JP2665150B2 - Serial printer with paper thickness detection mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer having a paper thickness detecting mechanism.

[0002]

2. Description of the Related Art Conventionally, in a serial printer of this type, characters to be printed are unclear or ink ribbon is stained due to the size of a gap between a print head and a sheet whose back surface is supported by a platen. And so on. As a countermeasure, a printer thickness is manually operated by a user of a printer to adjust a sheet thickness setting lever for adjusting a distance between a platen and a print head. The relationship between the setting position of the lever and the thickness of the paper to be used is specified in the user's manual etc. attached to the printer body, but the user's awareness of this lever itself is low, and adjustment to the optimal position is sure. It has not been done yet.

In order to solve the above-mentioned problem, a gap adjusting mechanism for a serial printer has been proposed, for example, as disclosed in Japanese Patent Application Laid-Open No. 3-39279. FIG. 5 is a plan view of a gap adjusting mechanism of the conventional serial printer, and FIG. 6 is a side view. Referring to FIG. 5 and FIG. 6, first, the print head 6 is fixed to the movable base 16 by using two fixing screws 17 so as to be at an optimum print position. Next, the paper 4 is sucked through the space between the platen 1 and the rotating ball 19. Then, the movable table 16 moves in the direction of arrow A with the contact point B between the movable table 16 and the carriage 7 as a fulcrum by the thickness of the paper 4. Is applied to the movable table 16 so that printing is always performed at the same print density while maintaining a constant gap amount even if the thickness and the number of sheets of paper 4 are different.

[0004]

Since the gap adjusting mechanism of the conventional serial printer adjusts the gap by pressing the rotating ball against the paper, the impression of the rotating ball is formed on the paper when copying paper or the like is used. Will happen.

SUMMARY OF THE INVENTION It is an object of the present invention to obtain a sheet thickness by a simple method, display the setting position of a sheet thickness setting lever based on the sheet thickness on an operation panel of a printer body, and raise the consciousness of the lever so that clear printing can be performed. It is to provide a printer capable of performing the above. Also,
An object of the present invention is to provide a printer capable of adjusting a gap between a print head and a platen based on a determined sheet thickness.

[0006]

A serial printer having a paper thickness detecting mechanism according to the present invention is in constant contact with paper conveyed by a platen near printing means and fixed to a housing.
A contacting means provided in the set paper traveling system and a moving amount of the contacting means depending on the paper thickness are fixed to the contacting means.
Encoder or strain gauge and the bridge containing it
Detection means for detecting by Tsu di circuit, a calculating means for calculating as a numerical value the position of the printing means from the amount of movement, and a display means for displaying the numerical value, the position of said printing means in response to the numerical manual Moving means for moving.

A serial printer having a paper thickness detecting mechanism according to the present invention is a paper printer which is always in contact with a paper conveyed by a platen near a printing means and is fixed to a housing.
A contacting means provided in the traveling system for contacting, and an amount of movement of the contacting means depending on the sheet thickness, an engine fixed to the contacting means;
For coder or strain gauge and bridge circuit containing it
Comprising a detection means for more detected, a calculating means for calculating the position of said printing means from said movement amount as a number, and a driving means for moving the optimum position said printing means from said value.

Further, in the serial printer having the sheet thickness detecting mechanism of the present invention, the contact means also serves as a guide plate for guiding the sheet to the platen.

Further, in the serial printer having the paper thickness detecting mechanism according to the present invention, the contact means is a needle-shaped member which comes into contact with the paper on the platen.

[0010]

[0011]

[0012]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of the present invention.
Referring to FIG. 1, the gap adjusting mechanism of the serial printer according to this embodiment includes a paper 4 conveyed by a platen 1.
Pressure plate 2 which comes into contact with print head 6
A strain gauge 5 and a detecting unit 9 for detecting the amount of movement of the pressure plate 2 due to the sheet thickness; a calculating unit 10 for calculating the position of the print head 6 from the amount of movement as a numerical value; and a display unit 11 for displaying the numerical value And a lever 8 for manually moving the position of the print head 6 according to this numerical value.

The operation of this embodiment will be described with reference to FIG. The paper 4 passes between the platen 1 and the pressure roller (not shown) in the direction of arrow A, and further passes through the gap between the platen 1 and the pressure plate 2 to face the print head 6. Z)
Advances in the direction of arrow B. At this time, the pressure plate 2 is attached to the housing 3 and has a function of guiding the paper 4 to the platen 1. However, when the paper 4 enters between the pressure plate 2 and the platen 1, the pressure The plate 2 acts in the same manner as a leaf spring, and bending occurs. This bending causes a dimensional change in the strain gauges 5 attached in the depth direction of the pressure plate 2. The calculation unit 1 calculates the change amount between the output value of the detection unit 9 due to the dimensional change and the output value of the detection unit 9 immediately before the paper 4 enters.
0 converts the thickness of the paper 4. The sheet thickness obtained in this manner is displayed on the display unit 11 as the setting position of the lever 8, and the user sets the lever 8 to an optimum position while watching this display, moves the carriage 7, and moves the platen 1. The print head 6 and the print head 6 are optimized.

FIG. 2 is a block diagram showing a second embodiment of the present invention. Referring to FIG. 2, the gap adjusting mechanism of the serial printer according to this embodiment includes a pressure plate 2 in contact with a sheet 4 conveyed by a platen 1 near a print head 6, and an amount of movement of the pressure plate 2 due to the sheet thickness. A strain gauge 5 to be detected and a detection unit 9;
And a drive unit 12 that moves the print head 6 to the optimum position based on the numerical values.

The operation of this embodiment will be described with reference to FIG. The functions of the strain gauge 5, the detection unit 9, and the calculation unit 10 are the same as those of the first embodiment. The drive unit 12 moves the carriage 7 based on an output signal indicating the thickness of the sheet 4 of the arithmetic unit 10, and optimizes the gap between the platen 1 and the print head 6.

FIG. 3 shows an embodiment of the strain gauge 5 and the detecting section 9 of the first embodiment and the second embodiment. When the dimensional change occurs in the strain gauge 5, the resistance value changes, so that the output value of the bridge circuit 20 is amplified by the amplifier 21 and output.

FIG. 4 shows another embodiment which replaces the strain gauge 5 and the detecting section 9 of the first embodiment and the second embodiment. That is, in this embodiment, the detection needle 15 is lightly contacted with the paper 4 on the platen 1 by the spring 14, and the encoder 13 detects the angle of the detection needle 15. Since the inclination of the detection needle 15 changes according to the thickness of the paper 4, the change value is measured by the encoder 13 and
Send to

[0018]

As described above, according to the present invention,
Contact means for contacting the paper conveyed by the platen in the vicinity of the printing means; detecting means for detecting the amount of movement of the contact means depending on the paper thickness; calculating means for calculating the position of the printing means from the movement amount as a numerical value; And a moving means for manually moving the position of the printing means in accordance with this numerical value, for example, for the printing of several spelled copy paper which is the greatest advantage of the impact serial dot printer. However, clear printing can always be performed. In addition, the sheet thickness can be measured by the amount of change from the state without the sheet every time the sheet is conveyed, so that an accurate measurement value can be obtained. In addition, since the contact means that makes light contact with the paper is used when measuring the thickness of the paper, no indentation is produced on the paper when copying paper or the like is used by other means.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a strain gauge and a detection unit according to the first embodiment and the second embodiment.

FIG. 4 is a view showing another embodiment that replaces the strain gauge and the detection unit of the first embodiment and the second embodiment.

FIG. 5 is a plan view of a gap adjusting mechanism of a conventional serial printer.

FIG. 6 is a side view of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Platen 2 Pressure plate 3 Case 4 Paper 5 Strain gauge 6 Print head 7 Carriage 8 Lever 9 Detector 10 Calculator 11 Display 12 Drive 13 Encoder 14 Spring 15 Detecting needle 20 Bridge circuit 21 Amplifier

Claims (4)

(57) [Claims] 1. A paper traveling device which is always in contact with a paper conveyed by a platen near a printing means and is fixed to a housing.
Contact means provided in the system, an encoder fixed to the contact means by an amount of movement of the contact means due to the sheet thickness or
Detecting means for detecting with a strain gauge and a bridge circuit including the same, calculating means for calculating the position of the printing means as a numerical value from the movement amount, display means for displaying the numerical value, and the printing means in accordance with the numerical value And a moving means for manually moving the position of the sheet. 2. A running paper sheet which is always in contact with a sheet conveyed by a platen near a printing means and is fixed to a housing.
Contact means provided in the system, an encoder fixed to the contact means by an amount of movement of the contact means due to the sheet thickness or
A strain gauge and detecting means for detecting by a bridge circuit including the strain gauge ; calculating means for calculating the position of the printing means as a numerical value from the movement amount; and driving means for moving the printing means to an optimum position from the numerical value. A serial printer having a sheet thickness detecting mechanism. 3. The serial printer according to claim 1, wherein said contact means also serves as a guide plate for guiding said sheet to said platen. 4. The apparatus according to claim 1, wherein said contact means is a needle-like member which contacts said sheet on said platen.
Or a serial printer having the paper thickness detecting mechanism according to 2.