JP2000238367A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gap adjusting mechanism which moves a carrier not in the vertical direction but only in the back and forth directions. SOLUTION: A printer comprises a platen 2, a print head 3 disposed oppositely to the platen 2, a carrier 4 carrying the print head 3, and a first guide shaft 5 for guiding the carrier 4 in parallel with the platen 2. The printer further comprises a rotatable shaft 5a fitted in the axial direction at an eccentric position in the first guide shaft 5, a drive shaft 5c disposed at an eccentric position at the end part of the shaft 5a, and guide means 7a, 7b for regulating vertical movement of the first guide shaft 5. Gap between the platen 2 and the print head 3 is adjusted by operating a lever 8 to turn the drive shaft 5c such that the first guide shaft 5 approaches the platen 2 or recedes therefrom.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer,
In particular, the present invention relates to a printer capable of adjusting a platen gap, that is, a distance of a print head from a platen.

[0002]

2. Description of the Related Art FIG. 5 is a side view showing an example of a platen gap adjusting mechanism in a conventional printer. Reference numeral 11 denotes a side frame of the printer, which is provided as a pair on the left and right. Reference numeral 12 denotes a platen, which is rotatably attached to the side frame 11. Reference numeral 13 denotes a print head, which is arranged to face the platen 12. The print head 13 is mounted on a carriage 14. The carriage 14 includes a first guide shaft 15 and a second guide shaft 1.
6 and is guided by the first and second guide shafts 15 and 16 to reciprocate in a direction perpendicular to the plane of FIG.

The first guide shaft 15 has a large diameter portion 15a,
A small-diameter portion 15b provided inside the large-diameter portion 15a. The small diameter portion 15b is eccentric with respect to the large diameter portion 15a, and the small diameter portion 15b is rotatably supported by the side frame 11. At one end of the small diameter portion 15b,
A platen gap adjustment lever 18 is fixed to the outside of the side frame 11 by screws. The rotation of the platen gap adjustment lever 18 causes the guide shaft 15 to rotate.

The carriage 14 has a first bearing portion 14a.
The bearing portion 14a is slidably supported by the large diameter portion 15a of the first guide shaft 15. The second guide shaft 16 is supported by the side frame 11. The carriage 14 has a second bearing portion 14b
The bearing portion 14b is slidably supported by the second guide shaft 16. The second bearing portion 14b is supported by the carriage 14 so as to be slidable in the b1 and b2 directions.

In such a printer, a recording medium (generally, paper) is provided between the platen 12 and the print head 13.
P is fed, and printing is performed on the paper P by the reciprocating print head 13. Then, according to the thickness of the paper P,
The gap G between the platen 12 and the print head 13 is adjusted by rotating the guide shaft 15 in the a1 or a2 direction. That is, the first guide shaft 15 which is an eccentric shaft
Is rotated, the carriage 14 moves back and forth and up and down to adjust the gap G.

[0006]

Generally, in the above-described printer, the gap G between the print head 13 and the platen 14 and the angle of the print head 13 with respect to the platen 14 are important for the reliability and print quality of the printer. Influence. In the conventional gap adjusting mechanism, the carrier 14 moves back and forth and up and down, thereby forming the gap G.
However, the angle of the print head 14 with respect to the platen 12 changes from an appropriate angle due to the vertical movement of the carrier 14.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gap adjusting mechanism that operates the carrier only in the front-rear direction without operating the carrier in the vertical direction.

[0008]

In order to achieve the above object, a printer according to the present invention comprises a platen, a print head arranged to face the platen, a carrier having the print head, and a carrier. A first guide shaft for guiding parallel to the platen, a rotatable insertion shaft axially inserted into an eccentric position in the first guide shaft, and an eccentric position at an end of the insertion shaft. It is constituted by a drive shaft and guide means for regulating the vertical movement of the first guide shaft.

The insertion shaft is rotated by rotating the drive shaft. When the insertion shaft rotates, the guide shaft also rotates. However, since the vertical movement of the guide shaft is regulated by the guide means, the guide shaft transmits the movement only in the front-rear direction to the carrier.

[0010]

Next, embodiments of the present invention will be described in detail with reference to the drawings. Referring to FIGS. 1 and 4, reference numeral 1 denotes a side frame of the printer, which is provided as a pair of left and right sides. Reference numeral 2 denotes a platen, and a side frame 1
It is rotatably mounted on. Reference numeral 3 denotes a print head, which is arranged to face the platen 2. The print head 3 is mounted on a carriage 4. Carriage 4
Is attached to a first guide shaft 5 and a second guide shaft 6, and is guided by the first and second guide shafts 5 and 6 to reciprocate in a direction perpendicular to the plane of FIG. It is supposed to.

The first guide shaft 5 has a fitting shaft 5b fitted in the first guide shaft 5 in the axial direction, and a drive shaft 5c provided with an end of the fitting shaft 5b. The fitting shaft 5b is eccentric with respect to the guide shaft 5, and the fitting shaft 5b is rotatably built in the guide shaft 5. The drive shaft 5c is eccentric with respect to the fitting shaft 5b, and the drive shaft 5c is rotatably supported by the side frame 1. Drive shaft 5
A platen gap adjustment lever 8 is fixed to one end of the outer side of the side frame 1 by a screw. By rotating the rotation of the platen gap adjusting lever 8, the drive shaft 5c and the fitting shaft 5b rotate.

The carriage 4 is provided with a first bearing 4a, and the bearing 4a is slidably supported by the first guide shaft 5.

The first guide shaft 5 is installed so as to slide along the guide plates 7a and 7b. The guide plate 7a and the guide plate 7b are installed inside the side frame 1 in parallel with a straight line extending through the centers of the guide shafts 5 and 6. The second guide shaft 6 is supported by the side frame 1. The carriage 4 has a second
The bearing portion 4b is provided, and the bearing portion 4b is slidably supported by the second guide shaft 6. The second bearing 4b is supported by the carriage 4 so as to be slidable in the directions b1 and b2.

In the above configuration, a recording medium (generally a sheet) P is fed between the platen 2 and the print head 3, and printing is performed on the sheet P by the reciprocating print head 3. Then, by rotating the guide shaft 5 in the a1 or a2 direction (by moving the platen 2 toward or away from the platen 2) according to the thickness of the sheet P, the distance between the platen 2 and the print head 3 is increased. Is adjusted. That is, the rotation of the first guide shaft 5, which is an eccentric shaft, causes the carriage 4 to move forward and backward to adjust the gap G.

The above-described gap adjusting operation will be described in detail with reference to FIGS. 2 and 3, the broken lines represent the positions before the adjustment, and the solid lines represent the positions after the adjustment. When the sheet thickness of the recording medium P is thin or the printing result is thin, the drive shaft 5c of the guide shaft 5 is rotated in the direction c1. With this rotation, the fitting shaft 5b also rotates to the position 5b '. With the rotational movement of the insertion shaft 5b, the guide shaft 5 incorporating the insertion shaft 5b also moves 5 ′ according to the guide plates 7a and 7b.
Rotate to the position.

If the recording medium P is thick or the printing result is dark, the drive shaft 5c is rotated in the direction c2. With this rotation, the fitting shaft 5b also rotates to the position 5b ''. With the rotational movement of the insertion shaft 5b, the guide shaft 5 containing the insertion shaft 5b also moves to the guide plate 7a and the guide plate 7b.
According to the above, it is rotated to the position 5a ″.

By the above operation, the carriage 4 shown in FIG.
Operates in the front-back direction (horizontal direction in FIG. 1), but does not operate in the up-down direction.

In the above example, the drive shaft 5c is rotated manually, but may be rotated by a motor or the like via a gear mechanism or the like.

[0019]

As described above, according to the present invention,
A gap adjusting mechanism that operates the carrier only in the front-rear direction without operating the carrier in the vertical direction can be provided.

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment of the present invention.

FIG. 2 is a view showing the operation of a guide shaft in FIG. 1;

FIG. 3 is a view showing the operation of the guide shaft of FIG. 1;

FIG. 4 is a perspective view of one embodiment of the present invention.

FIG. 5 is a side view of a conventional platen gap adjusting mechanism.

[Explanation of symbols]

 2 Platen 3 Printhead 4 Carrier 5 Guide shaft 5b Insertion shaft 5c Drive shaft 8 Platen gap adjustment lever P Paper G Gap

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[Procedure amendment]

[Submission date] November 29, 1999 (1999.11.
29)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

Generally, in the above-described printer, the gap G between the print head 13 and the platen 14 and the angle of the print head 13 with respect to the platen 14 are important for the reliability and print quality of the printer. Influence. In the conventional gap adjusting mechanism, the carrier 14 moves back and forth and up and down, thereby forming the gap G.
However, the angle of the print head 13 with respect to the platen 12 changes from an appropriate angle due to the vertical movement of the carrier 14.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction contents]

The first guide shaft 5 has a fitting shaft 5b fitted in the guide shaft 5a in the axial direction, and a drive shaft 5c provided at an end of the fitting shaft 5b. The fitting shaft 5b is eccentric with respect to the guide shaft 5a, and the fitting shaft 5b is rotatably built in the guide shaft 5a. The drive shaft 5c is eccentric with respect to the fitting shaft 5b, and the drive shaft 5c is rotatably supported by the side frame 1. Drive shaft 5
A platen gap adjustment lever 8 is fixed to one end of the outer side of the side frame 1 by a screw. By rotating the platen gap adjusting lever 8, the drive shaft 5c and the fitting shaft 5b rotate.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

The above-described gap adjusting operation will be described in detail with reference to FIGS. 2 and 3, the broken lines represent the positions before the adjustment, and the solid lines represent the positions after the adjustment. When the sheet thickness of the recording medium P is thin or the printing result is thin, the platen gap adjustment lever 8 is rotated in the direction a2 (FIG. 1). With this rotation, the drive shaft 5c connected to the lever 8 by a screw rotates in the direction c1. With this rotation, the fitting shaft 5b also rotates to the position 5b '. Fitting shaft 5b
The guide shaft 5a having the built-in shaft 5b also attempts to rotate in the c1 direction along with the rotational movement. However, since the vertical movement is regulated by the guide plates 7a and 7b, the guide shaft 5a is moved in the c1 direction. While moving in the opposite direction to the position from 5a to 5a '. By the movement of the guide shaft 5a,
The carriage 4 moves in the b1 direction via the bearing 4a, and the gap G is reduced.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

When the sheet thickness of the recording medium P is thick or the printing result is dark, the platen gap adjustment lever 8 is set to a
Rotate in one direction (FIG. 1). With this rotation, lever 8
And the drive shaft 5c connected by the screw rotates in the c2 direction. With this rotation, the fitting shaft 5b also rotates to the position 5b ''. With the rotational movement of the insertion shaft 5b, the insertion shaft 5b
The guide shaft 5a, which incorporates the guide shaft 5a, also attempts to rotate in the c2 direction. However, since the vertical movement is regulated by the guide plates 7a and 7b, the guide shaft 5a rotates in the direction opposite to the c2 direction while rotating 5a. To 5a ''. Due to the movement of the guide shaft 5a, the carriage 4 moves in the b2 direction via the bearing 4a, and the gap G is widened.

[Procedure amendment 5]

[Document name to be amended] Drawing

[Correction target item name] Fig. 5

[Correction method] Change

[Correction contents]

FIG. 5

Claims (6)

[Claims] 1. A platen, a print head arranged to face the platen, a carrier on which the print head is installed, a first guide shaft for guiding the carrier in parallel with the platen, A rotatable insertion shaft fitted in an eccentric position in the guide shaft in the axial direction, a drive shaft provided in an eccentric position of an end of the insertion shaft, and a vertical movement of the first guide shaft are regulated. A printer comprising: 2. The printer according to claim 1, wherein said guide means is a guide plate for sandwiching said guide shaft from above and below. 3. The printer according to claim 1, wherein the drive shaft is rotatably mounted on a frame of the apparatus main body. 4. The printer according to claim 1, wherein an operation lever is attached to the drive shaft. 5. The printer according to claim 1, wherein the drive shaft is rotated by a motor. 6. The printer according to claim 1, further comprising a second guide shaft for guiding the carrier.