because the tape surface 2 may be rumpled, the following problems may happen. When removing the tape surface 2 from the recording paper, the printing type of the type wheel may be catched with the rumpled tape surface 2. Also, the error correction tape 1 may not be smoothly moved down, and further, may not be smoothly winded by the tape storing spool. Accordingly, the above problems damage the printing operation of the printer. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved error correction member moving method for a printer or typewriter for speedly carrying out the movements of the error correction member without damaging the printing operation of the printer. To achieve the object, according to an embodiment of the present invention, a method for erasing a mistyped character printed on a record member by an error correction tape carried on a carriage of a printer or typewriter, said record member being forwarded along the surface of a platen and said carriage being movable along said platen, comprises the steps of: moving the carriage to face with a printing position corresponding to the character to be erased, lifting up the correction tape (15) from a normal position (B) to a correcting position (C) facing with the printing position, forwarding the correction tape (15) by a predetermined distance, typing the character corresponding to the mistyped character through the correction tape (15) on the record member (100) to thereby erase the error, and separating the correction tape (15) from the record member (100), is characterized in that the separating step includes the steps: moving the carriage for a certain distance parallel to the axis (10') of the platen (10), moving back the carriage for the same certain distance parallel to said axis (10'), and moving down the correction tape (15) to the normal position (B). BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be better understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein: FIG. 1 shows a perspective view of an error correction tape, explaining the damages by the conventional error correction member moving sytem; FIG. 2 shows a sectional view of a typewriter including an error correction device according to a preferred embodiment of the present invention; FIG. 3 shows a perspective view of an error correction member used in the typewriter of FIG. 2; FIG. 4 shows a block diagram of a control circuit of the typewriter of FIG. 2; and FIG. 5 shows a flowchart of the operation of the error correcton device. DETAILED DESCRIPTION OF THE INVENTION In the typewriter of FIGS. 2 and 3, a platen 10 is rotatably provided around an axis 10'. A recording paper 100 is inserted from a paper inserting section at the back side and the upper side of the platen 10 and is forwarded to a printing position faced with a printing device. The recording paper 100 is forwarded along the surface of the platen 10 according to the rotation of the platen 10. Under the platen 10, a plurality of feed rollers (not shown) are rotatably provided around an axis parallel with the axis 10' of the platen 10 and are in contact with the surface of the platen 10, so that the recording paper 100 is sandwiched between the platen 10 and the feed rollers. A plurality of paper pressing rollers (not shown) are rotatably provided around an axis parallel with the axis 10' of the platen 10. The recording paper 100 is pressed on the platen 10 by the plurality of paper pressing rollers so as to position the recording paper 100 at the printing position. After printing, the recorded paper 100 is taken out from the paper take-out portion at the front side and the upper side of the platen 10. A carriage carries the printing device, an ink ribbon 14, and an error correction device including an error correction tape 15, and reciprocates along an axis parallel with the axis 10' of the platen 10. The printing device includes a type wheel 13, a hammer 11, and a driving motor 12. The type wheel 13 has a plurality of different printing types, and is rotated around an axis connected to a rotating axis of the driving motor 12. Each of the printing types corresponds to each of keys on a keyboard 20. The hammer 11 hits a printing type selected in response to the key of the keyboard 20 to print a character corresponding to the selected printing type on the recording paper 100. The ink of the ink ribbon 14 prints the character by hitting the selected printing type from the type wheel 13 with the ink ribbon 14 by the hammer 11. The error correction device includes an error correction tape 15, tape tension rollers 103 and 104, a tape supply spool, a tape storing spool, a tape lift up/down mechanism, and a tape winding mechanim. The error correction tape 15 is hitted with the printing type of the type wheel 13 by the hammer 11 so as to remove the ink printed the character on the recording paper 100. The error correction tape 15 is extended by the tension rollers 103 and 104 in the horizontal direction. One end of the error corection tape 15 is connected to the tape supply spool, and the other end of the error correction tape 15 is connected with the tape storing spool. The tape supply spool is operated by the winding mechnaism for winding the error correction tape 15. The error correction tape 15 is winded to the arrow direction A. The error correction tape 15 is lifted up and moved down by the lift up/down mechansim. The error correction tape 15 is moved between a normal position B and a correcting position C by the tape lift up/down mechanism. In the normal printing mode of the printer, the error correction tape 15 is set at the normal position B. In the error correction mode of the printer, the correction tape 15 is set at the correcting position C. The operation of the error correction device will be described with reference to FIGS. 3, 4, and 5. In FIG. 4, a keyboard 20 includes a plurality of different keys. The signal corresponding to the depressed key is inputted to the controller 21. The type wheel 13 is driven by a wheel driver 25 to select one of the printing types corresponding to the depressed key in response to the controller 21. The hammer 11 is driven by a hammer driver 24 in response to the controller 21, so that the selected printing type is hitted by the hammer 11. The carriage is moved by a carriage driver 22 according to the controller 21 so that the carriage reciprocates along the platen 10. The error correction tape 15 is liftted up and moved down by the lift up/down mechanism driven by the correction tape driver 23 according to the controller 21. The tape storing spool at the side of the tension roller 104 is rotated by a winding driver. In the present invention, after the error correction tape 15 is in contact with the recorded paper 100 by an erasing operation (In this condition, the error correction tape 15 is indicated by a solid line), the error correction tape 15 with the carriage is forwarded to the direction A (or in the horizontal direction) so that the error correction tape 15 is separated from the recorded paper 100 (In this condition, the error correction tape 15 is indicated by a dotted line). Thereafter, the error correction tape 15 is moved down at the normal position B. Further, the error correcting operation of the error correction device when the mistyped character is erased will be described with reference to the flowchart of FIG.5. Step S1: The carriage is returned at the position of the mistyped character by a back space mechanism (or a forward space mechanism). The back space mechanism is responsive to a signal outputted from the controller 21 by depressing a back space key of the keyboard 20. The carriage is moved by the carriage driver 22 in response to the controller 21. Step S2: The same printing type as the mistyped character is selected from the plurality of printing types of the type wheel 13. In place of the same type as the mistyped character, an erase-purpose printing type can be operated. The printing type is selected by pressing a specific key such as an erase key on the keyboard 20. Step S3: When the specific key such as the erase key of the keyboard 20 is depressed, the output signal from the keyboard 20 is inputted in the controller 21. The correction tape driver 23 is driven in response to the output of the controller 21, so that the error correction tape 15 is lifted up to the correcting position C, and is winded by one character by the tape storing spool. Step 4: After the error correction tape 15 is lifted up, the hammer driver 24 and the type wheel driver 25 are operated according to the controller 21, so that the error correction tape 15 is in contact with the recorded paper 100 by hitting the selected printing type thorugh the error correction tape 15 by the hammer 11, that the printed character is removed from the recorded paper 100. Step 5: After the mistyped character is thus erased, the carriage driver 22 is responsive to the controller 21. The carriage carrying the printing device and the error correction device is automatically moved in the horizontal direction (in the arrow direction A) by a predetermined distance to thereby separate the error correction tape 15 from the recorded paper 100. The carriage is automatically moved in the direction of winding direction of the error correction tape 15. In this case, propably, only the error correction tape 15 can be moved in the direction A without moving the carriage. However, the movement of only the correction tape 15 causes a large load to the tape winding operation. Therefore, the tape winding mechanism is required to withstand a load more than the load applied from the movement of the error correction tape 15. The cost of the tape winding mechanism may be increased. Because the error correction device with the carriage is automatically moved in the correction tape winding direction by the predetemined distance, the error correction tape 15 is easily separated from the recorded paper 100. Any additional mechanism may not be provided for the above purpose. Because the error correction tape 15 is moved in the horizontal direction to be detached from the recorded paper 100, the error correction tape 15 is not rumpled. Step S6: After the carriage is automatically forwarded by the predetermined distance to detach the error correction tape 15 from the recorded paper 100, the carriage with the error correction device is automatically returned to the erased position by the predetermined distance according to the controller 21. Step S7: After the carriage is returned to the erased position, the error correction tape 15 is moved down from the correcting position C to the normal position B. The lift up/down mechansim of the error correction device is driven by the error correcting tape driver 23 according to the controller 21. When the error correction tape 15 is moved down, the error correction tape 15 and the recording paper 100 have been detached from each other already, so that the down movement of the error correction tape 15 is smoothly carried out. Step S8: The type wheel 13 is set the initialized position. The type wheel 13 is driven by the type wheel driver 25 according to the controller 21. Step S9: A correct character is typed by hitting a desired type selected from the type wheel 13 according to the keyboard 20. The selected printing type is hitted by the hummer 11 with the ink ribbon 14. The hammer 11 is driven by the hammer driver 24. The correct character is typed at the mistyped position on the recording paper 100. The error correcting operation is completed. In the preferred embodiment, the carriage is automatically forwarded by the predetermined distance in the arrow direction A by the forward space operation after the erasing operation, and thereafter, the carriage is automatically moved back by the back space operation. For this purpose, the spool at the side of the tension roller 104 is operated as the tape storing spool. If the spool at the side of the tension roller 103 is operated as the tape storing spool, the carriage may be automatically moved back by the predetermined distance after the erasing operation, and thereafter, the carriage may be automatically forwarded to the erased position. As described above, in accordance with the present invention, after the erasing operation, the carriage carrying the error correction tape is automatically forwarded in the direction of the winding of the correction tape to thereby separate the error correcting tape from the recorded paper, and thereafter, the carriage is automatically moved back at the erased position. The error correction tape is moved down at the normal position when the carriage is reached at the erased position. Therefore, the error correction tape is smoothly separated from the recorded paper. The surafce of the correction tape cannot be rumpled when the the saurface of the error correction tape is separated from the recorded paper. Further, the down movement of the error correction tape is smoothly carried out. A character erasing ribbon which erases the typed character may be used in place of the error correction tape. The present invention is not limited to the typewriter, and can be applied to various printers. The invention being thus described, it will be obvious that the same may be varied within the scope of the following claims.

Claims: A method for erasing a mistyped character printed on a record member (100) by an error correction tape (15) carried on a carriage of a printer or typewriter, said record member (100) being forwarded along the surface of a platen (10) and said carriage being movable along said platen (10), the method comprising the steps of: moving the carriage to face with a printing position corresponding to the character to be erased, lifting up the correction tape (15) from a normal position (B) to a correcting position (C) facing with the printing position, forwarding the correction tape (15) by a predetermined distance, typing the character corresponding to the mistyped character through the correction tape (15) on the record member (100) to thereby erase the error, and separating the correction tape (15) from the record member (100), characterized in that the separating step includes the steps: moving the carriage for a certain distance parallel to the axis (10') of the platen (10), moving back the carriage for the same certain distance parallel to said axis (10'), and moving down the correction tape (15) to the normal position (B). Method as claimed in claim 1, wherein the moving direction of the carriage parallel to the axis (10') is the winding direction of said correction tape (15).

Inventors: IWAI, HIROJI, YAMAJI, KOJI
Applicants: SHARP KABUSHIKI KAISHA
Application year: 1985
Main classification: B41J29
IPC codes: B41J29, B41J35