JP2665157B2 - Gap control mechanism of serial printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gap control mechanism for a serial printer, and more particularly to a gap control mechanism for a serial printer for adjusting a gap between a print head and a sheet.

[0002]

2. Description of the Related Art Conventionally, a gap control mechanism of a serial printer of this type is designed so that the print quality does not deteriorate even when the thickness of a print sheet changes, as disclosed in Japanese Patent Application Laid-Open No. 4-265777. It is used for the purpose.

FIG. 4 is a perspective view showing an example of a gap control mechanism of the conventional serial printer. Referring to FIG. 4, the gap control mechanism of the serial printer includes:
Paper thickness detection rollers 102 and 110 that travel on the surface of the paper 103 and transmit changes in the unevenness 104 of the paper, and the paper 10 from the movement of the paper thickness detection rollers 102 and 110
Paper thickness detection sensors 105 and 1 for detecting the thickness of No. 3
11, a sheet thickness detection controller 106 for controlling the print head unit drive motor controller 108 based on signals from the sheet thickness detection sensors 105 and 111 and the head position sensor 107, and a sheet thickness detection controller 106
, A print head drive motor controller 108 for operating the print head drive motor 109 in response to the command, a print head drive motor 109 for moving the print head 101, and the print head 101 for printing.

Next, the operation will be described. Print head 101
When printing in the B direction from A, the paper thickness detection roller 10
2 runs on the paper 103. When the sheet thickness detecting roller 102 reaches the sheet unevenness 104, the sheet thickness detecting sensor 105 detects the sheet unevenness 104, and the degree and length of the unevenness are taken in by the sheet thickness detecting controller 106. The sheet thickness detection controller 106 detects the sheet unevenness 104 and, at the same time, takes in the head position detected by the head position sensor 107. Next, the print head 10
A drive signal is sent from the paper thickness detection controller 106 to the print head drive motor controller 108 immediately before the print head 1
09 is operated to move the print head 101 in the direction of the paper so as to keep the gap between the paper unevenness 104 and the print head 1 constant. When the print head 101 performs printing from the direction B to the direction A, the same operation is performed by the sheet thickness detecting roller 110 and the sheet thickness detecting sensor 111.

[0005]

As described above, the gap control mechanism of the conventional serial printer makes the paper thickness detecting roller contact the paper and travels in the lateral direction together with the print head, so that the surface of the paper is detected. Dirty on the track of the roller. In addition, when a copy sheet is used, the running trace of the sheet thickness detection roller appears on the second sheet, so that the copy sheet cannot be used.

[0006]

The gap control mechanism of the serial printer according to the present invention has one end divided into two and the other half.
A laser beam emitted from a conductor laser is incident and the other is light
Connected to the detector, the other end of the laser beam through a lens
And the reflected light of the laser beam from the paper is
It includes an optical fiber bundle that is incident through the lens, digitized to quantify detecting means for detecting the reflected light intensity, the reflected light intensity by irradiating the laser beam toward the paper traveling with the print head Means, reflected light intensity storing means for storing the reflected light intensity of the light beam corresponding to the reference gap amount between the print head and the sheet, and the gap corresponding to the quantified reflected light intensity and a moving means for the gap amount by comparing the amount with the reference gap amount to move the print head to approach the reference gap amount.

[0007]

[0008]

[0009]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention, and FIG. 2 is a perspective view showing a mechanism section of the embodiment.
Referring to FIGS. 1 and 2, the gap control mechanism of the serial printer according to this embodiment includes a semiconductor laser 5 that emits a laser beam, a photodetector 8 that detects a laser beam reflected from a sheet 10, and a semiconductor laser. 5 is condensed on the paper 10 and the condensed light
A lens 7 for condensing the light reflected by the laser beam 0 on the photodetector 8, one end of which is divided into two parts, one of which receives a laser beam irradiated from the semiconductor laser 5 and the other is connected to the photodetector 8, A laser beam is irradiated through a lens 7 and a gap sensor 9 composed of an optical fiber bundle 6 which receives reflected light of the laser beam from the paper 10 through the lens 7; and converts the reflected light intensity into numerical data. A / D converter 4; print head 1
A reflected light intensity storage unit 2 for storing the reflected light intensity of the laser beam corresponding to the gap between the sheet 4 and the sheet 10; and a gap for storing the reference gap between the print head 14 and the sheet 10 for each print column. Storage unit 3
A gap amount is obtained from the numerical value data of the reflected light intensity from the A / D conversion unit 4, the gap amount is compared with the reference gap amount, and the print head 14 is moved so that the gap amount approaches the reference gap amount. An arithmetic and control unit 1 for generating a signal; and a guide shaft front 15 mounted in two parallels
And guide shaft rear 16 and guide shaft front 15
And a print head 14 fixed to the carriage 13 for printing, and mounted on an eccentric shaft in front of the guide shaft 15 to change the gap by rotation. It comprises a drive gear 17, a step motor 12 for rotating the drive gear 17, and a mechanism section 18 having a motor drive section 11 for driving the step motor 12.

Next, the operation of this embodiment will be described with reference to FIGS. The semiconductor laser 5 emits irradiation light 21 according to a signal from the arithmetic and control unit 1. The irradiation light 21 passes through the optical fiber bundle 6 and is collected by the lens 7 to
Hit. The reflected light 22 which is irregularly reflected on the paper 10, condensed again by the lens 7 and passed through the optical fiber bundle 6 is detected by the light
It is led to. The intensity of the reflected light 22 detected by the light detector 8 is converted into numerical data by the A / D converter 4 and sent to the arithmetic and control unit 1. The arithmetic control unit 1 reads a reference gap amount corresponding to the numerical data from the reflected light intensity storage unit 2,
This gap amount is written to the address of the gap storage unit 3 corresponding to the current position of the gap sensor 9. The arithmetic control unit 1 reads a reference gap amount corresponding to the current position of the print head 14 from the gap storage unit 3 and sends a movement amount and a forward or reverse rotation signal to the motor drive unit 11 based on comparison with the current gap amount. . The step motor 12 rotates forward or backward to rotate the drive gear 17, and moves the carriage 13 forward or backward to keep the gap between the print head 14 fixed to the carriage 13 and the paper 10 constant.

The intensity of the reflected light 22 is, as shown in FIG.
Since the same gap amount changes depending on the quality and color of the paper 10, a reference value suitable for each paper is set as follows. First, the arithmetic and control unit 1 causes the stepping motor 12 to rotate forward through the motor driving unit 11 to hit the print head 14 against the paper 10. Then, set the stepping motor 12 to 50
Reverse by the gap amount of micrometer. The intensity of the reflected light 22 and the gap amount at that time are stored in the reflected light intensity storage unit 2.
Write to. This is repeated until the gap between the print head 14 and the paper 10 becomes 5 mm. This data is used as a reference value for the reflection intensity and the gap amount of each sheet.

In the above-described embodiment, the optical fiber bundle 6 is provided between the semiconductor laser 5, the lens 7 and the photodetector 8, but the optical fiber bundle 6 is not provided and the semiconductor laser 5 is provided.
It is also possible to arrange such that the laser beam from is directly condensed on the paper 10 by the lens 7, and the reflected light is incident on the light detection unit 8 by the lens 7.

[0013]

As described above, according to the present invention,
It travels along with the print head, irradiates a light beam to the paper, detects the reflected light intensity, quantifies the reflected light intensity, compares this value with the reference gap amount, and compares this value with the reference gap amount. By moving the print head, clear printing can be performed even on paper having an uneven surface.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a mechanism section of the embodiment.

FIG. 3 is a diagram illustrating a relationship between a difference between sheets, a gap amount, and a reflected light intensity.

FIG. 4 is a perspective view showing an example of a gap control mechanism of a conventional serial printer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 arithmetic control unit 2 reflectance storage unit 3 gap storage unit 4 A / D conversion unit 5 semiconductor laser 6 optical fiber bundle 7 lens 8 light detection unit 9 gap sensor 10 paper 11 motor drive unit 12 step motor 13 carriage 14 print head 15 Before the guide shaft 16 After the guide shaft 17 Drive gear 18 Mechanism 21 Irradiation light 22 Reflected light

Claims (1)

(57) [Claims] 1. A semiconductor laser wherein one end is divided into two and one is divided into two.
Laser beam emitted from the
Then, the other end is irradiated with the laser beam through a lens,
The reflected light of the laser beam from the paper passes through the lens
A digitizing means comprises an optical fiber bundle, to quantify and detection means for detecting the reflected light intensity, the reflected light intensity by irradiating the laser beam toward the paper traveling with the print head for incident Te, Between the print head and the paper
And the reflected light intensity storing means for storing the reflected light intensity with respect to the sheet of the light beam corresponding to the reference gap amount, the gap amount corresponding to digitized the reflected light intensity before
Serial reference gap amount and the gap control mechanism of a serial printer, characterized in that it comprises a moving means for said gap weight compared to move the print head to approach the reference gap amount.