DE4315510A1 - Printer for line-by-line printing of at least one print carrier - Google Patents

Description

The invention relates to a printer for line by line Printing at least one print carrier with one Printhead rotating in the direction of the line of a reversible motor along a predetermined one The route can be moved back and forth while maintaining the pressure printed carrier, and with a feed device for the advance of the print carrier by a predetermined Line spacing.

Such a printer is for example from DE 35 11 386 A1 known and serves as a POS printer for printing the receipt or for journal printing. Of the The print head of the known printer is on a Print head holder arranged by a motor in  Line direction is moved back and forth. A feed device contains another motor, which after the Print a line of a feed roller around a pass agreed twisted angle of rotation that a predetermined Line spacing corresponds. The control of the printer controls the reversible motor of the print head and the Motor of the feed device independent of each other through separate signals. By using two Motors and the associated control system is the hardware expenditure in the known printer relatively large.

It is an object of the invention to provide a printer that of a reduced number of electromechanical Components exist and its control simply opened is building.

This task is mentioned at the beginning for a printer Art solved in that the engine with a gearbox the feed device is coupled, the one Zei lenfeed if the printhead at least drives over a predetermined section of the route.

The invention is based on the consideration that not while driving the entire route along the the print head is moved to perform printing are. While driving over sections of the route without printing processes, the drive energy of the Motors are used for the line feed. By the connection of the feed device to the motor Via the gearbox, a separate motor for the Zei oil feed is eliminated. Accordingly, the Control can be constructed more simply because it is only Must provide signals for an engine.

For a printer that only prints in one direction runs, for example when moving the  Print head from left to right, is along the route to provide only one section, preferably at the beginning or at the end of the route, within which the front feeder executes the line feed. When bi directional printing, d. H. there will be printing in executed in both line directions are along the Route to provide two such sections at for example, at the ends of the lines outside the Print area on the print medium.

In a preferred embodiment of the invention the feed device contains a control disc which depends on the rotation of the motor and thus depends on the distance traveled by the printhead, the control disc when reaching the section a ratchet actuated that a transport roller for the print carrier by a predetermined angle of rotation turns. By using the aforementioned mechani components is a simple structure of the printer reached, which is for mass production too low cost.

Furthermore, it can be provided that the control disk has at least one switch cam, one by one Swivel axis swiveling ratchet lever operated, wel over a transport pawl a ratchet wheel by one Tooth division transported further. The switch cam can in predetermined angular positions with the control disk be releasably connected. In this way, the Ab cut in which the line feed takes place to the Width of the print medium can be adjusted. This can furthermore, the overall printing speed is increased because the total length of the route is kept small that can.  

Another embodiment of the invention is thereby characterized in that at least two ratchet wheels are featured are seen, the transport roller when actuated turn different angles of rotation, and that the Klin through a rear derailleur either with one of the Pawls can be engaged. By this can be done by moving the line feed from line to line Line can be changed. This is required, for example This is the case if of an operating mode in which alphanu meric characters are printed on graphics mode is switched with the line spacing selected in this way must be that the pixels are consecutive Connect lines together. The different Angle of rotation can, for example, by a different tooth pitch of the ratchet wheels set become.

The invention can also be used for printers the several print carriers arranged side by side have that from the printhead in a single movement are to be printed along one line. Everyone has this Print carrier a feed device, which when crossing of a section assigned to it one line ahead thrust executes. This embodiment of the invention is preferred for POS printers that have a Print media for issuing receipts and a another print medium for temporary stay in the Kas Print on send printer (journal printing).

In another development of the invention contains the feed device is an actuating device that at Driving over at least one further section of the Route through the printhead to a cutter Cut the print carrier actuated. For POS printers is the print medium for the receipt either cut partially or completely so that it is light  can be removed from the printer. By the aforementioned The feed device fulfills a measure of ten measures peel function. On the one hand it leads you when you run over one selected line feed and others on the other hand it actuates when driving over another Section the cutter that holds the print carrier cuts.

An embodiment of the invention is as follows explained using the drawing. In it shows

Fig. 1 is a schematic view of a printer, which is used as a structural unit in a cash register housing,

Fig. 2 is a schematic, partially Wegge brochene plan view of the printer of FIG. 1,

Fig. 3 is a schematic representation of the feeding device for the line feed

Fig. 4 different sections along the route that passes over the print head in the reciprocating movement,

Fig. 5 shows the operation of a ratchet mechanism by a control disc,

Fig. 6, the control disc having a switching mechanism for actuating various ratchet wheels,

Fig. 7, the control wheel shortly before the betae term of the switching mechanism,

Fig. 8 is a side view and a plan view of the control disc to the actuation of the derailleur,

Fig. 9, the control disc with a Stellvor direction for actuating a cutting device.

Fig. 1 shows a printer 10 , which is designed as a unit for use in a till (not shown). Two side walls 12 hold parallel to ordered cylindrical guide rails 14 , between which a print head holder 16 is guided. The print head holder 16 can accommodate a print head that prints line-by-line color dots according to the mosaic printing process. The print head holder 16 is moved back and forth on the guide rails 14 by a toothed belt 17 driven by a reversible DC motor. The toothed belt 17 is firmly connected to the pressure carrier 16 , so that various printing positions along the guide rails 14 can be controlled with high repeatability by the rotation of the reversible motor.

The printer 10 includes a paper supply roll 18 for receipts and a paper supply roll 20 for journal printing. The paper of the paper supply rolls 18 , 20 is guided along the guides, not shown, past the print head and can be output ben through output chutes 22 .

The movement of the toothed belt 17 is transmitted via a gear to a control disk 24 with a ring gear. This control disc 24 has a switching cam 26 which actuates a ratchet mechanism 30 , as will be explained in more detail.

In FIG. 2, the printer 10 is shown in FIG. 1 in a schematic, partially broken away view from above. The print head holder 16 is equipped with a print head 15 . The print head holder 16 can be moved back and forth by the motor along a distance L, wherein it moves into recesses 32 in its outer positions (the right outer position is shown in broken lines). The print head 15 can print a paper strip for receipts from the paper supply roll 18 and a paper strip for journal printing from the paper supply roll 20 when moving along the path L. In order to be able to produce different line spacings for these paper strips, the printer 10 contains a feed device 27 , 29 for each paper strip, the feed device 29 being provided with a further control disk 25 . The paper feed is carried out by Transportrol len 34 and 36 , press against the counter rollers 38 . The longitudinal movement of the print head holder 16 is transmitted via a gear to the control disc 24 or 25 gene. The translation of the gear is selected so that the control discs 24 , 25 with a movement of the print head holder 16 along the distance L a revolution of 318 ° perform, as indicated in Fig. 2 left.

The control disk 24 actuates the pawl switching mechanism 30 , which contains a ratchet wheel 40 connected to the transport roller 34 with a number of teeth z = 9. The control disc 25 actuates a ratchet mechanism 42 , which is optionally with a ratchet wheel 44 with the number of teeth z = 9 or a ratchet wheel 46 with the number of teeth z = 12 in engagement. The pawl switching mechanism 42 is connected to a switching mechanism 50 , which effects the selective engagement in one of the ratchet wheels 44 , 46 , as will be explained in more detail. The switching mechanism 50 is actuated by a magnet 52 , the armature 54 of which is biased by a spring 56 into a rest position (shown in FIG. 2). When the magnet 52 is energized, the armature 54 engages in a slide 58 , which finally a switch to a ratchet wheel 44 , 46 acts on the other be.

In Fig. 3 is shown in a schematic side view of the structure of the feed device 27 for the line feed of the paper web on which the journal is printed. The paper web (not shown) is guided along a guideway 62 past a pressure abutment 60 which faces the print head 15 . The movement of the print head 15 in the row direction is gen via a gear 64 on the control disc 24 übertra. The transmission 64 includes gears 70, 72 and 74. The gear 72 is driven by a drive shaft 73 connected to the motor (not shown). The rotational movement of the gear 72 is transmitted to the gear 74 and the gear 70 which engages in the ring gear of the control disk 24 . The gear 70 drives fer ner the toothed belt 17 , which is guided over a pulley 66 .

The gear 74 carries an angle coding disk 78 , the coding of which is read by a sensor 80 . The angle encoder disk 78 and the sensor 80 form a rotary encoder 76 , which generates digital signals. The Co dation is carried out so that when the print head 15 is shifted in the line direction by a dot spacing (dot), a pulse is generated by the sensor 80 . The control of the printhead along the distance L takes place depending on pulses which the angle encoder 76 emits.

The pawl switching mechanism 39 has a pawl lever 82 which can be pivoted about a rotary shaft 84 fastened to the housing. The pawl lever 82 moves along a circular path 85, a transport pawl 86 which engages in the teeth of the clin kenrads 40 . This is rigidly connected to the trans roller 34 and moves it by an angle of rotation which corresponds to a standard line spacing of 4.233 mm. When the switching cam 26 passes on the pawl lever 82 , the transport pawl 86 performs a lifting movement. As a result, the ratchet wheel 40 is moved further by one tooth pitch, ie a line feed is carried out.

Fig. 4 shows a schematic representation of the path that the print head 15 travels during its line-wise back and forth movement. The print head 15 is shown with solid lines in its extreme right position and with dashed lines in its extreme left position. The distance between these two positions corresponds to the distance L. As it moves, the print head 15 passes over the length PS of the paper chute in which the paper web for the receipt with the paper width P1 and the paper web for journal printing with the paper width P2 are arranged. Only a part of these paper webs is printed with a line width D1.

The distance L traversable by the print head 15 is divided into different sections, which are identified by location points 11 to 18 in FIG. 4. These location points 11 to 18 correspond to angular positions a1 to a8 of the control disks 24 , 25 . The outermost right position of the print head 15 is set as the zero position. Starting from this zero position, the print head 15 moves 296 pressure point distances ( 296 dot) when moving in the direction of the arrow LL (counterclockwise rotation) until it reaches its extreme left position. Covering this distance L corresponds to a rotation of the control discs 24 , 25 by 318 °. The print head 15 prints in both line directions, ie during the counterclockwise rotation in the direction LL and during the clockwise rotation in the direction RL. Accordingly, a line feed must be provided at each line end. This line feed takes place in the section between the location points 11 , 12 or 13 , 14 . To perform the line feed in section 11 , 12 , the switching cam 26 is arranged on the control disk 24 in the area of the associated angular positions a1 to a2. This means that during clockwise rotation of the print head 15 in the direction RL at a distance of 20 dot from the zero position (21 ° on the control disk 24 ) the ratchet mechanism 30 begins to switch. The line feed is completed at a distance of 10 dot (11 ° on the control disk 24 ) from the zero position. When the print head 15 runs counterclockwise in the direction LL, the ratchet mechanism 42 is actuated by the control disk 25 in section 13 , 14 at a distance 269 dot (289 ° on the control disk 25 ) from the zero position. The line feed is completed at a distance of 279 dot (300 °).

The sketched in Fig. 4 further switching operations at the local points 15 to 18 relate to a Schneidein direction for cutting a receipt or the actuation of a pivoting lever for setting under different line feeds. These switching operations who explained the below in more detail.

In FIG. 5, the control disk is shown in a state 24 wherein the switch cam 26 has the latch lever 82 just pivots. The transport pawl 86 has moved the ratchet wheel 40 further by one tooth pitch, ie has carried out a standard line feed. The control disc 24 has an angular position of 11 ° bezüg Lich the zero position.

In Fig. 6, the feed device 29 is shown with the control disk 25 in the angular position 300 °. A switching cam 88 pivots a ratchet lever 90 about a pivot shaft 92 , so that a transport pawl 94 moves the ratchet wheel 44 by one tooth pitch and thus executes the line feed. In Fig. 6, the switching mechanism 50 is also shown, with which two different line feeds are adjustable. The clin kenhebel 90 is displaceable on the pivot shaft 92 in the direction of its longitudinal axis. An intermediate lever 98 which can be pivoted out of the plane of the drawing about an axis of rotation 96 engages in a pin 100 of the ratchet lever 90 and can move it on the pivot shaft 92 in such a way that the transport pawl 94 connected to it moves into another ratchet wheel 44 (not visible in FIG. 6). engages with tooth pitch deviating from the ratchet wheel 46 . The intermediate lever 98 has a flange 99 which can be brought into engagement with the lifting cam 102 of a slide 58 . The slide 58 is displaceable along an elongated hole 104 (see also FIG. 2). It has at its end opposite the lifting cam 102 a pin 106 which protrudes through an elongated hole 108 in the control disc 25 on the other side. When the magnet 52 is actuated, the pin 106 is brought into engagement via the armature 54 with a switching shoe 110 which displaces the slide along the elongated hole 104 .

In Figs. 7 and 8, the operation of the switching mechanism 50 is shown. At an angular position of the control disc 25 of 230 ° the solenoid 52 is Untitled betae, so that the switching shoe 110 in the direction of erscheibe STEU pivots 25 (see also Fig. 2). As can be seen in FIGS . 7 and 8, the pin 106 is deflected out of its path 111 as it passes by (change in the angular position from 230 ° to 300 °) on the switching shoe 110 , as a result of which the slide 58 moves in the direction of the intermediate lever 98 to move so that the lifting cam 102 comes into engagement with the flange 99 . The intermediate lever 98 is pivoted out of the plane of the drawing and thereby moves the ratchet lever 90 on the pivot shaft 92 . The transport pawl 94 is brought into engagement with the ratchet wheel 46 with a number of teeth z = 12. When the switching cam 88 passes, the ratchet lever 90 now actuates the ratchet wheel 46 via the transport pawl 94 and sets a reduced line spacing of 3.1747 mm, which is required for the graphics operation of the printer 10 . It should be noted that the magnet 52 only has to be excited during the angular phase of 230 ° to 300 ° in order to switch over from the ratchet wheel 44 to the ratchet wheel 46 . In the further angular phases, the magnet 52 does not have to be supplied with current. The slide 58 and the intermediate lever 98 are biased by Fe (not shown) so that they move back outside the angular range of 230 ° to 300 ° in the starting position shown in Fig. 6.

In Fig. 9, a perspective view of the control disc 25 is shown, which controls a cutting device 110 . The cutting device 110 is used to cut or cut the paper strip for receipts and has a knife 112 which is moved to cut the paper strip against a stationary counter knife 114 be. The knife 112 has two guide elements 118 , which are mounted on the pin 120 of a swivel bracket 121 . The swivel bracket 121 is rigidly connected to a swivel shaft 123 which is rotatably mounted in the Druckerge housing. The pivot shaft 123 is connected to a U-shaped bracket 125 which holds an engagement lever 122 which can be pivoted about the axis A. This has at its outer end a control pin 124 which is pressed elastically against the control disk 25 under spring pressure.

The control disc 25 has a circumferential control groove 126 ver, the radial distance from the center point of the control disc 25 increases over the angle of rotation. The engagement of the control pin 124 in the control groove 126 is prevented by a locking device 128 which covers the control groove 126 with a bolt 132 guided in an elongated hole 130 . A Druckfe the 134 biases the latch 132 in the direction of the pivot shaft 123 .

When the print head 15 runs counterclockwise in the direction LL, a control cam 136 firmly connected to the control disk 25 at position point 15 corresponding to an angular position a5 (distance 288 dot corresponding to 310 ° from the zero position in FIG. 4) pushes the latch 132 to the right and gives the control pin 124 free so that it can engage in the control groove 126 . When following the clockwise rotation of the print head 15 in the direction RL, the control pin 124 is guided in the control groove 126 , the engagement lever 122 executing a stroke along a control path 138 . About the swivel bracket 121 , the knife is moved from the open position to a closed position, whereby it cuts through the paper strip (not shown).

The control groove 126 ends in a curve outlet 140 , which guides the control pin 124 out of the guidance of the control groove 126 . The knife 112 is connected via a tension spring 142 to the swivel bracket 121 . The tension spring 142 biases the knife so that it is retracted into its open position. As a result of the force of the tension spring 142 , the swivel bracket 122 pivots back together with the engagement lever 121 into its starting position, which speaks to the open position of the cutting device 110 .

The curve outlet 140 is arranged in an angular position of 130 ° with respect to the zero position of the control disk (121 dot corresponding to location point 17 and Win angle a7 in Fig. 4). At this angular position, the stroke of the knife 112 is sufficient to cut through the paper strip completely. If the paper strip is only to be cut, the stroke of the control pin 124 must be reduced. For this purpose, a switching device 144 is provided which is operated by hand. To the switching device 144 has a GE in an elongated hole 146 actuating element 148 which has a wedge-shaped flange 150 . If the actuating element 148 is displaced in the direction of arrow B, the flange 150 engages in the movement of the engagement lever 122 in the radial direction in an obliquely extending recess 152 formed thereon and guides the control pin 124 out of the control groove 126 (181 dot corresponding to location point 16 and angle a6 in FIG. 4) before it reaches the curve exit 140 . By the force of the Zugfe 142 , the cutting device 110 is moved back to the open position in a state in which the paper strip is only partially severed.

Claims (18)

1. Printer for line-by-line printing of at least one print carrier, with a print head which can be moved back and forth along a predetermined distance in the line direction by the rotation of a reversible motor and thereby prints the print carrier, and with a feed device for feeding the print carrier by one predetermined line spacing, characterized in that the motor is coupled via a gear ( 64 ) to the feed device which carries out a line feed when the print head ( 15 ) has at least one predetermined section ( 11 , 12 ; 13 , 14 ) of the line (L ) runs over. 2. Printer according to claim 1, characterized in that the section ( 11 , 12 ; 13 , 14 ) is outside the printing area of the printing medium, preferably at the beginning and / or at the end of the path (L). 3. Printer according to claim 1 or 2, characterized in that the feed device ( 27 , 29 ) contains a control disc ( 24 , 25 ), which depends on the rotation of the motor and thus depends on the distance traveled by the print head ( 15th ) rotates, and that the control disc ( 24 , 25 ) when He reach the section ( 11 , 12 ; 13 , 14 ) a Klin kenschaltwerk ( 30 , 42 ) actuated, the trans port roller ( 34 , 36 ) for the print medium by one predetermined rotation angle rotates. 4. Printer according to claim 3, characterized in that the control disc ( 24 , 25 ) has at least one switching cam ( 26 , 88 ) which actuates a pawl lever ( 82 , 90 ) which can be pivoted about a pivot axis and which is operated via a transport pawl ( 86 , 94 ) a ratchet wheel ( 40 , 44 , 46 ) is further transported around a tooth division. 5. The device according to claim 4, characterized in that the switching cam ( 26 , 88 ) in predetermined th angular positions with the control disc ( 24 , 25 ) can be detachably connected. 6. Printer according to claim 4 or 5, characterized in that at least two ratchet wheels ( 44 , 46 ) are provided which, when actuated, the trans roller ( 36 ) rotate by different angles of rotation ver, and that the ratchet lever ( 90 ) by a switching mechanism ( 50 ) optionally with one of the ratchet wheels ( 44 , 46 ) can be brought into engagement. 7. Printer according to claim 6, characterized in that the ratchet wheels ( 44 , 46 ) are arranged side by side on a shaft connected to the transport roller ( 36 ), that the ratchet lever ( 90 ) opposite the ratchet wheels ( 44 , 46 ) on a pivot shaft ( 92 ) is arranged displaceably in the direction of its longitudinal axis, and that the switching mechanism ( 50 ) moves the pawl lever ( 90 ) into a position in which it engages in one of the ratchet wheels ( 44 , 46 ) when actuated. 8. Printer according to claim 6 or 7, characterized in that the switching mechanism ( 50 ) by a Ma gneten ( 52 ) can be actuated. 9. Printer according to claim 8, characterized in that the magnet ( 52 ) actuates a on the control disc ( 25 ) in a predetermined angular position arranged th slide ( 58 ) which moves the pawl lever ( 90 ) via a pivotably mounted intermediate lever ( 98 ) . 10. Printer according to one of the preceding claims, characterized in that the motor is a DC motor, the rotational movement of a rotary encoder ( 76 ) is detected, the digital signals generated, and that a control head ( 15 ) along the route (L) depending on the signals of the rotary encoder ( 74 ) controls. 11. Printer according to one of the preceding claims, characterized in that in the case of a plurality of mutually separately arranged print carriers which are printed line by line by the print head ( 15 ), each print carrier has a feed device ( 27 , 29 ) which cuts off when it passes over an associated therewith performs a line feed. 12. Printer according to one of the preceding claims, characterized in that the feed device ( 29 ) contains an actuating device which, when driving over at least a further section of the line (L) through the print head ( 15 ), has a cutting device ( 110 ) for cutting off the print carrier operated. 13. Printer according to claim 12, characterized in that the adjusting device has a control pin ( 124 ) which engages with a control groove ( 126 ) of the control disc ( 25 ) when it is rotated by a predetermined angle of rotation. 14. Printer according to claim 13, characterized in that the engagement of the control pin ( 124 ) in the control groove ( 126 ) is locked by a locking device that a control cam ( 136 ) is provided on the control disc, which upon rotation of the control disc ( 25 ) engages in the locking device by the predetermined angle of rotation and unlocks the control pin ( 124 ). 15. Printer according to claim 13 or 14, characterized in that the control groove ( 126 ) extends in the circumferential direction and its radial distance from the center of the control disc increases with increasing angle of rotation, and that the control pin ( 124 ) with a about a pivot axis ( 123 ) is connected to a rotatable swivel bracket ( 121 ) which actuates a knife ( 112 ) of the cutting device ( 110 ). 16. Printer according to claim 15, characterized in that the control groove ( 126 ) in a predetermined angle of rotation of the control disc ( 25 ) has a curve outlet ( 140 ) which disengages the control pin ( 124 ) from the control groove ( 126 ), and that the swivel bracket ( 121 ) is pretensioned by a spring ( 142 ) which moves the knife ( 112 ) into a ru position. 17. Printer according to one of claims 13 to 16, characterized in that a switching device ( 144 ) is provided which the control pin ( 124 ) when reaching a predetermined radial distance from the center of the control disc ( 25 ) from the control groove ( 126 ) solves. 18. Printer according to one of claims 15 to 17, characterized in that the knife ( 112 ) depending on the radial distance of the control pin from the center point of the control disc ( 25 ) completely or partially cuts through the printing medium.