JPH0361068A - Recording medium cassette - Google Patents

Abstract

PURPOSE:To simplify a structure, to also facilitate assembling and to reduce manufacturing cost by providing the reversal preventing mechanism of a taking-up means to the engaging part of the taking-up means and a cassette main body. CONSTITUTION:A taking-up reel 7 is mounted to a bottom wall 2 so that the thin-wall cylindrical part 7b thereof is inserted in the piercing hole 25 of the bottom wall 22 through a ratchet 28 as shown by an imaginary line arrow and made rotatable only in one direction by the action of ratchets 27, 28. When a leaf spring 17 is ready to return to a solid line position from an imaginary line position, the taking-up reel 7 is pulled by an ink ribbon 1A to be ready to reverse but, when the ratchet 27 is only slightly meshed with the ratchet 28 integrally provided to the bottom wall 22, the reversal of the taking-up reel 7 is prevented. Therefore, the slackening of the ink ribbon in the periphery of a head HE is eliminated and, of course, it is prevented that the part of the ink ribbon once subjected to printing returns to the front surface of the head.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a recording medium, for example, a ribbon cassette used in thermal transfer recording.

A prior art thermal recording head (hereinafter simply referred to as a head) has a large number of heating elements (for example, two
4) has an arranged structure. In thermal transfer recording, the head is brought into contact with the recording paper through an ink ribbon as a recording medium, and the head is moved one line in the main scanning direction (printing direction) while selectively generating heat from the heating elements to print dots. Print in the form. When printing for one line is completed, the head is released from the ink ribbon and returned to its original position, and the recording paper is moved by one line in the sub-scanning direction to start printing the next line. Such a recording method is called a serial method.

What is a ribbon cassette that houses the head and ink ribbon?
It is mounted on a common carriage, and during printing, the ink ribbon is sent from the downstream side of the head movement to the upstream side so that the ink ribbon does not stop relative to the recording paper and rub against it. It has become. Such thermal transfer recording is widely used in printers used in personal computers, word processors, and the like.

FIG. 12 is an enlarged plan view of the ribbon cassette.

A cassette body is constituted by the bottom wall 22, a side wall 26 integrally formed with the bottom wall 22, and a top wall 29.

The upper wall 29 is transparent or translucent with a satin-finished surface so that the state of use of the ink ribbon 1A inside the cassette body can be observed from the outside, and also from the viewpoint of aesthetics. A reel 6.77 is housed in the cassette body, and the reel 6.
The take-up reel 77 is fitted onto the hollow shaft 23 standing up from the bottom wall 22, and the lower end of the take-up reel 77 is fitted into the through hole 25 of the bottom wall 22, so that the reel 6. located in position. The positional relationship between the take-up reel 77 and the cassette body is as shown in FIG. 13, which is an enlarged sectional view taken along the line xm-xm in FIG. 12. The take-up reel 77 has a thin cylindrical portion 77b on the lower end side that fits into the through hole 25 of the bottom wall 22, and an upper end portion of the take-up reel 77 that fits into the through hole 10 of the wall 29 and can rotate on the bottom wall 22. will be placed on.

A leader tape IB is connected to the tip of the ink ribbon 1A wound around the feed reel 6, and the leader tape 1B is guided by a guide bin 11 and a guide wall 12 to a pair of side wall ends on both sides of the four head insertion parts. (Exit of ink ribbon, repopulation) 4J is hung from one side of 26a and 26a to the other. This portion of the side wall has a U-shape, and in this portion, the head 1-IE shown in phantom is located in the space between the leader tape and the side wall portion 26b facing the leader tape.
is inserted, the ink ribbon 1A connected to the leader tape 1B moves to this position, and then printing is performed here. The leader tape 1 is attached to the take-up reel 77 via the other side wall end 26a, guided by the guide wall 13 and guide pin 14. A spindle of a carriage (not shown) is fitted into a through hole 77a of the take-up reel 77, and during printing, the take-up reel 77 rotates due to the rotation of the spindle, and the ink ribbon 1A connected to the leader tape 1B is moved above the leader tape 1B. It passes through the position and is wound onto a take-up reel 77.

Some resistance is applied to the leader tape 1B and ink ribbon 1A so that they do not loosen during running. That is, the side wall protrusions 2 are close to each other and face each other.
6C and pins 22a (provided at two locations) standing from the bottom wall 22, the rear end of the leaf spring 15.19 is locked,
The rear end of the leaf spring 17 is engaged with the hook-shaped portion 26d of the side wall. The felt 16 at the tip of the leaf spring 15 connects the ink ribbon IA to the guide pin 11, and the felt 18 at the tip of the leaf spring 17 connects the ink ribbon 1A to the guide wall 12.
The felts 20 at the tips of the ink ribbons 9 lightly press the ink ribbons 1A against the guide bins 14, respectively. The leaf spring 15 on the most liquid side is for applying appropriate bank tension to the ink ribbon, and the intermediate leaf spring 17 is for absorbing slack in the ink ribbon. The leaf spring 19 on the most downstream side performs the following functions. During printing, the front leaf spring 17 is elastically deformed by the tension of the ink ribbon as shown by the imaginary line. When the carriage returns to its original position after printing one line, move the ink ribbon 1A onto the recording paper 6.
The head HE, which had been pulled out to 0, retreats, leaves the recording paper, and further leaves the ink ribbon 1A. As the head separates from the ink ribbon, the ink ribbon that had been pulled out to the recording paper 60 returns. It will be resolved at this time. However, if there is no spring 19, the remaining force of the movement of the ink ribbon at this time will cause the take-up reel to rotate in the opposite direction, causing the ink ribbon to be fed backwards, causing the ink ribbon to slacken and cause the ink ribbon to move in the opposite direction. If you print the lines, the ink ribbon will bend or run diagonally, making it impossible to print normally. Alternatively, when printing of the next line starts, the part of the ink ribbon that has already been used for printing and from which ink has drained returns to the position of the head, and the printing at this part becomes unclear. The leaf spring 19 is also provided to prevent the ink ribbon from returning as described above and from loosening due to the return. In the figure, 10 is a circular through hole provided in the upper wall 29 for fitting the upper end of the take-up reel 77, and 35 is an arrow indicating the rotation direction of the take-up reel 77, which is provided in the upper wall 29. There is.

By the way, the leaf springs 15, 17, and 19 are made of phosphor bronze, for example, and it takes a lot of effort to attach felt and to mold the spring and felt, and the cost of the spring parts is not cheap. Ribbon force sensor i of these leaf springs
~The proportion of the manufacturing cost is that of the cassette parts group.
It can take up almost a minute. Also, the leaf spring holder
- For example, the width of the cassette body is 76 mm.
It is small, measuring 5 mm, height 10 mm, and depth 50 mm, and requires precision work during the assembly process. As described above, the presence of the leaf spring is an obstacle to reducing the cost of ribbon cassettes.

C.3 Objective of the Invention The present invention aims to provide a recording medium force sensor 1- which can omit at least a part of elastic means such as leaf springs and reduce manufacturing costs.

21 Structure of the Invention The present invention provides a recording medium cassette in which a recording medium is housed in a cassette body, in which an engaging portion between a winding means (for example, a reel) for winding up the recording medium and the force center body is provided. , the winding means M only in the winding direction
The present invention relates to a recording medium cassette characterized in that it is provided with a reverse lvj locking mechanism that allows rotation of the recording medium.

E, Example The present invention will be explained in detail below.

FIG. 3 is an enlarged plan view of the inside of the ribbon force sensor I with the earthen wall removed from the ribbon cassette. In addition, the 12th
Components Qli that are common to those in FIG. 1 and FIG. 13 are denoted by the same reference numerals, and explanations thereof will be omitted since they have already been described (hereinafter, the same applies).

This ribbon cassette 30A includes a leaf spring 19 on the most downstream side shown in FIG. 12 and a felt 20 attached to it.
has not been established. As shown in FIG. 4, which is an enlarged sectional view taken along the line TV-IV in FIG. A thin cylindrical portion 7b extends toward.

The take-up reel 7 has a through hole 7a, and a rib 7c that engages with a spindle on the carriage side (not shown) is formed on the inner peripheral surface. A ratchet 28 is erected upward on the bottom wall 22 so as to face the through hole 25, and the ratchets 27 and 28 can mesh with each other.

The bottom wall 22, the side walls 26, and the top wall 29 constitute a cassette main body 30El.

FIG. 1 is an enlarged perspective view showing the bottom wall 22 and the take-up reel 7 separately. In the take-up reel 7, the thin cylindrical portion 7b passes through the inside of the ratchet 28 and fits into the through hole 25 of the bottom wall 22 as shown by the imaginary line arrow, and the ratchet 1-27.2
80 is rotatably attached to the bottom wall 22 in only one direction.

Figure 2 is an enlarged front view (partial cross section) of the take-up reel and its surroundings when the ribbon cassette is in use;
(b) shows the state during printing, and (b) shows the state when the carriage is moving back (not printing).

In the state shown in FIG. 2(a), the through hole 7a of the take-up reel 7
The take-up reel 7 is rotated by the rotation of a spindle (provided on the carriage side) fitted into the holder. At this time, since the slope of the inclined bottom surfaces of the ratchets 27 and 28 is made small, the ratchet 27 floats slightly and rotates on the ratchet 28. In the state shown in FIG. 2(b), the spindle 33 is stopped, and the take-up reel 7 is pulled by the ink ribbon 1A as the leaf spring 17 in FIG. 3 attempts to return from the imaginary line position to the solid line position. I try to reverse the rotation, but the ratchet 2 integrally provided on the bottom wall 22
If the ratchet 27 engages even slightly with the reel 8, the take-up reel 7 is prevented from rotating in the reverse direction. Therefore, the ink ribbon loosens around the head HE L;i j!
! Furthermore, the part of the ink ribbon used for printing does not return to the front of the head. At this time, in order to absorb the slack in the ink ribbon 1A that occurs when the head separates from the recording paper, and the slack that occurs when the take-up reel rotates in reverse until the ratchet engages, the second The leaf spring 17 in FIG. 3 returns from the imaginary line position to the solid line position. The reversal prevention mechanism using the ratchet as described above eliminates the need for the leaf spring 19 shown in FIG. 12, and the manufacturing cost of the ribbon cassette is significantly reduced. ratchet 2
7 and 28 are integrally molded on the take-up reel 7 and the bottom wall 22, respectively, so that these moldings, especially at the same time, cause an increase in manufacturing costs to be negligible.

Note that the thin cylindrical portion 7b may be provided i-1 on the bottom wall 22 side and fitted into the through hole 7a of the take-up reel 7.

Conventionally, when an ink ribbon is used up to its end, it is discarded together with the cassette body. If the used ink ribbon can be replaced with a new ink ribbon, the cassette body will not be as large as 111 (!! l), which is economical and convenient. However, as mentioned above, the ribbon cassette is small,
Since the traveling path of the ink ribbon is complicatedly twisted, replacing the ink ribbon is extremely troublesome. Omitting the leaf spring 19 of FIG. 12 is very advantageous because it makes replacing the ink ribbon considerably easier. To replace the ink ribbon, use tweezers and a toothpick-like tool.

In order to replace the ink ribbon, it is desirable to detachably attach the upper wall 29 to the side wall 26 (conventionally, it was fixed with adhesive).

Therefore, in this example, the upper wall 29 is attached to the side wall 26 by a mechanism as shown in an enlarged view in FIG. 5 (11). Through holes 22 are provided in at least two locations around the bottom wall 22.
b, 22b (see FIG. 3), and the upper wall 29 is provided with hooks 29g at two locations corresponding to these through holes. The hook 2 of the top wall 29 is inserted into the through hole 22b of the bottom wall 22.
The tip of 9g is inserted and locked to the lower end surface of the side wall 26, and the cassette body is assembled. Press the tip of the 29g hook with your finger to attach it to the side wall! >: Remove from the Ii side and hold the upper wall 29 -
1. After passing through the state shown by the dotted line, the top wall 29 separates from the bottom wall 22 and side wall 26 as shown by the three-dot chain line. Conversely, the separated upper wall 29 is fixed onto the side wall 26 via the state shown by the three-dot chain line and the two-dot chain line.

Next, an overview of the operation of each part constituting the printing device will be explained.

Figure 10 is a schematic front view of the main parts of the printing device, and Figure 11 is the first
FIG. 2 is an enlarged cross-sectional view taken along the line XI-XI in FIG.

The recording paper 60 is brought into close contact with the plate (12) 58 by the paper pressing roller 59 and remains stationary. Ribbon force seven 1-3
The carriage 31 on which the OA is mounted is located to the right of the leading edge of the recording paper 60 with a margin left in FIG. 10):! The recording paper 60 is moved along the guide rail 51 as shown by the solid line arrow toward the direction .

When the head opening E reaches a predetermined position on the right side of the recording paper 60, from 7:jj to the remaining 1'1, the head HE moves slightly backward by a tilting means (not shown) and leaves the recording paper 60.
The recording paper 60 is fed by one line as indicated by the dashed-dotted line arrow in FIG. At the same time, the carriage 31
As shown by the dashed-dotted line arrow in the figure, it moves back and returns to its original position, and the next line is printed.

While repeating these operations, sentences are written on the recording paper 60.
Tables, figures, etc. are recorded.

Figure 8 shows the carriage 3 loaded with the ribbon cassette 30A.
1 and its surroundings are shown, and 3OA to the ribbon cassette 1 is set (13) on the carriage 31 as shown by the arrow.

The upper plate 32 of the carriage 31 has projecting pieces 46A, 46 into which the front and rear recesses 26d, 26e of the ribbon cassette 30A fit.
B is provided. The head HE has its base end rotatably supported by a carriage 31, and is tilted by a tilting means (not shown) to print the recording paper (No. 11) via the ink ribbon 1A.
60) in the figure for printing, and is designed to separate from the recording paper when the recording paper is moved and the carriage 31 moves back as described above. 45 is a head support plate that supports the head opening E and also serves as a heat sink. A spindle 33 projects from the upper surface of the carriage 31, and as shown in FIG. 9, the spindle 33 is positioned so as to fit into the through hole 7a of the take-up reel 7 of the ribbon cassette 30A.

In FIG. 8, reference numeral 53 denotes a carriage traveling motor that rotates the toothed heald 52 connected to the carriage 31;
is a guide rail for running the carriage 31, and a pinion 44 provided on the rear side of the carriage 31 meshes with a rack 54. When the carriage (14) 31 moves forward, the pinion 44 rotates, and the pinion 44 is rotated when the carriage 31 moves forward.
The rotation of the winding shaft 33 is made to rotate through the Hirata Etj43.41.38.35.

The mechanism for determining the width of the winding shaft will be explained after L in FIGS. 6 and 7. When the carriage 31 moves to the right (forward movement), the take-up shaft 33 and take-up reel 7 rotate, the ink ribbon IA moves in the direction of the arrow and is taken up on the take-up reel 7, and the feed reel 6 rotates freely. Pay out ink ribbon 1A.

FIG. 6 is a partial plan view of the carriage 31, and FIG. 7IA is a partial plan view of the carriage 31.
It is a sectional view taken along the line v■-■ in the figure.

A pinion 44 is located on the rear end side of the plate 32 slightly exposed from the end, and the pinion 44 is attached to the shaft 42 via a one-way ring (not shown), When going (going), rank (54 in Figure 8)
) rotates clockwise, and the shaft 42 rotates in the hourly direction. A spur gear 43 is fixed to a shaft 42 below the pinion 44, and the spur gear 43 rotates clockwise only when the carriage 31 moves to the right. The clockwise rotation of the spur gear (15) 43 causes the spur gear 40 to rotate clockwise via the spur gear 41 meshing therewith.

The spur gear 35 is coaxially and rotatably pressed against the shaft 36 by upper and lower coil springs 38A and 38El, and the same clockwise rotation of the spur gear 40 causes the spur gear 35 to rotate clockwise. Rotate the same time.

The spindle 33 passes through the upper plate 32 from above to below, and a spur gear 3 that meshes with the spur gear 35 is provided in this downward protrusion.
4 is fixed, and the spindle 33 is rotated counterclockwise by the clockwise rotation of the lower teeth 7rj35, thereby moving the ink ribbon (not shown) to the left while winding it up. The contact pressure between spur gears 40.35 is the same as that of coil springs 38A and 38B.
It is adjustable by receiving nuts 37A and 37B, and even if the outer diameter changes depending on the number of windings of the ink ribbon, the spur gears 40 and 35 slide against each other to ink.
The 1" cylinder was designed to be moved at a constant speed.

That is, when the print head ' moves during printing, the ink ribbon is pressed against the print head with a constant pressing force, and this constant pressing force causes the W head (16) and the ink ribbon to move at a relatively constant speed. Moving.

The moving speed of the Wf head is kept constant, and the ink ribbon winding speed is kept constant by rotating the spur gear 35 at a constant speed due to the frictional engagement between the spur gears 40 and 35. The rotational speed of the spindle 33 changes as the number of turns of the ink ribbon changes, and therefore the rotational speed of the spur gear 35 also changes. The difference in speed is absorbed by the mutual sliding of the spur gears 40.35.

When the carriage 31 moves leftward (backwards) (carriage return), the pinion 44 rotates counterclockwise.
The one-way ring allows the shaft 42 to remain stationary without rotating. Therefore, the spindle 33 does not rotate, and the take-up reel 7 does not rotate in either the forward or reverse direction due to the engagement of the ratchets 27 and 28 mentioned above. We/l
Me 5etsdvd katsuifumaa introductionytzvertical otlshiobubetazezozo♂'1181 Regarding the engagement of ratchet teeth 27 and 28, (17
) If the vertical movement of the take-up reel 7 is large during the printing operation, the ink ribbon will be wound irregularly. Therefore, it is desirable to design the meshing portion so that the downward movement (vibration) of the take-up reel 7 is as small as possible.

In order to prevent the take-up reel from reversing, in addition to the meshing of the pair of ratchets as described above, an appropriate reversal prevention mechanism such as a combination of a ratchet and a detent (claw) that is biased and comes into contact with the ratchet can be used. can be adopted.

The present invention can be similarly applied to ribbon cassettes for recording and typewriters, and can also be applied to cassettes that accommodate recording media other than ink ribbons, such as magnetic tape.

1. Effects of the Invention The present invention has a mechanism for preventing the reversal of the slicing means at the engagement portion between the winding means for winding the recording medium and the cassette body, so that it is different from the conventional recording medium force separator (18). There is no need to provide another reversal prevention means (for example, a phosphor bronze leaf spring) in the casera I body as in the case of
At least the main part of the reversal prevention means can be integrally formed with the stocking means and/or the cassette body. As a result, the recording medium cassette has a simple structure and is easy to assemble, reducing manufacturing costs.

[Brief explanation of drawings]

1 to 11 show embodiments of the present invention, FIG. 1 is an enlarged partial perspective view showing the take-up reel separated from the bottom wall of the cassette body, and FIG. 2 is an enlarged partial perspective view of the take-up reel. Figure (a) is an enlarged partial front view (partial cross section) of the take-up reel and bottom wall during printing, and Figure (b) is an enlarged front view of the take-up reel and bottom wall during non-printing. Figure 3 is an enlarged internal plan view of the ribbon cassette, Figure 4 is an enlarged sectional view taken along the line IV-rV in Figure 3, and Figure 5 shows how to disassemble and assemble the cassette body. (19) Fig. 6 is an enlarged partial sectional view of the carriage, Fig. 7 is a sectional view taken along the line ■-■ in Fig. 6, and Fig. 8 is an outline of the carriage, ribbon cassette, and their surroundings. Figure 9 is a sectional view of the upper part of the carriage and the ribbon force set, Figure 10 is a schematic front view of the main parts of the printing device, and Figure 11 is the first
FIG. 2 is an enlarged cross-sectional view taken along the line xr-xr in FIG. 12 and 13 show a conventional example. FIG. 12 is an enlarged plan view of the ribbon cassette, and FIG. 13 is an enlarged sectional view taken along the line xm-xm in FIG. 12. In addition, in the symbols shown in the drawings, 1A... Ink ribbon 6... Payout reel (20) 7... Take-up reel 22...Bottom wall 25...Through hole 26...Side wall 27.28...Ratchet 29. ...
...Top wall 30A...Ribbon force sensor 1-30B...
. . . Cassette body 31 . . . Carriage 33 . . . Spindle.

Claims (1)

[Claims] 1. In a recording medium cassette in which a recording medium is housed in a cassette body, the winding means is attached to the engagement portion between the winding means for winding the recording medium and the cassette body in the winding direction. A recording medium cassette characterized in that it is provided with a reversal prevention mechanism that allows rotation only in the direction in which the recording medium cassette is rotated.