JPH11268258A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise in recording without increasing the number of ink jet heads by arranging a nozzle for printing a dot of first size and a nozzle for printing a dot of second size alternately. SOLUTION: An ink jet head 10 is arranged alternately with large diameter nozzles 207 and small diameter nozzles 208. The piezoelectric element 213 for driving the large diameter nozzle 207 is applied with a voltage at 7.5 V whereas the piezoelectric element 213 for driving the small diameter nozzle 208 is applied with a voltage of 12.5 V. Consequently, a row of adhesion dots from the large diameter nozzle 207 is printed while partially overlapping the row of adhesion dots from the small diameter nozzle 208. Consequently, no gap appear between adhesion dots of adjacent rows even if the hitting position of ink drop from the large diameter nozzle 207 or the small diameter nozzle 208 is shifted in the arranging direction of nozzle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an ink jet type ink jet recording apparatus for recording on a recording sheet by discharging ink from nozzles.

[0002]

2. Description of the Related Art Conventionally, there has been known an ink-jet recording apparatus in which a plurality of nozzles are arranged in a line in an ink-jet head, and the ink-jet head is operated in a direction perpendicular to the arrangement direction of the nozzles to record on a recording sheet.

Here, an ink jet head in a conventional ink jet recording apparatus will be described.

FIGS. 17 to 19 are views for explaining the configuration of a conventional ink jet head. 17 is a plan view showing a part of a surface having nozzles of a conventional inkjet head, FIG. 18 is a sectional view taken along line DD of FIG. 17, and FIG. 19 is a sectional view taken along line EE of FIG. It is.

A conventional ink jet head includes a nozzle plate 201, a partition wall 202, a vibration plate 203, and a substrate 204.
And are integrally laminated.

[0006] A plurality of ink channels 206 for accommodating ink are provided between the nozzle plate 201 and the partition wall 202.
, A common ink chamber 209, and each ink channel 206
And an inlet 210 that connects the common ink chamber 209 to the common ink chamber 209. The common ink chamber 209 is connected to an ink tank (not shown), and the ink in the common ink chamber 209 is supplied to the ink channel 206.

[0007] The vibration plate 203 is provided with each ink channel 2.
In addition, a plurality of driving piezoelectric elements 213 corresponding to No. 06 are included.

The common electrode 211 on the substrate 304 is commonly connected to the driving piezoelectric element 213. Individual electrode 212
Are individually connected to the driving piezoelectric elements 213.

The operation of the ink jet head having such a configuration is controlled by a control unit of the ink jet recording apparatus. A predetermined voltage, which is a print signal, is applied between the common electrode 211 and the individual electrode 212 from the control unit, and the driving piezoelectric element 213 is deformed in a direction to push the partition wall 202. The deformation of the driving piezoelectric element 213 is transmitted to the partition wall 202, whereby the ink in the ink channel 206 is pressurized, and the ink drop flies toward the recording sheet via the nozzle 205.

[0010]

However, in the conventional ink jet recording apparatus, when recording is performed in such a manner that nozzles of one color correspond to each other in the scanning direction, the size of the flying ink drop and the variation in the flying direction appear remarkably. As a result, noises such as white stripes were sometimes conspicuous on the recording sheet.

FIG. 20 shows the result of normal printing using an ink jet head having an attached dot diameter of 60 [μm] and a nozzle density of 600 [dpi]. Referring to FIG. 20, it can be seen that the entire sheet surface of the recording sheet is filled with the attached dots. Next, FIG. 2 shows the result when the landing position of the second dot of the inkjet head of the same performance was shifted by 10 [μm] and was not recorded normally.
It is shown in FIG. Referring to FIG. 21, as a result of shifting the attached dots in the second column from the left by 10 [μm] to the right, there is a slight gap between the first and second columns from the left of the attached dots. I understand. This gap appears in a state where the color of the recording sheet remains as it is because no ink was recorded. This is perceived by human eyes as white streak noise.

The white streak noise is generated when ink droplet landing positions are shifted due to variations in nozzle diameters and positions, and ink drops do not land at equal intervals. In order to cope with this, noise is corrected by inputting a correction value of a voltage applied to a piezoelectric element corresponding to a nozzle whose landing position is shifted from a printing result to an ink jet printing apparatus and adjusting the size of a flying ink drop. Correction to remove has been made. This correction requires a correction value creation operation for specifying the nozzle to be corrected and a correction value for the specified nozzle, and an operation for inputting the correction value. The correction value creation operation is a difficult operation because it is necessary to inspect all nozzles and determine a correction value for each nozzle whose landing position is shifted. The input of the correction value must be performed by the end user, which is inconvenient.

Further, by recording the same color twice in the same place by associating a plurality of nozzles for each color in the scanning direction,
There is an ink jet recording apparatus in which the variation is not noticeable. However, if a plurality of nozzles are made to correspond to each color, a plurality of ink jet heads are required and the manufacturing cost increases. In addition, the consumption of ink increases as the number of inkjet heads increases, and the running cost also increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to enable recording with less noise without increasing the number of ink jet heads.
An object of the present invention is to provide an ink jet recording apparatus which does not require adjustment for each nozzle and has a low manufacturing cost.

[0015]

According to one aspect of the present invention, there is provided an ink jet recording apparatus in which a plurality of nozzles are arranged in a predetermined direction, wherein the plurality of nozzles prints a dot of a first size; A nozzle for printing dots of the second size is alternately arranged.

According to the present invention, it is possible to provide an ink jet recording apparatus which enables recording with less noise without increasing the number of ink jet heads, does not require adjustment for each nozzle, and has a low manufacturing cost.

According to another aspect of the present invention, a first nozzle for printing dots of a first size and a nozzle for printing dots of a second size are arranged alternately in a predetermined direction.
And a nozzle for printing a dot of a second size is provided at a position corresponding to a nozzle of the first head for printing a dot of a first size, and a second size of the first head is provided. And a second head provided with a nozzle for printing a dot of a first size at a position corresponding to the nozzle for printing the dot of the first size. The first head and the second head perform printing. It is characterized in that the colors of the dots are different.

According to the present invention, by compensating for variations in ink jet heads with ink jet heads of different colors, it is possible to perform recording with less noise without color unevenness without increasing the number of ink jet heads, and to adjust for each nozzle. Is unnecessary, and an ink jet recording apparatus with low manufacturing cost can be provided.

[0019]

Embodiments of the present invention will be described below.

[First Embodiment] FIG. 1 is a diagram showing a schematic configuration of an ink jet recording apparatus according to a first embodiment of the present invention. Referring to the figure, an ink jet recording apparatus 1 includes a paper cassette 2, a paper feed roller 3, a transport plate 4, transport rollers 5a to 5g, an inkjet head 10, a fixing unit 6, a paper discharge unit 7, , A power supply / control unit 8.

First, the recording sheet in the paper cassette 2 is fed to the transport plate 4 by the feed roller 3. The recording sheet fed to the transport plate 4 is horizontally transported on the transport plate 4 by the transport rollers 5a to 5e. While the recording sheet moves on the transport plate 4, information such as an image is recorded on the recording sheet by the inkjet head 10 on the transport plate 4.
The recording sheet is sequentially conveyed by conveying rollers 5a to 5e and conveyed to fixing unit 6. In the fixing unit 6, an operation of fixing the ink on the recording sheet is performed. The fixing unit 6 includes an infrared lamp and a blower, and heats the recording sheet and sends air to fix the ink to the recording sheet. The recording sheet on which the ink has been fixed is discharged to the paper discharge unit 7 by the conveying rollers 5f and 5g.

The ink jet head 10 has a plurality of ink jet heads 10a to 10d. A yellow head 10a for discharging yellow ink, a magenta head 10b for discharging magenta ink, and a cyan head 10c for discharging cyan ink. And a black head 10d for ejecting black ink, and by mixing these inks for recording, full-color recording is possible. In addition, this inkjet head 1
Reference numeral 0 denotes a fixed line head having a nozzle density of 600.
[Dpi] enables high-speed printing.

The maintenance section 11 for restoring the nozzle surface of the ink jet head 10 to a good state is connected to a pump (not shown). Inkjet head 10
The recovery operation is performed by first raising the ink jet head 10, then moving the maintenance unit 11 laterally below the ink jet head 10, and bringing the maintenance unit 11 into contact with the nozzle surface of the ink jet head 10. On the contrary, the ink jet head 10 descends after the maintenance section 11 returns to the original position.

The power supply / control section 8 is a power supply of the ink jet recording apparatus 1 and a control section. Power supply / control unit 8
As a result, power is supplied to necessary portions in the inkjet recording apparatus 1. Next, control performed by the power supply / control unit 8 will be described. FIG. 2 is a control block diagram for describing control performed by the power supply / control unit 8 of the inkjet recording apparatus 1 according to the first embodiment.

Referring to the drawings, the ink jet recording apparatus 1
The power supply / control unit 8 includes a CPU 101 and a RAM 102
, ROM 103, data receiving unit 104, head ejection driving unit 105, paper feed driving unit 106, fixing unit driving unit 107, recovery system driving unit 108, various sensor units 10
9 is included.

The CPU 101 for controlling the whole executes a program stored in the ROM 103 by using the RAM 102 as necessary. This program includes, based on image data and the like read from the data receiving unit 104,
A section for controlling the head ejection drive section 105, the paper feed drive section 106, the fixing section drive section 107, and various sensor sections 109 to record image information and the like on a recording sheet, and a recovery system drive section 108 when necessary. Control the various sensor units 109,
And a portion for restoring the nozzle surface of the inkjet head 10 to a favorable state.

The data receiving unit 104 is connected to a host computer or the like and receives image data to be recorded.

Under the control of the CPU 101, the head ejection drive unit 105 drives the piezoelectric element of the ink jet head 10, and the paper feed drive unit 106 drives the paper feed roller 3 and the transport rollers 5a to 5g, and the fixing unit. The driving unit 107
The infrared lamp and the blower of the fixing unit 6 are driven. Also,
Based on the control of the CPU 101, the recovery system driving unit 108
Drives a motor, a pump, and the like necessary for the recovery operation of the inkjet head 10.

FIGS. 3 to 6 are views for explaining the configuration of the ink jet head 10 according to the first embodiment. 3 is a plan view showing a part of the surface of the inkjet head 10 having nozzles, FIG. 4 is a sectional view taken along line AA of FIG. 3, and FIG. 5 is a sectional view taken along line BB of FIG. FIG. 6 is a sectional view taken along line CC of FIGS. 4 and 5.

The ink jet head 10 has a configuration in which a nozzle plate 201, a partition wall 202, a vibration plate 203, and a substrate 204 are integrally laminated.

The nozzle plate 201 is made of metal or synthetic resin, and has a large-diameter nozzle 207 and a small-diameter nozzle 20.
8 and an ink-repellent layer on the surface. Partition wall 202
, A thin film is used, and is fixed between the nozzle plate 201 and the diaphragm 203.

The nozzle plate 201 and the partition wall 202
, A plurality of ink channels 206 for accommodating ink, a common ink chamber 209, and an inlet 21 connecting each ink channel 206 to the common ink chamber 209.
0 is formed. The common ink chamber 209 is connected to an ink tank (not shown).
The ink inside is supplied to the ink channel 206.

Each ink channel 2 is provided on the vibration plate 203.
In addition, a plurality of driving piezoelectric elements 213 corresponding to No. 06 are included. In the processing of the diaphragm 203, first, the diaphragm 203 is fixed to the substrate 204 having the common electrode 211 with an adhesive, and thereafter, a separator groove 215 is formed by dicer processing,
This is performed by dividing the diaphragm 203. Further, by this division, the driving piezoelectric element 213 corresponding to each ink channel 206 and the piezoelectric element column portion 214 located between the adjacent driving piezoelectric elements 213 are separated.

The common electrode 211 on the substrate 304 is connected to the ground, and is commonly connected to all the driving piezoelectric elements 213 in the ink jet head 10. Individual electrode 21
2 is individually connected to each driving piezoelectric element 213 in the inkjet head 10.

The operation of the ink jet head 10 having the above-described configuration is performed by the power supply of the ink jet recording apparatus 1.
It is controlled by the control unit 8. Power supply / control unit 8
A predetermined voltage, which is a printing signal, is applied between the common electrode 211 and the individual electrode 212 from the head ejection driving unit 105 (see FIG. 2), and the driving piezoelectric element 213
Deform in the direction of pressing 2. The deformation of the driving piezoelectric element 213 is transmitted to the partition wall 202, whereby the ink in the ink channel 206 is pressurized, and the ink drop flies toward the recording sheet via the large-diameter nozzle 207 or the small-diameter nozzle 208.

The ink drop flying from the ink jet head 10 applies the same applied voltage to the driving piezoelectric element 213.
Is applied to the large-diameter nozzle 207 and the small-diameter nozzle 2
08, the dot diameter when attached to the recording sheet is different.

FIG. 7 shows the relationship between the voltage applied to the driving piezoelectric element 213 and the diameter of the dot adhering to the recording sheet for each nozzle diameter. Reference numeral 301 denotes a characteristic due to the ink drop flying from the large-diameter nozzle 207, and reference numeral 302 denotes a characteristic due to the ink drop flying from the small-diameter nozzle 208.

For example, when an applied voltage of 10 [V] is applied to the driving piezoelectric element 213 of the large-diameter nozzle 207, the diameter of the attached dot landed on the recording sheet becomes 90 [μm], and the small-diameter nozzle 208 is driven. When the voltage is applied to the piezoelectric element 213, the diameter of the attached dot that lands on the recording sheet is 50 [μ].
m].

Further, as is apparent from FIG. 7, by using nozzles having different diameters, it is possible to select the diameter of the attached dots that land on the recording sheet in a wide range without expanding the range of the applied voltage. For example, when it is desired to set the diameters of the attached dots that land on the recording sheet to 80 [μm] and 60 [μm], a voltage of 7.5 [V] is applied to the driving piezoelectric element 213 of the large-diameter nozzle 207. And apply a diameter of 8
The attached dots having a diameter of 60 [μm] are applied by applying a voltage of 12.5 [V] to the driving piezoelectric element 213 of the small-diameter nozzle 208 so that the attached dots having a diameter of 60 [μm] land. I just need.

As described above, by controlling the value of the voltage applied to the driving piezoelectric element 213 of the large-diameter nozzle 207 and the small-diameter nozzle 208 by the head ejection drive unit 105, the diameter of the attached dot can be controlled. Further, the diameter of the attached dot can be selected in a wide range without expanding the range of the applied voltage.

Referring back to FIG.
In the figure, large-diameter nozzles 207 and small-diameter nozzles 208 are alternately arranged. The piezoelectric element 2 for driving the large-diameter nozzle 207 is provided on the inkjet head 10 having the nozzles arranged as described above.
FIG. 8 shows the results of recording by applying a voltage of 7.5 [V] to 13 and a voltage of 12.5 [V] to the driving piezoelectric element 213 of the small-diameter nozzle 208. The rows of attached dots formed by the ink drops flying from the large-diameter nozzles 208 land on the recording sheet partially overlap the rows of attached dots formed by the ink drops flying from the small-diameter nozzles 208 landing on the recording sheet. FIG. 9 shows a recording result when the landing position of the ink drop flying from the large-diameter nozzle 208 of the second dot of the inkjet head is shifted in the nozzle arrangement direction (rightward in the drawing). In this case, the attached dots in the second column from the left are shifted in the nozzle array direction (rightward in the drawing), but since the diameter of the attached dots in the second column is large, the attached dots in the first column and the second column are shifted. No gap is generated between the attached dots. Therefore, no noise occurs in which the color of the recording sheet appears as it is because no ink is recorded. Although the case where the landing position of the ink drop flying from the large-diameter nozzle 208 shifts has been described, noise does not similarly occur when the landing position of the ink drop flying from the small-diameter nozzle 207 shifts.

Further, in this embodiment, the case where the landing position is shifted in the nozzle arrangement direction (horizontal direction in FIG. 8) is described, but the landing position is shifted in the direction perpendicular to the nozzle arrangement direction (vertical direction in FIG. 8). Even in this case, partial overlap of the attached dots formed by landing on the recording sheet is maintained, so that the same effect as in the case of displacement in the nozzle arrangement direction can be obtained.

[Modification] Next, a modification of the first embodiment of the present invention will be described.

An ink jet recording apparatus according to a modification is the same as the ink jet head 1 according to the first embodiment.
This is a configuration using only the small-diameter nozzle 207 of zero.

As described above, the diameter of the attached dot that lands on the recording sheet differs depending on the voltage applied to the driving piezoelectric element 203. Utilizing this, the driving piezoelectric element 2
The voltage applied to 13 is controlled by the head ejection drive unit 105 so that the large-diameter attached dots and the small-diameter attached dots are alternately arranged and land on the recording sheet.

FIG. 10 shows the relationship between the voltage applied to the ink jet head 10 and the diameter of the attached dots that land on the recording sheet in the modified example. Referring to FIG. 10, in order to set the diameter of the attached dots that land on the recording sheet to 60 [μm], a voltage of 12.5 [V] from the plot point 310 d may be applied to the driving piezoelectric element 213. Further, in order to make the diameter of the attached dot landed on the recording sheet 80 [μm], a voltage of 17.5 [V] from the plot point 310 f may be applied to the driving piezoelectric element 213.

In order to perform the same recording as in the first embodiment, a voltage of 12.5 [V] is applied to the odd-numbered driving piezoelectric elements 213 of the ink-jet head 10 and the even-numbered piezoelectric elements 213 of the ink-jet head 10 are printed. The head ejection driving unit 105 may control the driving piezoelectric element 213 to apply a voltage of 17.5 [V].

Here, the waveform of the voltage applied to the driving piezoelectric element 213 will be described. FIG. 11 shows a waveform of a voltage applied to the driving piezoelectric element 213 by the head ejection driving unit 105. FIG. 11 is a graph in which the horizontal axis represents time and the vertical axis represents voltage. A solid line 320 is an applied voltage curve for large-diameter attached dots, and a dotted line 321 is an applied voltage curve for small-diameter attached dots.

Thus, the diameter of the attached dots landing on the recording sheet is 60 [μm] for the odd-numbered rows and 80 [μm] for the even-numbered rows.
m], and a recording result similar to that described in the first embodiment is obtained (see FIG. 8).

The rows of attached dots formed when the ink drops flying from the odd-numbered nozzles land on the recording sheet are:
The rows of attached dots formed when the ink drops flying from the even-numbered nozzles land on the recording sheet partially overlap.

Therefore, even if the attached dots formed on the recording sheet are shifted in the nozzle arrangement direction (horizontal direction in FIG. 8) or in the direction perpendicular to the nozzle arrangement direction (vertical direction in FIG. 8), No noise is generated because the partial overlap of the columns is maintained.

[Second Embodiment] An ink jet recording apparatus according to a second embodiment will be described. Second
The ink jet recording apparatus according to the embodiment
In the embodiment, the ink jet head 10 of the ink jet recording apparatus is arranged by changing the nozzle arrangement between the ink jet heads 10 of different colors.
Except for the difference in the arrangement of the nozzles between the inkjet heads 10 of different colors, since the configuration is the same as that of the inkjet recording apparatus 1 in the first embodiment, the description will not be repeated here.

FIG. 12 is a diagram schematically showing a surface having nozzles of the ink jet head 10 according to the present embodiment. Referring to FIG.
Consists of four color inkjet heads: a yellow head 10a for yellow ink, a magenta head 10b for magenta ink, a cyan head 10c for cyan ink, and a black head 10d for black ink. Then, the yellow head 10a and the black head 1
In the case of 0d, the odd-numbered nozzle is the small-diameter nozzle 208 and the even-numbered nozzle is the large-diameter nozzle 207. Conversely, the magenta head 10b and the cyan head 10c
The odd-numbered nozzle is the large-diameter nozzle 207, and the even-numbered nozzle is the small-diameter nozzle 208.

The yellow head 10a and the black head 1
The nozzles of the magenta head 10b and the cyan head 10c at the position corresponding to the small-diameter nozzle 208 of 0d are the large-diameter nozzles 207, and the magenta head 10b at the position corresponding to the large-diameter nozzles 207 of the yellow head 10a and the black head 10d. And the nozzles of the cyan head 10c
This is a small-diameter nozzle 207.

In the case of recording a secondary color using a plurality of inks with the ink jet head 10 configured as described above, for example, using the yellow ink and the cyan ink,
When recording the secondary color green or the secondary color red using yellow ink and magenta ink, even if the position where the ink drop flying from any nozzle adheres to the recording sheet is shifted, The ink drops flying from other nozzles are complemented by dots adhering to the recording sheet.

FIG. 13 schematically shows a state in which the ink jet head 10 according to the present embodiment adheres ink drops flying from the large-diameter nozzle 207 of the yellow head 10a and the small-diameter nozzle of the cyan head 10c to perform green recording. Is shown. In FIG. 13, dots adhering yellow ink are indicated by white circles, and dots adhering cyan ink are indicated by circles hatched by left diagonal lines. FIG. 13 (a) shows a case where the ink drop has normally adhered, and FIG. 13 (b) shows a case where the cyan ink adhered dot is 10 [μm] rightward in the drawing.
FIG. 13C shows a case where the attached dots of the cyan ink are shifted by 10 [μm] to the left in the drawing. In each of the cases shown in FIGS. 13A, 13B and 13C, the overlapping area of the yellow ink and the cyan ink and the non-overlapping area are the same. As a result, it looks the same green in both cases.

Therefore, even if the position where the ink drop flying from the nozzle adheres to the recording sheet is displaced, it is possible to eliminate the color unevenness of the green and red dots which are the secondary colors. The contribution ratio of red (R), green (G), and blue (B), which are the three primary colors of light, to human relative luminous efficiency (brightness) is R: G: B = 3: 6: 1. Eliminating the color irregularities of red (R) and green (G), which have a large contribution ratio, can improve the quality of the recorded image.

As a comparative example, a description will be given of color unevenness when a secondary color is recorded using two colors of ink with a conventional ink jet head. FIG. 14 is a diagram schematically illustrating a state in which ink drops adhere to a recording sheet when green recording as a secondary color is performed using two colors of yellow ink and cyan ink with a conventional inkjet head. is there. FIG. 14A shows a case where the ink drop is normally attached, FIG. 14B shows a case where the attached dot of the cyan ink is shifted by 10 [μm] rightward in the drawing, and FIG. This shows a case in which the attached dots of ink are shifted by 10 μm to the left in the drawing. FIG. 14A shows that all of the attached dots turn green, whereas FIG.
FIG. 14C shows a green portion, a yellow portion, and a blue-green portion. Therefore, the color shown in FIG. 14A looks different from the colors shown in FIGS. 14B and 14C.

As described above, in the ink jet head 10 according to the present embodiment, the color unevenness of the secondary colors green and red can be eliminated, so that the quality of the recorded image can be improved.

Further, when recording is performed in a single color of each of yellow, magenta, cyan, and black, the noise caused by the paper color of the recording sheet appearing as a streak as described in the first embodiment as it is is described. Can be eliminated.

[First Modification] A first modification of the second embodiment will be described. FIG. 15 is a diagram schematically illustrating a surface of the inkjet head 10 having a nozzle according to the first modification. In the yellow head 10a and the cyan head 10c, the odd-numbered nozzles are the small-diameter nozzles 208, and the even-numbered nozzles are the large-diameter nozzles 207. In the magenta head 10b and the black head 10d, the odd-numbered nozzles are the large-diameter nozzles 207, and the even-numbered nozzles are the small-diameter nozzles 208, contrary to the yellow head 10a and the cyan head 10c.

In the case of recording a secondary color using a plurality of inks with the ink jet head 10 having the above configuration, for example, red (R), which is a secondary color, using yellow ink and magenta ink, or When printing the secondary color blue (B) using magenta ink and cyan ink, even if the position where the ink drop flying from any of the nozzles adheres to the recording sheet is shifted,
Ink drops flying from other nozzles are complemented by dots adhering to the recording sheet. Accordingly, the ink jet head 10 according to the first modification can eliminate color unevenness between the secondary colors red (R) and blue (B), thereby improving the quality of a recorded image.

Further, when recording is performed in a single color of each of yellow, magenta, cyan, and black, it is possible to eliminate noise caused by the paper color of the recording sheet appearing as a streak as it is.

[Second Modification] A second modification of the second embodiment will be described. FIG. 16 is a diagram schematically illustrating a surface of the inkjet head 10 having nozzles according to the second modification. In the yellow head 10a, the magenta head 10b, and the cyan head 10c, the odd-numbered nozzles are the small-diameter nozzles 208, and the even-numbered nozzles are the large-diameter nozzles 207. Conversely, black head 1
0d indicates that the odd-numbered nozzle is the large-diameter nozzle 207,
The even-numbered nozzle is the small-diameter nozzle 208.

When the yellow ink, the magenta ink and the cyan ink are mixed, the color becomes black. Therefore, by arranging the nozzles as shown in FIG. 16, when recording black, recording using the black head 10d, yellow head 10a, magenta head 10b, and cyan head 10
The recording using c can be used together. Therefore, the ink jet head 10 according to the second modification example
In the case of printing black, the printing speed can be increased as compared with the case where printing is performed using only the black head 10d.

Further, in the case of recording in a single color of each of yellow, magenta, cyan and black, it is possible to eliminate noise caused by the paper color of the recording sheet appearing as a streak as it is.

As described above, the ink jet recording apparatus according to the present embodiment eliminates the need for complicated adjustment work for correcting variations in nozzles, and prints the same color twice in the same place on the recording sheet. Since there is no need to provide a plurality of ink jet heads, the manufacturing cost can be reduced.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an inkjet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a control block diagram illustrating control performed by a power supply / control unit of the inkjet recording apparatus according to the first embodiment of the present invention.

FIG. 3 is a plan view showing a part of a surface of the inkjet head having nozzles.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

FIG. 6 is a sectional view taken along line CC of FIGS. 4 and 5;

FIG. 7 is a diagram illustrating a relationship between a voltage applied to a driving piezoelectric element and a diameter of a dot adhering to a recording sheet.

FIG. 8 is a diagram illustrating a result of recording by the ink jet recording apparatus according to the first embodiment.

FIG. 9 is a diagram illustrating a recording result when the landing position of the second dot of the inkjet head is shifted.

FIG. 10 is a diagram illustrating a relationship between a voltage applied to a driving piezoelectric element of an inkjet head and a diameter of a dot adhering to a recording sheet according to a modification of the first embodiment.

FIG. 11 is a diagram illustrating a voltage applied to a piezoelectric element for driving an inkjet head according to a modification of the first embodiment.

FIG. 12 is a diagram schematically illustrating a surface having nozzles of an inkjet head according to a second embodiment.

FIG. 13 is a diagram schematically illustrating a state in which ink drops adhere to a recording sheet when recording of a secondary color is performed by the inkjet head according to the second embodiment.

FIG. 14 is a diagram schematically illustrating a state in which ink drops adhere to a recording sheet when recording of a secondary color is performed by a conventional inkjet head.

FIG. 15 is a diagram schematically illustrating a surface having nozzles of an inkjet head according to a first modification of the second embodiment.

FIG. 16 is a diagram schematically illustrating a surface having nozzles of an inkjet head according to a second modification of the second embodiment.

FIG. 17 is a plan view showing a part of a surface having nozzles of a conventional inkjet head.

18 is a sectional view taken along line DD of FIG. 17;

FIG. 19 is a sectional view taken along line EE of FIG. 18;

FIG. 20 is a diagram showing a recording result when normal printing is performed by a conventional inkjet head.

FIG. 21 is a diagram illustrating a recording result when the landing position of the second dot of the conventional inkjet head is shifted.

[Explanation of symbols]

 10 Inkjet head 207 Large diameter nozzle 208 Small diameter nozzle 213 Driving piezoelectric element

Claims (2)

[Claims] An ink jet recording apparatus in which a plurality of nozzles are arranged in a predetermined direction, wherein the plurality of nozzles print a first size dot and a second size dot print nozzle. And an ink jet recording apparatus, wherein are alternately arranged. 2. A first head in which nozzles for printing dots of a first size, and nozzles for printing dots of a second size are alternately arranged in a predetermined direction; A nozzle for printing a dot of a second size is provided at a position corresponding to a nozzle for printing a dot of a first size, and corresponds to a nozzle of the first head for printing a dot of the second size. A second head provided with a nozzle for printing a dot of a first size at a position where the first head and the second head have different colors of dots to be printed. apparatus.