JPH03173674A - Ribbon take-up mechanism for printer - Google Patents

Abstract

PURPOSE:To achieve such functions as ribbon drive, retraction,and unilateral clutching through a single mechanism by an arrangement wherein a member to be engaged with a driving section and a member subjected to external rotary driving are rotatable and slidable in the direction of rotation axis. CONSTITUTION:Shaft section of an engaging member 1 idly penetrates through the hole of a drive member 2 so that the engaging member 1 and the drive member 2 are slidable in the rotary direction and axial direction just like a piston. A clutch spring 3 is press fit to the spring winding parts of the engaging member 1 and the drive member 2 with proper fastening force and further compressed moderately by a frame 4. Under a state where a ribbon cassette 6 is loaded, the spline part of the engaging member 1 is engaged in the spline hole 7a of a ribbon take-up shaft 7. By such arrangement, a single mechanism can provide four functions of ribbon drive, retraction upon locking of the ribbon, low torque interruption of driving path from a motor 5 at the time of manual winding, and retraction in case of unsufficient engagement of power transmitting section upon loading of the ribbon cassette 6.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an ink ribbon winding mechanism for a printer.

[Prior art] Conventionally, this type of technology has been used to drive the ribbon, an escape mechanism in case the ribbon locks, a one-sided clutch mechanism that cuts off the drive path from the motor when manually winding the ribbon using a knob, and a mechanism that cuts off the drive path from the motor when the ribbon cassette is installed. It is equipped with an escape mechanism in case the power transmission part fails to engage properly, and it is common to use separate components for each mechanism.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, the number of parts increases, resulting in high costs and poor assembly performance.

The present invention was made to solve these drawbacks, and its purpose is to minimize the number of parts and improve cost and ease of assembly by achieving the above four functions with one mechanism. be.

[Means for Solving the Problems] The ribbon winding mechanism of the present invention includes an engaging member having a spline-like engaging portion that engages with a driving portion of an ink ribbon cassette at one end and a cylindrical shape at the other end. a driving member having a cylindrical shape with an outer diameter substantially the same as the cylindrical shape of the retaining member and receiving rotational drive from the outside; a compression spring having an inner diameter slightly smaller than the cylindrical outer diameter of the engaging member and the driving member; The engaging member and the driving member are provided with a piston-like shape that passes through the engaging member and the driving member freely so that the engaging member and the driving member can rotate and slide in the direction of the rotation axis, and a compression spring is provided between the retaining member and the driving member. It is characterized in that it is press-fitted into a cylindrical shape, and that the engaging member and the driving member are held in a compressed state by a frame.

[Embodiment] FIG. 1 is a plan view of an embodiment of the present invention, showing a state in which an ink ribbon cassette 6 is inserted.

The engaging member 1 has a spline-shaped engaging portion at one end, a shaft portion at the other end, and a cylindrical spring-wound portion at the center, and these are integrally formed. The driving member 2 has a spring-wrapped portion having substantially the same shape as the spring-wrapped portion of the engagement member at one end, and a shaft portion and a gear at the other end, which are integrally formed. The shaft portion of the engaging member 1 is loosely inserted into the hole of the driving member 2, and the engaging member 1 and the driving member 2 are slidable in the rotational direction and the axial direction like a piston.

The clutch spring 3, which is a compression spring, is press-fitted to the engagement member 1 and drive member 2 with appropriate tightening force, and is further held in an appropriately compressed state by the frame 4. There is.

When the ribbon cassette 6 is attached, the spline portion of the engaging member 1 is engaged with the spline hole 7a of the ribbon winding shaft 7, as shown in FIG.

Next, the operation will be explained.

The power given by the motor 5 gives rotational force to the drive member 2 through the transmission gear 8. This rotational direction is a direction in which the clutch spring 3 is tightened according to the principle of a spring clutch, and the applied rotational force is transmitted from the drive member 2 to the engagement member 1 via the clutch spring 3.

Furthermore, the ribbon winding shaft 7 is rotated by the action of the spline to wind up the ribbon.

If the ribbon is overloaded or the ribbon take-up shaft 7 is locked for some reason, the torque of the drive member 2 exceeds the tightening torque of the clutch spring 3 and the clutch spring 3 and drive member 2 or engagement member are tightened. 1 starts to slip and the rotational force is cut off.

Next, we will explain the operation when winding by hand.

By turning the manual knob 7b of the ribbon winding shaft 7 toward the winding side, the clutch spring 3 moves toward the loosening side according to the principle of a spring clutch, and starts slipping with a slight torque, and ten rotations of the retaining member causes the drive member 2 to is not conveyed.

Next, the operation when inserting the ribbon cassette 6 will be explained.

When the ribbon cassette 6 is inserted from above, the engagement between the spline hole 7a of the ribbon winding shaft 7 and the spline portion of the engaging member 1 is not necessarily smooth. If the splines do not engage properly due to collisions, etc., use the second spline.
As shown in the figure, the clutch spring 3 acts as a compression spring, and the engaging member 1 and the driving member 2 contract and escape in the thrust direction. After that, when the engaging member 1 rotates a little, the clutch spring 3
Due to the spring force, the spline parts are properly engaged.

[Effects of the Invention] As described above, according to the present invention, 1. Driving the ribbon 2. Escape operation when the ribbon is locked 3. Operation of cutting off the drive path from the motor with low torque when manually winding with the knob 4. Since the four functions of escape operation in the case of poor engagement of the power transmission part when inserting the ribbon cassette are achieved by one mechanism, the number of parts can be minimized, and cost and assemblability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a ribbon winding mechanism according to the present invention, and FIG. 2 is a plan view of an operational view of the present invention. Engagement member Drive member Clutch Spring Frame Motor Ribbon cassette Ribbon winding shaft Transmission gear

Claims (1)

[Claims] The engaging member has a spline-shaped engaging portion that engages with the drive portion of the ink ribbon cassette at one end and a cylindrical shape at the other end, and a cylindrical shape having an outer diameter approximately the same as the cylindrical shape of the engaging member. and a frame, the engaging member and the driving member being rotatable. and the engaging member and the driving member are loosely inserted in the shape of a piston so as to be slidable in the rotational axis direction, and the compression spring is press-fitted into the cylindrical shapes of the engaging member and the driving member, and the engaging member and the driving member are press-fitted into the cylindrical shape. A ribbon winding mechanism for a printer, wherein the mating member and the driving member are held by the frame in a compressed state.