JP2984815B2 - Automatic paper thickness adjustment mechanism of printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic paper which presses the print head onto a paper and corrects the print head position in accordance with the thickness of the paper before the print head transfers ink to the paper to perform printing. Thickness adjustment (AGA: Automati
The present invention relates to an impact printer that performs c gap adjustment), and more particularly to an impact printer that can prevent paper contamination during automatic paper thickness adjustment with a simple configuration.

[0002]

2. Description of the Related Art Conventionally, in this type of impact printer, during automatic paper thickness adjustment (hereinafter referred to as AGA), after a paper is sucked into a predetermined position, a carriage moves a paper on a platen to an A position.
By detecting the paper thickness by pressing with the GA arm,
When the carriage retreats from this position by a certain amount, the distance between the print head and the paper is automatically kept at a predetermined value regardless of the type of paper.

Since the AGA is performed on the paper, when the AGA arm presses the paper to detect the thickness of the paper,
The leading end of the print head is at a first print position where the printer first prints print data sent from the computer. For this reason, it is unavoidable that the ink ribbon interposed between the print head and the paper comes into contact with the paper and the paper is stained.

[0004] That is, in the conventional automatic paper thickness adjustment procedure of the impact printer, as shown in FIG.
The print head moves so that the A-arm is positioned on the paper and the leading end of the print head is positioned at the first print position (step S11). Next, the carriage presses the sheet on the platen with the AGA arm and advances in the platen direction so that the sheet thickness can be detected (step S12).

Next, the AGA arm presses the paper on the platen to detect the thickness of the paper, and a predetermined AGA correction process for automatically maintaining the distance between the print head and the paper at a predetermined value is performed (step S13). ). Next, the carriage moves backward in the direction opposite to the platen (step S14), and waits for a printing operation by the print head.

On the other hand, as a second example, a technique for preventing the ink ribbon interposed between the print head and the paper from coming into contact with the paper and causing the paper to be stained is disclosed in, for example, Japanese Patent Application Laid-open No. Sho.
It is described in JP-A-2-284771. In the printer described in this publication, a flexible belt is inserted between the paper and the ink ribbon during automatic paper thickness adjustment, and the flexible belt is retracted during printing.

[0007]

In the first example of the conventional impact printer described above, when the AGA arm presses the paper to detect the paper thickness, the leading end of the print head is sent from the computer. The print data is located at the first print position where the printer first prints, and therefore, it is inevitable that the ink ribbon interposed between the print head and the paper comes into contact with the paper and the paper is stained. There is a point.

In the second example described in the above publication, the flexible belt is provided so that the ink ribbon does not come into contact with the paper. However, the flexible belt is provided and the supporting mechanism and movement are performed. Since the mechanism is added to the conventional one, and the configuration is complicated and expensive, there is a problem in practical use.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide an impact printer capable of avoiding dirt on paper during AGA with a simple configuration.

According to the present invention, prior to carrying out printer printing, a paper thickness is detected by pressing a contact detection sensor which is interlocked so that a distance to a fixed paper surface is equal to a print head, and the initial thickness of the print head is accordingly changed. In the automatic paper thickness adjustment mechanism of the printer for correcting the position, the carriage that is equipped with the print head and the contact detection sensor and moves while maintaining a constant distance from the fixed paper surface, and the paper settings are determined. Paper setting range detecting means for outputting the paper setting range information when the sheet thickness is detected, and when the sheet thickness is detected, the contact detection sensor is within the paper range based on the paper setting range information and the print head is outside the paper range. The movement of the carriage is controlled so as to be positioned.

The present invention is also characterized in that the paper setting range detecting means is provided on a card holder for fixing a paper surface, and the card holder is mounted on the carriage. It is an optical sensor.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention. FIG. 1A is an overall perspective view showing one embodiment of a carriage 1 and its peripheral portion.
FIG. 2B is a partial perspective view showing one mode of a portion of the card holder 7 in FIG.

In the impact printer shown in FIG. 1, a sensor 13 is attached to the card holder 7 as a sheet position detecting means for detecting the sheet 6 as compared with the conventional one, and the AGA
In this case, one AGA arm 11 is positioned on the paper and the tip of the other print head 5 is positioned outside the paper, based on the information sensed by the sensor 13. The sensor 13 optically identifies the black color of the platen 12 and the white color of the paper 6 and detects the position of the edge of the paper 6.

First, an impact printer having an AGA function will be described with reference to FIG.

As shown in the figure, the rotation of a motor (not shown) under the control of the carriage moving means is transmitted via a belt 4 to the carriage 1.
The eccentric shaft 2 and the guide shaft 3 can be moved left and right using the guide shaft 3 as a guide. The print head 5 on the carriage 1
A card holder 7 for suppressing the floating of the paper 6 during printing, and a ribbon base 10 for winding the ink ribbon 8 when the ink ribbon cassette 9 is fixed are mounted.

The AGA arm 11 forms a part of the carriage 1, and the tip of the AGA arm 11 is a portion that comes into contact with the sheet 6 interposed between the AGA arm 11 and the platen 12 during the AGA operation. The carriage 1 is provided with a guide shaft 3
Has a degree of freedom in the front-rear direction, and can be moved back and forth by rotating the eccentric shaft 2. Therefore, the distance between the print head 5 and the paper 6 can be changed.

As shown in the figure, the tip of the print head 5 on the surface of the paper 6 at the time of printing and the AGA arm 11 for holding down the surface of the paper 6 at the time of AGA are attached to the platen 12 in terms of structure and operation. They face each other and are provided with a predetermined interval. As shown in the figure, the position of the AGA
It is assumed that the arm 11 has the tip of the print head 5 on the right side.

The sensor 13 of the sheet position detecting means added according to the present invention is attached to the card holder 7.

Next, referring to FIG. 1 and FIG. 2, the function of the above configuration according to the main operation procedure will be described.

First, when printing is started, the carriage 1 moves in the left and right movable ranges of the carriage 1, and
The upper sensor 13 detects the position (left end and right end) of the sucked sheet 6 (step S1). Next, based on the paper position detected by the sensor 13, the leading end of one print head 5 is moved to the paper 6 by a carriage moving unit (not shown).
And the carriage 1 moves so that the other AGA arm 11 is positioned above the sheet 6 (step S2).

The illustrated AGA arm 11 is a platen 1
2, the carriage 1 moves to the right end of the sheet 6 and moves further from this position when the right end of the sheet 6 is detected by the sensor 13. Then, the AGA arm 11 and the tip of the print head 5 are fixed at the predetermined positions, respectively.

Next, the conventional procedure S12 to S14 is performed.
Similarly to the above, the carriage 1 moves forward so that the paper 6 on the platen 12 is pressed by the AGA arm 11 in the direction of the platen 12 so that the paper thickness can be detected (step S3).
The AGA arm 11 presses the paper 6 on the platen 12 to detect the thickness of the paper, and a predetermined correction process for automatically maintaining the distance between the print head 5 and the paper 6 at a predetermined value is performed (step S4). Next, the carriage 1 retreats in the direction opposite to the platen 12 (step S5), and waits for a printing operation by the print head 5. The printing operation is the same as the conventional one.

In the above description, a sensor has been illustrated and described as the paper position detecting means. However, other means such as setting of a paper positioning guide key, setting of a size designation button, detection of a continuous paper by a tractor feeder, and the like may be used. Also,
The sensor is attached to the card holder, but may be at any location that can move with the carriage. Further, although the position of the AGA arm is illustrated and described as being on the left side of the print head, the function can be similarly satisfied on the right side.

As described above, the position and shape of each element are free as long as the above functions are satisfied, and the above description does not limit the present invention.

[0025]

As described above, according to the present invention, the print head and the AGA arm are provided facing the platen at a predetermined interval, and before the print head transfers ink to paper and performs printing, When performing the automatic paper thickness adjustment (AGA) that presses the print head on this paper and corrects the print head position according to the paper thickness, the sensor works with the carriage that moves the print head and detects the sucked paper position. Then, an impact printer is obtained in which the carriage positions the AGA arm, which is the mechanism for automatically adjusting the sheet thickness, on the sheet and the print head outside the sheet.
With this simple configuration, it is possible to obtain an impact printer that can prevent the paper from being stained during the automatic paper thickness adjustment.

[Brief description of the drawings]

FIG. 1 is an overall perspective view (A) showing an outline of an embodiment of the present invention, and a partial perspective view (B) showing details of a part of the embodiment.

FIG. 2 is a flowchart showing main operations according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a main operation according to a conventional example.

[Explanation of symbols]

 Reference Signs List 1 carriage 2 eccentric shaft 3 guide shaft 4 rotating belt 5 print head 6 paper 7 card holder 8 ink ribbon 9 ink ribbon cassette 10 ribbon base 11 AGA (automatic paper thickness adjustment) arm 12 platen 13 sensor

Claims (4)

(57) [Claims] 1. Prior to printing, a contact detection sensor which is linked with the print head is pressed so as to make the distance to the fixed paper surface equal to the print head, and the paper thickness is detected, whereby the initial position of the print head is corrected. An automatic paper thickness adjusting mechanism of a printer, comprising: a carriage on which the print head and the contact detection sensor are mounted and which moves while keeping a constant distance from the fixed paper surface; and a paper when the paper setting is determined. Paper setting range detecting means for outputting setting range information, wherein when the paper thickness is detected, the contact detection sensor is positioned within the paper range and the print head is positioned outside the paper range based on the paper setting range information. An automatic sheet thickness adjusting mechanism for a printer, wherein the carriage is controlled to move. 2. The automatic sheet thickness adjusting mechanism of a printer according to claim 1, wherein said sheet setting range detecting means is provided on a card holder for fixing a sheet surface. 3. The automatic paper thickness adjusting mechanism according to claim 2, wherein said card holder is mounted on said carriage. 4. An automatic paper thickness adjusting mechanism according to claim 1, wherein said paper setting range detecting means is an optical sensor.