JPS62119089A - Ribbon feed mechanism of thermal printer - Google Patents

Abstract

PURPOSE:To make it possible to certainly release a ribbon without excessively feeding a printing head or the ribbon even if the ribbon is adhered to paper, by certainly locking the rotation of at least one of a ribbon take-up cam shaft and a ribbon supply cam shaft by a lock mechanism cooperated with the operation of the printing head from a printing position to a non-printing position. CONSTITUTION:The inclined surface 11a of a printing head 8 is engaged with the engaging part 39 of a shaking lever 35 by the movement of the printing head 8 to a dotted line position and the shaking lever 35 is revolved to a clockwise direction on the basis of said engagement and a gear 38 is spaced apart from a gear 34. At the same time, the engaging part 42a of a lock arm 42 is engaged with a gear 41 to lock the rotation of the gear 41 and that of a supply cam shaft 23 while the engaging part 43a of a lock arm 43 is engaged with a gear 19 to be driven to lock the rotation of a take-up cam shaft 17. Even if a ribbon R is adhered to paper P when the head 8 is returned to the left direction, the rotation of both cam shafts 17, 23 is locked to prevent the delivery of the ribbon R from take-up and supply spools and, therefore, the ribbon R is certainly released from the paper P.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a ribbon feeding mechanism of a thermal printer, especially when printing involves returning a carriage and a print head provided on the carriage at a space, a backspace, or at the end of a line of printing. The present invention relates to a ribbon that can be reliably peeled off from the paper when moving the dot to print.

(Prior art) Conventionally, in thermal printers applied to typewriters, computers, word processors, etc., when the print head is moved to a space, bank space, or return at the end of a line, the thermal transfer ribbon that adheres to the paper does not peel off, and the ribbon There is a problem with ribbons being unwound one after another from the supply spool.

Therefore, as described above, in order to separate the ribbon from the paper after printing, we have developed a ribbon feeding mechanism that moves the print head an extra amount without printing and winds the thermal transfer ribbon onto the take-up spool, thereby separating the ribbon. is widely known.

(Problem to be Solved by the Invention) As described above, printing is performed to the end of a line using a ribbon feeding mechanism that moves the print head further to the outside of the edge of the printing line to separate the ribbon from the paper. When performing a post-line feed, extra space is required to move the print head to the outside of the line edge, which increases the external dimensions of the printer casing, and also increases the need for extra print head space without printing. Since the thermal transfer ribbon is also wound up at the same time when moving the ribbon to the printer, the ribbon is wasted, and in the process of printing multiple lines until the ribbon is exhausted, approximately 3 to 5% of the total length of the ribbon is wasted. be.

(Means for Solving the Problems) The ribbon feeding mechanism of the thermal printer according to the present invention is swingably provided in the carriage body, and the swinging position is switched according to the printing position and non-printing position of the print head. a swing lever, a ribbon winding camshaft, a ribbon supply camshaft, and a rotation mechanism that rotates the ribbon winding camshaft as the carriage body moves when the print head is in the printing position. In the ribbon feed mechanism of a thermal printer, it operates based on the movement of the swing lever that is linked to the movement of the print head from the printing position to the non-printing position, and the ribbon winding camshaft and ribbon supply camshaft are connected to each other. A locking mechanism is provided to lock at least one rotation.

(Function) Since the ribbon feeding mechanism of the thermal printer according to the present invention is configured as described above, when the print head is in the printing position, the ribbon winding camshaft is rotated by the rotation mechanism as the carriage body moves. However, when the print head is in the non-printing position, the ribbon winding pulley is not rotated. Since one rotation is locked, the ribbon will not be wound up.

When the print head is spaced, backspaced or returned via the carriage body at the end of each line of printing, the print head is in the non-printing position and the ribbon winding is performed via the locking mechanism as described above. Since the rotation of at least one of the camshaft and the ribbon supply camshaft is locked, even if the thermal transfer ribbon is stuck to the paper,
This will ensure that the ribbon separates from the paper.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 to 5, a frame (path shown) of the thermal printer is provided with a platen l extending in the longitudinal direction, and below the platen 1, a paper guide section 2 and a paper feed roller are disposed within the frame. 3 are arranged.

A carriage body 5 is movably supported by left and right shaft supports 6 on a support shaft 4 extending parallel to the platen 1 below the platen 1, and its lower surface is supported on a guide member (not shown). ing. A head carriage 7 is rotatably supported at the base end of the support shaft 4 between the two shaft supports 6 . The head carriage 7
A print head 8 facing the platen 1 is provided on the upper surface of the printer.

A projecting piece 11 is formed at the base end of the print head 8 and has an inclined surface 11a that slopes from above toward the rear and downward. The tension spring 12, together with the head carriage 7, urges the print head 8 to rotate in the counterclockwise direction in FIG.

A release lever 10 controlled by a control device of the thermal printer is disposed within the frame so as to face a protruding piece 9 protruding from the rear side of the head carriage 7 from below. The protruding piece 9 is always engaged by the spring force of the tension spring 12.

When the release lever 10 is placed at the solid line position in FIG. 2, the print head 8 together with the head carriage 7 is held at the printing position shown by the solid line in FIG. When the release lever 10 is placed in the chain line position in FIG. 2, the head carriage 7 and the print head 8 are placed in the non-printing position shown in the chain line in the same figure.

Drive pulleys 13 are provided on both left and right sides of the frame and are driven to rotate in both forward and reverse directions by a drive motor (path shown).
and an idle pulley 14 are provided, both pulleys 13.1
An endless toothed drive belt 15 is hung between the belts 4 and 4. A part of the drive belt 15 meshes with a toothed wall 16a protruding from the upper surface of the carriage body 5, and in this state, there is a gap between the toothed wall 16a and the plurality of clamping walls 16b and 16c. being held in place.

As shown in FIGS. 1, 3, and 5, a camshaft 17 for ribbon winding is rotatably protruded from the upper surface of the carriage body 5 in front of the drive belt 15. A connecting tube 18 is fixed to the upper end of the tube. A driven gear 19 is loosely fitted on the base end side of the camshaft 17.

A coil spring 22 is wound around the camshaft 17 between the connecting cylinder 8 and the driven gear 19, and a coil spring 22 is wound around the camshaft 17 below the driven gear 19.
A rotation transmission disk (shown in the figure) is fixed to the drive gear 19 by the spring force of the coil spring 22.
is pressed against the rotation transmission plate, so that both 17 and 19 can rotate together.

A one-way clutch spring 20 is wound around the base end of the camshaft 17 between the driven gear I9 and the upper surface of the carriage body 5, and its outer end is held between a pair of fixing pieces 21 on the carriage body 5. has been done.

The camshaft 17, connecting cylinder 18 and driven gear 19
can be rotated only in the ribbon winding direction, that is, in the direction of the arrow in FIG. 5, by the action of the one-way clutch spring 20.

To the right of the ribbon winding camshaft 17, a ribbon supplying camshaft 23 is rotatably protruded from the carriage body 5, and a connecting cylinder 24 is fixed to the upper end of the camshaft 23.

A spring 2 having a smaller spring force than the one-way clutch spring 20 is provided at the base end of the camshaft 23 between a pair of discs 23a that can rotate together with the camshaft 23.
5 is wound, and its outer end is held by a fixing piece 26 on the carriage body 5. When the camshaft 23 is rotated in the ribbon supply direction, that is, in the direction of the arrow in FIG. 5, rotational resistance is applied by the spring 25.

The ribbon cassette 27 is removably mounted on the carriage main body 5, and a ribbon spool 28 for winding is rotatably housed on the bottom wall 27a of the ribbon cassette 27, which is mounted on the connecting cylinder 18 of the camshaft 17 for winding the ribbon. At the same time, a supply ribbon spool 29 externally mounted on the ribbon supply camshaft 23 is rotatably housed.

A pair of left and right ribbon passing ports 27b that open on both sides of the print head 8 are formed at the rear edge of the ribbon cassette 27, and a ribbon is passed between the right passing port 27b and the supply ribbon spool 29. Bottom wall 2 of cassette 27
A substantially arcuate guide wall 30 is formed protrudingly on 7a. A leaf spring 31 for applying tension is fixed at its base end between the guide wall 30 and the rear inner wall of the ribbon cassette 27. The thermal transfer ribbon R wound around the supply ribbon spool 29 is connected to the guide wall 30 and the leaf spring 31.
The ribbon is inserted between the ribbons, is supplied to the front of the print head 8 through the ribbon passage port 27b on the right side, and is wound onto the take-up ribbon spool 28 through the ribbon passage hole 27b on the left side. There is.

A driving body 32 that can rotate around a shaft 32a is provided on the carriage body 5 between the camshafts 17 and 23, and a lower outer periphery of the driving body 32 is constantly engaged with the inner surface of the driving belt 15. A drive gear 33 is provided. When the head carriage 7 is moved to the right (positive direction) together with the carriage body 5 as the drive belt 15 rotates, the drive gear 33 is rotated clockwise in FIG. 1 based on the engagement with the drive belt 15. Ru.

On the other hand, along with the carriage body 5, the hesod carriage 7
When is moved to the left (reverse direction), the drive gear 33 is rotated counterclockwise in FIG.

A first intermediate gear 34 is connected to a shaft 32a on the upper part of the driving body 32.
is fixed to. The driving gear 33 and the driven gear 1
9, a swing lever 35 is rotatably supported on a shaft 36 protruding from the carriage body 5 at a substantially intermediate portion thereof.

A second intermediate gear 37 is rotatably provided on this shaft 36 and is located on the swing lever 35 and always meshes with the driven gear 19. Furthermore, a third intermediate gear 38 is rotatably supported on the swing lever 35 and is always in mesh with the second intermediate gear 37 and can be engaged with and disengaged from the first intermediate gear 34 as the swing lever 35 rotates. ing.

An engaging portion 39 that can be engaged with and disengaged from the inclined surface 11a of the protruding piece 11 on the print head 8 is integrally formed at the rear end of the swing lever 35. A tension spring 40 shown in FIG. 5 urges the release lever 35 to pivot about the shaft 36 in the counterclockwise direction in FIG.

Here, a locking mechanism that locks the rotation of the winding camshaft 17 and the supply camshaft 23 only when the head 8 is switched to the non-printing position is provided as follows.

As shown in FIGS. 1, 3, and 5, a locking gear 41 that overlaps the upper surface of the disc 23a is fixed to the base end of the supply camshaft 23, and the third intermediate gear 3
On the front right side of the rocking lever 35 that protrudes forward than the pivot lever 8, a tenth claw arm 42 is provided horizontally protruding diagonally to the right and rearward. A removable locking portion 42a is provided.

Furthermore, a short 20th hook arm 43 is provided at a portion of the swinging lever 35 that is connected to the driven gear 19 so as to protrude toward the driven gear 19 side. 19 is provided with a locking portion 43a that can be freely locked and removed.

As shown in FIG. 1, when the print head 8 is in the printing position, the swing lever 35 is positioned as shown by the solid line,
The locking portion 42a of the 10th pick arm 42 is separated from the gear 41, and the locking portion 43a of the 20th pick arm 43 remains separated from the driven gear 19, while the print head 8 is in the non-printing position. When the position is changed, the swing lever 35 is positioned as shown in the phantom line, and the first
The locking portion 42a of the 0th lock arm 42 engages with the gear 41, and the locking portion 43a of the 20th lock arm 43 engages with the driven gear 19.

Next, the operation of the thermal printer configured as above and its ribbon feeding mechanism will be explained.

Now, when mounting the ribbon cassette 27 on the carriage body 5, first the release lever 10 shown in FIG. 2 is placed at the chain line position in the same figure.

Thereby, based on the spring force of the tension spring 12, the print head 8 on the head carriage 7 is placed and held at the printing position shown by the chain line in the figure.

Based on the engagement with the inclined surface 11a of the print head 8, the swing lever 35 is switched to the position shown in phantom lines in FIG. 1 against the spring force of the tension spring 40, and the third intermediate gear 38 1
It is arranged at a position separated from the intermediate gear 34.

In this state, the ribbon cassette 27 is placed on the carriage main body 5, its winding ribbon spool 28 is mounted on the connecting cylinder 18 of the ribbon winding camshaft 17, and the feeding ribbon spool 29 is attached to the ribbon feeding camshaft 17. 2
The ribbon cassette 27 can be installed by placing a part of the thermal transfer ribbon R exposed outside the ribbon cassette 27 through the ribbon passage port 27b in front of the print head 8. can be terminated.

Next, when a predetermined character key is pressed, the release lever 10 shown in FIG. 2 is automatically moved upward to the solid line position in the figure based on the action of a control device (not shown).

Therefore, the print head 8 is rotated together with the head carriage 7 against the spring force of the tension spring 12 to the printing position shown by the solid line in FIG.
Based on this engagement, the print head 8 is positioned and held at the print position.

As the print head 80 rotates, the swing lever 35 can be rotated counterclockwise. Thereby, based on the biasing force of the tension spring 40, the swing lever 35 is rotated to the position shown by the solid line in FIG. 1 (the position shown in FIG. 3), and the third intermediate gear 38 on the swing lever 35 is rotated. is the first intermediate gear 3
4, the drive gear 33 engages with the first intermediate gear 34, the third
It is operatively connected to the driven gear 19 via an intermediate gear 38 and a second intermediate gear 37 .

As the print head 8 rotates, the spring 25 shown in FIG.
The thermal transfer ribbon R is slightly pulled out from the supply spool 29 against the biasing force of the leaf spring 31 shown in FIG.

In this state, characters are printed on the print paper P by operating the print head 8 by the control device. Subsequently, the drive pulley 13 is rotated by a predetermined amount clockwise in FIG. 1, and the carriage body 5, head carriage 7, and print head 8 are integrally moved to the right (forward direction) in FIG. , the drive gear 33 is rotated a predetermined amount clockwise in FIG. 1 based on the engagement with the drive belt 15.

As the drive gear 33 rotates, the first to third intermediate gears 3
4, 37, and 38, the driven gear 19 is rotated by a predetermined amount in the counterclockwise direction in FIG. The take-up spool 28 is rotated. Based on this, the printed thermal transfer ribbon R is wound onto the take-up ribbon spool 28 against the urging force of the leaf spring 31 and the spring 25, and the unprinted ribbon R is let out from the supply ribbon spool 29. Therefore, the next digit can be printed.

When the carriage return button is pressed after the printing operation for one line is completed, the carriage body 5 is moved to the printing start position on the left side of the frame, and then the control device moves the release lever 10 as shown in the chain line in FIG. automatically moved to the desired position.

Then, based on the spring force of the tension spring 12, the print head 8 together with the head carriage 7 is switched to the non-printing position shown in FIG.

At this time, slack occurs in the thermal transfer ribbon R, but this slack is absorbed by the leaf spring 31 being moved toward the guide wall 30 based on its own spring force and placed in the position shown in FIG. 4.

In this embodiment, since the biasing force of the one-way clutch spring 20 is set to be larger than that of the spring 25, the ribbon R once wound onto the take-up spool 28 is not unwound, and in such a case It is always paid out from the supply spool 29.

When the print head 8 moves to the chain line position, the swing lever 35 rotates clockwise in FIG. 3 based on the engagement between the inclined surface 11a of the print head 8 and the engaging portion 39 of the swing lever 35. Then, the third intermediate gear 38 separates from the first intermediate gear 34. Therefore, the operative connection between the driving gear 33 and the driven gear 19 is released. At the same time, the locking portion 42a of the tenth lock arm 42 engages with the gear 41 to lock the rotation of the gear 41 and the supply camshaft 23, and the locking portion 43a of the twentieth lock arm 43 engages with the driven gear 1.
9 to lock the rotation of the winding camshaft 17.

In this state, the drive pulley 13 is rotated counterclockwise in FIG. 1, thereby moving the carriage body 5 to the left in FIG. 1, that is, in the opposite direction.

At this time, based on the engagement with the drive belt 15, the drive gear 3
3 is rotated in the counterclockwise direction in FIG. Therefore, neither the take-up ribbon spool 28 nor the supply ribbon spool 29 rotate.

As mentioned above, when the print head 8 is returned to the left at the end of the printing line, even if the ribbon R sticks to the gill P, the rotation of both camshafts 17 and 23 is locked and the ribbon Since the ribbon R is not unwound from the take-up spool 28 or the supply spool 29, the ribbon R is reliably peeled off from the paper P.

Furthermore, in the space and backspace operations, the ribbon R is reliably separated from the paper P by a similar effect.

Although the locking mechanism of the above embodiment is configured to lock both the take-up camshaft 17 and the supply camshaft 23, it is also possible to lock at least one of the camshafts 17 and 23. may be configured. In other words, the 10th hook arm 42 and the 20th hook arm 4
3 may be omitted.

In other words, even if the ribbon R sticks to the girdle P when the print head 8 returns, if the rotation of one of the spools 28 and 29 is locked, the ribbon R will surely peel off after the print head 8 starts returning. Because it does.

In addition, as a modification of the locking mechanism, a rubber roller is provided in place of the gear 41, and this rubber roller is held down by the tip of the tenth lock arm 42 to lock the rotation of the supply camshaft 23 by frictional force. You may.

(Effects of the Invention) According to the ribbon feeding mechanism of the thermal printer according to the present invention, as explained above, the locking mechanism is activated based on the operation of the swinging lever that is linked to the operation of the print head from the printing position to the non-printing position. The rotation of at least one of the ribbon winding camshaft and ribbon supply camshaft is securely locked, so when returning the print head from a space, bank space, or end of a printing line, the ribbon Even if it sticks to the paper, it can be reliably peeled off without having to feed the print head or print ribbon extra.

Therefore, compared to the case where an extra print head or print ribbon is fed to separate the ribbon from the paper, the outer dimensions of the printer casing can be reduced and the entire length of the ribbon can be effectively utilized.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention. Fig. 1 is a plan view of the main part of the ribbon feeding mechanism of a thermal printer, Fig. 2 is a longitudinal cross-sectional side view of the main part of the thermal printer, and Fig. 3 is a cross-sectional view showing the printing state. A plan view, FIG. 4 is a cross-sectional plan view showing a non-printing state,
FIG. 5 is a partial perspective view of the ribbon feeding mechanism. 5. Carriage body, 8. Print head, 17.
- Ribbon winding camshaft, 23... Ribbon supply camshaft, 32a... Shaft, 33... Drive gear, 34... First intermediate gear, 35... Rocking lever, 36...
・Shaft, 37.. Second intermediate gear, 38.. Third intermediate gear, 39.. Engaging portion, 40.. Tension spring, 41..
Gear, 42...10th hook arm, 42a...locking part, 43...20th hook arm, 43...locking part. Patent applicant: Brother Industries, Ltd. Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] (1) A swinging lever that is swingably provided on the carriage body and whose swinging position is switched depending on the print position and non-printing position of the print head, a ribbon winding camshaft, and a ribbon supply camshaft. , in a ribbon feeding mechanism of a thermal printer equipped with a rotation mechanism that rotates a ribbon winding camshaft as the carriage body moves when the print head is in the print position, from the print position of the print head to the non-print position. A thermal printer is provided with a locking mechanism that locks rotation of at least one of a ribbon winding camshaft and a ribbon supply camshaft, which operates based on the movement of a swing lever that is linked to the movement of the ribbon winding camshaft. ribbon feeding mechanism.