KR20040110162A - A paper skew detecting apparatus and method of paper skew detecting thereof - Google Patents

Abstract

PURPOSE: A paper skew detecting apparatus and a method thereof are provided to detect the skew of paper by using the length of the paper. CONSTITUTION: A paper skew detecting apparatus includes an optical sensor(30). The optical sensor(30) includes a light irradiating part(31) and a light receiving part(32). The light irradiating part(31) has an ink cartridge including a print head(22a) and is installed in a carriage going and coming in a vertical direction to a paper transporting direction. The light receiving part(32) receives the light irradiated by the light irradiating part(31). The optical sensor(30) detects the length of the paper at plural detection positions according to a paper transporting direction.

Description

Paper skew detecting apparatus of inkjet printer and paper skew detecting method using the same

The present invention relates to an inkjet printer, and more particularly, to a paper skew detection device of an inkjet printer for detecting skew of paper using one light sensor unit, and a paper skew detection method using the same.

In general, an inkjet printer is an output device which prints a desired image by injecting ink onto a paper surface while the ink cartridge mounted on the carriage moves in a vertical direction with respect to the paper conveying direction.

In such an inkjet printer, paper loaded in a paper tray not shown in the drawing is conveyed to the bottom of the inkjet head by a line feed roller rotated by a line feed motor at the time of printing.

The carriage equipped with the ink cartridge storing the ink is linearly reciprocated on the paper by the driving means. The inkjet head provided on the bottom of the ink cartridge ejects ink to form a desired image on the paper. The sheet on which the image is formed is discharged to the discharge bin by the discharge roller.

In the conventional inkjet printer configured as described above, when the user loads the paper in the paper tray, the paper may be loaded at an angle, and the paper may be inserted at an angle in the process of being transferred into the main body. In such a state that the paper is conveyed at an angle, the inkjet head ejects ink onto the paper to form an image.

Since the paper is discharged in a crooked state, the image formed on the paper by the inkjet head is skewed as a whole. In addition, a situation arises in which the paper fed at an angle during the printing operation is crumpled or torn.

In order to solve the above problems, as shown in FIG. 1, the carriage (not shown) attached to the optical sensor unit passes through the paper P, which is obliquely conveyed, irradiates light and detects the reflected light amount. By using the difference, whether the paper is skewed is detected and notified to the user or the printing is stopped.

That is, the carriage passes in the direction of arrow D on the sheet of paper P conveyed in the direction of arrow C. At this time, the light sensor unit emits light downward from the irradiation unit, and the light receiving unit receives the reflected light. The light receiving unit detects the difference between the amount of light reflected from the paper P and the printer body, recognizes the existence of the paper P, and calculates the length L 'of the paper P from the two points where the paper P is recognized. .

Then, if the measured length L 'is less than the length L of the original paper by comparing the length L of the paper P already known and the length L' of the paper measured above, skew occurs in the paper. Recognize that.

The above paper skew detection device must know the length L of the original paper so that it can be compared with the measured value. Therefore, in the case of using various types of paper, it is inconvenient to know the length L of each paper in advance and input them individually.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a paper skew detecting apparatus of an inkjet printer for detecting skew of paper through a difference in paper length measured at each point using a difference in the amount of light reflected from the paper with one optical sensor, and The purpose is to provide a paper skew detection method using the same.

1 is a view for explaining a method for detecting a paper skew in a conventional inkjet printer,

Figure 2 is a perspective view showing an inkjet printer to which the paper skew detection device according to the present invention is applied,

Figure 3 is a side view for explaining the installation position of the paper skew detection apparatus according to an embodiment of the present invention,

Figure 4 is a side view for explaining the installation position of the paper skew detection apparatus according to another embodiment of the present invention,

5 and 6 are views for explaining the operation of detecting the length of the paper at the first detection position in the paper skew detection device according to the present invention;

7 and 8 are views for explaining the operation of the paper skew detecting apparatus according to the present invention to detect the length of the paper at the second detection position,

Fig. 9 is a flowchart showing a method of detecting a skew of paper by the paper skew detecting apparatus according to the embodiment of the present invention.

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

21.Feeder 22.Ink cartridge

22a ... factor head 23 ... carriage

24 ... carriage shaft 25 ... line feed motor

30 ... light sensor part 31 ... irradiation part

32.Receiver

In order to achieve the above object, the paper skew detecting device of the inkjet printer of the present invention is installed in a carriage equipped with an ink cartridge having a print head and reciprocated vertically with respect to the conveying direction of paper, thereby irradiating light to the conveyed paper. And an optical sensor having a light receiving unit for receiving light reflected from the paper or the main body by being irradiated from the irradiating unit, wherein the optical sensor is a conveying direction of the paper at a plurality of detection positions along the conveying direction of the paper. The length of the paper is respectively detected in a direction perpendicular to, and the difference of the paper length detected by the optical sensor at a plurality of points is compared with a set value to detect whether the paper is skewed.

According to the invention, the optical sensor is located in front of the printing head with respect to the conveying direction of the paper.

According to the invention, the optical sensor is located under the carriage.

According to the invention, the optical sensor is located on the side of the carriage.

According to the present invention, the optical sensor detects the length L1 of the paper in a direction perpendicular to the conveying direction of the paper at the first detection position where the paper is located below the optical sensor, and the paper detects the paper. The length L2 of the sheet is detected in a direction perpendicular to the conveying direction of the sheet at the second detection position located below the print head.

According to another feature of the invention, the step of conveying the paper to the first detection position;

Detecting the length L1 of the sheet in a direction perpendicular to the conveying direction of the sheet using an optical sensor;

Detecting the length L2 of the paper in a direction perpendicular to the conveying direction of the paper at a second detection position using the optical sensor;

Comparing the difference value between the length L1 and L2 of the paper detected by the optical sensor with a setting value; And

And outputting a skew generation message of the paper when it is determined that the difference value of the detection value is larger than a set value.

According to the invention, before the step of the optical sensor detecting the length L2 of the paper at the second detection position, the method further includes the step of conveying the paper to the second detection position.

According to the invention, in the step of detecting the length (L1) of the paper,

The optical sensor detects the length L1 of the paper in a direction perpendicular to the conveying direction of the paper at the first detection position where the paper is located below the optical sensor.

According to the invention, in the step of detecting the length (L2) of the paper,

The optical sensor detects the length L2 of the paper in a direction perpendicular to the conveying direction of the paper at the second detection position where the paper is located below the print head.

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

2 is a perspective view illustrating an inkjet printer to which a paper skew detecting apparatus according to the present invention is applied, FIG. 3 is a side view for explaining an installation position of the paper skew detecting apparatus according to an embodiment of the present invention, and FIG. 5 and 6 are side views illustrating the installation position of the paper skew detecting apparatus according to another embodiment of the present invention. FIGS. 5 and 6 are views for explaining an operation of detecting the length of the paper at the first detection position by the paper skew detecting apparatus according to the present invention. 7 and 8 are diagrams for explaining an operation in which the paper skew detecting apparatus according to the present invention detects the length of the paper at the second detection position.

2 to 4, the inkjet printer detects a feed tray 21 for loading paper P, a printing unit for forming an image on the paper P, and a skew of the paper P. And a paper skew detecting device.

The printing unit is mounted on the carriage shaft 24 so as to be reciprocated in a vertical direction with respect to the conveying direction of the paper P, and loaded on the carriage 23 to receive ink, and to store ink below. And an ink cartridge 22 provided with a printing head 22a provided with a plurality of nozzles for ejecting the gas into the nozzle.

The paper skew detecting device is provided in front of the printing head 22a with respect to the conveying direction of the paper P, and irradiates light reflected from the irradiating portion 31 and the irradiating portion 31 to irradiate light. It includes an optical sensor unit 30 having a light receiving unit 32 for receiving.

The optical sensor unit 30 is installed at the lower portion of the carriage 23 as shown in FIG. 3, but may be installed at either side of both sides of the carriage 23 as shown in FIG. 4. It may be.

This is because the optical sensor unit 30 moves together in the moving direction of the carriage 23 and skews the paper P before an image is printed on the paper P by the printing head 22a. This is because the printing head 22a needs to be provided in front of the conveying direction of the paper P so as to be detected.

The paper P loaded on the tray 21 is transferred to the printer main body by a line feed roller (not shown) operated by the line feed motor 25 and passes through the print head 22a. After it is formed, it is discharged out of the body.

9 is a flowchart illustrating a method of detecting a skew of a sheet by the sheet skew detecting apparatus according to the embodiment of the present invention.

9, the optical sensor unit 30 detects lengths L1 and L2 of the paper P in a direction perpendicular to the conveying direction of the paper P at a plurality of detection positions, respectively. (S200), determining whether the difference value of the length (L1) (L2) of the paper (P) measured from the detecting step (S200) is larger than a set value (F) (S300), the determining step In step S300, if the difference value L2-L1 of the length L1 and L2 of the paper P is larger than the set value F, notifying the user of the paper skew generation (S400) and determining In operation S300, when the difference values L2 through L1 of the lengths L2 and L1 of the paper P are less than or equal to the set value F, printing may be performed (S600).

The set value F is a value which can be set in advance to a value within a range in which an image can be formed on the paper P, even if the paper P has some skew.

The optical sensor unit 30 detects lengths L1 and L2 of the paper P, respectively, in a direction perpendicular to the conveying direction of the paper P at a plurality of detection positions (S200). In step S210 of feeding (P) to the first detection position (I), the carriage 23 positioned at the home position is moved vertically with respect to the conveying direction of the paper P. In step S220, the optical sensor unit 30 detects the length L1 of the paper P placed in a direction perpendicular to the conveying direction of the paper P (S230) and the paper P. Feeding the paper to the second detection position (II) (S240), moving the carriage 23 in the vertical direction with respect to the conveying direction of the paper (P), and moving to the home position (S250) and the light The sensor unit 30 detects the length L2 of the paper P placed in a direction perpendicular to the conveying direction of the paper P (S260). It includes.

The method of detecting the skew of the paper by the paper skew detecting apparatus of the inkjet printer according to the present invention as described above will be described in detail with reference to the drawings.

3 to 6 and 9, when a print signal is transmitted from the outside, the controller (not shown) moves the paper P to the lower portion of the optical sensor unit 30, which is the first detection position I. Transfer (S210).

The carriage 23 is conveyed in a vertical direction with respect to the conveying direction of the paper P along the carriage shaft 24 from the home position position (S220). In this case, the irradiation unit 31 of the optical sensor unit 30 irradiates light downward, and the light receiving unit 32 receives the light reflected from below.

As shown in Fig. 6, when the paper P is placed at an angle to the conveying direction, the light irradiated from the irradiating portion 31 is first reflected from the printer main body and received by the light receiving portion 32. However, when the optical sensor unit 30 reaches the position of P1, light irradiated downward from the irradiation unit 31 is reflected from the paper P and received by the light receiving unit 32.

At this time, the amount of light reflected from the printer body and the amount of light reflected from the paper (P) is different, so that the control unit recognizes the presence or absence of the paper (P) by using this.

When the optical sensor unit 30 is moved to the P2 position and passes the P2 position, the light sensor unit 30 has a difference in the amount of light received by the light receiving unit 32, so that the control unit is reflected from the paper P, so that the amount of light is the same as the P1 position. And detect a vertical distance L1 between the positions P2 (S230).

In the step S230, after detecting the vertical distance L1 between P1 and P2 of the paper P, the controller (not shown) moves the paper P to the second detection position II of the printing head 22a. Transfer to the lower (S240).

The carriage 23 is located at the opposite side of the home position through the step S220, and is then transferred vertically with respect to the conveying direction of the paper P along the carriage shaft 24 (S250). In this case, the irradiation unit 31 of the optical sensor unit 30 irradiates light downward, and the light receiving unit 32 receives the light reflected from below.

As shown in FIG. 8, the light irradiated from the irradiator 31 is first reflected from the printer body and received by the light receiver 32. However, when the light sensor unit 30 reaches the position of P3, the light irradiated downward from the irradiation unit 31 is reflected from the paper P and received by the light receiving unit 32.

In this case, since the amount of light reflected from the printer body and the amount of light reflected from the paper P are different, the controller recognizes the paper P by using the difference.

When the light sensor unit 30 moves to the P4 position and passes the P4 position, the light sensor unit 30 has a difference in the amount of light received by the light receiving unit 32, so that the control unit is reflected from the paper P, so that the amount of light is the same as the P3 position. And vertical distance L2 between positions P4 (S260).

The controller determines whether the difference value L2-L1 between the paper length L1 detected in the step S230 and the paper length L2 detected in the step S260 is greater than the set value F (S300). At this time, L2-L1 uses the absolute value. Generally, the absolute value is used because the paper length L2 detected at the second detection position is larger than the paper length L1 detected at the first detection position when skew occurs in the paper. It doesn't matter if you don't.

In step S300, if it is determined that the absolute value L2-L1 of the difference between the paper lengths detected at the first detection position and the second detection position is larger than the set value F, the user is notified of "paper skew generation". (S400). Then, printing is stopped (S500). Here, the method of notifying the user of the paper skew generation is to output a paper skew generation message to the display panel, to flash the LED or the light emitting, to emit a beep or to send the skew generation message to the communication means used by the user Various methods, such as a method, can be used.

In step S300, when it is determined that the absolute value L2-L1 of the difference between the paper lengths detected at the first and second detection positions, respectively, is not greater than the set value F, that is, the absolute value of the difference of the paper lengths is determined. If it is determined that (L2-L1) is less than or equal to the set value (F), printing is performed (S600).

As described above, since the paper skew adjusting apparatus of the inkjet printer according to the present invention determines whether the paper is skewed by comparing the paper lengths measured at a plurality of detection positions with one optical sensor unit, the paper length is determined separately. There is no need to set, and the skew of the paper can be detected accurately regardless of the paper type.

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 (9)

An ink cartridge equipped with a printing head and installed in a carriage reciprocating in a vertical direction with respect to the conveying direction of the paper, the irradiating part for irradiating light to the conveyed paper, and the light irradiated from the irradiating part and reflected from the paper or the main body It includes an optical sensor having a light receiving unit for receiving the light, The optical sensor detects the length of the paper respectively in a direction perpendicular to the conveying direction of the paper at a plurality of detection positions along the conveying direction of the paper, The paper skew detection apparatus of the inkjet printer, characterized in that for detecting the skew of the paper by comparing the difference value of the paper length detected by the optical sensor at a plurality of points with a set value. The method of claim 1, And the optical sensor is located in front of the print head with respect to the conveying direction of the paper. The method of claim 1, The optical sensor is a paper skew detection device of the inkjet printer, characterized in that located below the carriage. The method of claim 1, The optical sensor is a paper skew detection device of the inkjet printer, characterized in that located on the side of the carriage. The method of claim 1, The optical sensor detects the length L1 of the paper in a direction perpendicular to the conveying direction of the paper at the first detection position where the paper is located below the optical sensor, The paper skew detection apparatus of the inkjet printer, characterized in that for detecting the length (L2) of the paper in a direction perpendicular to the conveying direction of the paper at the second detection position where the paper is located below the print head. Conveying the paper to the first detection position; Detecting the length L1 of the sheet in a direction perpendicular to the conveying direction of the sheet using an optical sensor; Detecting the length L2 of the paper in a direction perpendicular to the conveying direction of the paper at a second detection position using the optical sensor; Comparing the difference value between the length L1 and L2 of the paper detected by the optical sensor with a setting value; And And outputting a skew generation message of the paper when it is determined that the difference value of the detection value is larger than a set value. The method of claim 6, And before the optical sensor detects the length L2 of the paper at the second detection position, transferring the paper to the second detection position. The method of claim 6, In detecting the length L1 of the paper, The optical sensor detects the paper skew of the inkjet printer, wherein the paper length L1 is detected in a direction perpendicular to the conveying direction of the paper at the first detection position where the paper is located below the optical sensor. Way. The method of claim 6, In detecting the length L2 of the paper, The optical sensor detects the paper skew of the inkjet printer, wherein the paper length L2 is detected in a direction perpendicular to the conveying direction of the paper at a second detection position where the paper is located below the printing head. Way.