JPH06127098A - Ribbon end detector - Google Patents

Abstract

PURPOSE:To provide a ribbon end detector which can effectively detect a ribbon end irrespective of color, damage, dirt, etc., of a ribbon with a low-cost simple structure. CONSTITUTION:When an ink ribbon 54 becomes a ribbon end state from a normal using state, a tension of the ribbon 54 is varied, a tension spring 70 is deformed to be moved due to the tension change to press a ribbon end switch 22. The switch 22 is operated by the pressing to detect a ribbon end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ribbon end detecting device in a printing device such as a typewriter for printing using an ink ribbon.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a ribbon end detecting apparatus of this type has a silver-colored end tape 74 having a high reflectance at the end of a black ink ribbon 54 having a low reflectance.
And a reflection type photosensor 76 provided in the path of the ink ribbon 54 on the typewriter main body 48.
However, there is one that detects the ribbon end by reacting with the end tape 74 due to the difference in reflectance.

[0003]

However, in the conventional ribbon end detection device, since the photosensor 76 is used, the cost is high. Also, if the ink ribbon 54 is scratched or dirty,
In some cases, it was erroneously detected in response to the scratches and dirt. Furthermore, for a color ink ribbon, it reacts with the ink ribbon portion depending on the reflectance of that color,
It could not be used in some cases.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a ribbon end detecting device capable of surely detecting the ribbon end with a simple structure.

[0005]

To achieve this object, a ribbon end detecting device of the present invention comprises an ink ribbon whose both ends are fixed to a first spool and a second spool, respectively.
In a printing apparatus having a winding means for winding the ink ribbon from the first spool to the second spool, an interlocking member that moves in association with a change in tension of the ink ribbon and a first spool to a second spool of the ink ribbon. And a switch for detecting the movement of the interlocking member when the winding of the tape is completed or near the completion of the winding.

[0006]

In the ribbon end detecting device of the present invention having the above-mentioned structure, the tension generated in the ink ribbon changes when the ink ribbon is ready to be used, and the interlocking member interlocks with the change in the tension of the ink ribbon. The switch operates to detect the ribbon end.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A typewriter which is one embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic structure of this typewriter, and FIG. 2 is a plan view of an essential part.

This typewriter comprises a CPU 10 and a ROM 1
2, a microcomputer 18 including a RAM 14 and a bus 16, and a keyboard 2 as an input device
0, the ribbon end switch 22 for detecting the end of the ink ribbon 54 is connected. The ribbon end switch 22 is a leaf switch that detects whether or not it is pressed.

The bus 16 is further provided with a type wheel control circuit 24, a hammer control circuit 26, a carriage control circuit 28,
Through the paper feed control circuit 30, the ink ribbon control circuit 32, and the ribbon end display circuit 34, a type wheel drive motor 36, a hammer drive solenoid 38, a carriage drive motor 40, a paper feed drive motor 42, an ink ribbon take-up motor 44, respectively. The ribbon end display LED 46 is connected. The type wheel drive motor 36 selects the type 50 required for printing and positions it at the print position, and the hammer drive solenoid 38 operates the hammer 52 to move the type 50 via the ink ribbon 54.
Is hit on the printing paper 56. The carriage drive motor 40 moves the carriage 58 on which the hammer 52, the ink ribbon 54, the type 50, and the like are mounted to the print position, and the paper feed drive motor 42 includes the platen 60.
The printing paper 56 is set to the printing height by rotating the. In addition, the ink ribbon winding motor 4
Reference numeral 4 denotes a ribbon end display LED for driving the claw shaft 62 to feed the ink ribbon 54 by the amount used for printing.
Reference numeral 46 indicates that the printable ink ribbon 54 has run out.

Generally, in response to an input from the keyboard 20, selection of the character 50, operation of the hammer 52, movement of the carriage 58, feeding of the printing paper 56, and ink ribbon 54.
Is carried out, and the printing operation on the printing paper 56 is carried out. However, when the ribbon end switch 22 operates,
These printing operations are suspended and the ribbon end display LE
By lighting D46, the user is notified that the ink ribbon 54 needs to be replaced.

Next, the ribbon cassette 55 containing the ink ribbon 54 will be described. Ribbon cassette 55
In addition to the claw shaft 62, both ends of the ink ribbon 5 are fixed to the take-up spool 64 and the former winding spool 66, respectively.
4, a pressure contact spring 68 for pressing the take-up spool 64 against the claw shaft 62, and a tension spring 7 wound around the original winding spool 66 and forming a path for the ink ribbon 54.
0 and a ribbon case 72 that holds each of these members.

Usually, the winding operation of the ink ribbon 54 is performed as follows. First, when the claw shaft 62 is rotated by the ink ribbon winding motor 44, the pressure contact spring 6
The take-up spool 64, which is pressed against the claw shaft 62 by 8 rotates in conjunction with each other. The rotational movement of the take-up spool 64 causes the ink ribbon 54 to be drawn from the original take-up spool 66 side to the take-up spool 64 side. Since the original take-up spool 66 is subjected to a tightening force by the tension spring 70. Therefore, tension is generated in the ink ribbon 54.

On the other hand, one end of the tension spring 70 forms a path for the ink ribbon 54, and when tension acts on the ink ribbon 54, the original winding spool 66 of the tension spring 70.
It deforms and moves in the direction in which the tightening force on the is reduced. When the rotational force due to the tension of the ink ribbon 54 with respect to the original winding spool 66 becomes larger than the rotation blocking force due to the tightening force of the tension spring 70, the original winding spool 66 rotates,
The ink ribbon 54 is pulled out. This ink ribbon 54
The pulling-out operation reduces the tension of the ink ribbon 54, so that the deformation of the tension spring 70 is reduced and the tightening force to the original winding spool 66 is increased accordingly. The pulling-out operation of the ink ribbon 54 is completed in a state in which the rotational force by the force and the rotation blocking force by the tightening force of the tension spring 70 are balanced.

In a normal winding operation of the ink ribbon 54, the above series of operations is repeated. At this time, due to variations in the rotation speed and rotation angle of the claw shaft 62, a change in the winding angle of the ink ribbon 54 around the tension spring 70 due to a change in the winding amount of the ink ribbon 54 around the original winding spool 66, etc. Although the changing range of the tension spring 70 changes, the changing range of the tension spring 70 is limited to a certain range by proper selection and arrangement of the tension spring 70.

The above-described series of repetitive operations proceeds, and FIG.
From the normal use state shown in (a), when the ink ribbon 54 wound around the original winding spool 66 is completely withdrawn, and when the rotation operation of the tab shaft 62 progresses, the original winding spool of the ink ribbon 54. Since the end portion on the 66 side is adhered to the original winding spool 66, there is no decrease in tension due to the drawing operation of the ink ribbon 54 in the above series of operations, and the increase in tension of the ink ribbon 54 and the deformation of the tension spring 70 progress. To do. The deformation operation of the tension spring 70 exceeds the normal deformation range, and finally reaches the ribbon end detection state shown in FIG. 2B in which the ribbon end switch 22 is pressed to operate. Then, the printing operation corresponding to the user's keyboard 20 input is temporarily suspended,
When the ribbon end display LED 46 lights up,
The ribbon end will be notified to the user.

It should be noted that the present invention is not limited to this embodiment, but is applied within the scope of the present invention.

For example, although a leaf switch is used as the ribbon end switch 22 in this embodiment, the tension spring 70 is made of a conductive material and the energization between the tension spring 70 and the ribbon end switch 22 is detected. Good as a switch.

[0019]

As is clear from the above description,
According to the present invention, it is possible to reliably detect the ribbon end at a low cost with a very simple structure and without being affected by the color, scratches, stains, and the like of the ink ribbon.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a typewriter embodying the present invention.

FIG. 2A is a plan view of relevant parts showing a normal use state of the typewriter. FIG. 2B is a main part plan view showing the ribbon end detection state of the typewriter.

FIG. 3 is a plan view of a main part of a conventional ribbon end detection device.

[Explanation of symbols]

 22 Ribbon End Switch 44 Ink Ribbon Winding Motor 50 Type 54 Ink Ribbon 62 Claw Shaft 64 Winding Spool 66 Original Winding Spool 70 Tension Spring

Claims (1)

[Claims] 1. A printing apparatus comprising: an ink ribbon having both ends fixed to a first spool and a second spool, and a winding means for winding the ink ribbon from the first spool to the second spool. An interlocking member that moves in association with a change in the tension of the ribbon, and a switch that detects the movement of the interlocking member when the winding of the ink ribbon from the first spool to the second spool has been completed or is about to be completed. A ribbon end detection device characterized by being provided.