JPH07402B2 - Printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a carriage movable along a platen,
A printing apparatus including a print head movably mounted on the carriage between a printing position and a non-printing position, and a ribbon cassette detachably mounted on the carriage and storing a ribbon capable of printing many times Is.

(Prior Art) In a conventional printing apparatus of this type, a ribbon that can be printed multiple times is always wound in only one direction, and a ribbon cassette is wound when the entire amount of the ribbon is wound on a winding spool. There is a method of reversing and re-loading, or a method of reversing the winding direction of the ribbon when the entire amount of the ribbon is wound on one spool.

(Problems to be Solved by the Invention) However, according to these conventional printing apparatuses, there is a problem that the reversing operation of the ribbon cassette becomes very troublesome in the former case, and the reversing mechanism in the latter case. Had the inconvenience of becoming complicated. Furthermore, in a thermal transfer type printing device that performs printing in a state where the thermal head is pressed against the printing paper via the thermal ribbon, if the feeding direction of the thermal ribbon and the moving direction of the printing head are different,
At the pressure contact portion of the thermal head, relative movement occurs between the thermal ribbon and the printing paper, which causes a problem that the printing paper becomes dirty.

Configuration of the Invention (Means for Solving Problems) The present invention has been made by paying attention to each of the problems described above, and a means for solving the problems is a carriage movable along a platen and a carriage mounted on the carriage. A print head that is placed and is movable between a printing position that is pressed against the platen and a non-printing position that is separated from the platen; And a drive gear that is provided on the carriage and is driven to rotate as the carriage moves, the drive gear, and the ribbon cassette. Is provided between the take-up spool and a first spoop shaft for rotating the take-up spool, and is configured to move with the movement of the carriage in the one direction. A first rotation transmission mechanism that transmits the rotation of the drive gear to the first spool shaft so that the spool shaft rotates in the winding direction of the ribbon, and the print head is driven to separate the print head from the platen. When located at the non-printing position, first release means for releasing rotation transmission from the drive gear to the first spool shaft by the first rotation transmission mechanism, and rotation of the drive gear and the supply spool of the ribbon cassette. The second spool shaft is provided between the second spool shaft and the second spool shaft, and the second spool shaft rotates in the ribbon rewinding direction with the return movement of the carriage in the opposite direction to the one direction. A first rotation transmission mechanism that transmits the rotation of the drive gear to the second spool shaft so that the rotation amount is smaller than the rotation amount when the rotation is transmitted from the drive gear to the first spool shaft by the first rotation transmission mechanism. 2 rotation transmission mechanism, so that the rewinding amount of the ribbon is less than the winding amount of the ribbon printed immediately before by a certain ratio.
After releasing the rotation transmission by the first rotation transmitting mechanism and connecting the rotation transmission by the second rotation transmitting mechanism, the rotation transmission from the drive gear to the second spool shaft by the second rotation transmitting mechanism is released. And a second releasing means.

(Operation) Therefore, in the printing apparatus of the present invention, when the print head is arranged at the print position where the print head is in pressure contact with the platen and the carriage moves in one direction, the rotation of the drive gear is made to be the first by the first rotation transmission mechanism. The take-up spool of the ribbon cassette is rotated in the ribbon take-up direction by being transmitted to the spool shaft. Further, when the print head is arranged at the non-printing position separated from the platen, the first release means releases the rotation transmission from the drive gear to the first spool shaft. And
In this state, when the carriage returns to the opposite direction to the one direction, the rotation of the drive gear is transmitted to the second spool shaft via the second rotation transmission mechanism, and the supply spool of the ribbon cassette winds the ribbon. It is rotated in the return direction. At the time of rewinding of the ribbon, the second releasing means is operated so that the rewinding amount of the ribbon becomes smaller than the take-up amount of the ribbon printed immediately before by a fixed ratio.

(Embodiment) An embodiment in which the present invention is embodied in a thermal printer will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, a platen 1 is fixed to a frame (not shown) of the thermal printer, and a paper guide portion 2 and a paper feed roller 3 are arranged below the platen 1. A carriage body 5 is movably supported by left and right shaft support portions 6 on a support shaft 4 extending below the platen 1 and in parallel with the support shaft 4, and a lower surface of a front end portion thereof is supported on a guide member (not shown). A head carriage 7 is rotatably supported on the support shaft 4 between the shaft support portions 6,
A thermal type print head 8 facing the platen 1 is placed on the upper surface thereof.

At the base end of the print head 8, there is formed a projecting piece 11 having an inclined surface 11a which inclines downward from above. Further, a spring 12 for urging the print head 8 in a direction separating from the platen 1 is stretched between the head carriage 7 and the carriage body 5. Further, an engaging protrusion 9 is formed on the head carriage 7 in a protruding manner, and a release lever 10 which is operated and controlled by a control device (not shown) of the thermal printer is arranged below the engaging protrusion 9. The engagement protrusion 9 is always engaged with the upper surface of the release lever 10. When the release lever 10 is arranged in the solid line position in FIG. 2, the print head 8 is arranged and held in the print position in which the print head 8 is pressed against the platen 1 together with the head carriage 7, and the release lever 10 is arranged in the chain line position in FIG. When the printing is performed, the spring force of the spring 12 causes the print head 8 to be arranged at a non-printing position which is separated from the platen 1 to the front.

A drive pulley 13 and an idle pulley 14 which are normally and reversely rotated by a drive motor (not shown) are disposed on the left and right sides of the frame, and an endless toothed drive belt 15 is mounted between the pulleys 13 and 14. Has been done. A part of the drive belt 15 includes a toothed wall 16a and holding walls 16b and 16c of the carriage body 5.
And the carriage main body 5, the head carriage 7, and the print head 8 are fixed to each other by a toothed drive belt 15.
It is reciprocated along the platen 1 as it goes around.

As shown in FIGS. 1 and 4, the toothed drive belt
A first spool shaft 18 is provided on the upper surface of the left side portion of the carriage body 5 in front of 15 so as to be able to rotate forward and backward, a connecting cylinder 19 is fixed to the upper end thereof, and a first driven gear is provided to the lower end portion thereof. 20 is mounted so as to be rotatable integrally with the first spool shaft 18. A second spool shaft 21 is rotatably mounted on the upper surface of the carriage body 5 at a right position away from the first spool shaft 18 by a predetermined distance, and a connecting cylinder 22 is fixed to the upper end of the second spool shaft 21. A second driven gear 23 is attached to the lower end of the second spool shaft 21 so as to rotate integrally therewith.

As shown in FIG. 3, a ribbon cassette 25 is removably mounted on the upper surface of the carriage body 5, and a take-up spool 26 is fitted inside the connecting cylinder 19 of the first spool shaft 18 inside. And a supply spool 27 fitted onto the connecting cylinder 22 of the second spool shaft 21 are rotatably housed. A thermal ribbon R capable of printing a large number of times is wound around both the winding and supplying spools 26 and 27, and a part of the thermal ribbon R passes through a pair of left and right ribbon passage openings 28 and 29 opened at the rear edge of the ribbon cassette 25. Is exposed to the print head 8 side. Reference numeral 30 shown in FIG. 3 is a leaf spring for applying tension.

On the other hand, as shown in FIGS. 1 and 4, on the carriage main body 5 between the first and second spool shafts 18 and 21, a drive gear that is constantly meshed with the inner surface of the drive belt 15 with gears. A shaft 33 is rotatably supported by the shaft 32. Then, as shown in FIG. 1, the toothed drive belt 15 has an arrow A
When the print head 8 is moved in the printing direction (the direction of arrow B) together with the carriage body 5 while being rotated in the direction, the drive gear 33 is rotated clockwise in the figure. As shown in FIG. 4, when the toothed drive belt 15 is rotated in the direction of arrow D and the carriage main body 5 is driven to return in the direction of arrow E, the drive gear 33 is rotated counterclockwise in the same figure. It has become so.

A lever 36 as a first releasing means extending along the upper surface of the carriage body 5 is rotated on a fixed shaft 35 projecting on the carriage body 5 between the drive gear 33 and the first spool shaft 18. An engaging portion 37 that engages with the inclined surface 11a of the print head 8 is formed at its rear end, and this lever 36 is attached to the front end in the clockwise direction in FIGS. A spring 38 for biasing is attached. Above the lever 36, the fixed shaft 35 is fitted with a fixed position gear 39 which always meshes with the first driven gear 20, and the first arm portion 40 behind the lever 36 is always meshed with the fixed position gear 39. And a displacement gear 41 facing the drive gear 33 from the rear side.
Is pivoted.

The fixed position gear 39, the displacement gear 41 and the first
The driven gear 20 of FIG. 1 constitutes the first rotation transmission mechanism of this embodiment, and when the print head 8 is located at the print position as shown in FIG. 1, the lever 36 moves clockwise by the action of the spring 38. Displacement gears arranged in a rotating position in
41 is meshed with the drive gear 33, and the rotation of the drive gear 33 is transmitted to the first spool shaft 18 via the displacement gear 41, the fixed position gear 39 and the first driven gear 20, and the first spool shaft
The winding spool of the ribbon cassette 25 is generated by rotating 18 in the winding direction of the ribbon R (counterclockwise direction in the figure).
The thermal ribbon R is wound on the 26. Further, as shown in FIG. 4, when the print head 8 is located in the non-printing position separated from the platen 1, the lever 36 is arranged in the counterclockwise rotation position against the action of the spring 38. By disengaging the meshing between the displacement gear 41 and the drive gear 33, the operative connection between the drive gear 33 and the first spool shaft 18 is released, and the winding spool 26 of the ribbon cassette 25 in the ribbon winding direction is released. The rotation is set to stop.

As shown in FIGS. 1 and 5, a large-diameter gear 44 and a small-diameter gear 45 having a smaller number of gears than the large-diameter gear 44 can be integrally rotated on a shaft 43 provided on the front end portion of the lever 36. When the lever 36 is in the position shown in FIG. 1, the large diameter gear 44 is spaced forward from the drive gear 33, and when the lever 36 is in the position shown in FIG.
44 is adapted to mesh with the drive gear 33. Also, the second protruding portion is formed to protrude laterally from the right edge of the front end portion of the lever 36.
An intermediate gear 47, which meshes with the large-diameter gear 44 and faces the second driven gear 23 on the second spool shaft 21, is axially attached to the tip of the arm portion 46, and the lever 36 is shown in FIG. The intermediate gear 47 meshes with the second driven gear 23 when it is in the position shown in FIG.
It is designed to be transmitted to 45.

As shown in FIGS. 1 and 4, a bifurcated rotary arm 48 that extends by sandwiching a large-diameter gear 44 and a small-diameter gear 45 is rotatably supported at the base end on the shaft 43 of the lever 36. A planetary gear 49, which is always meshed with the small-diameter gear 45 and faces the second driven gear 23 from the front, is axially mounted on the intermediate portion of the second driven gear 23, and the planetary gear 49 is attached to the tip end of the planetary gear 49. A spring 50 is urged in the direction to engage with. Further, the front side edge of the second arm portion 46 of the lever 36 is in contact with the lower rear side edge of the rotating arm 48 to regulate the rotational position of the rotating arm 48 relative to the lever 36 in the counterclockwise direction. The protrusion 51 is integrally formed.

The second driven gear 23, the planetary gear 49, the small diameter gear 45, and the large diameter gear 44 constitute the second rotation transmission mechanism of this embodiment. As shown in FIG. When rotated in the clockwise direction, the rotating arm 48 is rotated counterclockwise about the shaft 43 by the action of the spring 50 following the backward movement of the second arm portion 46, and the planetary gear 49 is moved to the second position. Of the driven gear 23. In this state, the rotation of the drive gear 33 is such that the large diameter gear 44, the small diameter gear 45, the planetary gear 49 and the second driven gear 23.
Is transmitted to the second spool shaft 21 through the second spool shaft 21, and the second spool shaft 21 rewinds the ribbon R (clockwise direction in the figure).
And the thermal ribbon R is rewound on the supply spool 27.

On the other hand, an annular groove 54 is provided on the upper surface of the small diameter gear 45,
A ring spring 53, which constitutes the second releasing means of this embodiment, is wound and supported by its inner groove surface by its own spring force, and a projection 52 protruding from the upper surface of the small diameter gear 45 at one end thereof.
Is bent. Then, as shown in FIG.
When the second driven gear 23 and the large diameter gear 44 are operatively connected to each other through the intermediate gear 47, the ring spring is integrated with the small diameter gear 45 based on a predetermined rotation speed of the second spool shaft 21 in the winding direction. The protrusion 52 of 53 is moved by a predetermined amount in the counterclockwise direction in the figure. Also, as shown in FIG.
When the driven gear 23 and the small diameter gear 45 of the above are operatively connected,
As the drive gear 33 rotates, the protrusion 52 of the ring spring 53 moves in the clockwise direction in the figure. Further, when the protrusion 52 moves in the clockwise direction, the number of teeth of the small diameter gear 45 is set to be smaller than that of the large diameter gear 44, so that the second spool shaft 21
Is both gears 44, 4 than the predetermined number of rotations in the winding direction.
When rotated in the rewinding direction by a small number of rotations corresponding to the gear ratio of 5, the protrusion 52 engages the rotating arm 48 and resists the action of the spring 50. Rotate to the position of the chain line. Therefore, at this time, the meshing between the planetary gear 49 and the second driven gear 23 is disengaged, and the operative connection between the drive gear 33 and the second spool shaft 21 is released. When the protrusion 52 and the rotating arm 48 are engaged with each other, the large diameter gear 44 is further moved to the fourth position.
When rotated in the clockwise direction in the figure, the spring force of the spring 50 becomes larger than the tightening force of the ring spring 53 with respect to the inner groove surface of the annular groove 54, and the ring spring 53 moves on the inner groove surface of the annular groove 54. The projection 52 is slipped and held at the line-of-sight position.

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

Now, when the ribbon cassette 25 is not mounted on the carriage body 5, the release lever 10 is arranged at the chain line position as shown in FIG. 2, and the print head 8 is held at the non-print position by the action of the spring 12. Has been done. And
Due to the engagement between the inclined surface 11a of the print head 8 and the lever 36, the lever 36 is arranged at the position shown in FIG. 4 against the action of the spring 38. Then, in this state, as shown in FIG. 3, the ribbon cassette 25 is placed on the carriage main body 5 and both the winding and supply spools 26, 27 are attached to the first and second spool shafts 18, 21. When a part of the thermal ribbon R exposed to the outside of the ribbon cassette 25 is arranged between the platen 1 and the print head 8 while being fitted to the respective connecting cylinders 19 and 22, of the ribbon cassette 25, the ribbon cassette 25 is placed on the carriage body 5. Can be installed.

Next, when a character key or the like on a keyboard (not shown) is operated, the release lever 10 is raised to the position shown by the solid line in FIG. Then, it is rotationally arranged at the printing position. Following the rotation of the print head 8, the lever 36 is rotated to the position shown in FIG.
Are meshed with the drive gear 33. At the same time, drive gear 33
From the large driven gear 23, the intermediate gear 47 is meshed with the second driven gear 23, and the planetary gear 49 is separated from the second driven gear 23.

In this state, the control unit operates the print head 8 to transfer characters or the like onto the print paper P via the normal ribbon R. Then, the toothed drive belt 15 is rotated in the direction of arrow A in FIG. 1 by a predetermined amount, the carriage body 5 and the print head 8 are integrally moved in the print direction B, and the drive gear 33 is set in the timepiece of FIG. Is rotated in a predetermined direction. Then, as the drive gear 33 rotates, the displacement gear 41 and the low position gear 3
9. The first spool shaft 18 is rotated by a predetermined amount in the ribbon winding direction via the first driven gear 20, and the printed thermal ribbon R is wound in the ribbon cassette 25.
The unprinted thermal ribbon R is unwound from the supply spool 27 as it is wound around 26. In this way, when the printing operation for one line is completed, the second spool shaft 21 is rotated by the number of rotations corresponding to the winding amount of the thermal ribbon R, and the rotation at that time is the second driven gear 23 and Intermediate gear
It is transmitted to the large diameter gear 44 via 47. Therefore, the protrusion 52 of the ring spring 53 moves in a direction away from the rotating arm 48 based on the rotation speed of the second spool shaft 21 and the gear ratio of the second driven gear 23 and the large diameter gear 44. To be done.

Then, when a carriage return button (not shown) on the keyboard is operated, the release lever 10 is moved downward and the print head 8 is pivotally arranged at the non-printing position. Then, as the print head 8 rotates, the lever 36 is arranged at the position shown in FIG. 4, and the drive gear 33 and the first spool shaft are
The operative connection with 18 is released. At the same time, the large gear 44 is meshed with the drive gear 33, the intermediate gear 47 is separated from the second driven gear 23, and the second driven gear 23 is separated from the second driven gear 23.
The planet gear 49 is meshed with. Then the toothed drive belt
15 is rotated in the direction of arrow D in FIG.
The print head 8 is returned to and moved in the direction of arrow E integrally therewith and stopped at the left print start position. Then, when the carriage body 5 is returned, the rotation of the drive gear 33 is changed to the large diameter gear.
44, the small-diameter gear 45, the planetary gear 49, and the second driven gear 23 are transmitted to the second spool shaft 21, and in the ribbon cassette 25 as the second spool shaft 21 rotates in the rewinding direction. The thermal ribbon R on the take-up spool 26 is rewound on the supply spool 27. Further, at this time, the protrusion 52 of the ring spring 53 is moved in a direction approaching the rotating arm 48 as the large diameter gear 44 rotates clockwise.

By the way, since the number of teeth of the small diameter gear 45 is set to be smaller than the number of teeth of the large diameter gear 44, and both gears 44, 45 are configured to rotate integrally, when the carriage body 5 returns,
The amount of rotation of the second spool shaft 21 by the small-diameter gear 45 until the protrusion 52, which has moved by a predetermined amount, returns to the clockwise direction in FIG. The rotation amount of the second spool shaft 21 is smaller than the rotation amount of the second spool shaft 21 rotated by rotating the large diameter gear 44 and moving the projection 52 on the small diameter gear 45 counterclockwise in the figure. The ratio corresponds to the tooth number ratio of the large diameter gear 44 and the small diameter gear 45. Therefore, when the large diameter gear 44 is further rotated clockwise in the contact state of the protrusion 52 and the rotating arm 48,
The pivot arm 48 is pivotally arranged against the action of the spring 50 to the position shown by the chain line in FIG. 4, and the engagement between the second driven gear 23 and the planet gear 49 is released. Therefore, the rewinding amount of the thermal ribbon R by the supply spool 27 at the time of the return movement of the carriage main body 5 becomes smaller than the rewinding amount of the thermal ribbon R by the take-up spool 26 at the time of immediately preceding printing by a certain ratio.
That is, the thermal ribbon R capable of printing a large number of times in the one-line printing process is wound around the take-up spool 26 at a constant rate, and as shown in FIG. It is possible to start from a position separated by a predetermined amount depending on the head printing position of the above, and by repeating these operations as the printing operation progresses, the printing of the allowable number of times of use is overlaid on almost the same position of the thermal ribbon R capable of printing many times. Can be done by For example, when using the thermal ribbon R capable of printing 10 times, if the tooth ratio of the large diameter gear 44 and the small diameter gear 45 is 10: 9, it is 9/10 of the ribbon winding amount in the one-line printing process. Is rewound.

Therefore, unlike the conventional thermal printer in which the entire length of the thermal ribbon is printed and then the ribbon cassette is removed from the carriage and is inverted and reloaded, there is no risk of inconvenience in handling the ribbon cassette 25.

Moreover, if the amount of movement of the thermal ribbon R associated with one printing operation matches the amount of movement of the carriage body 5, the platen 1
The relative movement between the upper printing paper P and the thermal ribbon R can be prevented, and the printing paper P is not contaminated by the thermal ribbon R during printing. As the printing operation progresses, the take-up spool 26 of the ribbon cassette 25
Even when the winding amount of the thermal ribbon R is changed by changing the outer shape of the thermal ribbon R, the rewinding amount of the thermal ribbon R by the supply spool 27 is always constant based on the tooth ratio of the large diameter gear 44 and the small diameter gear 45. Since the ratio is set to the ratio, the thermal ribbon R can be sent over the entire length without any trouble and can be used efficiently.

In the above embodiment, the large-diameter and small-diameter gears 44, 45 are composed of upper and lower two layers, but instead of this, the second driven gear 23 is composed of upper and lower two-layer gears having a constant number of teeth. Even if it is configured, it is possible to obtain the same effect as that of the above-described embodiment. Further, the present invention is not limited to the configuration of the thermal printer of the above-described embodiment, and is applied to other printing devices of a type in which a ribbon cassette accommodating an ink ribbon capable of printing many times is mounted and used. It is also possible to do so.

EFFECTS OF THE INVENTION As described in detail above, according to the present invention, the rewinding amount of the ribbon due to the return movement of the carriage is reduced by a certain ratio than the rewinding amount of the ribbon due to the movement of the carriage in the printing direction. Since it is configured as described above, it is possible to efficiently print on the ribbon that can be printed many times without inconvenience of reversing and loading the ribbon cassette, and to move the ribbon relatively to the printing paper. If the paper can be sent in a state where it is not present and the printing paper is not polluted, an excellent effect is obtained.

[Brief description of drawings]

FIG. 1 is a plan view of a main part of a thermal printer showing one embodiment of the present invention, and FIG. 2 is a side sectional view of the same part,
3 is a plan sectional view showing a state in which a ribbon cassette is mounted, FIG. 4 is a plan view of an essential part showing an operating state different from FIG. 1, and FIG. 5 is a second rotation transmission mechanism and a second release. FIG. 6 is a partial perspective view showing the structure of the means, and FIG. 6 is a front view of the ribbon for explaining the printing operation. In the figure, 1 is a platen, 5 and 7 are a carriage main body and a head carriage that form a carriage, 8 is a print head, 18 is a first spool shaft, 21 is a second spool shaft, and 25.
Is a ribbon cassette, 26 is a take-up spool, 27 is a supply spool, 33 is a drive gear, 36 is a lever as a first releasing means, and 20, 39, 41 are first driven members constituting a first rotation transmission mechanism. Gears, fixed position gears and displacement gears, 23,44,45,49 are second
Second driven gear, large diameter gear, which constitutes the rotation transmission mechanism of
A small-diameter gear and a planetary gear, 53 is a ring spring having a protrusion 52 as a second releasing means, and R is a thermal ribbon.

Claims (1)

[Claims] 1. A carriage (5, 7) movable along a platen (1), a printing position placed on the carriage (5, 7) and pressed against the platen (1), and a platen (1). ), A print head movable between a non-printing position and
And a ribbon cassette (25) which is detachably attached to the carriage (5, 7) and stores a ribbon (R) capable of printing many times, and is provided in one direction of the carriage (5, 7). In a printing device that prints only when the carriage moves, the carriage (5,7) is provided on the carriage (5,7).
Drive gear (33), which is rotationally driven by the movement of the tape, and a first spool shaft (18) for rotating the drive gear (33) and the take-up spool (26) of the ribbon cassette (25).
Is provided between the drive unit and the drive unit such that the first spool shaft (18) rotates in the winding direction of the ribbon (R) as the carriage (5, 7) moves in the one direction. The first for transmitting the rotation of the gear (33) to the first spool shaft (18)
Driven by the rotation transmission mechanism (20, 39, 41) and the print head (8), and when the print head (8) is located at the non-printing position separated from the platen (1), the first rotation transmission is performed. First releasing means (36) for releasing rotation transmission from the drive gear (33) to the first spool shaft (18) by the mechanism (20, 39, 41), the drive gear (33) and the ribbon cassette It is provided between the supply spool (27) of (25) and the second spool shaft (21) for rotating the supply spool (27), and when the carriage (5, 7) returns to the one direction and the opposite direction, The second spool shaft (21) rotates in the rewinding direction of the ribbon (R), and the amount of rotation from the drive gear (33) by the first rotation transmission mechanism (20, 39, 41) to the first spool. The rotation of the drive gear (33) is changed to a second speed so as to be smaller than the rotation amount when the rotation is transmitted to the shaft (18). Second transmitting in Lumpur shaft (21)
Of the rotation transmitting mechanism (23, 44, 45, 49), and the rewinding amount of the ribbon (R) is smaller than the winding amount of the ribbon (R) printed immediately before by a certain ratio. The rotation transmission by the first rotation transmission mechanism (20, 39, 41) is released, and the second rotation transmission mechanism (23, 44, 4) is released.
5, 49) after connecting the rotation transmission by the second rotation transmission mechanism (23, 44, 45, 49) to release the rotation transmission from the drive gear (33) to the second spool shaft (21). And a releasing means (52).