JPH04158079A - Conveyor for ink ribbon - Google Patents

Abstract

PURPOSE:To prevent the generation of the creases and skew of an ink ribbon by installing first and second links rocked while using approximately central sections as fulcra and a spring connecting the first link and the second link. CONSTITUTION:A core 8 is mounted to a feed roll 2, and a frictional member 13 is set up on the outer circumference of the end section of the core 8. A roller 10 is fitted rotatably at the front end section of a link 9, and the link 9 can be rocked and moved while using a fulcrum 12 mounted at an approximately central section as a fulcrum. Pressure P is applied to the like 9 by a spring 15, and the pressure P follows up to the diameter of an ink ribbon, and does not prevent the rotary motion of the feed roll 2. Consequently, the link 9 follows up to the diameter of the ink ribbon, and conducts a rocking motion. The approximately central section of a link 11 is coupled with the fulcrum 12, and a frictional member 14 is installed at a position brought into contact with the frictional member 13 at the front end section of the link 11. The spring 15 connects the link 9 and the link 11, and applies pressure P in the direction that the roller 10 and the frictional member 14 are brought near.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink ribbon transport device, and more particularly to an ink ribbon transport device used in a so-called transfer printer that transfers ink from an ink ribbon onto recording paper.

[Conventional technology]

Conventional ink ribbon transport devices used in so-called transfer printers use a print head and platen to bring the ink ribbon and recording paper into close contact with each other under a predetermined pressure, and apply energy to the ink ribbon to transfer the ink from the ink ribbon to the recording paper. , a ribbon roll (supply roll) on the supply side serves as a mechanism that applies back tension to the ink ribbon.
One obtains pack tension by applying a braking force of a predetermined torque to the ink ribbon wound around the core of the other, and the other obtains hack tension by sandwiching the ink ribbon sent out from the supply roll between friction members and using the friction force. We are hiring things.

[Problem to be solved by the invention]

Among the pack tension mechanisms of conventional ink ribbon conveying devices as described above, in the former case, which applies a braking force of a predetermined torque to the core of the supply roll, the pack tension increases in inverse proportion to the diameter of the ink ribbon of the supply roll. Therefore, the size of the ink ribbon is not constant, which causes the problem that wrinkles and skew of the ink ribbon are likely to occur. There is also the problem of color shift. To avoid such problems, the diameter of the core of the supply roll is increased and the length of the ink ribbon is limited so that the diameter of the ink ribbon wound around the core is not much larger than the diameter of the core. .

On the other hand, in the latter case, in which the ink ribbon sent out from the supply roll is held between friction members and pack tension is obtained by the frictional force, ink is transferred from the ink ribbon to the friction member due to contact between the ink ribbon and the friction member, causing friction. Because the member gets dirty and its frictional force changes, the back tension becomes unstable, and the ink transferred to the friction member is transferred again to the ink ribbon, causing the ink to disappear.
This has the problem of deteriorating print quality.

[Means to solve the problem]

The ink ribbon conveying device of the present invention includes a first link that swings approximately at the center as a fulcrum and follows changes in the outer diameter of the supply roll, and a first link that is provided on the outer periphery of the end of the core of the supply roll. a second link that has a second friction member that contacts the first friction member at its tip and swings about the fulcrum; the first link and the second link; and a spring connecting the two.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a front view showing a ribbon conveying section according to an embodiment of the present invention.

In FIG. 2, an ink phone 1 is fed out from a supply roll 2 and wound onto a take-up roll 3. During this process, the thermal head 4 and platen 5 bring the ink into close contact with the paper 7 to transfer ink onto the paper 7, thereby performing printing. After printing, the paper 7 is moved with the ink ribbon 1 to f.
41M and conveyed by the pinch rollers 6 in the six directions of arrows.

FIG. 1 is a front view showing the pack tension mechanism on the ribbon supply side of the embodiment shown in FIG. 2.

In FIG. 1, the supply roll 2 is attached to a core 8, and a friction member 13 is provided on the outer periphery of the end of the core 8. A roller 10 is rotatably attached to the tip of the link 9, and the link 9 can swing about a fulcrum 12 provided approximately at the center. Link 9 has
A pressure P is applied by the spring 15, and this pressure P is sufficient for the link 9 to follow the diameter of the ink ribbon wound around the supply roll 2, and is a force that does not interfere with the rotational movement of the supply roll 20. be. Therefore, link 9 is
The swing motion follows the diameter of the ink ribbon wound around the supply roll 2. A substantially central portion of the link 11 is connected to the fulcrum 12, and a core 8 is connected to the tip of the link 11.
The friction member 1 is placed at a position where it contacts the friction member 13 provided in the
4 is a provision. The spring 15 connects the link 9 and the link 11 and applies pressure P in a direction that brings the roller 10 and the friction member 14 closer together.

When the printer starts printing, as shown in FIG. 2, the thermal head 4 is pressed against the platen 5 with a predetermined pressure in order to bring the paper 7 and the ink ribbon 1 into close contact with each other. In this state, the thermal head 4 is made to generate heat based on the print data to transfer ink. When this printing operation is finished,
The paper 7 is conveyed in the direction of arrow A by the pinch roller 6,
On the other hand, the ink ribbon 1 is wound up on a winding roll 3.

When the ink ribbon 1 is wound up, a desired pack tension is applied to the ink ribbon 1 by the pack tension mechanism shown in FIG.

The link 9 follows changes in the outer diameter of the supply roll 2 by bringing the roller 10 into contact with the outer periphery of the supply roll 2 . Therefore, the link 9 is connected to the fulcrum 12 as the outer diameter of the supply roll 2 decreases.
Rotate clockwise around the center. Therefore, the spring 15 contracts, the pressure P decreases, and the frictional force between the friction member 13 and the R1 friction member 14 decreases. The braking torque applied to the core 8 of the supply roll 2 is therefore reduced.

FIGS. 3(a) and 3(b) are explanatory diagrams showing the bank tension when the diameter of the supply roll is large and when the diameter is small in the embodiment of FIG. 2.

As shown in FIG. 3(a), the distances from the fulcrum 12 of the link 9 to both ends are both a, and the distances from the fulcrum 12 of the link 11 to both ends are also both a.

The outer diameter of the supply roll 2 is 2R, the outer diameter of the friction member 13 of the core 8 is 2r, the length of the spring 5 is Ll, the brake torque at this time is T1, and the Beck tension is BT. FIG. 3<b) shows the case where the outer diameter of the supply roll 2 is reduced to 2r, and the spring 15 at this time
The length of is L2. The brake torque in this state is T2, and the back tension is BT2. Friction member]
3 and the friction coefficient of the friction member 14 are both μ, spring] 5
If the spring constant of is k and its free length is L, then Tl =llk (L, 1 -1-) ・r
−(] )T2−μk(L2−L)・1− −・・
・・(2) BT,=T, ・'R0310,,(3) B
T2 = T2'r - (4) Here, if R=2r, then B T 2 /' B T (= 2 T 2 /Tr
= (LL-L)/(L2-L)...(5)
(LI L2) = (R-
-r) = r-- (6) L2 = (LL - r) where k = 40 g/nm, μ = 0.1. r =
15mm, R=30mm+, LH=35im, L=1
If 0 ■■, then from (1) T1・0. lX40X(3
5-10) X15・1500g・From mouth (3) BT,
・1500/30・50gf(2) to T 2=
0.1x40X(35-10-15)X15□600g
From Ilm(4) BT2・600/15・40gf
Therefore, even if the diameter of the supply roller is reduced to 1/2, the back tension remains unchanged at (50-40=10) gfL.

〔Effect of the invention〕

As described above, the ink ribbon conveying device of the present invention includes a first link that swings in accordance with changes in the outer diameter of the supply roll, and an outer circumference of the end of the core of the supply roll, in the back tension mechanism section. A first friction material provided at the tip, and a second friction material provided at the tip.
a second link that has a second friction member in contact with the friction member of the first link and swings about the fulcrum of the swing motion of the first link; and a spring that connects the first link and the second link. By having the This has the effect of preventing color misregistration when performing color printing using a multi-color ink ribbon coated with ink in sequence.

Furthermore, since there is no contact between the ink ribbon and the R1 rubbing member,
This has the effect of preventing deterioration of print quality due to ink scum.

[Brief explanation of drawings]

FIG. 1 is a front view showing the back tension mechanism section on the ribbon supply side of the embodiment shown in FIG. 2, FIG. (b)
2 is an explanatory diagram showing the pack tension when the diameter of the supply roll is large and small in the embodiment of FIG. 2. FIG. DESCRIPTION OF SYMBOLS 1... Ink ribbon, 2... Supply roll, 3... Winding roll, 4... Thermal head, 5... Platen, 6... ... Pinch roller, 7 ... Paper, 8 ... Core, 9
...Link, 10... Laura, 11...
...link, 12...fulcrum, 13...
・Friction member, 14...Friction member, 15...
··spring.

Claims (1)

[Claims] a first link that swings approximately at the center as a fulcrum to follow changes in the outer diameter of the supply roll; a first friction member provided on the outer periphery of the end of the core of the supply roll; A second link that has a second friction member that contacts the first friction member and swings about the fulcrum, and a spring that connects the first link and the second link. An ink ribbon conveying device featuring: