KR20040034887A - Image printing apparatus - Google Patents

Abstract

PURPOSE: A video recording device is provided to include a sensing unit to automatically sense the thickness of a transferred paper, without deciding the paper thickness by a user, thereby correctly measuring the paper thickness. CONSTITUTION: A driving roller(123) is provided. An idle roller(124) facing with the driving roller(123) by interposing a paper therebetween is elastically biased toward the driving roller(123) and pushes and transfers the paper while rolling. A sensing unit(140) senses location variation of the idle roller(124) according to the thickness of the paper passing between the driving roller(123) and the idle roller(124) to sense the thickness of the transferred paper. The sensing unit(140) comprises a first gear(141) rotatively installed adjacently to the idle roller(124), a sensor(143) of which one end is fixed on the first gear(141) and the other end contacts an external circumference of the idle roller(124), a second gear(145) rotatively installed by gearing with the first gear(141), and an indicator(147) of which one end is fixed on the second gear(145) and the location of the other end varies according to the location variation of the sensor(143) to indicate the location variation of the sensor(143).

Description

Image recording apparatus

The present invention relates to an image recording apparatus, and more particularly, to an image recording apparatus having a sensing means capable of sensing the thickness of a sheet.

In general, image recording apparatuses such as printers, copiers, and facsimiles record images on paper or overhaul project (OHP) films. Such image recording apparatuses are designed based on the case where plain paper is used, since plain paper is used the most.

However, when using thicker or thinner paper than plain paper, the thickness of the paper used is different from that of the plain paper, which causes a deterioration in image quality recorded on the paper.

In particular, the ink-jet method of the recording method is a method of spraying ink onto paper and recording an image. The printhead of such an image recording apparatus has a plurality of nozzles which are fine ejection holes for ejecting ink. The heating means is provided in the chamber in which the ink is accommodated. The air in the ink is expanded by the heating means, and the ink is ejected to the outside through the nozzle by the air pressure.

Since the inkjet method is a method of injecting ink onto the paper, the distance between the printhead and the paper (hereinafter referred to as the head spacing) should be kept constant so as to optimize the print quality. In other words, when the head spacing becomes smaller or larger, the pixels become wider or narrower, and the shape of each pixel is deformed and the image quality recorded there is deteriorated.

The head spacing is determined on the basis of plain paper. When the paper is thicker or thinner than the plain paper, the head spacing becomes smaller or larger and the image quality recorded on the paper is degraded.

Therefore, a method of determining the head spacing according to the thickness of the paper in advance and allowing the user to adjust the head spacing using the operation lever according to the paper used is made.

However, even if the thickness of the paper is standardized, a predetermined deviation occurs even with respect to the thickness of the paper, and when using a paper whose thickness is not standardized, the user has to arbitrarily adjust the head spacing, and thus high quality images cannot be obtained.

In particular, if the head spacing is not maintained in an optimal state, the portion of the paper on which the ink ejected by the print head is buried is raised so that it is raised convexly toward the print head. When the carriage in which the print head is accommodated reciprocates in the vertical direction with respect to the paper discharge direction, the print head comes into contact with a portion where ink is ejected and convexly raised to disperse the ejected portion.

In addition, the position of the device for sensing the thickness of the paper is conventionally adjacent to the print head, there is a problem that the adjustment of the head spacing is delayed because the thickness of the paper is detected in a state near the print head.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide an image recording apparatus having a sensing means capable of automatically detecting the thickness of a paper to be used as printing paper.

1 is a perspective view showing an image recording apparatus according to the present invention;

FIG. 2 is a side view showing a schematic configuration of the image recording apparatus shown in FIG. 1;

3 is a view showing a configuration according to an embodiment of a paper thickness detecting means according to the present invention;

4 and 5 are views for explaining the operation of the sensing means shown in FIG.

6 is a view showing a configuration according to another embodiment of the paper thickness detecting means according to the present invention.

<Description of the symbols for the main parts of the drawings>

123 ... drive roller 124 ... idle roller

140 Detecting means 141 First gear

143 ... detector 145 ... second gear

147 ...

In order to achieve the above object, the image recording apparatus of the present invention includes an idle roller for conveying a sheet of paper while being rotated by being biased toward the driving roller by being installed oppositely with a sheet of paper between a driving roller and the driving roller. An image recording apparatus, comprising: sensing means for detecting a thickness of a conveyed paper by sensing an amount of positional change of the idle roller according to a thickness of a paper passing between the driving roller and an idle roller.

According to the present invention, the sensing means is the first gear portion rotatably installed adjacent to the idle roller, the first gear portion is fixed to the first end, the other end is detected to be installed to contact the outer peripheral surface of the idle roller Part, a second gear part which is installed to be rotatable in engagement with the first gear part, and one end of which is fixed to the second gear part, and the other end is changed in position corresponding to the position change amount of the sensing part so that the position change amount of the sensing part is changed. It is provided with an indicating unit.

According to the invention, the diameter of the pitch circle of the first gear portion is larger than the diameter of the pitch circle of the second gear portion.

According to the invention, the length of the sensing unit is characterized in that different from the length of the indicating unit.

According to the present invention, the detector and the indicator are characterized by forming a predetermined angle.

According to the present invention, the sensing means has a central portion as a rotating shaft, one end of the sensing unit is in contact with the outer peripheral surface of the idle roller, and the other end is formed integrally with an indicator indicating the displacement amount of the sensing unit, the sensing unit and the indicating unit Displace in the same direction.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing an image recording apparatus according to the present invention, and FIG. 2 is a side view showing a schematic configuration of the image recording apparatus shown in FIG. 1 and 2 show one of the image recording apparatuses. The paper cassette in which the paper is loaded is located at the lower part of the main body, and the paper is transferred to the printing unit by the pickup roller and printed. It is a figure which shows the inkjet printer in which the exit method was employ | adopted.

1 and 2, the paper feeding cassette 110 on which the paper P is loaded is installed at the front lower side of the printer main body. The paper P loaded in the paper feed cassette 110 is picked up by the pickup roller 121, and is disposed between the driving roller 123 and the idle roller 124 provided with the paper to be conveyed on the paper feed path. Pass through. The drive roller 123 is rotated by a separate transmission not shown, the idle roller 124 is elastically biased toward the drive roller 123 by an elastic means (not shown). Therefore, the idle roller 124 is capable of varying the position of the central axis corresponding to the thickness of the paper conveyed between the drive roller 123.

An unillustrated discharge roller which rotates in response to the rotational force of the driving roller 123 is installed on a paper discharge path, and a star wheel (not shown) is installed on the top of the discharge roller. Here, the star wheel which is in contact with the discharge roller acts to press the paper at a constant pressure at all times to keep the direction of paper constant, and the discharge roller receives the rotational force from the driving roller 123 and always drives the driving roller. Rotate at the same linear speed as (123). Then, on the conveying path of the paper between the drive roller 123 and the discharge roller is installed an ink cartridge 130 for printing on the paper while reciprocating left and right along the guide shaft 190 by the carriage motor 170 And a discharge bin 150 on which printed paper P is to be stacked is provided on the paper feed cassette 110.

Detecting means 140 for detecting the thickness of the paper adjacent to the idle roller 124 is installed. 3 is a view showing a configuration according to an embodiment of the paper thickness detecting means 140 according to the present invention.

Referring to FIG. 3, a first gear part 141 is rotatable adjacent to the idle roller 124, and teeth are formed on an outer circumferential surface thereof and have a length of a. One end is fixed to one side of the first gear portion 141, the other end is in contact with the outer peripheral surface of the idle roller 124, the sensing unit 143 having a pitch circle diameter of b is provided.

The second gear part 145 is rotatably engaged with the first gear part 141 and has a pitch circle diameter of c. One end is fixed to the second gear part 145, the other end is not restrained, and an instruction part 147 having a length of d is provided.

The sensing unit 147 detects a position change amount of the idle roller 124 whose position is shifted in correspondence to the thickness of the paper conveyed between the driving roller 123 and the idle roller 124.

The pitch circle diameter b of the first gear unit 141 may be larger than the pitch circle diameter d of the second gear unit 145. This is to amplify the displacement amount of the sensing unit 147 by using the reduction ratios of the first gear unit 141 and the second gear unit 145.

The indicating unit 147 transmits the position change amount of the idle roller 124 through the first gear unit 141 and the second gear unit 145 in response to the thickness of the paper detected by the sensing unit 143. Received and displayed. Preferably, the detector 143 and the indicator 147 are formed at a predetermined angle. Preferably, the angle formed by the detector 143 and the indicator 147 is between 90 and 180 degrees, and the length a of the detector 143 and the length d of the indicator 147 are different from each other. Do. This is to allow the indicator 147 to amplify and instruct the position change of the idle roller 124 detected by the detector 143.

The position displacement of the idle roller 124 is amplified by the indicator 147 and applied to a variable resistor (not shown) provided adjacent to the indicator 147. Therefore, the value of the resistance is changed in accordance with the amount of change of the indicator 147. When the resistance value changes, an amplifier not shown converts and amplifies the resistance value to the power value. Then, the gap L (see Fig. 2) between the paper P and the ink cartridge 130 is adjusted by a head gap adjusting device (not shown).

Here, an encoder strip or a photo sensor may be applied instead of an amplifier using a variable resistor.

Meanwhile, the current value of the pickup motor picking up the paper loaded in the cassette 110 may be adjusted by sensing the thickness of the paper. Since the current value of picking up thick paper differs from that of picking up thick paper, the current value is more consumed than picking up plain paper.

The operation of the sensing means according to the present invention will be described with reference to the drawings.

4 and 5 show the operation of the sensing means according to the present invention, Figure 4 shows the operation of the sensing means when the paper is thicker than the plain paper, Figure 5 is a detection when the paper is thinner than the plain paper It shows the operation of the means.

First, referring to FIG. 4, when the paper P is transferred between the driving roller 123 and the idle roller 124, the idle roller 124 has a central axis because the paper P is thicker than the plain paper. It is in O1 and moves to O2. Therefore, the sensing unit 143 is located at the position indicated by the dotted line and moves to the position indicated by the solid line. The change in position of the sensing unit 143 is represented by θ1. Meanwhile, since one end of the sensing unit 143 is fixed to the first gear unit 141, when the sensing unit 143 is displaced by θ1, the first gear unit 141 corresponds to an arrow A. FIG. Direction, the second gear portion 145 meshing with the first gear portion 141 is rotated in the direction of the arrow B. As the second gear 145 rotates, the indicator 147 is in the dotted line position and then rotates by θ2.

It is preferable that the size of θ2 is larger than the size of θ1, which depends on the length of the sensing unit 143 and the indicator 147 and the pitch circumferences of the first gear unit 141 and the second gear unit 145. Depends on the car on the deceleration ratio.

For example, if a = 20 mm, b = 10 mm, c = 5 mm, d = 10 mm, and the paper has a thickness of 1 mm,

The change amount θ2 of the indicator 147 is represented by the product of the change amount θ1 of the detector 143 and the magnification.

The change amount θ2 of the sensing unit 143 is 360: 20 mm * π = Χ: 1 mm

Χ = 360 * 1/20 * 3.14 = 5.73 °

The magnification is A / B * C / D, so 20/10 * 10/5 = 4

Therefore, the change amount θ2 of the indicating portion 147 is 5.73 ° * 4 = 22.9 °.

As described above, the magnification, the change amount θ1 of the sensing unit 143, and the change amount θ2 of the indicating unit 147 are the lengths of the sensing unit 143 and the indicating unit 147, the first gear unit 141, and the first gear unit 141. It is possible to have different values by varying the pitch circle diameters of the two gear parts 145.

Referring to FIG. 5, when the paper P is transferred between the driving roller 123 and the idle roller 124, since the paper P is thinner than the plain paper, the idle roller 124 has a central axis at O4. Is moved to O3. Therefore, the sensing unit 143 is located at the position indicated by the dotted line and moves to the position indicated by the solid line. Since one end of the D sensing unit 143 is fixed to the first gear unit 141, when the sensing unit 143 changes position, the first gear unit 141 rotates in the direction of an arrow C in response thereto. do. In addition, the second gear part 145 engaged with the first gear part 141 is rotated in the direction of arrow D. FIG.

Compared with the case where the thick paper shown in FIG. 6 is conveyed, it can be seen that the rotation directions of the first gear part 141 and the second gear part 145 are opposite.

6 is a view showing a configuration according to another embodiment of the paper thickness detecting means according to the present invention. The same reference numerals as in Fig. 3 denote the same members having the same function.

Referring to FIG. 6, the driving roller 123 and the idle roller 124 are disposed to face each other with the paper P therebetween, and the sensing means 240 is in contact with the outer circumferential surface of the idle roller 124. It is installed.

The sensing means 240 is rotatably installed around the central portion 242, one end of which is in contact with the outer circumferential surface of the idle roller 124 to detect a position change amount of the idle roller 124 ( 241, the other end of which is composed of an indicator 243 indicating a position change amount of the idle roller 124 measured by the detector 241. The sensing means 240 uses the principle of the lever.

The sensing unit 240 is integrally formed with the sensing unit 241 and the indicating unit 243, the rotation direction of the sensing unit 241 and the indicating unit 243 is the same. That is, when paper thicker than plain paper is conveyed, the sensing means 240 is rotated clockwise around the center portion 242, and when paper thinner than plain paper is conveyed, the sensing means 240 is moved. The center portion 242 is rotated counterclockwise.

As described above, the image recording apparatus according to the present invention does not determine the thickness of the paper, but the user can detect the thickness of the paper that is automatically fed using the sensing means, so that the thickness of the paper can be measured more accurately. There is.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and will be understood by those of ordinary skill in the art that various modifications and variations can be made therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (8)

An image recording apparatus comprising: an idling roller installed opposite to a driving roller with a sheet of paper interposed therebetween, and having an idler roller which is elastically biased toward the driving roller to push and rotate the sheet of paper. And sensing means for detecting the thickness of the conveyed paper by detecting an amount of position change of the idle roller according to the thickness of the paper passing between the driving roller and the idle roller. The method of claim 1, The sensing means A first gear part rotatably installed adjacent to the idle roller; One end is fixed to the first gear portion, the other end and the sensing unit is installed to be in contact with the outer peripheral surface of the idle roller A second gear part installed to be rotatably engaged with the first gear part; One end is fixed to the second gear portion, and the other end has an indication portion indicating a position change amount of the detection portion by changing a position corresponding to the position change amount of the detection portion. The method of claim 2, And the diameter of the pitch circle of the first gear portion is larger than that of the pitch circle of the second gear portion. The method of claim 2, And the sensing unit has a length different from that of the indicating unit. The method of claim 2, And the sensing unit and the indicating unit form a predetermined angle. The method of claim 1, The sensing means The sensing unit which is in contact with the outer circumferential surface of the idle roller, and the other end is integrally formed with an indicator indicating the displacement amount of the sensing unit, the sensing unit and the indicator are displaced in the same direction. An image recording apparatus. The method of claim 6, And the sensing unit has a length different from that of the indicating unit. The method of claim 6, And the sensing unit and the indicating unit form a predetermined angle.