JPH0358599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ink ribbon cartridge.
More specifically, the present invention relates to an ink ribbon cartridge for storing ink ribbons used in typewriters, computer printers, and the like.

[Prior Art] Conventionally, ink ribbon cartridges include an unwinding core that is rotatably attached to a spindle in a cartridge case, a winding core that can move toward and away from the unwinding core, and the winding core. It consists of a driving rotating body for applying winding drive to the winding machine. The driving rotating body rotates while being pressed against the outer peripheral surface of the ink ribbon wound around the winding core,
The ink ribbon is wound around the winding core. The unwinding core is provided with resistance to its rotation to apply tension to the ink ribbon so as to prevent the ink ribbon from becoming loose in the printing section.

[Problems to be Solved by the Invention] In conventional ink ribbon cartridges that provide rotational resistance to the unwinding core, as the ink ribbon is used more and more and the ribbon winding diameter of the unwinding core becomes smaller, the ink ribbon becomes As the applied tension increases, elongation occurs in the ink ribbon. Therefore, printing defects may occur at the end of the ink ribbon's use.

In order to prevent such printing defects from occurring, if the rotational resistance applied to the unwinding core is made small from the beginning, the ink ribbon will become sagging at the end of its use, which will also cause printing defects. .

As described above, in conventional ink ribbon cartridges, it is difficult to eliminate printing defects caused by elongation of the ink ribbon itself or sagging in the printing section.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to provide an ink ribbon cartridge configured to apply almost average tension to an ink ribbon from the initial stage of use to the end of use of the ink ribbon. shall be.

[Means for Solving the Problems] The ink ribbon cartridge of the present invention has an unwinding core rotatably and non-displaceably attached to the cartridge case, and the ink ribbon cartridge is rotatable and movable toward and near the unwinding core. An ink ribbon cartridge in which a take-up core is attached which is biased toward the separation side, and a driving rotating body is attached to the cartridge case to cooperate with the take-up core to nip the ink ribbon and drive the ink ribbon to be wound. The upper part of the winding core is attached to one end of a tension spring that presses the upper parts of both cores so as to be relatively rotatable but not relatively movable, and the upper part of the unwinding core is attached to the other end of the tension spring so as to be relatively rotatable. The winding core is attached so as to be slidable relative to the winding core, and as the upper part of the winding core approaches a fulcrum part provided between both ends and abutting the cartridge case, the pressing force applied to the winding core is reduced. A configuration in which the tension spring is formed is adopted.

[Operation and Effects of the Invention] At the beginning of the ink ribbon's use, the winding diameter of the ink ribbon is larger on the unwinding core side and smaller on the winding core side, but as the ink ribbon is used, the winding diameter of the unwinding core becomes smaller. The winding diameter of the winding core changes to become larger, and at the end of the ink ribbon's use, the winding diameter of the unwinding core becomes smaller and the winding diameter of the winding core becomes smaller, which is exactly the opposite of the state at the beginning of use. It's getting bigger.

Due to such a change in the winding diameter, the winding core gradually approaches the unwinding core from a distance, and since one end of the tension spring is attached to the winding core, the winding of the winding core is It moves as it approaches the unwinding core, and initially the tip of the other end of the tension spring was in contact with the upper surface of the unwinding core, but gradually the fulcrum part is displaced so that it is in contact with the upper surface of the unwinding core. Therefore, the pressing force exerted by the tension spring on the unwinding core is initially strong, but is gradually and continuously reduced.

In this way, when the winding diameter of the unwinding core is large, the rotational resistance is large, and when the winding diameter is small, the rotational resistance is also small, so that the tension acting on the ink ribbon itself can be averaged.

However, in the present invention, since the ink ribbon does not stretch or sag, it is possible to eliminate printing defects caused by this.

[Example] Next, an example of the present invention will be described based on the drawings.

FIG. 1 is an internal plan view of an ink ribbon cartridge according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views taken along the line -- in FIG.
Both are drawings explaining the function of the ink ribbon cartridge.

1 and 2, reference numeral 1 denotes a box-shaped cartridge case body, and a ribbon storage section 2.
It consists of a ribbon ejection arm 3 and a ribbon return arm 4, and when it is set in a printer or typewriter, the ribbon stretching path 5 between the tips of the arms 3 and 4 faces the recording paper. The impression forming head is configured to transfer the ink of the ink ribbon A onto the recording paper to form an impression on the recording paper. A lid 6 serves as a top plate of the cartridge case, and is fitted onto the top surface of the case body 1. Reference numeral 7 denotes an unwinding core, which is rotatably supported by a fixed shaft 8 erected at a location near one side of the ribbon storage section 2 . Note that a cylindrical protrusion 9 is formed on the upper part thereof. Reference numeral 12 denotes a winding core, which has a cylindrical protrusion 14 formed at its lower part and a cylindrical protrusion 15 formed at its upper part. Reference numeral 13 denotes a guide groove, which is formed at the bottom of the ribbon storage section 2 on the other side (the right side in the figure). The winding core 12 has its protrusion 14 loosely fitted into the guide groove 13, and is located far away from the unwinding core 7 (see FIGS. 1 and 2).
(as shown in FIG. 3) and a position close to the unwinding core 7 (as shown in FIG. 3). 1
8 is a driving rotary body, and the winding core 12
It is arranged on the right side in the figure (that is, the part on the opposite side to the side facing the unwinding core 7), and rotates by an external drive while pinching the ink ribbon A between it and the winding core 12. , the winding core 1
2. Wind up the ink ribbon A. Reference numeral 10 denotes a tension spring, which is shaped like a strip in plan view, and is bent at one place in the center so that its cross-sectional shape in the longitudinal direction is doglegged, and its bending point is used as a fulcrum portion 17.
A protrusion 21 is formed on the right side of the tension spring 10 in the drawing (that is, a portion closer to the winding core 12 side) for engaging a biasing spring 20, which will be described later. A long hole 11 having a length of approximately 1/2 of the length of the tension spring 10 is formed in the portion . This tension spring 10 has a small hole 1 at one end thereof.
6 is inserted into and supported by the protrusion 15 of the winding core 12, and the central fulcrum portion 17 is attached to the back surface of the lid 6 in elastic contact. On the other hand, the free end side of the tension spring 10 is in sliding contact with the upper surface of the unwinding core 7 so that the elongated hole 11 is inserted into the protrusion 9 of the unwinding core 7. In this way, the tension spring 10 is attached in pressure contact between the cores 7, 12 and the lid 6 so that the cross-sectional shape in the longitudinal direction is flat, so that the free end side elastically touches the upper surface of the unwinding core 7. It seems to be pushed down. The biasing spring 20 is a scissor-shaped spring whose base is fixed to a protrusion 22 of the case body 1, and its free end is engaged with the protrusion 21 of the tension spring 10. The winding core 12 is pressed against the driving rotary body 8 via the tension spring 10 by the elastic force of the biasing spring 20.

Next, the operation of the above embodiment will be explained. As shown in FIG. 2, when the ink ribbon A is first used, only a small amount of the ink ribbon A is wound around the winding core 12, so the winding diameter of the winding core 12 is small. Its position is closer to the left side in the figure. Therefore, the unwinding core 7 is pressed by the tip of the tension spring 10, and strong rotational resistance is applied to it. Conversely, as shown in FIG. 3, at the end of the use of the ink ribbon A, a large amount of ink ribbon A is wound around the winding core 12,
As the winding diameter increases, the distance from the driving rotor 18 increases, and the winding core 12 gradually moves to the left in the figure. When the winding diameter of the unwinding core 7 is reduced in this manner, the unwinding core 7 is pressed at a portion close to the fulcrum portion 17 of the tension spring 10, so that a small rotational resistance is applied.

As described above, since a rotational resistance proportional to the winding diameter is applied to the unwinding core 7, a tension that is neither too large nor too small is constantly applied to the ink ribbon A on average during use. Become. In this way, the occurrence of printing defects due to insufficient or excessive tension is effectively prevented.

[Brief explanation of drawings]

FIG. 1 is an internal plan view of an ink ribbon cartridge according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views taken along the line -- in FIG.
Both are drawings explaining the function of the ink ribbon cartridge. Main symbols in the drawing: 1: Cartridge case body, 7: Unwinding core, 10... Tension spring, 1
2: Winding core, 13: Guide groove, 17: Fulcrum part,
20: Biasing spring.

Claims (1)

[Claims] 1. An unwinding core is installed in a cartridge case so as to be rotatable and non-displaceable, and a winding core is installed so as to be rotatable and capable of moving toward and away from the unwinding core, and is biased away from the unwinding core. In an ink ribbon cartridge in which a drive rotor is attached to the cartridge case to clamp the ink ribbon and drive the ink ribbon in cooperation with the cartridge case, one end of a tension spring that presses the upper part of both cores is attached to the take-up core. The upper part of the unwinding core is relatively rotatably and relatively immovably attached to the other end of the tension spring, and the upper part of the unwinding core is relatively rotatably and relatively slidably attached to the other end of the tension spring. An ink ribbon cartridge in which the tension spring is formed so that as the upper part of the winding core approaches a fulcrum part that contacts a cartridge case, the pressing force applied to the winding core decreases.