JPH07156501A - Printer - Google Patents

Abstract

PURPOSE:To easily unload paper by a method wherein when a printing head is separated from the paper in a jamming processing, a depressing force of a paper presser on the paper is attenuated. CONSTITUTION:A printing gap regulating mechanism 12 for regulating a printing gap G by displacing a carriage shaft 3 is provided. A paper presser 15 moving into/out of contact with a transport part 17 for transporting paper is connected to a spring support body 20 moving close to/apart from the back surface of the paper presser 15 by a spring 16. A pressing part for pressing the spring support body 20 against the urging force of the spring 16 is provided in conjunction with the printing gap regulating mechanism 12. When a printing gap G is increased beyond a fixed range in a jamming processing, the pressing part is retracted for permitting the displacement of the spring support body 20 by the urging force of the spring 16. In this manner, the urging force of the spring 16 pressing the paper presser 15 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus having a print gap adjusting mechanism and a paper presser for pressing a paper on a platen.

[0002]

2. Description of the Related Art A conventional example of this type of printing apparatus is shown in FIG. Reference numeral 1 denotes a print frame, on which a guide rail 2 is formed and a carriage shaft 3 is installed. An inkjet cartridge 5 is mounted on a carriage 4 which is slidably held by a guide rail 2 and a carriage shaft 3. The inkjet cartridge 5 has an inkjet head 7 which is a print head facing a paper guide 6 which also has a function as a flat platen, and an ink tank 8 which supplies ink to the inkjet head 7.

Further, eccentric shafts 9 having a circular cross section and eccentric with respect to the center of the carriage shaft 3 are integrally formed at both ends of the carriage shaft 3, and these eccentric shafts 9 are provided on both sides of the print frame 1. A bearing portion (not shown) formed on the side plate 10 is rotatably held on a fixed axis. And the eccentric shaft 9 and the carriage shaft 3
A print gap adjusting mechanism 12 is formed by the operation lever 11 fixedly fitted to one end of the.

Further, the print frame 1 includes a sheet 1
A paper presser 15 for pressing 3 is held rotatably around the support shaft 14. The paper retainer 15 is urged by a spring 16 in a direction in which the paper 13 is pressed against a conveyor roller 17 which is a conveyor. The transport roller 17 is connected to a motor 19 via a plurality of transmission mechanisms 18 including gears fixed to one end thereof.

Next, the operation will be described. When the adjusting lever 11 is rotated to an arbitrary position in accordance with the thickness of the paper 13 used, the position of the shaft center of the carriage shaft 3 is displaced in the direction around the shaft center of the eccentric shaft 9, so that the carriage 4 is moved to the inkjet head. Along with 7, the sheet guide 6 is displaced toward and away from the sheet guide 6. That is, the print gap between the inkjet head 7 and the paper guide 6 is adjusted. At the time of printing, the paper 13 is pressed by the paper presser 15 which is urged by the spring 16.

[0006]

In the printing apparatus shown as the conventional example, when a jam occurs, the printing gap is widened and the paper 13 is taken out.
Since it is pressed by 5, it is difficult to take out the paper 13. When the speed reduction ratio of the transmission mechanism 18 is as large as 1/20, it is particularly difficult to pull out the paper 13 sandwiched between the paper retainer 15 and the transport roller 17.

[0007]

SUMMARY OF THE INVENTION According to the present invention, a print gap adjusting mechanism for adjusting a print gap by displacing a carriage shaft for slidably holding a carriage for holding a print head, and a conveying section for conveying a sheet. A paper retainer held so as to be able to come in contact with and away from the paper retainer is provided, and a spring support body retained so as to be able to approach and separate from the back surface of the paper retainer is provided. When the print gap is widened by a predetermined distance or more in conjunction with pressing the spring support member against the biasing force of the spring and operating the print gap adjusting mechanism, the spring support member is retracted. The pressing part is provided.

[0008]

When the print gap adjusting mechanism is operated to widen the print gap to a certain range or more, the pressing portion retracts from the spring support body, and therefore the displacement operation of the spring support body by the biasing force of the spring is allowed. The biasing force of the spring can be weakened, and thus the pressing force of the paper pressing member against the paper can be attenuated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The same parts as those described with reference to FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. As shown in FIGS. 1 to 3, a spring support member 20 is provided on the bottom surface of the print frame 1.
Both sides of the sheet are held by the guide pins 21 so as to be able to move back and forth in the directions of arrows A and B, which move away from and approach the rear surface of the paper retainer 15. The spring support 20 and the paper retainer 15
And are long in the width direction of the sheet 13, and are connected by a pair of springs 16 on the left and right.

Further, as shown in FIG. 4, irregular portions 22 having a D-shaped cross section are formed at both ends of the carriage shaft 3, and the end faces of these irregular portions 22 are eccentric with respect to the axis of the carriage shaft 3. Eccentric shaft 9 is formed. The bushes 23 are fitted in the left and right atypical parts 22 so as not to rotate. These bushes 23 have the spring supports 20 (see FIGS. 1 to 3).
The pressing cam 24 that is a pressing portion that presses (see) is integrally formed. Further, the operation lever 11 is formed on either one of the left and right bushes 23. The operation lever 11 described with reference to FIG. 6 corresponds to the pressing cam 2 shown in FIG.
4 is not provided and only the bush 23 fitted to the carriage shaft 3 is provided. Further, as shown in FIG. 5, a projection 25 is formed on the side surface of the operation lever 11, and a plurality of locking recesses 26 for selectively locking the projection 25 extend along the radius from the center of the eccentric shaft 9. Then, the side plate 10 of the print frame 1 (see FIGS. 1 to 3) is formed.

When the thin paper 13 is used in such a structure, as shown in FIG.
Is rotated toward the paper guide 6 to set a small print gap G. At this time, the pressing cam 24 rotates together with the eccentric shaft 9 and the carriage shaft 3, but maintains the state in which the spring support 20 is pressed in the arrow A direction. As a result, the spring 16 is maintained in the tensioned state, and the paper presser 1
The sheet 5 is urged clockwise around the support shaft 14 to press the sheet 13.

When the thick paper 13 is used, as shown in FIG. 3, the operation lever 11 is positioned in the center to set a large print gap G. By this operation, the pressing cam 2
4 changes the position of pressing the spring support 20,
The shape of the pressing cam 24 is determined so as to maintain the spring 16 in the tensioned state as in the state shown in FIG.

When a jam occurs, as shown in FIG. 1, the operating lever 11 is rotated in a direction away from the paper guide 6 to enlarge the printing gap G. By this operation, the pressing cam 24 rotates counterclockwise to change the position for receiving the spring supporting body 20, but by keeping the radius of the pressing cam 24 in this portion small, the spring supporting force by the spring 16 is applied. It is possible to allow the body 20 to move in the direction of the paper retainer 15 (the direction of arrow B) and weaken the urging force of the spring 16. This makes it possible to reduce the pressing force of the paper retainer 15 against the paper 13 when the printing gap G is widened. Therefore,
Spread the space between the paper retainer 15 and the transport roller 17
Can be taken out easily with a small force. Along with this, it is possible to prevent the sheet 13 from breaking.

[0014]

As described above, according to the present invention, the print gap adjusting mechanism for adjusting the print gap by displacing the shaft center of the carriage shaft and the print gap adjusting mechanism for holding the print gap are held so as to be separable. A presser for pressing the spring support member against the biasing force of the spring by connecting the paper presser with a spring support body that is held close to and away from the back surface of the paper supporter by a spring. When the print gap is expanded by the print gap adjustment mechanism to a certain range or more, the pressing part is retracted from the spring support. Is
The displacement of the spring support by the biasing force of the spring can be allowed to weaken the biasing force of the spring, which can reduce the pressing force of the paper retainer against the paper. The paper under the presser can be easily taken out with a small force, and accordingly, the paper can be prevented from being damaged.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing a state in which a print gap is widened to a certain range or more according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view showing a state in which a small print gap is set.

FIG. 3 is a vertical cross-sectional side view showing a state in which a large print gap is set.

FIG. 4 is an exploded perspective view showing a print gap adjusting mechanism.

FIG. 5 is a side view showing a positioning structure of an operation lever.

FIG. 6 is a vertical sectional side view showing a conventional example.

[Explanation of symbols]

 3 Carriage Shaft 4 Carriage 7 Print Head 12 Print Gap Adjusting Mechanism 13 Paper 15 Paper Presser 16 Spring 17 Conveying Section 20 Spring Support 24 Pressing Section

Claims (1)

[Claims] 1. A print gap adjusting mechanism that adjusts a print gap by displacing a carriage shaft that slidably holds a carriage that holds a print head,
A paper retainer that is held in contact with and away from a conveyance unit that conveys a sheet is provided, and a spring support body that is retained toward and away from the back surface of the paper retainer is provided. When the paper presser is connected by a spring, the spring support is pressed against the urging force of the spring, and the print gap is widened beyond a certain interval in conjunction with the operation of the print gap adjusting mechanism. A printing apparatus comprising a pressing portion that retracts from the spring support.