JP2002361857A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ink jet printer which can place ink drops from nozzles of an ink jet head to desired positions of a medium surface correctly without a deviation in a Y direction even when a linear scale extends or contracts in accordance with a temperature or humidity change in the surroundings. SOLUTION: A ratio R between an actual travel distance A travelled by the ink jet head 10 in the Y direction and a measured travel distance B of the ink jet head 10 read from a scale 72 of the linear scale is calculated by a calculating means 100. The measured travel distance B in the Y direction of the ink jet head 10 read from the scale 72 of the linear scale is corrected on the basis of the ratio R by a correcting means 110 to agree with the actual travel distance A. Ink drops are discharged by a predetermined timing from nozzles 12 of the ink jet head by an ink jet means 120 on the basis of Y direction travel position data of the ink jet head 10 obtained by the correction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer which prints a picture or a character consisting of an array of a plurality of ink dots on a surface of a medium such as a sheet using ink droplets ejected from nozzles of an ink jet head. .

[0002]

2. Description of the Related Art As shown in FIGS. 3 and 4, an ink jet head 10 is arranged above a medium 30 such as a sheet mounted on a platen 20 in a Y direction substantially parallel to the medium 30.
Relatively (horizontal) direction or X (front-back) direction,
A plurality of nozzles 1 arranged on the lower surface of the inkjet head 10
Ink droplets ejected from each of the plurality of nozzles 12 arranged on the lower surface of the ink jet head 10 are ejected from each of the nozzles 12 at predetermined positions on the medium 30 by ejecting ink droplets toward the medium 30 at predetermined timing. 2. Description of the Related Art Ink jet printers that land in a shape are well known. According to this inkjet printer, the media 3
A picture or character consisting of an array of a plurality of ink dots can be printed on the zero surface. Among these, an ink jet printer that moves the medium 30 on the platen 20 in the X direction and moves the ink jet head 10 relatively above the medium 30 in the X direction is called a paper moving type printer. On the other hand, the medium 30 is fixedly mounted on the flat platen 20 and the upper side of the medium 30 is positioned above the ink jet head 10.
The inkjet printer which moves in the XY directions
It is called a flatbed type printer.

In this paper moving type and flat bed type ink jet printer, an ink jet head 10 is moved in a Y direction above a media 30 mounted on a platen 20 by using an electric motor 50 whose rotation is controlled by an encoder 40. Is running. More specifically, as shown in FIGS. 3 and 4, an endless belt 60 is looped around a driving pulley 62 and a driven pulley 64 in a loopable manner. A drive shaft 52 of an electric motor for rotating the drive pulley is connected to the drive pulley 62. The electric motor 50 is provided with an encoder 40 for controlling the rotation of the electric motor. Then, the electric motor 50 is rotated by the encoder 40 in the normal / reverse direction by a predetermined angle, and the endless belt 60 wrapped around the drive pulley 62 and the driven pulley 64 is circulated in the normal / reverse direction.
Then, the inkjet head 10 supported by the endless belt 60 is made to run in the forward and reverse directions in the Y direction corresponding to the circulating direction of the endless belt 60.

In the same Y direction as the running direction of the ink jet head 10, as shown in FIG.
0 is stretched. The linear scale 70 is formed from a strip-shaped transparent polyester film or the like,
A large number of linear scales 72 are printed on the linear scale 70 at a pitch of, for example, 720 dpi. A linear scale sensor 80 is integrally attached to the head frame 14 that supports the inkjet head 10 on the endless belt 60. The linear scale sensor 80 is, as shown in FIG.
And is moved in the Y direction along the linear scale 70. The linear scale sensor 80 including the light emitting element 82 and the light receiving element 84 provided so as to sandwich the linear scale 70 allows the inkjet head 10 traveling in the Y direction integrally with the linear scale sensor 80 to move in the Y direction. Reading is made from a scale 72 engraved on a transparent linear scale 70.

[0005] In the ink jet printer shown in FIGS. 3 and 4, the endless belt 60 can be circulated by using the electric motor 50 whose rotation is controlled by the encoder 40. Then, the inkjet head 10 supported by the endless belt 60 can be run in the Y direction. At this time, the graduation 72 engraved on the linear scale 70 extended in the same Y direction as the traveling direction of the inkjet head 10 is set to the Y-direction traveling position of the inkjet head 10 so as to be integrated with the inkjet head 10 in the Y direction. It can be detected by reading from the linear scale sensor 80 traveling in the direction. And
Based on the detected travel position data of the inkjet head 10 in the Y direction, ink droplets are ejected from a plurality of nozzles 12 arranged on the lower surface of the inkjet head 10 in accordance with a picture or character data input to a host computer or the like for driving the inkjet printer. Can be injected at a predetermined timing. Then, with the ink droplets, a picture or a character composed of an array of a plurality of ink dots can be printed on the surface of the medium 30.

[0006]

However, the scale 72 of the linear scale 70 is read by the linear scale sensor 80, and the Y scale of the ink jet head 10 is read.
Direction, and based on the detected traveling position data of the inkjet head 10 in the Y direction, ink droplets are ejected from a plurality of nozzles 12 arranged on the lower surface of the inkjet head 10 at a predetermined timing in accordance with a picture or character data. When ejected, the length in the Y direction of a picture or character composed of an array of a plurality of ink dots printed on the surface of the medium 30 by the ink droplets is printed using the ink jet printer from the picture or character data. The length of the picture or character to be attempted is longer or shorter than the length in the Y direction. For this reason, it has not been possible to print a small poster picture for a large poster combination or an original drawing for a printing plate, which requires accurate accuracy, by the above-described ink jet printer.

[0007] The reason is that the linear scale 70 made of a polyester film or the like expands and contracts in the Y direction depending on the weather conditions around the linear scale. Specifically, for example, when the linear scale 70 is formed from a polyester film, the linear scale 70
Of the linear scale 70 with respect to the humidity is 0.01% / ° C.
01% /% RH. Therefore, when the temperature around the linear scale 70 formed from the polyester film rises by 30 ° C., the linear scale 70
The elongation per 0 mm is 45 μm. When the humidity around the linear scale 70 formed from the polyester film increases by 60%, the elongation of the linear scale 70 per 150 mm becomes 90 μm. as a result,
Scale 7 engraved on linear scale 70 placed under predetermined weather conditions that expands and contracts with changes in ambient temperature and humidity.
This is because the travel position data in the Y direction of the inkjet head 10 read by the linear scale sensor 80 from Step 2 may be out of order.

The present invention has been made in order to solve such a problem, and even if the linear scale expands and contracts in the Y direction due to a change in the surrounding temperature and humidity, the linear scale is not affected by the expansion and contraction. In accordance with the position of the picture or character to be printed using the ink jet printer from the picture or character data, the ink droplet ejected from the nozzle of the ink jet head at a predetermined timing in the Y direction to the desired position on the media surface. It is an object of the present invention to provide an ink jet printer that can accurately land without deviation.

[0009]

In order to achieve the above object, a first ink jet printer according to the present invention is an ink jet printer having a structure in which an ink jet head is run in a Y direction by using an electric motor whose rotation is controlled by an encoder. A printer, wherein:
Direction is detected by reading a scale engraved on a linear scale extending in the same Y direction as the traveling direction of the inkjet head by a linear scale sensor traveling in the Y direction integrally with the inkjet head. The electric motor is rotated by a predetermined angle by the encoder in an ink jet printer having a structure in which ink droplets are ejected from nozzles of the ink jet head at a predetermined timing based on travel position data of the ink jet head in the Y direction according to a picture or character data. At this time, the actual travel distance A that the inkjet head actually travels in the Y direction calculated from the rotation angle of the electric motor rotated by the encoder, and the scale engraved on a linear scale placed under predetermined weather conditions, The linear scale sensor reads Y of the inkjet head taken
Calculating means for calculating a ratio R to the measured traveling distance B in the direction, and based on the ratio R calculated by the calculating means,
Correction for correcting the measured travel distance B of the inkjet head in the Y direction read by the linear scale sensor from the scale of the linear scale placed under the predetermined weather conditions so as to match the actual travel distance A of the inkjet head in the Y direction. Means, and an ink jet head obtained by correcting the measured traveling distance B in the Y direction of the ink jet head read by the linear scale sensor from the scale engraved on the linear scale placed under the predetermined weather conditions by the correction means. An ink ejecting means for ejecting ink droplets from the nozzles of the inkjet head at a predetermined timing based on the travel position data in the Y direction and in accordance with the picture or character data is provided.

In the first ink jet printer, when the electric motor is rotated by a predetermined angle by the encoder to move the ink jet head in the Y direction,
The actual travel distance A that the ink jet head has actually traveled in the Y direction can always be accurately calculated from the rotation angle of the electric motor rotated by an encoder that is not affected by changes in ambient temperature or humidity. At the same time, the measured travel distance B of the inkjet head in the Y direction at that time is measured by a linear scale sensor that travels in the Y direction integrally with the inkjet head under a predetermined weather condition that expands and contracts with changes in ambient temperature and humidity. It can be read from the scale engraved on the placed linear scale. Then, the ratio R between the actual traveling distance A and the measured traveling distance B can be calculated by the calculating means. Then, based on the ratio R, the measured travel distance B in the Y direction of the ink jet head read by the linear scale sensor from the scale of the linear scale placed under predetermined weather conditions that expands and contracts with changes in the surrounding temperature and humidity.
Can be corrected by the correction means so as to match the actual traveling distance A of the inkjet head in the Y direction. Then, the measured travel distance B in the Y direction of the inkjet head read by the linear scale sensor from the scale engraved on the linear scale placed under predetermined weather conditions that expands and contracts with changes in the surrounding temperature and humidity is corrected. Based on the accurate traveling position data in the Y direction of the ink jet head obtained by the correction according to the above, ink droplets are ejected from the nozzles of the ink jet head at a predetermined timing by the ink ejecting means in accordance with a picture or character data, and the ink is ejected. The droplet can be accurately landed at a desired position on the surface of the medium without displacement in the Y direction. Then, the length of the Y direction in the Y direction of the picture or character to be printed using the ink jet printer from the picture or character data is determined by the ink droplet that has been accurately landed at a desired position on the surface of the medium without displacement in the Y direction. It is possible to accurately print a picture or a character composed of an array of a plurality of ink dots having the same length as the length of the ink on the surface of the medium.

According to a second ink jet printer of the present invention, in the first ink jet head printer of the present invention, instead of the correction means, a picture or a character to be printed from a picture or character data using an ink jet printer is used. A correction device for creating a corrected picture or character data enlarged or reduced in the Y direction by a ratio R of the actual traveling distance A to the measured traveling distance B calculated by the calculating means, and In place of the means, the travel position in the Y direction of the ink jet head read by the linear scale sensor from the scale engraved on the linear scale placed under the predetermined weather conditions according to the corrected picture or character data created by the correction device Based on the data, the ink droplets from the nozzles of the inkjet head It is characterized in that the ink ejection device for ejecting at timing is provided.

In the second ink jet printer, a picture or character to be printed using the ink jet printer from a picture or character data is expanded and contracted in accordance with a change in ambient temperature or humidity using a correction device. The ratio R of the actual travel distance A in the Y direction of the inkjet head to the measured travel distance B in the Y direction of the inkjet head read by the linear scale sensor from the scale of the linear scale placed under weather conditions, in the Y direction A corrected picture or character data enlarged or reduced in size can be created. Then, in accordance with the correction picture or character data created by the correction device, the Y of the inkjet head read by the linear scale sensor from the scale of the linear scale placed under predetermined weather conditions that expands and contracts with changes in ambient temperature and humidity. Based on the traveling position data of the direction,
By the ink ejection device, an ink droplet can be ejected from a nozzle of the inkjet head at a predetermined timing. Then, the ink droplets are corrected according to the correction pictorial diagram or character data created by the correction device in accordance with the expansion / contraction state of the linear scale placed under predetermined weather conditions that expand and contract with changes in the surrounding temperature and humidity. Based on the previous picture or character data, it is possible to accurately land at a desired position on the surface of the medium to be landed without shifting in the Y direction. Then, Y is placed at a desired position on the surface of the medium.
A plurality of ink droplets whose length in the Y direction is the same as the length in the Y direction of the picture or character to be printed from the picture or character data using an ink jet printer by ink droplets that have been accurately landed without deviation in direction. It is possible to accurately print a picture or a character composed of an array of ink dots on the surface of a medium.

[0013]

FIG. 1 shows a preferred embodiment of a first ink jet printer of the present invention, and FIG. 1 is a front view showing a schematic structure thereof. Hereinafter, the first inkjet printer will be described.

In the first ink jet printer,
When the electric motor 50 that drives the inkjet head 10 in the Y direction is rotated by a predetermined angle by the encoder 40, the electric motor 5 that is rotated by the encoder 40
The actual travel distance A of the inkjet head 10 actually traveled in the Y direction calculated by an electronic circuit (not shown) or the like connected to the encoder 40 from the rotation angle of 0, and the ambient temperature and humidity change. An ink jet head 10 read by an electronic circuit (not shown) or the like connected to a linear scale sensor 80 running integrally with the ink jet head 10 from a scale 72 engraved on a linear scale 70 placed under predetermined weather conditions that expand and contract. Calculating means 100 for calculating a ratio R to the measured traveling distance B in the Y direction. The calculation means 100 is formed of an electronic circuit or the like. Also, based on the ratio R between the actual mileage A and the measured mileage B calculated by the calculating means 100, a linear scale graduation 72 set under predetermined weather conditions that expands and contracts with changes in ambient temperature and humidity. From inkjet head 1
0, the measured travel distance B in the Y direction of the inkjet head 10 read by the linear scale sensor 80 traveling integrally with
Is the actual traveling distance A of the inkjet head 10 in the Y direction.
Is provided. The correction unit 110 is formed from an electronic circuit or the like. Further, the ink-jet head 10 is read from a scale 72 engraved on a linear scale 70 placed under predetermined weather conditions.
The measured travel distance B in the Y direction of the inkjet head 10 read by the linear scale sensor 80 traveling integrally with
Is corrected by the correction means 110 based on the traveling position data in the Y direction of the ink jet head 10, ink droplets are discharged at predetermined timing from a plurality of nozzles 12 arranged on the lower surface of the ink jet head 10 in accordance with a pictorial diagram or character data. An ink jetting unit 120 for jetting is provided. The ink ejecting means 120 is formed from an electronic circuit or the like.

The rest of the configuration is the same as that of the above-described ink jet printer shown in FIGS. 3 and 4. This first
In the inkjet printer, the encoder 40
When the electric motor 50 is rotated by a predetermined angle to cause the inkjet head 10 to travel in the Y direction, the actual travel distance A traveled by the inkjet head 10 in the Y direction is determined by the change in ambient temperature and humidity. An electronic circuit or the like connected to the encoder 40 can always accurately calculate the rotation angle of the electric motor 50 rotated by the unaffected encoder 40. At the same time, the measured traveling distance B of the inkjet head 10 in the Y direction at that time is changed by an electronic circuit or the like connected to the linear scale sensor 80 traveling integrally with the inkjet head 10 in accordance with a change in ambient temperature or humidity. It can be read from a scale 72 engraved on a linear scale 70 placed under predetermined weather conditions that expand and contract. Then, the calculating means 100 can calculate the ratio R between the actual mileage A and the measured mileage B. Then, based on the ratio R, the measured travel distance in the Y direction of the inkjet head 10 read by the linear scale sensor 80 from the scale 72 of the linear scale placed under predetermined weather conditions that expands and contracts with changes in the surrounding temperature and humidity. B,
The correction unit 110 controls the Y
Correction can be made to match the actual traveling distance A in the direction. Then, based on accurate traveling position data in the Y direction of the ink jet head 10 obtained by correcting the measured traveling distance B of the ink jet head 10 in the Y direction by the correcting means 110, the ink jetting means 120 Accordingly, ink droplets ejected from the plurality of nozzles 12 arranged on the lower surface of the inkjet head 10 at a predetermined timing can be accurately landed at a desired position on the surface of the medium 30 without displacement in the Y direction. And that Y
The length of the direction is Y of the picture or character to be printed from the picture or character data using the inkjet printer.
It is possible to accurately print a picture or a character composed of an array of a plurality of ink dots having the same length as the length in the Y direction without displacement or distortion in the Y direction on the surface of the medium 30.

FIG. 2 shows a preferred embodiment of the second ink jet printer of the present invention, and FIG. 2 is a front view showing a schematic structure thereof. Hereinafter, the second inkjet printer will be described.

In the second ink jet printer, instead of the correction means 110, a picture or a character to be printed from the picture or character data using the ink jet printer is calculated with respect to the measured travel distance B calculated by the calculation means 100. A correction device 112 is provided for creating a corrected picture or character data enlarged or reduced in the Y direction by a ratio R (= A / B) of the actual actual traveling distance A in the Y direction of all the ink jet heads 10. . Correction device 11
2 is a program for creating a picture or character data incorporated in a host computer or the like for driving the ink jet printer, and the picture or character to be printed from the picture or character data using the ink jet printer in the Y direction. It is made up of program software and an electronic circuit capable of creating a corrected picture or character data whose length is appropriately enlarged or reduced by an appropriate amount. At the same time, the linear scale sensor 80 reads the scale 72 engraved on the linear scale 70 placed under a predetermined weather condition in accordance with the corrected picture or character data created by the correction device 112 instead of the ink ejecting means 120. Based on the traveling position data of the inkjet head 10 in the Y direction, a plurality of nozzles 12
And an ink ejecting device 122 for ejecting ink droplets at a predetermined timing. The ink ejection device 122 is formed from an electronic circuit or the like.

The rest of the configuration is the same as that of the above-described first ink jet printer shown in FIG. This second
In the inkjet printer, the correction device 1
12, a pictorial image or character to be printed from the pictorial image or character data using an ink jet printer is read from a linear scale graduation 72 placed under a predetermined weather condition that expands and contracts with changes in ambient temperature and humidity. Inkjet head 1 read by linear scale sensor 80
A ratio R of an actual actual traveling distance A in the Y direction of the inkjet head 10 to a measured traveling distance B in the Y direction of 0,
A corrected picture or character data enlarged or reduced in the Y direction can be created. Then, the linear scale sensor 80 reads from the scale 72 of the linear scale placed under a predetermined weather condition that expands and contracts with a change in the surrounding temperature and humidity according to the corrected picture or character data created by the correction device 112. Based on the traveling position data of the inkjet head 10 in the Y direction, the ink ejection device 122 can eject ink droplets from the plurality of nozzles 12 arranged on the lower surface of the inkjet head 10 at a predetermined timing. Then, the ink droplets are drawn according to the corrected picture or character data created by the correction device 112 in accordance with the expansion / contraction state of the linear scale 70 placed under a predetermined weather condition that expands / contracts with changes in the surrounding temperature and humidity. Thus, it is possible to accurately land at a desired position on the surface of the medium 30 to be landed based on the pictorial image or character data before correction without any displacement in the Y direction. Then, the length of the Y direction in the picture or character to be printed from the picture or character data using an ink jet printer is determined by ink droplets that have been accurately landed at a desired position on the surface of the medium 30 without displacement in the Y direction. It is possible to accurately print a picture or a character composed of an array of a plurality of ink dots having the same length as the length on the surface of the medium 30.

[0019]

As described above, according to the first or second ink jet printer of the present invention, the linear scale formed from a polyester film or the like expands and contracts with a change in ambient temperature and humidity. Even without being affected by this, ink droplets ejected at predetermined timing from a plurality of nozzles arranged on the lower surface of the ink jet head are drawn from the picture or character data to the position of the picture or character to be printed using the ink jet printer. Together,
It is possible to accurately land at a desired position on the surface of the medium without shifting in the Y direction. Then, by the ink droplet, Y
The length of the direction is Y of the picture or character to be printed from the picture or character data using the inkjet printer.
A picture or character composed of an array of a plurality of ink dots having the same length as the length in the direction can be accurately printed on the medium surface. As a result, using the first or second ink jet printer of the present invention makes it possible to print a small poster picture for a large poster combination, an original drawing for a printing plate, and the like, which require accurate precision.

[Brief description of the drawings]

FIG. 1 is a front view showing a schematic structure of a first ink jet printer of the present invention.

FIG. 2 is a front view showing a schematic structure of a second inkjet printer of the present invention.

FIG. 3 is a front view showing a schematic structure of a conventional ink jet printer.

FIG. 4 is a plan view showing a schematic structure of a conventional ink jet printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ink jet head 12 Nozzle 20 Platen 30 Media 40 Encoder 50 Electric motor 60 Endless belt 62 Driving pulley 64 Followed pulley 70 Linear scale 72 Linear scale scale 80 Linear scale sensor 100 Calculation means 110 Correction means 112 Correction device 120 Ink ejection Means 122 Ink jetting device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2C056 EA04 EB11 EB36 EC07 EC37 FA10 2C480 CA01 CA36 CB35 EC04 EC15

Claims (2)

[Claims] 1. An ink jet printer having a structure in which an ink jet head is driven in a Y direction by use of an electric motor whose rotation is controlled by an encoder, wherein the position of the ink jet head in the Y direction is the same as the running direction of the ink jet head. The scale engraved on the linear scale stretched in the direction is detected by reading the linear scale sensor that travels in the Y direction integrally with the inkjet head, and based on the detected travel position data of the inkjet head in the Y direction, a pictorial diagram is obtained. Or, in an ink jet printer having a structure in which ink droplets are ejected at predetermined timing from nozzles of the ink jet head according to character data, an electric motor rotated by the encoder when the electric motor is rotated by a predetermined angle by the encoder The actual travel distance A that the inkjet head actually travels in the Y direction calculated from the rotation angle, and the Y direction of the inkjet head read by the linear scale sensor from the scale engraved on the linear scale placed under predetermined weather conditions Calculating means for calculating a ratio R to the measured traveling distance B, and an ink jet read by the linear scale sensor from a scale of a linear scale placed under the predetermined weather condition based on the ratio R calculated by the calculating means. Correction means for correcting the measured travel distance B of the head in the Y direction so as to match the actual travel distance A of the inkjet head in the Y direction, and a linear scale from the scale engraved on the linear scale placed under the predetermined weather conditions. The measured travel distance B in the Y direction of the inkjet head read by the scale sensor is calculated by the correction means. Ink jetting means for jetting ink droplets from nozzles of the ink jet head at a predetermined timing in accordance with a picture or character data based on the travel position data in the Y direction of the ink jet head obtained by correction. Inkjet printer. 2. A picture or character to be printed from a picture or character data using an ink-jet printer in place of the correction means, the actual mileage A relative to the measured mileage B calculated by the calculation means. The ratio R of
A correction device for creating a corrected picture or character data enlarged or reduced in the Y direction is provided, and in place of the ink jetting means, according to the corrected picture or character data created by the correction device, the predetermined weather condition An ink ejecting device for ejecting ink droplets from nozzles of the inkjet head at a predetermined timing based on travel position data in the Y direction of the inkjet head read by the linear scale sensor from a scale engraved on the linear scale placed at The ink jet printer according to claim 1, wherein: