JP2008188804A - Inkjet printer, and alignment method of inkjet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer which can simply and surely perform the alignment adjustment of inkjet heads, and to provide an alignment method of the inkjet heads. <P>SOLUTION: The inkjet printer is equipped with a head unit 60 which has ink ejection openings of a plurality of the inkjet heads 50a-50e arranged concentrically. The inkjet printer is equipped with a light source 20 prepared at least in one of the inkjet heads 50a-50e, an alignment mirror 21 which is held at a predetermined position with respect to the light source 20 and reflects the light of the light source 20, a photodetecting part 22 which receives the reflected light by the alignment mirror 21, a determination part 23 which determines a positional shift of the inkjet heads 50a, 50b, 50d and 50e from data of the photodetecting part 22, and head moving means 24a, 24b and 24c which carry out alignment adjustment on the basis of the result of the determination part 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an inkjet printer and an inkjet head alignment method.

In recent years, the performance of ink jet printers has been increasing in quality so as to be comparable to that of photographs. Inkjet printers produce colors by changing the color of ink that is ejected within a certain area (dot). In addition, as one of the methods for obtaining a higher quality image with an inkjet printer, in addition to the three primary colors (cyan, magenta, yellow), intermediate colors (light cyan, light magenta, etc.) are added, Alternatively, the color reproducibility is enhanced by using eight colors. As a method for creating such an intermediate color, there is a technique for adjusting ink density by ejecting inks having different densities from two heads and mixing them (for example, see Patent Document 1).
JP-A-6-305163

  When the ink is ejected from the two inkjet heads to the same position, the alignment of the heads is important. A method of creating a desired color by mixing a plurality of inks having different colors to a predetermined position to mix the inks is also conceivable. However, in this case, since the number of heads increases, the alignment adjustment becomes more complicated, and there is a possibility that a desired color cannot be obtained even if any one of the alignments is shifted.

  The present invention has been made in view of such circumstances, and an object thereof is to provide an inkjet printer and an inkjet head alignment method capable of easily and reliably adjusting the alignment of the inkjet head. .

  The ink jet printer of the present invention includes a head unit having a plurality of ink jet heads, and the ink discharge ports of the respective ink jet heads are arranged concentrically, and the ink discharged from the ink discharge ports of the respective ink jet heads. An ink jet printer that drops by mixing colors, wherein the light source unit is provided in at least one of the ink jet heads, is held at a predetermined position with respect to the light source unit, and reflects light emitted from the light source unit An alignment mirror, a light receiving unit that is provided in an ink jet head that does not include the light source unit, and receives light reflected by the alignment mirror, and data of the light receiving unit are used to determine a positional deviation of the ink jet head that includes the light receiving unit. A determination unit; and a light receiving unit based on the determination result of the determination unit. Characterized in that it comprises a head moving means for performing alignment adjustment by moving the ink jet head.

  According to the ink jet printer of the present invention, since the light source unit and the alignment mirror are positioned, the alignment adjustment of the ink jet head not having the light source unit is performed by using the ink jet head having the light source unit as a reference. It can be carried out. The light receiving unit receives reflected light from the alignment mirror to calculate position data of the light receiving unit with respect to the light source unit. And based on this position data, the determination part can determine the amount of position shift of the ink jet head having the light receiving part with respect to the reference (ink jet head having the light source part). In addition, since the inkjet head having the light source unit is positioned in advance, the number of heads for alignment can be reduced, and the efficiency during alignment adjustment can be improved. Further, for example, by rotating the alignment mirror, it is possible to easily perform all the positional deviation determinations of the inkjet head having the light receiving unit. Therefore, it is possible to provide a printer that simply and reliably adjusts the alignment of the inkjet head.

  The ink jet printer of the present invention includes a head unit having a plurality of ink jet heads, and the ink discharge ports of the respective ink jet heads are arranged concentrically, and discharges from the ink discharge ports of the respective ink jet heads. An ink jet printer that drops ink by mixing colors, the light source unit provided in each ink jet head, the light from the light source unit, and a light receiving unit provided at a predetermined position; A determination unit that determines a positional deviation of each inkjet head from data; and a head moving unit that moves the inkjet heads to perform alignment adjustment based on a determination result of the determination unit. .

  According to the ink jet printer of the present invention, the light receiving portion that receives the light emitted from the light source portion provided in each head is provided at a predetermined position. Head alignment can be adjusted. The light receiving unit receives light from the light source unit to calculate position data for each light source unit. And based on this position data, the determination part can determine the positional deviation amount of each inkjet head having the light source part with respect to the reference (the light receiving part). Further, for example, by rotating the light receiving unit, it is possible to receive light emitted from the light source unit of each inkjet head, and it is possible to easily determine the positional deviation of all the inkjet heads. Therefore, it is possible to provide a printer that simply and reliably adjusts the alignment of the inkjet head.

  The ink jet printer of the present invention includes a head unit having a plurality of ink jet heads, and the ink discharge ports of the respective ink jet heads are arranged concentrically, and discharges from the ink discharge ports of the respective ink jet heads. An ink jet printer that drops ink by mixing inks, emits light toward each ink jet head, and includes a light source unit provided at a predetermined position, each ink jet head, A light receiving unit that receives light, a determination unit that determines the positional deviation of each inkjet head from the data of the light receiving unit, and the alignment adjustment by moving each inkjet head based on the determination result of the determination unit And a head moving means.

  According to the ink jet printer of the present invention, since the light source unit is provided at a predetermined position and the light receiving unit that receives light from the light source unit is provided in each ink jet head, by using the light source unit as a reference, The alignment of each inkjet head can be adjusted. The light receiving unit can calculate position data with respect to the light source unit, and based on this data, the determination unit can determine a positional shift amount of each inkjet head having the light receiving unit with respect to the reference (the light source). In addition, for example, by rotating the light source unit, light can be received by the light receiving unit of each inkjet head, and the positional deviation determination of all the inkjet heads can be easily performed. Therefore, it is possible to provide a printer that simply and reliably adjusts the alignment of the inkjet head.

In the inkjet printer, it is preferable that the predetermined position corresponds to a position where color mixing of ink occurs when ink is assumed to be ejected from each inkjet head.
According to this configuration, the alignment adjustment reference (the alignment mirror, the light receiving unit, or the light source unit) is set at a position where ink color mixture occurs, that is, at an equal distance from each head. Can be done automatically.

In the inkjet printer, the alignment adjustment is preferably performed in a head standby area where ink is not ejected from each inkjet head.
According to this configuration, alignment adjustment can be performed efficiently without interfering with the ink ejection process.

In the ink jet printer, it is preferable that a piezoelectric element is used as the head moving means.
According to this configuration, by using the piezoelectric element, it is possible to minutely control the moving amount of the head, and the alignment accuracy can be improved.

  The ink jet head alignment method of the present invention includes a head unit having a plurality of ink jet heads, the ink discharge ports of the respective ink jet heads being arranged concentrically, and discharging from the ink discharge ports of the respective ink jet heads. A method of adjusting the alignment of the inkjet head by an inkjet printer, wherein the light source unit includes a light source unit provided on at least one of the inkjet heads. The light is emitted to the alignment mirror held at a predetermined position, and the light reflected by the alignment mirror is received by the light receiving unit of the inkjet head that does not include the light source unit. Based on the light reception data, the light receiving unit Position of the installed inkjet head Determined, and performs alignment adjustment on the basis of the determination result.

  According to the inkjet head alignment method of the present invention, since the light source unit and the alignment mirror are positioned, the inkjet head having the light source unit is used as a reference, so that the inkjet head without the light source unit is used as a reference. Alignment adjustment can be performed. The light receiving unit receives reflected light from the alignment mirror, thereby calculating position data of the light receiving unit with respect to the light source unit, and an ink jet having a light receiving unit with respect to a reference (an ink jet head having the light source unit) based on the data. The amount of misalignment of the head can be determined. In addition, since the inkjet head having the light source portion is positioned in advance, the number of heads for alignment can be reduced, and the efficiency of alignment adjustment can be improved. Further, for example, by rotating the alignment mirror, it is possible to easily determine all the positional deviations of the inkjet head having the light receiving unit. Therefore, the alignment adjustment of the inkjet head can be performed easily and reliably.

  The ink jet head alignment method of the present invention includes a head unit having a plurality of ink jet heads, the ink discharge ports of the respective ink jet heads being arranged concentrically, and discharging from the ink discharge ports of the respective ink jet heads. A method of adjusting the alignment of the inkjet head with an inkjet printer, wherein the light emitted from the light source unit provided in each inkjet head is a predetermined amount. The light receiving unit provided at a position receives light, the positional deviation of each inkjet head is determined from the received light data, and alignment adjustment is performed based on the determination result.

  According to the ink jet head alignment method of the present invention, since the light receiving part for receiving the light emitted from the light source part provided in each head is provided at a predetermined position, the light receiving part can be used as a reference. The alignment of each inkjet head can be adjusted. The light receiving unit receives light from the light source unit to calculate position data for each light source unit. And based on this position data, the position shift amount of each inkjet head having the light source part with respect to the reference (the light receiving part) can be determined. Further, for example, by rotating the light receiving unit, it is possible to receive light emitted from the light source unit of each inkjet head, and it is possible to easily determine the positional deviation of all the inkjet heads. Therefore, the alignment adjustment of the inkjet head can be performed easily and reliably.

  The ink jet head alignment method of the present invention includes a head unit having a plurality of ink jet heads, the ink discharge ports of the respective ink jet heads being arranged concentrically, and discharging from the ink discharge ports of the respective ink jet heads. A method of adjusting the alignment of the inkjet head with an inkjet printer, in which the ink is dropped by mixing the mixed inks, and emitting light to each inkjet head from a light source provided at a predetermined position Then, the light receiving unit provided in each ink jet head receives light, the positional deviation of each ink jet head is determined from the data of the light receiving unit, and alignment adjustment is performed based on the determination result.

  According to the ink jet head alignment method of the present invention, since the light source unit is provided at a predetermined position and the light receiving unit that receives light from the light source unit is provided in each ink jet head, the light source unit is used as a reference. Thereby, alignment adjustment of each inkjet head can be performed. The light receiving unit calculates position data with respect to the light source unit, and can determine a positional shift amount of each inkjet head having the light receiving unit with respect to a reference (the light source) based on the data. In addition, for example, by rotating the light source unit, light can be received by the light receiving unit of each inkjet head, and the positional deviation determination of all the inkjet heads can be easily performed. Therefore, the alignment adjustment of the inkjet head can be performed easily and reliably.

In the inkjet head alignment method, it is preferable that the predetermined position corresponds to a position where color mixing of ink occurs when ink is assumed to be ejected from each inkjet head.
According to this configuration, the alignment adjustment reference (the alignment mirror, the light receiving unit, or the light source unit) is set at a position where ink color mixture occurs, that is, at an equal distance from each head. Can be increased.

In the ink jet head alignment method, it is preferable that the predetermined position corresponds to a position where color mixing of ink occurs when it is assumed that ink is ejected while the head is waiting.
According to this configuration, the ink discharge process is not hindered by the alignment adjustment.

In the above-described ink jet head alignment method, it is preferable to use a piezoelectric element as means for moving the head during alignment adjustment.
According to this configuration, by using the piezoelectric element, it is possible to minutely control the moving amount of the head, and the alignment accuracy can be improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of an inkjet printer and an alignment method of an inkjet printer according to the invention will be described with reference to the drawings. The following embodiments do not limit the technical scope of the present invention.

(Inkjet printer)
Hereinafter, an ink jet printer including an ink jet head according to an embodiment of the present invention will be described. In the present embodiment, a printer that prints characters and images on recording paper or the like will be described as an example. However, the ink jet printer according to the present invention is configured to print on recording paper or the like.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing an embodiment in which the ink jet printer of the present invention is applied to a general printer that prints on paper or the like. Reference numeral 60 in FIG. 1 denotes an ink jet printer. In the following description, the upper side in the Z direction in FIG. 1 is referred to as “upper”, and the lower side in the Z direction is referred to as “lower”.

  The ink jet printer 100 includes an apparatus main body 62. The inkjet printer 100 has a tray 121 for installing the recording paper P in the upper rear part, and a discharge port 122 for discharging the recording paper P in the lower front part. Has an operation panel 67.

  The operation panel 67 is configured by a display device such as a liquid crystal display, an organic EL display, and an LED lamp display, and includes a display unit (not shown) that displays an error message, various switches, and the like. An operation unit (not shown) is provided.

  Inside the apparatus main body 62, there are mainly a printing apparatus 64 having a reciprocating head unit 60, a paper feeding apparatus 65 for feeding the recording paper P one by one to the printing apparatus 64, a printing apparatus 64 and a paper feeding apparatus. And a control unit 66 for controlling 65.

  Under the control of the control unit 66, the paper feeding device 65 is configured to intermittently feed recording sheets one by one. The recording paper that is intermittently fed passes near the lower portion of the head unit 60. At this time, the head unit 60 reciprocates in a direction substantially perpendicular to the feeding direction of the recording paper to print on the recording paper. That is, the reciprocating motion of the head unit 60 and the intermittent feeding of the recording paper are the main scanning and the sub scanning in printing, and ink jet printing is performed.

  The printing apparatus 64 includes a head unit 60, a carriage motor 141 that is a drive source of the head unit 60, and a reciprocating mechanism 142 that reciprocates the head unit 60 in response to the rotation of the carriage motor 141. .

  As will be described in detail later, the head unit 60 includes a plurality of inkjet heads having a large number of nozzles (ink ejection ports), an ink cartridge that supplies ink to each head, and a carriage on which the inkjet head and the ink cartridge are mounted. I have it.

The reciprocating mechanism 142 includes a carriage guide shaft 144 whose both ends are supported by a frame (not shown), and a timing belt 143 that extends in parallel with the carriage guide shaft 144 and operates. The carriage constituting the head unit 60 is supported by the carriage guide shaft 144 so as to reciprocate and is fixed to a part of the timing belt 143.
When the timing belt 143 travels forward and backward through a pulley by the operation of the carriage motor 141, the head unit 60 reciprocates while being guided by the carriage guide shaft 144. During this reciprocation, ink is appropriately discharged from the inkjet head 50 and printing on the recording paper P is performed. Note that the head unit 60 is guided to the head standby area by the carriage guide shaft 144 during a period in which ink is not ejected from the nozzles 11, for example, when the printer power is turned off or when the recording paper P is fed. In this head standby area, the alignment adjustment of the inkjet head, which will be described later in detail, is performed.

The sheet feeding device 65 includes a sheet feeding motor 151 as a driving source thereof, and a sheet feeding roller 152 that rotates around an axis by the operation of the sheet feeding motor 151.
The paper feed roller 152 includes a driven roller 152a and a drive roller 152b that are opposed to each other across the recording paper feed path, and the drive roller 152b is connected to a paper feed motor 151. is there. With such a configuration, the paper feed roller 152 can feed a large number of recording sheets set on the tray 121 one by one toward the printing device 64. Instead of the tray 121, a configuration may be adopted in which a paper feed cassette that stores recording paper can be detachably mounted.

  The control unit 66 controls the printing operation by driving the printing device 64, the paper feeding device 65, and the like based on print data input from a host computer such as a personal computer or a digital camera. Although not shown, the control unit 66 mainly includes a memory that stores a control program for controlling each unit, a head drive circuit that drives the ink jet head 50 to control ink ejection timing, and a printing device 64 (carriage). A control circuit that drives the motor 141), a drive circuit that drives the paper feeding device 65 (paper feeding motor 151), and a communication circuit that obtains print data from the host computer, and these are electrically connected to each other. And a CPU for performing various controls.

  In addition, for example, various sensors capable of detecting a printing environment such as the remaining amount of ink in the ink cartridge K, the position of the head unit 60, temperature, and humidity are electrically connected to the CPU. The control unit 66 obtains print data via the communication circuit and stores it in the memory. The CPU processes the print data and outputs a drive signal to each drive circuit based on the process data and input data from various sensors. The inkjet head 50, the printing device 64, and the paper feeding device 65 are operated by this drive signal. Thereby, desired printing is performed on the recording paper.

(Overall configuration of inkjet head)
Next, the configuration of the ink jet head constituting the head unit 60 will be specifically described. FIG. 2 is an exploded perspective view of the inkjet head, and FIG. 3 is a side sectional view showing a schematic configuration of the inkjet head. In the following description, the ink jet head may be simply referred to as a head.

  2 and 3, the head 50 is mainly composed of a nozzle plate 51, a head main body 57, and a piezoelectric element 54. The head main body 57 includes an ink flow path (reservoir) and a cavity. Ink chamber substrate 52 patterned in a predetermined plane shape so as to form a partition 31 and a diaphragm 55 formed integrally with the ink chamber substrate 52 are provided. As shown in FIG. 2, the head main body 57 is accommodated in the base body 56. The head 50 constitutes an on-demand piezo jet head.

  The nozzle plate 51 is made of, for example, a stainless steel plate or a nickel plate, and has a large number of nozzles (droplet ejection ports) 11 for ejecting ink droplets penetrating in a line. The pitch between these nozzles 11 is appropriately set according to the printing accuracy. An ink chamber substrate 52 is fixed (fixed) to the nozzle plate 51. The ink chamber substrate 52 is formed by the manufacturing method according to the present invention, and a plurality of cavities (ink cavities) 31 and ink cartridges are formed by the side walls (partition walls) 32, the nozzle plate 51 and the vibration plate 55. A reservoir 33 that temporarily stores ink supplied from K and a supply port 34 that supplies ink from the reservoir 33 to each cavity 31 are partitioned.

  The cavities 31 are arranged corresponding to the respective nozzles 11 as shown in FIG. 2, and the volume thereof is variable by elastic deformation of a diaphragm 55 described later. The pressure is instantaneously increased and ink is ejected from the nozzle 11.

  The average thickness of the ink chamber substrate 52, that is, the thickness including the cavity 31, is not particularly limited, but is preferably about 10 to 1000 μm, and more preferably about 100 to 500 μm. Further, the volume of the cavity 31 is not particularly limited, but is preferably about 0.1 to 100 nL, and more preferably about 0.1 to 10 nL.

On the other hand, a vibration plate 55 is provided on the side of the ink chamber substrate 52 opposite to the nozzle plate 51, and a plurality of piezoelectric elements 54 are disposed on the surface of the vibration plate 55 opposite to the ink chamber substrate 52. Has been. The diaphragm 55 may include a buffer layer for promoting crystal growth of each constituent layer in the piezoelectric element 54 described later in detail.
Further, a communication hole 35 is formed at a predetermined position of the diaphragm 55 so as to penetrate in the thickness direction of the diaphragm 55 as shown in FIG. Ink is supplied from the ink cartridge K to the reservoir 33 through the communication hole 35.

  As a constituent material of the head main body 57, for example, nickel, copper, or the like can be exemplified as a suitable material, and the side wall 32, the beam member 53, and the diaphragm 55 can be made of the same material. By forming the constituent members of the head main body 57 from the same material as described above, the head main body 57 can be integrally formed, and even if the extremely small cavity 31 is formed, good durability can be obtained, and manufacturing can be performed. Can be performed efficiently. However, it does not prevent these from being made of different materials.

  Each piezoelectric element 54 is constructed by inserting the piezoelectric layer 5 between the lower electrode 4 and the upper electrode 6 as described above. As shown in FIG. It is disposed substantially corresponding to the central portion. The detailed configuration of the piezoelectric element 54 will be described later.

Each of these piezoelectric elements 54 is electrically connected to, for example, a piezoelectric element drive circuit, and is configured to operate (vibrate, deform) based on a signal from the piezoelectric element drive circuit. That is, each piezoelectric element 54 functions as a vibration source (head actuator), and the diaphragm 55 vibrates (deflects) due to the vibration (deflection) of the piezoelectric element 54, and the internal pressure of the cavity 31. It functions to raise the momentary.
The base 56 is formed of, for example, various resin materials, various metal materials, and the like, and the ink chamber substrate 52 is fixed and supported on the base 56 as shown in FIG.

(Head unit)
FIG. 4 is a diagram illustrating a schematic configuration of the head unit 60, FIG. 4A illustrates a perspective view illustrating the configuration of the head unit 60, and FIG. 4B illustrates a cross-sectional view of the head unit 60. . In FIG. 4, only the ink jet head is illustrated, and an ink cartridge that supplies ink to each head and a carriage that holds the head and the cartridge are not illustrated.

  As shown in FIG. 4A, the head unit 60 includes a head 50 corresponding to each of the five colors of ink. Note that an ink cartridge (not shown) is connected to the head 50. Examples of such an ink cartridge include those filled with five types of ink such as cyan, magenta, yellow, black (black), and transparent color. It should be noted that full-color printing is possible if an ink cartridge filled with at least cyan, magenta, yellow, and black is provided. In this embodiment, however, five colors of ink are used in addition to transparent ink. ing. As a result, for example, light cyan can be created by mixing cyan and transparent ink, and by changing the combination of other colors as appropriate, the shade of each color can be adjusted, and high gradation expression can be achieved. ing.

  Specifically, as shown in FIG. 4A, the head unit 60 includes a head 50a corresponding to a cartridge (not shown) filled with magenta ink, and a cartridge (filled with yellow ink). A head 50b corresponding to a cartridge (not shown) filled with cyan ink, a head 50d corresponding to a cartridge (not shown) filled with black ink, a head 50d corresponding to a cartridge (not shown) filled with black ink, And a head 50e corresponding to a cartridge (not shown) filled with transparent ink. Each of the heads 50a to 50e has the same configuration, and the pitch of the nozzles 11 formed on the nozzle plate 51 is the same.

  In the head unit 60 according to the present embodiment, the nozzles 11 of the heads 50a to 50e are concentrically arranged, and thereby drawing is performed by mixing the colors ejected from the nozzles 11 of the heads 50a to 50e. It is like that.

  Specifically, the ink jet printer 100 has the ink ejected from the nozzles 11 of the heads 50a to 50e before the ink is landed on the surface (ejection surface) of the recording paper (ejection target) P. These inks are mixed in color by colliding with each other.

  The point (point) where such ink collision occurs is the color mixing point MP. The color mixing point MP is preferably set immediately above the surface to be ejected, that is, directly above the recording paper P. As a result, the ink is landed on the recording paper P immediately after the ink is mixed at the color mixing point MP, so that it is possible to prevent a problem that the ink is bent and the landing position is shifted.

  Each head 50 is arranged so that the nozzles 11 are concentric with the color mixing point MP as the center, and each head 50 is held by a carriage (not shown) and positioned.

  As shown in FIG. 4A, each of the heads 50a to 50e is arranged such that each nozzle 11 provided in a line on the nozzle plate 51 follows the height direction of the semi-cylindrical surface (the −X direction in the figure). It is arranged. That is, the line connecting the color mixing points MP where the inks ejected from the nozzles 11 of the heads 50 a to 50 e are mixed becomes the center line C of the cylindrical surface R.

  FIG. 4B is a cross-sectional view in the radial direction of the cylindrical surface R (a cross section of the cylindrical surface R taken along the YZ plane) corresponding to the position where a certain nozzle 11 is provided in the head unit 60. As shown in FIG. 4B, each nozzle 11 is disposed on the surface of the cylindrical surface R. Therefore, the length of the line connecting each nozzle 11 and the center line C coincides with the radius of the cylindrical surface R.

  Incidentally, in the inkjet printer 100, the alignment of the heads 50a to 50e is important. The reason is that, for example, if any one of the inks ejected from the heads 50a to 50e deviates from the color mixing point MP, a desired color cannot be created at the color mixing point MP, and a desired color is formed on the recording paper P. This is because it may be impossible to reproduce.

In order to eliminate such problems, the ink jet printer 100 according to the present embodiment is held at a predetermined position with respect to the light source unit 20 provided in at least one of the ink jet heads 50a to 50e and the light source unit 20. , An alignment mirror 21 that reflects light emitted from the light source unit 20, a light receiving unit 22 that is provided in the inkjet heads 50 a to 50 e that do not include the light source unit 20, and receives reflected light from the alignment mirror 21, Based on the data of the light receiving unit 22, a determination unit 23 that determines the positional deviation of the ink jet heads 50 a to 50 e having the light receiving unit 22, and the ink jet head 50 a including the light receiving unit 22 based on the result of the determination unit 23. And a head moving means 24 for adjusting the alignment by moving ~ 50e. That.
The features of the present invention will be specifically described below.

  In the inkjet printer 100, as shown in FIG. 5, the head unit 60 is sent from the ink discharge area (on the recording paper P) to the ink non-discharge area, that is, the head standby area by the carriage guide shaft 144. In this case, alignment adjustment is performed. According to this, it is possible to prevent the ink ejection process from being hindered by the alignment adjustment. Specifically, in the inkjet printer 100 according to the present embodiment, alignment adjustment is performed each time the printer is driven.

  FIG. 6 is a schematic diagram showing the head unit 60 sent into the ink non-ejection area (standby area). As shown in FIG. 6, in the head unit 60, a light source unit 20 made of, for example, a semiconductor laser is provided on a head 50c connected to a cyan ink cartridge (not shown). The light source unit 20 is provided on a nozzle plate 51 on which the nozzles 11 are formed, for example.

An alignment mirror (alignment mirror) 21 that is provided at a predetermined position with respect to the light source unit 20 and reflects light from the light source unit 20 is provided. Here, the predetermined position means a position corresponding to a color mixing point MP (see FIG. 4) where ink mixing occurs when it is assumed that ink is ejected in the standby area.
Therefore, the alignment mirror 21 has a predetermined positional relationship with the light source unit 20 only when the head unit 60 exists in the standby area.

  The alignment mirror 21 is positioned with respect to the head 50c so that the surface thereof coincides with the color mixing point MP described above. Thereby, the distance between the light source unit 20 and the alignment mirror 21 can be matched with the distance from each nozzle 11 to the color mixing point MP.

  Since the light source unit 20 is positioned with respect to the alignment mirror 21, the head 50 c including the light source unit 20 is positioned with respect to the alignment mirror 21.

  Thus, since the reference (the light source unit 20) at the time of alignment adjustment is set at the position where the color mixture of ink occurs (color mixture point MP), that is, the same distance from each head, the efficiency of alignment adjustment can be improved. .

  On the other hand, the heads 50a, 50b, 50d, and 50e that do not include the light source unit 20 are provided with a light receiving unit 22 that receives reflected light from the alignment mirror 21. An example of the light receiving unit 22 is a photodiode.

  Further, the ink jet printer 60 determines the positional deviation of the heads 50a, 50b, 50d, and 50e having the light receiving unit 22 from the data of the light receiving unit 22, and based on the result of the determination unit 23, Head moving means 24a, 24b, and 24c that adjust the alignment by moving the heads 50a, 50b, 50d, and 50e including the light receiving unit 22 are provided.

  Piezoelectric elements were used as the head moving means 24a, 24b, and 24c. If the piezoelectric element is used as means for moving the head in this way, the amount of movement of the head can be controlled minutely, and the alignment accuracy can be increased.

(Head alignment method)
Next, an alignment method in the inkjet printer 100 will be described. In the following, a case where the alignment of the head 50e corresponding to the ink cartridge filled with the transparent ink is adjusted will be described as an example.

  First, prior to the alignment adjustment of the head 50e, the alignment mirror 21 is rotated in a predetermined direction (clockwise direction in FIG. 6) and aligned with the light receiving portion 22 of the head 50e. Then, light is emitted from the light source unit 20 provided in the head 50 c toward the alignment mirror 21. The light of the light source unit 20 reflected by the alignment mirror 21 is received by the light receiving unit 22 of the head 50e.

  At this time, the light receiving unit 22 calculates the incident position data of the laser beam. Based on the position data, the determination unit 23 determines how much the head 50e is deviated from the desired position, that is, the amount of positional deviation. And based on this determination result, the determination part 23 drives the moving means 24a, 24b, 24c, moves the head 50e, and performs alignment adjustment.

  Here, since the light source unit 20 is positioned with respect to the alignment mirror 21, the alignment of the head 50e can be adjusted with reference to the head 50c having the light source unit 20. In the present embodiment, as described above, the three head piezoelectric elements 24a, 24b, and 24c are provided for the head 50e. Accordingly, the head 50e can be moved in various directions by changing the combination for driving the piezoelectric elements 24a, 24b, and 24c.

  For example, by bending the piezoelectric elements 24a and 24c to the head 50e side, the piezoelectric elements 24a and 24c respectively apply a compressive force in the opposite direction to the head 50e, thereby causing a reaction to be centered in the direction perpendicular to the paper surface. The head 50e can be rotated in the clockwise direction. On the other hand, by bending the piezoelectric elements 24a and 24c to the opposite side of the head 50e, a tensile force is applied to the head, and thus the head 50e can be rotated in the clockwise direction with the direction perpendicular to the paper surface as the central axis.

  As described above, the alignment of the head 50e can be appropriately adjusted by using the piezoelectric elements 24a, 24b, and 24c. For the other inkjet heads 50a, 50b, and 50d, the alignment mirror 21 is rotated so that the light receiving unit 22 provided in each head receives light to determine the positional deviation of each head. In the same manner as described above, alignment adjustment can be performed. As described above, the ink jet printer 100 can perform drawing with high accuracy by ejecting ink from the heads 50a to 50e that are accurately aligned.

  In the present embodiment, the three piezoelectric elements 24 are provided. However, the present invention is not limited to this, and more piezoelectric elements may be provided. In this way, the degree of freedom in the moving direction of the head 50e is improved, and the alignment accuracy can be increased.

(Ink ejection operation)
FIG. 7 is a partial cross-sectional configuration diagram for explaining the operation of the head 50. FIG. 7A shows the case where the piezoelectric element 54 is in a non-voltage application state, and FIG. 7B shows the piezoelectric element. The case where 54 is in a voltage application state is illustrated. As shown in FIG. 7A, the head 50 having the above configuration is in a state where a predetermined ejection signal is not input via the piezoelectric element drive circuit, that is, the lower electrode 4 and the upper part of the piezoelectric element 54. In the state where no voltage is applied between the electrodes 6, the piezoelectric layer 5 is not deformed. For this reason, the diaphragm 55 is not deformed, and the volume of the cavity 31 is not changed. Accordingly, no ink droplet is ejected from the nozzle 11.
On the other hand, as shown in FIG. 7B, a predetermined discharge signal is input via the piezoelectric element driving circuit, that is, a constant voltage (between the lower electrode 4 and the upper electrode 6 of the piezoelectric element 54). In a state in which, for example, about 30 V is applied, the piezoelectric layer 5 is bent and deformed in the minor axis direction. Thereby, the diaphragm 55 bends, for example, about 500 nm, and the volume of the cavity 31 changes. At this time, the pressure in the cavity 31 increases momentarily, and ink droplets are ejected from the nozzle 11.

  That is, when a voltage is applied, the crystal lattice of the piezoelectric layer 5 is stretched in a direction perpendicular to the plane, but is simultaneously compressed in a direction parallel to the plane. In this state, a tensile stress is applied to the piezoelectric layer 5 in the plane. Therefore, the diaphragm 55 is warped and bent by this stress. The greater the displacement amount (absolute value) of the piezoelectric layer 5 in the minor axis direction of the cavity 31, the greater the deflection amount of the vibration plate 55, making it possible to eject ink droplets more efficiently. Here, “efficient” means that the same amount of ink droplets can be ejected with a smaller voltage. That is, the drive circuit can be simplified and the power consumption can be reduced at the same time, so that the pitch of the nozzles 11 can be formed at a higher density. Or since the length of the long side direction of the cavity 31 can be shortened, the whole head can be reduced in size.

  When the ejection of one ink is completed in this way, the piezoelectric element drive circuit stops applying the voltage between the lower electrode 4 and the upper electrode 6. As a result, the piezoelectric element 54 returns to its original shape, and the volume of the cavity 31 increases. At this time, a pressure from the ink cartridge toward the nozzle 11 (a pressure in the positive direction) acts on the ink. Therefore, air does not enter the cavity 31 from the nozzle 11, and an amount of ink corresponding to the discharged amount is supplied from the ink cartridge K to the cavity 31 via the reservoir 33.

  As described above, the ink jet printer 100 according to the present embodiment mixes the ink ejected from each nozzle 11 at the color mixing point MP. At this time, since each of the heads 50a to 50e is aligned with high accuracy, the ink can be reliably mixed at the color mixing point MP.

  Specifically, as shown in FIG. 8A, ink ejected from the nozzles 11 of the heads 50a to 50e collide with each other at the color mixing point MP. The energy at this time results in a state where the five types of ink are uniformly mixed and ink droplets of a desired color are generated as shown in FIG. Then, the ink droplets land on the recording paper P as shown in FIG.

  In the inkjet printer 100 according to the present embodiment, all colors can be expressed by one drop of ink that has landed on the recording paper P. That is, a color can be expressed by a point. Further, if the amount of ink droplets after color mixing is reduced, higher-definition drawing can be performed. Furthermore, by adjusting the amount of ink ejected from each nozzle 11, the color produced at the color mixing point MP can be freely controlled.

As described above, according to the inkjet printer 100 and the head alignment method according to the present embodiment, since the light source unit 20 and the alignment mirror 21 are positioned, the head 50c having the light source unit 20 is used as a reference. By doing so, it is possible to adjust the alignment of the heads 50a, 50b, 50d, and 50e that do not have the light source unit 20. Further, the light receiving unit 22 calculates the position data of the light receiving unit 22 with respect to the light source unit 20 by receiving the reflected light from the alignment mirror 21. Based on this position data, the determination unit 23 can determine the positional deviations of the heads 50a, 50b, 50d, and 50e having the light receiving unit 22 with respect to the reference (the head 50c having the light source unit 20). . Since the head 50c having the light source unit 20 is positioned in advance, the number of heads for alignment can be reduced, and the efficiency during alignment adjustment can be improved.
Therefore, the head alignment can be adjusted easily and reliably.

(Second embodiment)
Next, a second embodiment of the present invention will be described. Also in the head according to the present embodiment, since the inks are mixed with each other by causing the inks to collide with each other, the alignment of each head is important. In the following description, the same reference numerals are given to the same configurations and members as in the above embodiment, and the description thereof is simplified or omitted.

  The ink jet printer according to the present embodiment includes a light source unit 20 provided in each of the heads 50 a to 50 e, a light receiving unit 22 provided at a predetermined position and receiving light from the light source unit 20, and the light receiving unit 22. A determination unit 23 that determines the positional deviation of each of the heads 50a to 50e from the data, and a head moving unit 24 that performs alignment adjustment based on the result of the determination unit 23 are provided.

The configuration of the ink jet printer and the head alignment method in the present embodiment will be described below.
FIG. 9 is a diagram showing a schematic configuration of the head unit 70 of the head according to the second embodiment, and corresponds to FIG. 6 shown in the first embodiment.

  As shown in FIG. 9, in the ink jet printer according to the present embodiment, each head 50a to 50e is provided with a light source unit 20 made of, for example, a semiconductor laser. The light source unit 20 is provided on a nozzle plate 51 on which the nozzles 11 are formed.

  In addition, a light receiving unit 22 that receives light from the light source unit 20 is provided at a predetermined position (a position where the alignment mirror 21 is provided in the first embodiment).

  Furthermore, a head moving unit comprising a piezoelectric element is provided that includes a determination unit 23 that determines the positional deviation of each of the heads 50a to 50e based on the data of the light receiving unit 22, and performs alignment adjustment based on the result of the determination unit 23. Means 24a, 24b, 24c are provided.

(Head alignment method)
Next, an alignment method according to this embodiment will be described. Hereinafter, a case where the alignment of the head 50c corresponding to the ink cartridge filled with cyan ink is adjusted will be described as an example.

  First, prior to the alignment adjustment of the head 50c, the light receiving unit 23 is rotated in a predetermined direction, and the light receiving surface of the light receiving unit 23 is opposed to the light emission port of the light source unit 20 provided in the head 50c. . Then, the light emitted from the light source unit 20 provided in the head 50 c toward the light receiving unit 22 is received by the light receiving unit 22.

  At this time, the light receiving unit 22 calculates the incident position data of the laser beam. Then, the determination unit 23 determines how much the head 50c is deviated from a desired position based on this position data, that is, its positional deviation amount. And based on this determination result, the determination part 23 drives the moving means 24a, 24b, 24c, moves the head 50c, and performs alignment adjustment.

  As described above, since the light receiving unit 22 is provided at a predetermined position, the predetermined position where the head 50c is to be disposed can be determined by using the light receiving unit 22 as a reference. Therefore, the alignment of the head 50c can be adjusted. In the present embodiment, as shown in FIG. 9, head piezoelectric elements 24a, 24b, and 24c are provided on the head 50c. Therefore, the head 50c can be moved in various directions by appropriately changing the combination of the piezoelectric elements 24a, 24b, and 24c to be driven.

  For example, by bending the piezoelectric elements 24a and 24c toward the head 50c, the piezoelectric elements 24a and 24c respectively apply a compressive force in the opposite direction to the head 50c, thereby counterclockwise with the direction perpendicular to the paper surface as the central axis. The head can be rotated in the turning direction. On the other hand, by bending the piezoelectric elements 24a and 24c to the opposite side of the head 50c, the piezoelectric elements 24a and 24c apply a tensile force to the head 50c, thereby causing the perpendicular direction to the paper surface to be the clockwise direction. The head can be rotated.

  As described above, the alignment of the head 50c can be appropriately adjusted by using the piezoelectric elements 24a, 24b, and 24c. Also, with respect to the other inkjet heads 50a, 50b, 50d, and 50e, the positional deviation of each head is determined by receiving the light of the light source unit 20 from each head by rotating the light receiving unit 22, and the above process. Similarly, alignment adjustment can be performed. As described above, the ink jet printer according to the present embodiment can perform drawing with high accuracy by discharging ink from the heads 50a to 50e that are accurately aligned.

According to the inkjet printer and the head alignment method according to the present embodiment, the light receiving unit 22 that receives the light emitted from the light source unit 20 provided in each of the heads 50a to 50e is provided at a predetermined position. The alignment of each head can be adjusted by using the light receiving unit 22 as a reference. Further, the light receiving unit 22 receives the light from the light source unit 20 to calculate position data for each light source unit 20. And based on this position data, the determination part 23 can determine the position shift of each head 50a-50e with respect to a reference | standard (the said light-receiving part 23).
Therefore, the head alignment can be adjusted easily and reliably.

(Third embodiment)
Next, a third embodiment of the present invention will be described. Also in the head according to the present embodiment, since the inks are mixed with each other by causing the inks to collide with each other, the alignment of each head is important. In the following description, the same reference numerals are given to the same configurations and members as in the above embodiment, and the description thereof is simplified or omitted.

  The ink jet printer according to the present embodiment is provided at a predetermined position, and the light source unit 20 that emits light toward each of the heads 50 a to 50 e and the light from the light source unit 20 are provided to each of the heads 50 a to 50 e. A light receiving unit 22 that receives light, a determination unit 23 that determines the positional deviation of each of the heads 50a to 50e from the data of the light receiving unit 22, and a head moving unit 24 that performs alignment adjustment based on the result of the determination unit 23. And.

The configuration of the ink jet printer and the head alignment method in the present embodiment will be described below.
FIG. 10 is a diagram showing a schematic configuration of the head unit 80 of the head according to the third embodiment, and corresponds to FIG. 6 of the first embodiment and FIG. 9 of the second embodiment.

  As shown in FIG. 10, in the ink jet printer according to the present embodiment, the light source unit 20 made of, for example, a semiconductor laser that emits light toward each of the heads 50 a to 50 e is in a predetermined position (the first and second embodiments described above). The position where the alignment mirror 21 and the light receiving unit 22 are provided) is provided. Each of the heads 50a to 50e is provided with a light receiving unit 22 that receives light from the light source unit 20.

  Further, a determination unit 23 that determines the positional deviation of each head 50a to 50e based on the data of the light receiving unit 22 is provided. Based on the result of the determination unit 23, each of the heads 50a to 50e is moved to adjust the alignment. And a head moving means 24 composed of a piezoelectric element.

(Head alignment method)
Next, an alignment method according to this embodiment will be described. Hereinafter, a case where the alignment of the head 50c corresponding to the ink cartridge filled with cyan ink is adjusted will be described as an example.

  First, prior to the alignment adjustment of the head 50c, the light source unit 20 is rotated in a predetermined direction, and the light emission surface of the light source unit 20 is opposed to the light receiving unit 22 provided in the head 50c. Then, light is emitted from the light source unit 20 toward the light receiving unit 22 provided in the head 50c, and the light receiving unit 22 receives the light.

  At this time, the light receiving unit 22 calculates the incident position data of the laser beam. Then, the determination unit 23 determines how much the head 50c is deviated from a desired position based on this position data, that is, its positional deviation amount. And based on this determination result, the determination part 23 drives the moving means 24a, 24b, 24c, moves the head 50c, and performs alignment adjustment.

  Since the light source unit 20 is provided at a predetermined position as described above, the predetermined position where the head 50c is to be disposed can be determined by using the light source unit 20 as a reference. Therefore, the alignment of the head 50c can be adjusted. In the present embodiment, as shown in FIG. 10, the head 50c is provided with three head piezoelectric elements 24a, 24b, and 24c. Therefore, the head 50c can be moved in various directions by appropriately changing the combination of the piezoelectric elements 24a, 24b, and 24c to be driven.

  For example, by bending the piezoelectric elements 24a and 24c toward the head 50c, the piezoelectric elements 24a and 24c respectively apply a compressive force in the opposite direction to the head 50c, thereby counterclockwise with the direction perpendicular to the paper surface as the central axis. The head can be rotated in the turning direction. On the other hand, by bending the piezoelectric elements 24a and 24c to the opposite side of the head 50c, the piezoelectric elements 24a and 24c apply a tensile force to the head 50c, thereby causing the perpendicular direction to the paper surface to be the clockwise direction. The head can be rotated.

  As described above, the alignment of the head 50c can be appropriately adjusted by using the piezoelectric elements 24a, 24b, and 24c. In addition, for the other inkjet heads 50a, 50b, 50d, and 50e, the light source unit 20 is rotated to receive light from the light source unit 20 so that the positional deviation of each head is determined. In the same manner as described above, alignment adjustment can be performed. As described above, the ink jet printer according to the present embodiment can perform drawing with high accuracy by ejecting ink from the accurately aligned heads 50a to 50e.

According to the ink jet printer and the head alignment method according to the present embodiment, the light source unit 20 is provided at a predetermined position, and the light receiving unit 22 that receives light from the light source unit 20 is provided in each of the heads 50a to 50e. Therefore, the alignment adjustment of each of the heads 50a to 50e can be performed by using the light source unit 20 as a reference. The light receiving unit 22 receives the light from the light source unit 20 to calculate position data for the light source unit 20. And based on this position data, the determination part 23 can determine the position shift of each head 50a-50e which has the light-receiving part 22 with respect to the reference | standard (the said light source part 20).
Therefore, the head alignment can be adjusted easily and reliably.

1 is a schematic configuration diagram according to an embodiment of an inkjet printer. It is a disassembled perspective view of an inkjet head. It is a sectional side view which shows schematic structure of an inkjet head. It is a figure which shows schematic structure of a head unit. It is a figure for demonstrating the ink non-ejection area which performs alignment adjustment. FIG. 2 is a schematic configuration diagram of a head unit 60 in an ink non-ejection area. It is component structure sectional drawing for demonstrating operation | movement of an inkjet head. FIG. 5 is a diagram for explaining an ink collision state at a color mixing point. It is a figure which shows schematic structure of the head unit which concerns on 2nd embodiment. It is a figure which shows schematic structure of the head unit which concerns on 3rd embodiment.

Explanation of symbols

MP ... color mixing point, 11 ... nozzle (ink ejection port), 20 ... light source, 21 ... alignment mirror, 22 ... light receiving part, 23 ... determining part, 24a, 24b, 24c ... head moving means, 50a to 50e ... inkjet head , 60 ... head unit, 70 ... head unit, 80 ... head unit, 100 ... inkjet printer

Claims (12)

An ink jet having a plurality of ink jet heads and having a head unit in which the ink discharge ports of the respective ink jet heads are arranged concentrically, and dropping by mixing ink discharged from the ink discharge ports of the respective ink jet heads A printer,
A light source provided in at least one of the inkjet heads;
An alignment mirror that is held at a predetermined position with respect to the light source unit and reflects light emitted from the light source unit;
A light receiving unit that is provided in an inkjet head that does not include the light source unit, and that receives reflected light from the alignment mirror;
A determination unit that determines the positional deviation of the inkjet head having the light receiving unit from the data of the light receiving unit, and a head that performs alignment adjustment by moving the inkjet head including the light receiving unit based on the determination result of the determination unit An inkjet printer comprising: a moving unit; An ink jet having a plurality of ink jet heads and having a head unit in which the ink discharge ports of the respective ink jet heads are arranged concentrically, and dropping by mixing ink discharged from the ink discharge ports of the respective ink jet heads A printer,
A light source provided in each of the inkjet heads;
A light receiving unit that receives light from the light source unit and is provided at a predetermined position;
A determination unit that determines a positional shift of each inkjet head from the data of the light receiving unit; and a head moving unit that adjusts alignment by moving the inkjet head based on a determination result of the determination unit. Inkjet printer characterized by. An ink jet having a plurality of ink jet heads and having a head unit in which the ink discharge ports of the respective ink jet heads are arranged concentrically, and dropping by mixing ink discharged from the ink discharge ports of the respective ink jet heads A printer,
A light source unit that emits light toward each of the inkjet heads and is provided at a predetermined position;
A light receiving portion provided in each of the inkjet heads for receiving light from the light source portion;
A determination unit that determines a positional shift of each inkjet head from the data of the light receiving unit; and a head moving unit that adjusts alignment by moving the inkjet head based on a determination result of the determination unit. Inkjet printer characterized by.   The inkjet printer according to any one of claims 1 to 3, wherein the predetermined position corresponds to a position where color mixing of ink occurs when ink is assumed to be ejected from each inkjet head.   5. The inkjet printer according to claim 1, wherein the alignment adjustment is performed in a head standby area where ink is not ejected from each of the inkjet heads.   The inkjet printer according to claim 1, wherein a piezoelectric element is used as the head moving unit. An ink jet having a plurality of ink jet heads and having a head unit in which the ink discharge ports of the respective ink jet heads are arranged concentrically, and dropping by mixing ink discharged from the ink discharge ports of the respective ink jet heads A method for adjusting the alignment of the inkjet head by an inkjet printer.
Light is emitted from a light source unit provided in at least one of the ink jet heads to an alignment mirror held at a predetermined position with respect to the light source unit, and the light reflected by the alignment mirror is not provided with the light source unit. An inkjet head alignment method comprising: receiving light by a light receiving unit of the head; determining a positional shift of the inkjet head provided with the light receiving unit based on the received light data; and performing alignment adjustment based on the determination result. An ink jet having a plurality of ink jet heads and having a head unit in which the ink discharge ports of the respective ink jet heads are arranged concentrically, and dropping by mixing ink discharged from the ink discharge ports of the respective ink jet heads A method for adjusting the alignment of the inkjet head by an inkjet printer.
Light emitted from the light source unit provided in each inkjet head is received by a light receiving unit provided at a predetermined position, the positional deviation of each inkjet head is determined from the received light data, and alignment adjustment is performed based on the determination result An ink jet head alignment method comprising: An ink jet having a plurality of ink jet heads and having a head unit in which the ink discharge ports of the respective ink jet heads are arranged concentrically, and dropping by mixing ink discharged from the ink discharge ports of the respective ink jet heads A method for adjusting the alignment of the inkjet head by an inkjet printer.
Light is emitted to each inkjet head from the light source unit provided at a predetermined position, received by the light receiving unit provided on each inkjet head, and the positional deviation of each inkjet head is determined from the data of the light receiving unit. An alignment method for an ink jet head, wherein alignment adjustment is performed based on the determination result.   The ink jet head according to any one of claims 7 to 9, wherein the predetermined position corresponds to a position where color mixing of ink occurs when ink is assumed to be ejected from each ink jet head. Alignment method.   11. The inkjet head alignment method according to claim 7, wherein the alignment adjustment is performed in a head standby region where ink is not ejected from each of the inkjet heads.   10. The inkjet head alignment method according to claim 6, wherein a piezoelectric element is used as means for moving the head during alignment adjustment.

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