JPH02248279A - Thermal printer - Google Patents

Abstract

PURPOSE:To enable a printing ribbon part which is sent in an unused state to be effectively utilized by a method wherein a rewinding means which rewinds a used part of the printing ribbon by a specific amount by rotating a supply spool in a reverse direction to a supply direction of the ribbon before, an approach run operation is established. CONSTITUTION:In order not to draw out excessively an unused part of a printing ribbon 14 from a supply spool 13a by a blank feed operation of the printing ribbon 14 which sends the printing ribbon 14 by a specific amount, a rewinding means which rewinds the printing ribbon 14 by a specific amount by rotating the supply spool 13a in a reverse direction to a ribbon supply direction before an blank feed operation of the printing ribbon 14, is established. Therefore, a used part of the printing ribbon 14 is rewound by a specific amount by rotating the supply spool 13a in the reverse direction to the ribbon supply direction by operating the rewinding means before an approach run operation, and an used part of the printing ink ribbon 14 is made incapable of drawing out excessively the unused part of the printing ribbon 14 from the supply spool 13a in approach run operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a thermal printer that performs printing while sequentially drawing out a printing ribbon from a supply spool using a thermal head that moves while pressing against printing lines on a platen. be.

[Prior Art] Regarding the above-mentioned thermal printer, conventionally, in order to eliminate slack in the printing ribbon at the start of printing and to stabilize the movement of the carriage motor, the thermal head is pressed against the platen before the printing start position. In order to perform a run-up operation that moves by a fixed amount, or to separate the used part of the printing ribbon held between the thermal head and the printing paper from the surface of the paper after printing, move the thermal head to the final printing position, that is, the - character. Printing quality has been improved by performing an overrun operation in which the dot row that is located furthest forward in the direction of movement of the thermal head among the plurality of dot rows forming the dot row is moved beyond the print end position.

[Problem 8 to be solved by the invention] However, in the thermal printer as described above, during run-up and overrun, a new portion of the printing ribbon is fed by a predetermined amount in an unused state, so the ribbon portion in between is wasted. As a result, the running cost of this type of thermal printer is high.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide a thermal printer that can effectively utilize the printing ribbon portion that is fed unused during run-up and overrun. It's about doing.

[Means for Solving the Problems] In order to achieve this object, the thermal printer of the present invention rotates the supply spool in a direction opposite to the ribbon supply direction before the run-up operation, and moves the used portion of the printing ribbon to a desired location. It is equipped with a rewinding means for rewinding a fixed amount.

[Function] The thermal printer of the present invention having the above configuration rotates the supply spool in the opposite direction to the ribbon supply direction by activating the rewinding means before the run-up operation, thereby removing the used portion of the printing ribbon. To prevent an unused portion of a printing ribbon from being excessively pulled out from a supply spool during quantitative rewinding and run-up operations.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

As shown in FIG. 1, a flat platen 2 is fixed laterally between a pair of frames (not shown) disposed on both sides of a thermal printer main body 1. As shown in FIG. This platen 2 supports a printing paper 5 inserted into a paper insertion path as a paper feed roller 4 rotates and is driven and connected to a paper feed motor 3. Further, a carriage guide 6 and a guide shaft 7, which are parallel to the platen 2, are respectively fixed to the frame. A carriage 8 is supported by the carriage guide 6 and the guide shaft 7 so as to be able to reciprocate along the longitudinal direction of the platen 2 .

A drive wire 11 connected to a carriage drive motor 9 via a drive pulley 10 is attached to the carriage 8, so that the carriage 8 is reciprocated as the carriage drive motor 9 rotates forward and backward. It is configured as follows. A ribbon cassette 12 is removably placed on the carriage 8. Inside this ribbon cassette 12 are a supply spool 13a and a take-up spool 1.
3b is rotatably supported, and an ink ribbon 14 is wound on both spools. This ink ribbon 1
4, the surface of a film-like support made of polyester or the like is coated with heat-melting ink.

Next, the internal structure of the carriage 8 will be explained using FIGS. 2 and 3. In addition, in FIG. 2, only the outer frame of the carriage 8 is broken at the lower part in order to make it easier to understand the internal structure of the carriage 8.

At the rear of the carriage 8, a support arm 15 is rotatably supported by a support shaft 16 at a position to the right of its middle portion, and a thermal head 17 is supported and fixed at the left end of the support arm 15. . As shown in FIG. 2, this thermal head 17 has a heating element group 17a at its left end.

The heating element group has a large number of heating elements arranged in a vertical line, and prints in dot format on the printing paper 5 by selectively causing the required heating elements to generate heat based on print data. A coil spring 18 is adjusted between the support arm 15 and the carriage 8.
As a result, the support arm 15 is biased clockwise in FIG. 2 around the support shaft 16. As a result, the thermal pad 17 at the left end of the support arm 15 is pressed against the platen 2 with a constant pressure. Further, in FIG. 2, a fixing plate 21 is disposed near the right end of the support arm 15, and a cam shaft 22 is fixed to the fixing plate 21 in parallel with the platen 2. An elliptical cam 24 integrally formed with an idle gear 23 is rotatably supported on the camshaft 22. Further, the idle gear 23 meshes with a pinion 26 fixed to a motor shaft 2 of a drive motor 25 fixed within the carriage 8. With the above configuration, the elliptical cam 24 rotates with the rotation of the drive motor 25 and engages with the right front surface of the support arm 15.
The thermal head 17 at the left end of the support arm 15 is moved away from the platen 2 against the action of the coil spring 18, as shown by the dashed line in FIG. , the thermal head 17 is moved between the printing position and the printing position where it is in contact with the platen 2 by the action of the coil spring 18. Further, on the left front side of the support arm 15, an actuation arm 27 is provided for separating a planetary gear 41, which will be described later, from a take-up spool gear 28a during non-printing.
A is formed to protrude forward. Its actuating arm 27a
The distal end of the planetary gear 41 has a sloped surface that engages with the support shaft of the planetary gear 41, and when engaged, the support shaft moves along that surface due to the cam action of both.

Further, a planetary gear 4 is provided on the central front surface of the support arm 15.
An actuating arm 27b is formed to protrude forward for separating 1 from the supply spool gear 29a during non-printing.

The distal end of the operating arm 27b has a sloped surface that engages with the support shaft of the planetary gear 41, and when engaged, the support shaft is configured to move along that surface due to the cam action of both.

Further, on the carriage s, a lower end of a take-up spool shaft 28 extending upward is rotatably supported, and a supply spool shaft 29 is rotatably supported on the right side thereof. and,
A take-up spool gear 28a is provided at the intermediate portion of both the spool shafts 28, 29, respectively.

A supply spool gear 29a is rotatably supported integrally with the shaft. Further, a shaft 31 is fixed on the carriage 8 in front of the spool shafts 28 and 29, and a shaft cover 32 made of resin and having a disc-shaped upper part is loosely fitted onto the shaft 31. has been done. As shown in FIG. 3, a driven gear 33 is supported at an intermediate portion of the shaft cover 32 so as to be slidable and rotatable together with the shaft cover 32. The driven gear 33 is the platen 2
It is constantly connected to a pinion 35 rotatably supported on the carriage 8 in a state of engagement with a rack 34 disposed parallel to the carriage 8 . Further, a slip gear 36 is slidable in the axial direction on the shaft cover 32 portion above the driven gear 33.
Moreover, it is rotatably supported. Furthermore, a pulley 37 is loosely fitted into the lower part of the shaft cover 32, and a compression coil spring 3B is interposed in the portion of the shaft cover 32 between the pulley 37 and the driven gear 33. Due to the spring force, the driven gear 33 and slip gear 36 are urged upward, and the spring receiver and pulley 37 are urged downward. As a result, the shaft cover 32, driven gear 33, slip gear 36, and spring receiver are connected to the pulley 3.
7 is constructed so that it can always rotate integrally. Further, felt 39 is attached to both sides of the slip gear 36, and the slip gear 36 is configured to slip between the shaft cover 32 and the driven gear 33 when a load exceeding a predetermined value is applied to the slip gear 36. .

Incidentally, the predetermined value described here means that the ribbon portion to be rewound or wound up is on both spools 13a.

The size is such that no plastic change occurs due to tension between 13b and 13b.

A movable arm 40 is rotatably supported at one end of the portion of the shaft 31 that protrudes from the upper part of the shaft cover 32. A planetary gear 41 is rotatably supported at the other terminal portion of the movable arm 40, and the planetary gear 41 is always meshed with the slip gear 36. Furthermore, as the carriage 8 moves in the forward or backward direction, the movable arm 40 rotates counterclockwise or clockwise in FIG. It is configured to be able to engage with the spool gear 29a.

Next, the operation of the thermal printer configured as above will be briefly explained.

Prior to the printing operation, the drive motor 25 rotates by a predetermined amount, rotates the elliptical cam 24 via the idle gear 23, and releases the engagement between the elliptical cam 24 and the support arm 15. As a result, the support arm 15 at the release position is moved by the restoring force of the coil spring 18 to the printing position shown by the solid line in FIG.

The carriage 8 moves in the print line direction as the carriage drive motor 9 rotates. Along with this movement of the carriage 8, when printing, required heating elements in the heating element group 17a at the left end of the thermal head 17 are energized based on print data.

At this time, the ink ribbon 14 is heated, and when the temperature reaches a predetermined printing temperature, the heat-melting ink coated on the ink ribbon 14 becomes molten and has increased adhesive strength, and is transferred onto the printing paper 5 to perform printing.

Also, the printing ribbon 1 is wound around the supply spool 13a in the ribbon cassette 12 by the movement of the thermal head 17.
4 are drawn out sequentially. Further, as the carriage 8 moves, the pinion 35 that engages with the rack 34 rotates clockwise in FIG. Rotate the arm 40 counterclockwise. Thereby, the planetary gear 41 meshes with the take-up spool gear 28a, and the rotational force acts to rotate the take-up spool 13b counterclockwise via the take-up spool shaft 28. By this rotation, the print ribbon 14 is sequentially wound onto the take-up spool 13b. After that, when a load of more than a predetermined value is applied to the take-up spool 13b due to the tension generated in the ribbon portion between the take-up spool 13b and the thermal head 17, the slip gear 3
6, the shaft cover 32, and the driven gear 33, and the amount of rotation of the a-star gear 41 decreases, thereby suppressing the rotation of the take-up spool 13b.

Next, when rewinding the ink ribbon 14, the carriage 8 is moved to the left while the thermal head 17 remains in pressure contact. As the carriage 8 moves leftward in FIG. 2, the pinion 35 that engages with the rack 34 rotates counterclockwise in FIG. 2, and this rotational force is applied to the slip gear 36 via the driven gear 33. communicated. slip gear 3
6. The planetary gear 41 and the movable arm 40 rotate integrally around the shaft 31 without relative movement, so that the planetary gear 41 meshes with the supply spool gear 29a. When the driven gear 33 is further rotated, the planetary gear 41 rotates the supply spool 29a clockwise via the supply spool shaft 29. As a result of this rotation, the print ribbon portions pulled out from the supply spool 13a by the thermal radar 17 during printing are sequentially rewound onto the supply spool 13a.

Next, the electrical configuration of the electronic typewriter constructed as described above will be explained based on FIG. 4.

The central processing unit (hereinafter referred to as CPU) 50 has a program memory 61 that stores control programs and a print pattern memory 62 that stores character patterns to be printed out.
A random φ access ◆memory (hereinafter referred to as RAM) 70 having various memories for temporarily storing the calculation results of the CPU 50 and the like is connected. Then, the CPU 50 performs a printing operation based on the control program stored in the program memory 61. Also, RAM7
0 is provided with a head flag 72 indicating that the thermal head 17 is at the printing position, as well as a print buffer 71 that sequentially stores data entered manually using the keys. A number of data corresponding to the number of characters to be printed are stored.

Further, the character/symbol keys of a keyboard 80 are connected to the CPU 50, and a thermal printer 90 having the mechanism shown in FIGS. 1 to 3 is connected to the CPU 50.
Printing is performed based on instructions from 50.

The CPU 50 sequentially stores character/symbol data inputted from the character/symbol keys of the keyboard 80 in a predetermined storage area of the print buffer 71 in correspondence with the print position, and also supports the read position using the buffer pointer and transfers the data to the print buffer 71. The data is sequentially read out and printing is performed while the head position of the thermal head 17 is advanced.

Next, the operation of the thermal printer configured as described above will be explained based on the flowchart shown in FIG.

First, in step Sl (hereinafter simply referred to as Sl; the same applies to other steps), the head flag 72 is turned off.
Perform initial settings such as setting. Next, in 82, it is determined whether or not the key was manually applied, and if it is determined that the key was manually applied, the process goes to S3; otherwise, the process goes to Sll. In S3, it is determined whether the key input is a character/symbol, and if it is a character/symbol, the process moves to S4; otherwise, the process moves to SIO to perform processing corresponding to the input. In S4, it is determined whether or not the rad 17 is in pressure contact with the thermal.

In other words, it is determined whether the head flag 72 is ON or OFF.
If N, skip to S8. Also, if it is OFF, S
The process moves to step 5, where the rad 17 is brought into pressure contact with the thermal, and the head flag 72 is turned on at step S6, and the process moves to step S7.

In S7, the thermal head 17 is moved leftward in FIG. 2 while the head is in pressure contact, thereby causing the supply spool 13a to rotate in the reverse direction and rewinding the print ribbon 14 as described above. At this time, the printing ribbon 14 is pressed against the printing paper 5 by the thermal head 17 in the same way as during the printing operation, so the printing ribbon 14 does not slip on the printing paper 5 and is wound by the amount that the rad 17 is transferred to the thermal. be returned.

Further, the amount of movement of the thermal head 17 is set equal to the sum of the amount of movement due to overrun and the amount of movement due to run-up operation performed before the start of printing.

When the leftward movement of the thermal head 17 is completed, the process moves to step 59. At this point, the unused portion of the printing ribbon 14 pulled out by the overrun and the used portion of the printing ribbon 14 corresponding to the amount to be pulled out by the run-up operation performed before the start of the next printing are rewound. It becomes. In S8, the thermal head 17 performs a run-up operation to the right, and from the time the head reaches the printing start position, S9
Then, the heating element group 17a is selectively heated to print characters, symbols, etc. In other words, the thermal head 17
Due to the movement of the supply spool 13 in the ribbon cassette 12
The printing ribbon 14 wound around a is sequentially pulled out, and the CPU
50, printing is performed by reading character/symbol data from the print buffer 71 and reading a dot pattern corresponding to the data from the print pattern memory 62. When printing is completed and it is determined in S2 that there is no key power, press S1.
Move to 1. In Sll, it is determined whether or not the thermal head 17 is in pressure contact, and if it is not in pressure contact, the process returns to S2, and if it is in pressure contact, the process moves to S12 and the thermal head 17 is pressed.
overrun. Then, after the overrun operation is completed, move to 513 and release Rad 17 to the thermal,
After turning off the head flag 73 in S14, the process moves to S15, the carriage is returned, and the process returns to S2. At this time, the thermal head 17 is positioned to the right of the next printing start position by the amount of shift during overrun and remains stationary.

Thereafter, input data such as characters and symbols are printed through the same steps as described above, so that the unused portion of the printing ribbon 14 is used without wastage.

The thermal printer of the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit thereof. For example, a dedicated motor may be provided as the rewinding means.

Furthermore, when using a self-collecting ribbon that performs both printing and collection with the same ribbon as the printing ribbon, it is also possible to apply a rewinding means during the collection operation.

[Effects of the Invention] As is clear from the detailed description above, according to the thermal printer of the present invention, the unused portion of the printing ribbon that was wasted during run-up and overrun is unwound by the operation of the rewinding means. Since the printing ribbon is returned, the printing ribbon can be used more effectively, and as a result, the running cost of the printer can be reduced.

Furthermore, it becomes possible to increase the amount of run-up and overrun, which had been limited due to running costs, and it is possible to obtain higher quality printing.

[Brief explanation of drawings]

1 to 5 show embodiments embodying the present invention. FIG. 1 is a perspective view of main parts showing the main body of the thermal printer, FIG. 2 is a partial sectional view showing the internal structure of the carriage, and FIG. 3 is a sectional view of the internal structure of the carriage, FIG. 4 is a block diagram showing the control system of the thermal printer, and FIG. 5 is a flow chart showing the operation of the thermal printer. In the figure, 2 is a platen, 5 is a printing paper, 8 is a carriage,
13a is a supply spool, 13b is a take-up spool, 14 is a printing ribbon, 17 is a thermal head, 26, 28a, 3
6, 37, 38, 39 are winding members, 29a, 40.41
is a rewinding means. Figure 4 @ Figure 2 @ Figure 3

Claims (1)

[Claims] 1. A carriage that is reciprocated along the printing line of a platen that supports printing paper; a printing position that is arranged on the carriage and is in pressure contact with the platen; and a release position that is spaced apart from the platen. a thermal head selectively movable to; a supply spool rotatably disposed on the carriage around which a print ribbon is wound to be supplied between the thermal head and the platen; and a supply spool rotatably disposed on the carriage. a take-up spool for winding the print ribbon; and a take-up for transmitting rotational force to the take-up spool in order to wind the print ribbon pulled out from the supply spool by a thermal head that moves while being in pressure contact with the platen. a member, and by moving the thermal head in the direction of the printing start position with the thermal head in pressure contact with the platen before the printing start position, the printing ribbon is fed by a predetermined amount. In order to prevent the unused portion of the printing ribbon from being pulled out excessively, the supply spool is rotated in the opposite direction to the ribbon feeding direction before the printing ribbon is fed, and the used portion of the printing ribbon is pulled out by a predetermined amount. A thermal printer characterized by being equipped with a rewinding means for rewinding.