JPS61154869A - Position-adjusting mechanism for printing head - Google Patents

Abstract

PURPOSE:To simplify construction, by a construction wherein an outer peripheral surface of a carriage bush is formed to be eccentric with respect to a central axial hole so that the material thickness of the bush on the front side of a guide shaft is varied simply by turning the bush. CONSTITUTION:In finely adjusting the gap between the front end of a printing head 5 and a platen 1 according to the thickness of a recording paper P or the like, when an operating part 6d is positioned by contact with a stopper 4b, the material thickness of the carriage bush 6 on the front side of the guide shaft 2 is larger than that on the rear side of the guide shaft 2, so that the gap is small. To the contrary, when the operating part 6d is moved to a position for contact with a stopper 4c, the material thickness of the bush 6 on the front side of the shaft 2 is gradually reduced, so that the gap is enlarged. Accordingly, position adjustment can be performed without requiring any separate member, the weight of the carriage is small, the construction is simple, and cost can be lowered.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a printer equipped with a print head that performs a predetermined printing operation in response to a print signal. Relating to an adjustment device.

(Prior Art) This type of printer is equipped with a position adjustment device in order to keep the distance between the printing head Fi, the tip of the printing wire or dot plate, and the printing surface within a predetermined range. According to the conventional device, a long groove is provided on one side of the transport platform and the frame of the print head, and a screw having an inclined surface is provided on the other side, whereby the print head is moved forward and backward in the direction of the platen with respect to the transport platform, and the position is adjusted. A structure that is firmly established (for example, the
(Japanese Patent Laid-Open No. 42122), a structure in which a screw provided on the carriage is brought into contact with an inclined surface provided on the print head, thereby moving the print head forward and backward in the direction of the platen with respect to the carriage to adjust the position (Japanese Patent Laid-Open No. 50 -149417 Publication)
, an eccentric cam member is attached to a moving table, a follower is fixed to the print head to clamp the eccentric cam, and the position is adjusted by moving the print head forward and backward in the direction of the platen with respect to the moving table. -71930).

(Problems to be Solved by the Invention) All of the conventional techniques require extra members such as screws, inclined surfaces, eccentric cam members, etc. for the conveying platform, which increases the weight and puts a burden on the driving force of the conveying platform. becomes.

The present invention is capable of adjusting the position of the print head without requiring any extra members, reducing the mass of the carriage to eliminate the load on driving force, and simplifying the structure to reduce costs.

(Means for Solving the Problems) The present invention includes a carriage 4 that carries a 5ft print head and moves it, a guide shaft 2 that guides the carriage,
A carriage bush 6 is interposed between the two. This carriage bushing 6 has a central shaft hole 6a through which the guide shaft 2 passes, a cylindrical outer peripheral surface 6b formed eccentrically with respect to the stop shaft hole, and an adjustment lever for rotating the carriage bushing. It consists of 6c. The carriage bush 6 is mounted on the carriage 4 by fitting its outer circumferential surface 6b into a hole 4a so that it can rotate freely, and the adjustment lever 6
c is a degree setting 4b provided on the carriage 4;

The carriage 4 and the print head 5 can be rotated within a range of 4c, and the carriage 4 and the print head 5 can move forward and backward toward the recording paper P by rotating the adjustment lever 6c. Further, a click spring 4dt'' is integrally formed on the carriage 4, and is configured to selectively come into elastic contact with a plurality of clicks #6e formed on the outer peripheral surface of the carriage bush 6.

Carriage shoes 9160 aim to maintain stable rotational position.

(Function) Since the outer circumferential surface 6b of the carriage bushing 6 is formed eccentrically with respect to the center shaft hole 6a, the wall thickness on the front side of the guide shaft 20 changes simply by rotating the carriage bushing. When the thickness is large, the carriage 4 and print head 5
The front end of the print head 5 is in the forward position, and the gap between the front end of the print head 5 and the platen 1 is small. Therefore, it is suitable for cases where thin recording paper P is used all around. Furthermore, when the thickness of the carriage bushing 6 on the front side of the guide shaft 2 is small, the gap between the front end of the print head 5 and the platen 1 is large, and therefore, when recording thick recording paper P or recording a large number of multiple sheets. Applicable when using paper.

(Example) In FIGS. 1 to 3, a recording paper is fed by winding a pVi platen 1, and a pair of guide shafts 2 and 3 are provided parallel to the width direction of the recording paper P.

A print head 5 is fixed on a carriage 4 that is movable along guide shafts 2 and 5. A carriage bush 6 is interposed between the carriage 4 and the guide shaft 2 located near the platen 1.

The carriage bush 6 has a central shaft hole 6at- through which the guide shaft 2 passes. The outer peripheral surface 6b of the carriage bush 6 is a cylindrical surface formed eccentrically with respect to the central shaft hole 6a, and therefore the wall thickness around the central shaft hole 6a gradually changes. Adjustment levers 6 Q * 60 are integrally formed at both ends of the carriage bush 6 . The operating portions 6d, 6d of the adjustment lever protrude upward from the carriage 4.

A mounting hole 4a for a carriage bush 6 is formed in the lower surface of the carriage 4. It has a hole 4a and opens downward.
The carriage bush 6 is fitted into the mounting hole 4a from the lower opening. Carriage bushing 6 is inserted into this mounting hole 4a.
The outer circumferential surface 6b of the hole is in contact with the hole, and the hole is rotatable. Adjustments 4b and 4c are provided at both ends of the carriage 4 to restrict the rotation range of the adjustment lever 6c, and an operating portion 6d is provided.
protrudes toward the upper surface from between the fixings 4b and 40.

A click spring 4d is vertically disposed on the lower surface of the carriage 4 and is in elastic contact with the outer circumferential surface 6b in order to stably maintain the rotational position of the carriage bush 6. click spring 4d
is provided on the outer peripheral surface of the carriage bushing 6 and selectively comes into elastic contact with a plurality of click grooves 6e. Further, a belt connecting portion 4e is provided to securely attach a tth timing belt (not shown) that transmits driving force to the carriage 4. Further, the carriage 4 is provided with a /dU-shaped groove 4g, which holds the guide shaft 3 therebetween.

During assembly, the guide shaft 2 is passed through the carriage bush 6 and fixed at a predetermined position within the frame 7.

The guide shaft s is held between the U-shaped groove 4g of the carriage 4, and the lower opening of the mounting hole 4a is pressed against the upper part of the carriage bushing 6, so that the outer peripheral surface 6b of the carriage bushing is fitted into the mounting hole 4a. Match. At this time, the operating portion 6d of the adjustment lever 6C is positioned between the carriage adjustment 4b and 4a. The carriage bush 6 has its center shaft hole 6.
It is slidable along the guide shaft 2 at a point a, and the inner metal of the mounting hole 4a is rotatable at its outer peripheral surface 6b. The print head is then fixed to the upper surface of the 5'ft carriage 4.

Therefore, in order to finely adjust the gap between the front end of the print head 5 and the platen 1 in accordance with the thickness of the recording paper P, the operation section 6dt is first set and moved to a predetermined position within the 4b and 4c.
For example, as shown in FIG.
Since the thickness of the carriage bushing 6 on the platen side is greater than the thickness of the carriage bushing on the rear side of the guide shaft 2, the carriage 4#i advances toward the platen side and reaches the next position. That is, the gap between the front end of the print head 5 and the platen 1 becomes small. On the contrary, adjust the operating part 6d to a certain degree 4c.
When the guide shaft 2 is moved to the position indicated by the chain line in Fig.
Since the thickness of the carriage bushing 6 on the front side of the printhead gradually decreases, the carriage 4 retreats from the platen 1 to the t position, ie, the gap between the front end of the print head 5 and the platen 1 becomes large.

In this forward and backward movement of the carriage 4 and the print head 5, the horizontal posture of the carriage 4 is maintained by sliding back and forth while holding the guide shaft 3 between the inner surfaces of the U-shaped groove 4g of the carriage. The position of the carriage bushing 6 set by the operating portion 6d is clicked by the click spring 4d pressing against the outer peripheral surface 6b of the carriage bushing as shown in the second figure, and is not easily displaced. If a plurality of click grooves 6e are provided on the outer peripheral surface, the position can be maintained even more reliably.

(Effects of the Invention) The present invention allows the position of the print head to be adjusted without the need for any separate components by simply making the center axis hole and the outer peripheral surface of the carriage bushing eccentric, and the weight of the carriage is small. , easy to build without putting any load on the driving force,
Cost reduction can be achieved continuously.

[Brief explanation of drawings]

1 is a cross-sectional view taken along the line IX in FIG. 3, showing a main part of an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line If-It in FIG. 3, and FIG. 3 is a plan view. P... Recording paper 2.3... Guide shaft 4...
・Carriage 4a...Mounting holes 4b, 4Q...
Degree determination 4d...Kritsukuno (nee 5...Print head 6...Carriage bushing 6a...Central shaft hole 6b...Outer circumferential surface 6c...
Adjustment lever 6e...Click groove or more

Claims (1)

[Claims] 1. A pair of guide shafts parallel to the width direction of the recording paper, a carriage movable along the guide shafts, a print head fixed to the carriage, and a print head mounted on the carriage. A carriage bush is provided, through which one of the guide shafts slidably passes, and the carriage bush is formed eccentrically with respect to the center shaft hole through which the one guide shaft passes. It consists of a cylindrical outer peripheral surface and an adjustment lever for rotating the carriage bush, and the carriage bush is rotatable by fitting its outer peripheral surface into a mounting hole provided in the carriage. The adjustment lever is rotatable within a range determined by the carriage, and the carriage and the print head can be moved forward and backward toward the recording paper by rotating the adjustment lever. Head position adjustment mechanism. 2. In claim 1, the carriage includes:
A print head position adjustment mechanism characterized by integrally forming a click spring that selectively comes into elastic contact with a plurality of click grooves provided on the outer peripheral surface of a carriage bush.