JP2598630B2 - How to drive a printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method of driving a printer for driving a paper feed mechanism and the like in a printer, and more particularly to a method of releasing stress on a synthetic resin gear group. The present invention relates to a printer driving method suitable for the above. [0002] Conventionally known printers include:
For example, there is a thermal printer as shown in FIG. In FIG. 1, reference numeral 1 denotes a frame forming a main body, 2 denotes a platen on which a recording paper is wound, and 3 denotes a platen rubber mounted at a printing position on the front surface of the platen 2. Reference numeral 4 denotes a thermal head disposed so as to face the platen 2; 5, a tape cassette; and 6, a cassette holder for holding the tape cassette 5 and constituting a cassette shift mechanism described later. Note that the entire cassette shift mechanism is supported by a carriage 7 described below, which is located below the tape cassette 5. Reference numeral 7a denotes a rotatable shaft that extends along the platen 2 and penetrates a carriage 7 described later. Although not shown, a cam and a worm wheel are provided integrally with the shaft 7a at the left end of the shaft 7a, and a worm (not shown) engaged with the worm wheel is rotated by a pulse motor 8 so that the shaft is rotated. 7a rotates. Reference numeral 9 denotes a lever having one end engaged with a cam provided integrally with the shaft 7a. The lever 9 is rotatable about a support shaft 10, and the other end is movable in the left-right direction in the figure. With the body of the slider 11. The slider 11 is provided so as to be rotatable integrally with the output shaft of the pulse motor 12, and gears are formed on both sides. The gears on both sides of the slider 11 can be selectively engaged with drive gears 13 and 14 that are loosely fitted to the output shaft of the pulse motor 12. A driven gear 15 is engaged with the driving gear 13 and rotates integrally with the driving gear 13. The driven gear 15 has a bevel gear 16 on its side. Reference numeral 17 denotes a bevel gear which engages with the bevel gear 16 and is provided integrally with a pulley 19 having a projection 18 on the circumferential side. Reference numeral 20 denotes a metal belt whose both ends are connected to the carriage 7 described later, and has a square hole 21 that engages with the projection 18 of the pulley 19. A pulley 22 is disposed on the opposite side of the pulley 19 and around which the metal belt 20 is wound. The above-described metal belt 20, pulley 19,
22, driven gear 1 having bevel gear 17 and bevel gear 16
The carriage 5 and the slider 11 are provided with a carriage transfer mechanism 33 for moving the carriage 7 holding the thermal head 4, the tape cassette 5 and the like along the platen 2, that is, in the left-right direction in the drawing via the drive gear 13 connected to the pulse motor 12. Make up. Reference numeral 23 denotes a driven gear which is engaged with the driving gear 14 and has a small-diameter gear 24 on a side portion thereof.
It is freely rotatably fitted to. 26 is a gear that engages with the gear 24, and has a small-diameter gear 27 on the side. Reference numeral 28 denotes a gear engaged with the gear 27, which is integrally and rotatably mounted on the paper feed shaft 25. Reference numeral 29 denotes a sprocket provided integrally with the paper feed shaft 25, and has, for example, a projection 30 fitted into holes formed at both edges of the recording paper 31. The above-described sprocket 29 and paper feed shaft 2
5, a gear 26 having a gear 27, a driven gear 23 having a gear 24, and the slider 11
The recording paper 31 indicated by a two-dot chain line wound around
The paper feed mechanism 34 feeds in a direction orthogonal to the feed direction of the pulse motor 12, that is, in the direction of arrow 32 via the drive gear 14 connected to the pulse motor 12. Although not shown, the thermal head 4 is pressed or released from the platen 2 via a cam or the like (not shown) as the shaft 7a rotates. Next, a carriage transfer operation and a paper feed operation of the thermal printer will be described. [Carriage transfer operation] With the rotation of the pulse motor 8 shown in FIG. 3, the lever 9 rotates counterclockwise about the support shaft 10 via a worm, worm wheel, and cam (not shown). I do. Therefore, the slider 11 engaged with the lever 9 moves to the left in the figure, and the gear formed on the left side of the slider 11 engages with the drive gear 13. When the pulse motor 12 rotates, the slider 11 rotates, and the driven gear 15 and the bevel gear 16 rotate with the rotation of the drive gear 13, and the bevel gear 17 and the pulley with the rotation of the bevel gear 16. 19 rotates. When the pulley 19 rotates, the metal belt 20 moves,
Thereby, the carriage 7 on which the tape cassette 5, the thermal head 4, the cassette shift mechanism and the like are mounted moves in the left-right direction of FIG. [Paper feed operation] The pulse motor 8 shown in FIG.
Rotates, the lever 9 rotates clockwise from the state shown in the figure around the support shaft 10 via a worm, worm wheel, and cam (not shown), that is, the state in the above-described carriage driving operation. Therefore, the slider 11 engaged with the lever 9 moves rightward in the figure, and the gear formed on the right side of the slider 11 is the driving gear 1.
4 is engaged. When the pulse motor 12 rotates, the slider 11 rotates, and with the rotation of the slider 11, the gears 14, 23, 24, 26, 27, 28 rotate, and the paper feed shaft 25 rotates. The sprocket 29 rotates with the rotation of the paper feed shaft 25, and thereby the recording paper 31 wound around the platen 2 is fed by a predetermined amount, for example, in the direction of arrow 32 perpendicular to the moving direction of the carriage 7 for one line. . Although not mentioned here, the pulse motor 8 is also used for rotating the shaft 7a to shift the tape cassette 5. In this conventional printer, the carriage 7 is moved and the paper feed mechanism is driven by using the pulse motor 12 as described above. A pulse motor is also called a stepping motor. When a pulse is sent once to a pulse motor driving device, the motor rotates by a certain angle (step angle). This motor is used for digital control. Suitable and suitable as an incremental drive motor. Since the motor rotates in synchronization with an external input signal, it can be used as a variable speed synchronous motor. [0018] The generated torque is large with respect to the inertia moment of the rotor, and the start-up capability is far superior to that of a normal synchronous motor. Also, the reaction torque against an external force that attempts to maintain a fixed position is large. Unlike a brush of a DC motor, there is no need to worry about mechanical wear and no maintenance is required. There are advantages such as
In particular, applications to printers, XY plotters, and the like have been actively performed in recent years. Although the prior art described above also employs a pulse motor for such a reason, there is one problem with the use of this pulse motor. As shown in FIG. 4, the conventional method of driving a pulse motor always rotates in one direction by a predetermined number of pulses to perform, for example, paper feeding, and This is caused by repeating a cycle in which printing is performed in the stopped state, and then a predetermined pulse is again rotated in the same direction and stopped. That is, in this driving method, as shown in FIG. 5, the driving gears 13 and 14 connected to the pulse motor and the driven gear 1 connected to the carriage transfer mechanism 34 and the paper feed mechanism 33 are used.
5 and 23 are always in pressure contact with each other.
Since the characteristic of the pulse motor is that the reaction torque against the external force is large as described above, the driving gears 13 and 14 and the driven gears 15 and 2 become considerably large.
The third meshing tooth is stressed, and this state of stress is maintained while the teeth are stopped. Normally, since the drive gears 13 and 14 and the driven gears 15 and 23 are formed of a synthetic resin material, if a stress state is maintained, stress cracking and stress deformation are likely to occur. The deformation results in malfunction. Therefore, rotation and stop are repeated only in the same direction to transfer the carriage 7 and the paper feed mechanism 3.
In the conventional driving method of the pulse motor for performing the driving of No. 3,
Short-term maintenance was required, always with the danger of malfunction. Further, conventionally, a proposal as described in JP-A-54-49026 has been made. The invention described therein is a printer that repeats operations in both directions of feeding and returning a sheet using a pulse motor,
The purpose is to correct the backlash of each gear so that the amount of paper feeding and returning is constant. A specific method of controlling the number of paper feed pulses is as follows: five paper feed pulses are sent from the meshing state of the "feed" of the gear (one of them is used for correcting backlash). Then, the pulse motor is "returned" by adding one paper feed pulse for the backlash correction, and four paper feed pulses are issued from the meshing state of the "return" to the meshing state of the corrected "feed" and the "return" The backlash of “feed from” is corrected in advance and waits. However, in the present invention, the steps are "feed" → "return" → "feed" → "standby (stop)".
Finally, after driving the gear with a predetermined number of pulses (four in the specific example), the gear stops and the stress (load) on the gear is
Remains, causing stress cracking and stress deformation of the gear as in the above-mentioned prior art. The present invention has been made in view of such circumstances in the prior art, and an object of the present invention is to provide a method of driving a printer which eliminates malfunctions of the printer and does not require maintenance related to a driving mechanism. It is in. In order to achieve this object, the present invention provides a platen on which a recording paper comes in contact, a carriage movable along the platen, and a platen mounted on the carriage. A print head, which is disposed to face, a carriage transfer mechanism that transfers the carriage, a paper feed mechanism that sends a recording sheet between the print head and a platen, and a gear group formed of synthetic resin and meshed with each other. A pulse motor for performing a desired operation of the printer by rotating the pulse motor in the positive direction by a predetermined number of pulses to perform a desired operation such as a paper feed operation, a carriage transfer, a ribbon feed, and the like. After stopping the motor, the pulse motor is rotated in the forward direction again to perform the next desired operation.
It is intended for a driving method of a printer which repeats a cycle of stop and forward rotation. When the pulse motor is rotated in the forward direction, the pulse motor is fed at least one extra step beyond the forward feed step to the target position. Thereafter, when the pulse motor is stopped, the extra step is required. The pulse motor is configured to be stopped in the returned state, and the extra step for returning is the number of steps required to release the stress of the synthetic resin gear group accompanying the desired operation. It is characterized by the following. According to the present invention, by adopting the above-described structure, stress is released before stopping of the synthetic resin gear, stress cracking and stress deformation are prevented, and operation reliability is improved. An excellent printer driving method can be provided. A method for driving a pulse motor according to the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing a relationship between an input pulse and a driving step of a pulse motor showing a driving method of the present invention. The pulse motor used in the present invention is shown in FIG.
Pulse motor 1 used in the conventional printer shown in FIG.
2, since only the driving method is different, the description of the other parts of the printer is omitted. A pulse motor 1 used in this printer
2 is set to stop at the 4-pulse input positions A, C, E, and G, for example, the conventional driving method is as follows.
As shown in FIG. 4, when there are four pulse inputs, the pulse motor 12 advances four steps in the same direction from the stop position A to the stop position C, and when there are four more pulse inputs, the stop position C
From the stop position E to the stop position G when four more pulses are input. By the way, in the method of the present invention, five pulses are input from the stop position A, the vehicle moves forward in five steps to the position D, and further one pulse is input in the backward direction, and then moves backward one step and stops at the position C. After printing or the like at the stop position C, the robot further advances to the F position after receiving an additional 5 pulses, further inputs one pulse in the backward direction, retracts one step, and stops at the E position. The pulse motor 12 is driven in such a cycle that five pulses are inputted from the position E, the pulse motor 12 moves forward to the position H, receives a backward signal of one pulse, returns to the stop position G and stops. When driven in this manner, a total of 6 pulses must be input to drive from the stop position A to the stop position C. However, since the last one pulse works to reverse the pulse motor 12, FIG. As shown in FIG. 2, the drive gear 13 (14) on the pulse motor 12 side and the driven gear 15 (23) on the drive mechanism side do not mesh with each other during operation of the printing mechanism or the like, and do not come into pressure contact with each other. (14), 15
(23) The stop-time stress does not occur on the teeth. Therefore, the pulse motor 12 having the longest press-contact time between the driving gear 13 (14) and the driven gear 15 (23)
When the gear stops, the members do not come into pressure contact with each other and both gears 13 (14), 15
The fact that no stress is applied to the members forming the teeth of (23) results in effectively suppressing stress cracking, stress deformation, and the like occurring in these members. That is, since a stress is generated in the member only during the transfer of the carriage 7 and during the paper feed driving, the stress state does not continue for a long time, and the occurrence of the deformation and the like is extremely reduced. Although the present embodiment shows an example using a thermal printer, the method of the present invention is not limited to a non-impact printer such as an electrostatic printer, a discharge breakdown printer, and an energizing printer. It can also be applied to impact type printers such as wire dot printers and type selection printers. Further, in the type selection printer, the present invention can be applied not only to paper feed and carriage transfer but also to a type selection mechanism, a ribbon cassette shift mechanism, a ribbon feed mechanism, and the like. According to the present invention, as is apparent from the above description, the driving pulse motor used in the printer returns to a predetermined step when stopping at a predetermined position and stops. The generation of stress between gears can be effectively suppressed, and the occurrence of stress cracking and stress deformation between gears can be minimized. For the same reason as above, printer malfunction can be effectively prevented, and the same For this reason, there is an effect that the maintenance related to the driving mechanism is minimized and the maintenance cost is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing a relationship between an input pulse and a driving step in a pulse motor driving method according to a specific example of the present invention. FIG. 2 is an explanatory diagram showing a relationship between a driving gear and a driven gear when a specific example of the present invention is applied. FIG. 3 is a plan view showing an outline of the entire thermal printer. FIG. 4 is an explanatory diagram showing a relationship between an input pulse and a driving step in a conventional pulse motor driving method. FIG. 5 is an explanatory diagram showing a conventional relationship between a driving gear and a driven gear. [Description of Signs] 1 frame 2 platen 4 thermal head 7 carriage 8, 12 pulse motor 14 drive gear 23 driven gear 24, 26, 27, 28 gear 25 paper feed shaft 29 sprocket 31 recording paper 33 carriage transport mechanism 34 paper transport mechanism

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References JP-A-54-49026 (JP, A)                 JP-A-54-72416 (JP, A)                 JP-A-54-78211 (JP, A)

Claims (1)

(57) [Claims] (1) A platen with which a recording paper contacts, a carriage movable along the platen, a print head mounted on the carriage and arranged to face the platen. A carriage transport mechanism for transporting the carriage, a paper transport mechanism for transporting recording paper between the print head and a platen, and a pulse motor for performing a desired operation of the printer via a gear group formed of synthetic resin and meshed with each other. The desired operation is performed by rotating the pulse motor in the positive direction by a predetermined number of pulses, and after stopping the pulse motor, the pulse motor is rotated in the positive direction again to perform the next desired operation. In the method of driving a printer, which repeats a forward rotation-stop-forward rotation cycle, the pulse motor is rotated in a forward direction. When the pulse motor is stopped by at least one step more than the forward feed step to the target position, and then the pulse motor is stopped, the pulse motor is stopped in a state returned by the extra step, The method of driving a printer according to claim 1, wherein the extra steps for returning are the number of steps required to release the stress of the synthetic resin gear group accompanying the desired operation. (2) The method according to claim 1, wherein the desired operation is a paper feeding operation. (3) The method according to claim 1, wherein the desired operation is a carriage transfer operation. (4) The method according to claim 1, wherein the desired operation is a ribbon feeding operation.