JP2007098611A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure that a device is downsized and manufacturing costs are lowered by reducing the capacity of a power supply. <P>SOLUTION: The inkjet recording device has a plurality of recording heads 8, 9, 10 and 11 each having a nozzle array composed of many nozzles 12 and discharging inks to a recording medium P from the nozzle array and a control section 18 which controls the rising timing of a driving voltage instructing the nozzle array to drive the inks to discharge so as to make it differ from each other within the application time of the driving voltage applied to specific recording heads. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus provided with a drive circuit that controls rising and falling timings of a voltage applied to a piezoelectric element.

  2. Description of the Related Art Conventionally, an ink jet recording apparatus is known as a recording apparatus capable of printing on various recording media represented by plain paper. An ink jet recording apparatus ejects ink, which is a coloring material, directly onto a recording medium from an ejection port (hereinafter referred to as a nozzle) provided on the surface of the recording head that faces the recording medium, and is landed, permeated, or This is a recording apparatus that forms an image on a recording medium by fixing, and has very excellent characteristics in terms of process simplicity, quietness during printing, printing, and print quality.

  As one of the ink ejection methods in the above-described ink jet recording apparatus, a piezoelectric method in which a piezoelectric element that is deformed by applying a voltage presses the wall surface of an ink chamber provided inside the recording head to eject ink. Is mentioned. The recording head of the ink jet recording apparatus using the piezo method is provided with a drive circuit for independently driving each recording head. As shown in FIG. The recording heads were driven simultaneously. The same applies to a case where a plurality of recording heads in which one or a plurality of nozzle arrays are arranged, the nozzle designation is divided into three and each nozzle is asserted, that is, driven using a three-phase ink jet recording apparatus. As shown in FIG. 16, charging and discharging were simultaneously performed on the recording heads of the respective colors.

  However, recent ink jet recording apparatuses tend to increase the number of nozzles of the recording head in order to improve printing and printing speed. In addition, as the drive speed of the recording head is increased, the charge / discharge cycle of the piezoelectric element is shortened, so that power consumption tends to increase. Therefore, as the number of nozzles that are driven simultaneously increases, the current that instantaneously flows in the drive circuit of the recording head increases, causing problems such as an increase in the amount of heat generated by the resistance in the drive circuit and the occurrence of electromagnetic interference.

Therefore, as an inkjet recording apparatus that can suppress interference with nozzles that are not driven while reducing excessive current associated with charging and discharging of the piezoelectric body, the recording head is divided into a plurality of blocks. The charge / discharge period of the piezoelectric elements in each block excluding the piezoelectric element at the boundary of the phase is different between the different blocks for each phase drive so that at least a part of each charge does not overlap between the different blocks. An ink jet recording apparatus has been developed in which at least a part of each of the suction and discharge periods is overlapped between different blocks for driving (see, for example, Patent Document 1).
JP 2005-41074 A

However, when a large number of nozzle rows are arranged in the recording head in the above-described ink jet recording apparatus, as shown in FIG. 17, charging and discharging are simultaneously performed, and thus an excessive current flows in the drive circuit. The same applies to the case of a three-phase ink jet recording apparatus as shown in FIG. For this reason, it is necessary to use a large-capacity power supply, and there is a problem that it is difficult to reduce the size of the power supply apparatus, and hence the inkjet recording apparatus.
In addition, since a large-capacity power supply device is very expensive, there is a problem that the manufacturing cost increases.

  SUMMARY An advantage of some aspects of the invention is that it provides an ink jet recording apparatus that can reduce power supply capacity, reduce the size of the apparatus, and reduce manufacturing costs.

In order to solve the above problems, an ink jet recording apparatus according to the first aspect of the present invention provides:
A plurality of recording heads each including a nozzle row including a plurality of nozzles and discharging ink from the nozzle row to a recording medium;
A control unit that controls the rising timing of the drive voltage for instructing the ejection of ink to each nozzle row so as to be different from each other within the application time of the drive voltage applied to a specific recording head. It is characterized by.

  In the ink jet recording apparatus according to a second aspect of the present invention, the control unit mutually determines the rising timing of the drive voltage in each nozzle row for each time obtained by dividing the drive voltage application time by the number of nozzle rows arranged. It is characterized by controlling to be different.

An ink jet recording apparatus according to the invention of claim 3 is:
A plurality of recording heads each including a nozzle row including a plurality of nozzles and discharging ink from the nozzle row to a recording medium;
Control is performed so that the fall time of the drive voltage that instructs ink ejection drive to one nozzle row is the same as the rise time of the drive voltage applied to the nozzle row adjacent to the one nozzle row. And a control unit.

  The ink jet recording apparatus according to a fourth aspect of the invention is characterized in that the plurality of recording heads include two or more nozzle rows in each recording head.

  According to a fifth aspect of the present invention, in the ink jet recording apparatus, the nozzle arrays of the plurality of recording heads are divided into a plurality of blocks including a plurality of nozzle arrays having the same rising timing or falling timing of the drive potential. It is characterized by that.

According to the first aspect of the present invention, the rising timings of the driving voltages for instructing the ink ejection driving to the respective nozzle arrays are different from each other within the application time of the driving voltage applied to the specific recording head. Therefore, it is possible to use an inexpensive and small-capacity power supply device that disperses an excessive current generated at the time of rising of the drive voltage, and has a small size.
Therefore, it is possible to reduce the size of the power supply device, and consequently the size of the ink jet recording apparatus 1, and to reduce the manufacturing cost.

According to the second aspect of the invention, the control unit controls the rising timing of the drive voltage in each nozzle row so as to be different from each other every time obtained by dividing the application time of the drive voltage by the number of nozzle rows arranged. Therefore, by applying a driving voltage to each recording head at a constant time interval, stable ink ejection driving can be realized and control can be facilitated.
For this reason, it is possible to improve printing and printing quality and to suppress manufacturing costs.

According to the third aspect of the present invention, the fall time of the drive voltage for instructing the ejection drive of ink to one nozzle row, and the drive voltage applied to the nozzle row adjacent to the one nozzle row Since the control unit controls so that the rising timing of the piezoelectric element becomes the same, it is possible to use a smaller capacity power supply device by simultaneously charging and discharging the piezoelectric element and canceling the potential difference of the driving voltage. Become.
Therefore, it is possible to further reduce the size of the power supply device, and thus further reduce the size of the ink jet recording apparatus 1, and more effectively suppress the manufacturing cost.

According to the invention described in claim 4, the plurality of recording heads include two or more nozzle rows in each recording head. Similar to Item 2, it is possible to use an inexpensive and small-capacity power supply device having a small size by dispersing an excessive current generated at the time of rising of the drive voltage.
Therefore, it is possible to reduce the size of the power supply device, and consequently the size of the ink jet recording apparatus 1, and to reduce the manufacturing cost.

According to the fifth aspect of the present invention, the nozzle row of the plurality of recording heads is divided into a plurality of blocks composed of a plurality of nozzle rows having the same rising timing or falling timing of the drive potential. It is possible to simultaneously eject ink from a plurality of nozzle rows constituting the.
Therefore, it is possible to improve the printing and printing speed.

[First Embodiment]
The best mode for carrying out the present invention will be described below with reference to the drawings. However, the embodiments described below are provided with various technically preferable limitations for carrying out the present invention, but the scope of the invention is not limited to the following embodiments and illustrated examples.

  As shown in FIG. 1, the ink jet recording apparatus 1 according to the present embodiment includes a housing (not shown), and each constituent member is covered by the housing. In addition, a part of the housing is opened, and a slit-shaped entrance (not shown) for feeding the recording medium P into the housing is provided on the side opposite to the opened side.

A flat platen 2 that supports the recording medium P from one surface side is provided inside the casing described above, and conveying rollers 3 and 4 are disposed on the front and rear sides of the platen 2, respectively. Each of the transport rollers 3 and 4 is rotated in a predetermined direction around the axis before and after the platen 2, and the recording medium P has a non-recording surface along with the rotation direction of the transport rollers 3 and 4. It is conveyed from the upstream side toward the downstream side while being supported by the platen 2.
Here, the conveyance direction of the recording medium P is defined as a sub-scanning direction Y.

  Two long guide rails 5 and 6 extending in a direction orthogonal to the sub-scanning direction Y are provided above the platen 2. A substantially rectangular parallelepiped carriage 7 is engaged and supported on the guide rails 5 and 6, and is guided in the direction perpendicular to the sub-scanning direction Y (hereinafter referred to as a main scanning direction X) while being guided by the guide rails 5 and 6. ) Can be reciprocated freely.

Inside the carriage 7 described above, as shown in FIGS. 1 and 2, each process of yellow (Y), magenta (M), cyan (C), and black (K) is directed toward the recording surface of the recording medium P. Four recording heads 8, 9, 10, 11 for discharging color ink are mounted. These recording heads 8, 9, 10, and 11 are formed in a substantially rectangular parallelepiped shape, and ink is stored therein. The recording heads 8, 9, 10, and 11 are arranged in a line along the main scanning direction X so that their longitudinal sides are substantially parallel to each other, and are moved as the carriage 7 reciprocates. It has become. Further, as shown in FIG. 3, a number of substantially circular nozzles for ejecting ink as ink droplets are provided on the surfaces (hereinafter referred to as ejection surfaces) of the recording heads 8, 9, 10, and 11 facing the recording medium P. 12 are arranged in a line along the longitudinal direction of each recording head 8, 9, 10, 11.
Here, in FIG. 1, the alphabetic characters attached to the recording heads 8, 9, 10, 11 represent the color of the ink to be ejected.

  The nozzles 12 in the present embodiment are arranged in a line along the longitudinal direction of the recording head, but are not particularly limited. For example, as shown in FIG. It may be arranged in two rows on the 10, 11 ejection surfaces.

As shown in FIG. 5, each of the recording heads 8, 9, 10, and 11 described above is provided with a piezoelectric element 13 such as a piezo element that applies pressure to the ink inside, for each nozzle 12. The level shift circuit 16 is connected via a first analog switch 14 and a second analog switch 15 that can be switched by a control signal having information “0” or “1” that controls ink ejection drive. The level shift circuit 16 is connected to a power supply device (not shown) via a shift register 17 that temporarily stores input data and a control unit 18 that controls transmission of a control signal. In order to apply an appropriate bias, the voltage of the power supply is lowered to a predetermined potential. The first analog switch 14, a first wiring _{L 1,} second analog switch 15 is connected to the second wiring _{L 2,} respectively.

The recording heads 8, 9, 10, and 11 having such a configuration have a voltage adjusted by the level shift circuit 16 based on a control signal transmitted from the control unit 18 and a driving voltage that instructs ink ejection driving. Alternatively, whether or not to apply to the piezoelectric element 13 as a stop voltage for instructing to stop ink ejection is controlled.
More specifically, when a control signal having information “1” is transmitted, the first analog switch 14 is turned on and the second analog switch 15 is turned off, thereby turning on the waveform (on wave) is applied to the piezoelectric element 13 as a driving voltage, so that the piezoelectric element 13 is driven and ink is individually ejected from each nozzle 12 as droplets. On the other hand, when a control signal having information of “0” is transmitted, the first analog switch 14 is turned off and the second analog switch 15 is turned on, so that the off waveform is stopped. By being applied to the piezoelectric element 13 as a voltage, driving of the piezoelectric element 13 is suppressed, and ink ejection is stopped.

  The application time of the drive voltage and the stop voltage in the present embodiment is 4 μsec, but is not particularly limited, and may be 0.1 μsec or 10 μsec, for example.

Next, the operation of the ink jet recording apparatus 1 in the present embodiment will be described.
Here, the application time of the drive voltage applied to each recording head 8, 9, 10, 11 is the same.
When predetermined image information is sent to the ink jet recording apparatus 1, each of the conveying rollers 3 and 4 repeats predetermined rotation and stop, and the recording medium P has a platen 2 with its non-recording surface supported by the platen 2. 2 is conveyed intermittently in the sub-scanning direction Y.
Each time the transport rollers 3 and 4 are stopped, the carriage 7 is operated, and when the carriage 7 reciprocates in the main scanning direction X immediately above the recording medium P, the recording heads 8, 9, 10, and 11 mounted on the carriage 7 are also moved. As the carriage 7 moves, the ink reciprocates directly above the recording medium P, and ink of a required color is ejected from the nozzles of the recording heads 8, 9, 10, 11 to the recording medium P.
Thereafter, the same operation is repeated, a desired image is formed on the recording surface of the recording medium P, and a series of image recording operations is completed.

At this time, as shown in FIG. 6, first, a drive voltage is applied to the piezoelectric element 13 of the recording head 11 in which black (K) ink is stored. Next, a time obtained by dividing the drive voltage application time by the number of installed print heads from the start of applying the drive voltage to the print head 11, that is, after 1 μsec has elapsed, the piezoelectric of the print head 10 in which cyan (C) ink is stored. A drive voltage is applied to the element 13. Further, the drive voltage is applied to the piezoelectric element 13 of the recording head 9 in which the magenta (M) ink is stored after the elapse of 1 μsec from the start of the application of the driving voltage to the recording head 10. Finally, a drive voltage is applied to the piezoelectric element 13 of the recording head 8 in which yellow (Y) ink is stored after the elapse of 1 μsec from the start of applying the driving voltage to the recording head 9.
That is, the rising timing of the drive voltage applied to each recording head 8, 9, 10, 11 is controlled so as to be different from each other within the application time of the drive voltage applied to the piezoelectric element of the recording head 11. It is possible to use an inexpensive and small-capacity power supply apparatus that disperses an excessive current generated at the time of rising of the drive voltage and is inexpensive.

  Further, the rising timing of the drive voltage applied to each of the recording heads 8, 9, 10, and 11 is different by 1 μsec. That is, the drive voltage application time is different for each time obtained by dividing the drive voltage application time by the number of nozzle arrays. Therefore, by applying a driving voltage to each of the recording heads 8, 9, 10, and 11 at a constant time interval, stable ink ejection driving is realized and control is facilitated. Is possible.

As described above, according to the ink jet recording apparatus 1 of the present embodiment, it is possible to reduce the size of the power supply device, and consequently to reduce the size of the ink jet recording apparatus 1, and to reduce the manufacturing cost.
It is also possible to improve printing and printing quality.

  Note that the recording head of the ink jet recording apparatus 1 in the present embodiment has the nozzles 12 arranged in a row, but a case where a plurality of nozzle rows are arranged in one recording head as shown in FIG. Even in such a case, as shown in FIG. 7, it is within the application time and is different for each predetermined time. For the same reason as described above, downsizing of the power supply device, and consequently the inkjet recording device 1 can be reduced in size and the manufacturing cost can be reduced.

[Modification]
Next, a modification of the ink jet recording apparatus 1 in the first embodiment described above will be described with reference to FIGS. However, since the inkjet recording apparatus 1 in the present modification has the same configuration as that of the inkjet recording apparatus 1 in the first embodiment, the same reference numerals are given to the respective constituent members and the detailed description thereof is omitted.

The operation of the inkjet recording apparatus 21 in this modification will be described.
As shown in FIG. 8, first, a driving voltage is applied to the recording head 11 in which black (K) ink is stored and the piezoelectric element 13 in the recording head 9 in which magenta (M) ink is stored. After the elapse of 4 μsec from the start of the application of the drive voltage, the drive voltage application to the piezoelectric elements 13 of the print heads 11 and 9 is stopped, and at the same time, the print head 10 storing cyan (C) ink and the yellow (Y) ink are stored. A driving voltage is applied to the piezoelectric element 13 of the recording head 8.
Therefore, it is possible to use a power supply device with a smaller capacity by simultaneously charging and discharging the piezoelectric element 13 and canceling out the potential difference of the drive voltage.

  As described above, according to the ink jet recording apparatus 1 in the present modification, the power supply device can be further downsized, and further the ink jet recording apparatus 1 can be further downsized, and the manufacturing cost can be more effectively suppressed. .

As shown in FIG. 9, the same applies to the case where a plurality of nozzle rows are arranged in each of the recording heads 8, 9, 10, and 11. The piezoelectric element 13 is simultaneously charged and discharged, and the potential difference of the drive voltage is increased. By canceling out, it is possible to use a power supply device with a smaller capacity.
Therefore, it is possible to further reduce the size of the power supply device, and thus further reduce the size of the ink jet recording apparatus 1, and more effectively suppress the manufacturing cost.

Further, as shown in FIG. 10, the case of a three-phase driving ink jet recording apparatus including a plurality of recording heads in which one or a plurality of nozzle arrays are arranged is the same as that of the above-described embodiment and modification. As shown in FIG. 11 and FIG. 12, it is possible to use an inexpensive and small-capacity power supply device having a small size by dispersing an excessive current generated at the rise of the drive voltage.
Therefore, it is possible to reduce the size of the power supply device, and consequently the size of the ink jet recording apparatus 1, and to reduce the manufacturing cost.
It is also possible to improve printing and printing quality.

Furthermore, as shown in FIG. 10, in the above-described three-phase driving ink jet recording apparatus, the falling timing of the drive voltage applied to one recording head or nozzle row and the recording head or nozzle row are adjacent to each other. The case where the drive voltage rise timing for the recording head or the nozzle array is controlled to be the same is the same as in the above-described embodiment and modification, and as shown in FIGS. By simultaneously discharging and canceling out the potential difference of the drive voltage, it becomes possible to use a power supply device with a smaller capacity.
Therefore, according to the ink jet recording apparatus in the present embodiment, it is possible to further reduce the size of the power supply apparatus, and further reduce the size of the ink jet recording apparatus, and more effectively suppress the manufacturing cost.

1 is a plan view showing an external configuration of an ink jet recording apparatus. FIG. 3 is a cross-sectional view taken along an arrow showing a configuration of a main part of the ink jet recording apparatus. FIG. 3 is a plan view illustrating a configuration of a nozzle surface in each recording head. It is a top view which shows the other structure of the nozzle surface in each recording head. FIG. 3 is a block diagram illustrating a circuit configuration of each recording head. 6 is a timing chart showing an operation mode of each recording head. It is a timing chart which shows the other operation mode of each recording head. 10 is a timing chart showing an operation mode of each recording head in a modified example. 10 is a timing chart showing another operation mode of each recording head in a modified example. It is a block diagram which shows the other circuit structure of each recording head in a modification. 10 is a timing chart showing another operation mode of each recording head in a modified example. 10 is a timing chart showing another operation mode of each recording head in a modified example. 10 is a timing chart showing another operation mode of each recording head in a modified example. 10 is a timing chart showing another operation mode of each recording head in a modified example. It is a timing chart which shows the operation | movement aspect of each recording head in a prior art. 6 is a timing chart showing an operation mode of three-phase driving of each recording head in the prior art. It is a timing chart which shows the operation | movement aspect of each recording head in a prior art. 6 is a timing chart showing an operation mode of three-phase driving of each recording head in the prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 8, 9, 10, 11 Recording head 12 Nozzle 16 Level shift circuit 17 Shift register 18 Control part

Claims (5)

A plurality of recording heads each including a nozzle row including a plurality of nozzles and discharging ink from the nozzle row to a recording medium;
A control unit that controls the rising timing of the drive voltage for instructing the ejection of ink to each nozzle row so as to be different from each other within the application time of the drive voltage applied to a specific recording head. An ink jet recording apparatus.   The control unit controls the rising timing of the drive voltage in each nozzle row so as to be different for each time obtained by dividing the application time of the drive voltage by the number of nozzle rows arranged. 2. An ink jet recording apparatus according to 1. A plurality of recording heads each including a nozzle row including a plurality of nozzles and discharging ink from the nozzle row to a recording medium;
Control is performed so that the fall time of the drive voltage that instructs ink ejection drive to one nozzle row is the same as the rise time of the drive voltage applied to the nozzle row adjacent to the one nozzle row. And an ink jet recording apparatus.   4. The inkjet recording apparatus according to claim 1, wherein each of the plurality of recording heads includes two or more nozzle arrays in each recording head. 5.   5. The nozzle array of the plurality of recording heads is divided into a plurality of blocks composed of a plurality of nozzle arrays having the same rising timing or falling timing of the drive potential. An ink jet recording apparatus according to claim 1.

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