JP3038590B2 - Ink ribbon reproduction pad - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) By recovering the print density of an ink ribbon by applying an ink made of a communicating porous material and held by capillary force by contact with the ink ribbon. The present invention relates to an ink ribbon regenerating pad.

(Prior Art) The printing density of an ink ribbon of a dot printer or the like gradually decreases as it is used. However, it is not surprising that discarding the print density has lowered it. Therefore, reproduction is being studied. The object is exclusively the device structure. Various measures have been taken to prevent the operator's hands from being stained, to allow one-touch preparation for reproduction, and to automatically end reproduction even with an endless ribbon. These include the basic performance of reproduction, such as eliminating excess / deficiency of reproduction.

Here, the way of reproduction is exemplified in principle. In FIG. 1, reference numeral 1 denotes an ink ribbon.
It is conscious of endless things. The ink ribbon 1 is sent out from one of the two rollers 2 and 3 and is taken up by the other roller. A pad 4 is arranged between these rollers, and the ink ribbon 1
When the tension is applied so as to contact the ink ribbon 1, the pad 4 is rotated by the movement of the ink ribbon 1, and the ink held by the pad 4 is applied to the ink ribbon 1. In FIG. 2, the ink ribbon 1 passes between the other roller 5 and the pad 4. The roller 5 is rotated by applying tension to the ink ribbon 1, thereby rotating the roller 5. At this time, if a force is applied between the roller 5 and the pad 4 in a direction in which the roller 5 contacts the pad, the rotation of the roller 5 causes the pad 4 to rotate. Also rotates, and ink is applied to the ink ribbon passing between them. In FIGS. 1 and 2, there are portions indicated by alternate long and short dash lines, but this is merely in consideration of the fact that ink ribbons are often commercially available as cassettes. In addition to being used for a dedicated playback device, the pad itself is, for example, incorporated in a cassette, or
It can also be one of the components of the printer itself.

1 and 2, the ink on the pad 4 is transferred to the ink ribbon 1 by bringing the ink ribbon 1 into contact with the pad 4. This is possible because the pad holds the ink by capillary force. When reproducing in such a manner, the first attempt to reduce coating unevenness is to make the pad itself soft so that the contact unevenness is reduced. In fact, conventionally, there are many pads in which “sponge” is used. here,
A typical sponge is a communicating porous body of polyurethane.

(Problems to be Solved by the Invention) The softness of the pad certainly helps to reduce uneven contact. However, the present inventors have found that reducing contact unevenness may not always be helpful in reducing coating unevenness.

 This is described below.

The portion of the pad where the ink is applied to the ink ribbon is a rotating peripheral wall. That is, the ink moves from the peripheral wall to the ink ribbon steadily. The ink inside the pad moves to the peripheral wall to compensate for the lack of ink on the peripheral wall. At this time, if ink is uniformly replenished to the peripheral wall, coating unevenness can be suppressed.
However, when in contact with the ink ribbon, the peripheral wall portion contracts. It may be said that the application involves squeezing. And this shrinkage depends on the rotation of the pad. That is, contraction and recovery are periodically performed according to the rotation. It is considered that the replenishment of the ink from inside is performed at the time of this recovery. It is like placing a compressed sponge next to a water-moistened sponge and releasing the compression transfers water from the water-moistened sponge to the compressed sponge.

And this movement is not always performed uniformly. Influencing is the weight of the ink.
In other words, when the reproduction is performed with the attached drawing being horizontal, the ink ribbon has its "width" in the vertical direction, but regardless of the large amount of ink held, the ink ribbon is gradually located on the upper side. The coating density is lower than that on the lower side.

Further, softness has a large relationship with the material of the pad, the porosity, the pore diameter, and the like. These materials affect the holding power of the ink. Too much softness is required, so that the ink holding power is weak, and the density of the ink may occur over time due to its own weight.

(Means for Solving the Problems) The material of the pad is polyvinyl formal. That is,
The present invention relates to an ink ribbon reproduction pad which is made of a communicating porous body, and which recovers the print density of an ink ribbon by applying ink held by capillary force by contact with the ink ribbon. The gist of the present invention is an ink ribbon regenerating pad, wherein the material of the pad that directly contacts the ink ribbon is polyvinyl formal and has a hardness that does not substantially shrink when contacting the ink ribbon.

 The details will be described below.

Pads are not just hard. Some ink ribbons have a long overall length of, for example, 17 m. On the other hand, the pads themselves cannot be so large. There is inaction in the equipment. Moreover, therefore, the pad rotates many times in one playback operation. In addition, it is desired to increase the number of revolutions in consideration of shortening the operation time. As a result, the peripheral wall of the pad makes a large amount of application to the ink ribbon many times in a short period. In addition to being hard, the pad can stably hold a sufficient amount of ink over time in order to satisfy such conditions, and quickly move ink from the inside to the peripheral wall. It is hoped that it can be done.

In this regard, polyvinyl formal has a large porosity,
Accordingly, the amount of ink that can be held is large, and the hole diameter that greatly affects the movement of the ink can be preferable. It is possible to sufficiently suppress the movement of the ink due to its own weight over time and to have sufficient hardness. Here, the preferable pore diameter varies depending on the type of ink, and thus cannot be determined unconditionally.However, for inks usually used for ink ribbons, for example, inks having oleic acid at least as a main solvent and a viscosity of about 100 to 500 cps are used. On the other hand, it is about 200 to 400 μm (average). The porosity can be 85%, 90% or more. Further, the shape may be, for example, a polygonal column shape other than the column shape.

(Example) Example 1 A communicating porous polyvinyl formal columnar body having an average pore diameter of 350 μm, a porosity of 91%, a diameter of 25 mm (center hole diameter for inserting a shaft center of 5 mm), and a height of 16 mm is prepared, and this is used as an ink ribbon reproduction pad. It was immersed in a commercially available replenishing ink (oleic acid was used as a main solvent and the viscosity was about 150 cps), and the ink was filled from the outer wall surface (excess portion was removed). As a result of weight measurement, the ink filling amount was 6.1 g.

Example 2 In Example 1, all except that the diameter of the center hole for inserting the shaft center was 15 mm (in FIG. 1, the pad 4 is indicated by a dotted line, but the dotted line portion becomes the center hole). A communicating porous polyvinyl formal columnar body similar to that in Example 1 was prepared and filled with ink under the same conditions as in Example 1. As a result of weight measurement, the ink filling amount was 5.0 g.

Example 3 In Example 1, the average pore diameter was 250 μm and the porosity was 87%.
Except for the above, a communicating porous polyvinyl formal columnar body having the same shape as in Example 1 was prepared, and ink was filled under the same conditions as in Example 1. As a result of weight measurement, the ink filling amount was 5.4 g.

Comparative Example In Example 1, the average pore diameter was 300 μm, and the porosity was 76%.
Except for the above, a communicating porous polyurethane columnar body having the same shape as in Example 1 was prepared, and ink was filled under the same conditions as in Example 1. When the weight was measured, the ink filling amount was 5.7 g.

(Effects of the Invention) The results obtained in each example are the same as those obtained immediately after ink filling.
A test of recycling the ink ribbon was performed using one that had been left at a temperature of one month for one month. The ink ribbon is a virgin ribbon (endless; 17m long) without any ink. The tension is 50g, the ink ribbon speed is 10cm / sec, the rotation time is 8 minutes 30 seconds (the ink ribbon rotates 3 times) Do).

First, in the case of the comparative example which was left at 50 ° C. for one month, the print density at both ends of the ink ribbon was changed in the test of the first ink ribbon. In the comparative example immediately after ink filling, the second test also produced shading. On the other hand, no shading was observed in the fourth example in each example. Incidentally, when a fluoroscopic photograph was taken of the sample of Example 1 with soft X-rays, the ink was present over a substantially uniform depth from the outer wall surface. Those left for one month were not much different. It is considered that the reason for the small volume of Example 2 was as good as that of Example 1 because of good test results.

As described above, the pad of the present invention has excellent ink holding properties, is less likely to be adversely affected by the ink's own weight during ink ribbon regeneration or over time, and can hold a sufficient amount of ink.
It can have excellent reproduction ability.

[Brief description of the drawings]

FIG. 1 and FIG. 2 are schematic diagrams showing an example of a method of regenerating an ink ribbon in principle. 1 ... Ink ribbon, 2,3,5 ... Roller, 4 ... Pad.

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Claims (1)

(57) [Claims] 1. An ink ribbon reproduction pad comprising a communicating porous body, wherein ink held by capillary force is applied by contact with an ink ribbon to recover the print density of the ink ribbon. The pad for directly contacting the ink ribbon is made of polyvinyl formal, and has a hardness that does not substantially shrink upon contact with the ink ribbon.