JP2005103818A - Control method for car-mounted printer, and car-mounted printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a car-mounted printer control method that prevents bubbles from getting into nozzle openings and prevents an ink from jumping out due to impact and vibration, and a car-mounted printer. <P>SOLUTION: The inkjet car-mounted printer performs printing by discharging an ink from the nozzle openings due to a pressure change of a pressure generation element in a recording head, and has an impact detection means for sensing impact or vibration applied to the printer, a direction detection means for detecting the direction of the impact or vibration, a level detection means for detecting whether the magnitude of the impact or the vibration is over a prescribed threshold value, and a pressure generation element control means for generating a pressure in the direction of negating a force applied to the ink by the impact or the vibration when the magnitude of the impact of the vibration is a prescribed threshold value or higher. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control method for an ink jet in-vehicle printer that records an image or the like by ejecting ink from a nozzle opening due to pressure fluctuations of a pressure generating element in a recording head, and an in-vehicle printer.

  In an ink jet recording apparatus such as an ink jet printer or plotter, the recording head is moved in the main scanning direction and the recording paper is moved in the sub scanning direction, and ink is ejected from the nozzle openings of the recording head in conjunction with these movements. As a result, images and characters are recorded on the recording paper. The ink is ejected by operating a pressure generating element (for example, a piezoelectric vibrator such as a piezo element) provided corresponding to the nozzle to cause a pressure fluctuation in a pressure chamber communicating with the nozzle.

  In addition, in a recording head of a conventional ink jet printer, gradation expression is performed using a plurality of types of dots having different sizes in order to improve image quality. For this reason, an ejection pulse signal is selected from a series of drive signals including a plurality of ejection pulse signals having the same waveform shape for ejecting ink, supplied to the pressure generating element, and according to the number of ejection pulse signals supplied to the pressure generating element. The size of the dots is changed (this will be described in detail in the section “Best Mode for Carrying Out the Invention”).

  By the way, when such a conventional ink jet printer is used as a vehicle-mounted printer with a moving body such as an automobile, impacts and vibrations due to road irregularities are applied to the recording head of the printer, which adversely affects the printing result. There is.

  In order to deal with such problems, a pressure sensor that detects vibration from the outside of the head as pressure vibration is provided on the element substrate that constitutes the liquid discharge head, so that impact from the outside of the recording apparatus or vibration due to vibration is detected. A method has been proposed in which the recording operation is stopped immediately when detected by the pressure sensor, and then recording is restarted from the next image position where recording was stopped by a trigger signal derived in the head ( For example, see Patent Document 1).

  However, even in such an ink jet printer, ink is ejected from the nozzle opening due to an impact and stains the printing paper, or the meniscus of the nozzle opening (the free surface of the ink exposed at the nozzle opening: see FIG. 5) is destroyed. Bubbles may be mixed in the ink and defective ink discharge may occur.

Also, a method has been proposed in which the ink is pushed out by reducing the rigidity of the upper part of the ink bag to increase the amount of deformation when subjected to an impact, thereby preventing bubbles from being mixed into the nozzle openings (for example, Patent Documents). 2).
However, in this method, it is necessary to change the structure of the ink head and the ink storage container to a special one.
JP 2002-166552 A JP-A-9-99563

  The present invention has been made to solve such problems, and the object thereof is to change the ink head and the ink storage container into a special structure without introducing bubbles into the nozzle opening due to impact and vibration, and the ink. It is an object of the present invention to provide a method for controlling an in-vehicle printer and an in-vehicle printer that can prevent the pop-up from occurring.

A control method for an in-vehicle printer according to the present invention is a control method for an ink-jet in-vehicle printer that performs recording by ejecting ink from a nozzle opening due to pressure fluctuations of a pressure generating element in a recording head. A procedure for detecting the magnitude of the impact or vibration to be detected, a procedure for detecting the direction of the impact or vibration acting on the printer, and if the magnitude of the impact or vibration exceeds a predetermined threshold, And a step of driving the pressure generating element in a direction to cancel the applied force.
With such a procedure, the magnitude and direction of the impact or vibration applied to the ink jet in-vehicle printer is detected, and the pressure generating element is controlled so as to generate a pressure in the direction opposite to the force applied to the ink.
As a result, even when impact or vibration is applied to the printer, ink can be prevented from popping out from the nozzle opening of the recording head and air bubbles can be prevented from entering the nozzle opening, and printing defects due to impact or vibration can be prevented. it can.

In the on-vehicle printer control method according to the present invention, the threshold value is a limit value that can maintain a meniscus of the ink liquid level in the nozzle opening of the recording head.
With such a procedure, the meniscus due to the ink liquid formed in the nozzle opening is prevented from being destroyed by impact or vibration.
Thereby, it is possible to prevent printing defects due to mixing of bubbles into the nozzle openings.

The in-vehicle printer of the present invention is an ink jet type in-vehicle printer that performs recording by ejecting ink from a nozzle opening due to a pressure variation of a pressure generating element in a recording head, and the impact or vibration applied to the printer is detected. Impact detection means for detecting, direction detection means for detecting the direction of the impact or vibration, level detection means for detecting whether the magnitude of the impact or vibration is equal to or greater than a predetermined threshold, and the impact or vibration The pressure generating element is provided with pressure generating element control means for generating a pressure in a direction to cancel the force applied to the ink by impact or vibration when the magnitude of the pressure is greater than or equal to a predetermined threshold value.
With such a configuration, the impact or vibration applied to the printer (or recording head) is detected by an impact detection means such as an impact sensor, and the direction of the impact or vibration is detected by the direction detection means. Further, the level detection means detects whether the magnitude of the impact or vibration is greater than or equal to a predetermined threshold value. When the magnitude of the impact or vibration is greater than or equal to a predetermined threshold value, the pressure control means causes the pressure generating element to generate pressure in a direction that cancels the force applied to the ink by the impact or vibration.
As a result, even when impact or vibration is applied to the printer, ink can be prevented from popping out from the nozzle opening of the recording head and air bubbles can be prevented from entering the nozzle opening, and printing defects due to impact or vibration can be prevented. it can.

The on-vehicle printer of the present invention is characterized in that the threshold value is a limit value that can maintain a meniscus of the ink liquid level in the nozzle opening of the recording head.
With such a configuration, the meniscus by the ink liquid formed in the nozzle opening is prevented from being destroyed by impact or vibration.
Thereby, it is possible to prevent printing defects due to mixing of bubbles into the nozzle openings.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  First, an example of an ink jet recording head to which the present invention is applied will be briefly described (for details, refer to “Japanese Patent Laid-Open No. 2002-211010”).

  FIG. 2 is a diagram illustrating an example of an ink jet recording head. The illustrated recording head 15 has a flow path unit 21 bonded to the front end surface of a case 20. The vibrator unit 22 housed inside the case 20 causes a pressure fluctuation in the pressure chamber 23 in the flow path unit 21 and discharges ink from the nozzle openings 16.

  The case 20 is a box-shaped body in which a housing chamber 24 for housing the vibrator unit 22 is formed, and is molded by, for example, a resin material.

  The flow path unit 21 has a configuration in which the nozzle plate 26 is bonded to one surface of the flow path forming substrate 25 and the vibration plate 27 is bonded to the other surface of the flow path forming substrate 25. The flow path forming substrate 25 is formed of a silicon wafer or the like, and is partitioned into a predetermined pattern by etching the plurality of pressure chambers 23, the common ink chambers 28, and the common ink chambers that communicate with the nozzle openings 16. A partition that forms a plurality of ink supply paths 29 and the like connected from the ink chamber 28 to each pressure chamber 23 is appropriately formed. The common ink chamber 28 is provided with a connection port connected to the ink supply pipe 30, and ink stored in an ink cartridge (not shown) is supplied to the common ink chamber 28 through this connection port.

In the nozzle plate 26, a plurality of nozzle openings 16 are formed in rows at a pitch corresponding to the dot formation density, and the nozzle rows are configured by these nozzle openings 16. The nozzle rows are formed in the paper feed direction, that is, the sub-scanning direction.
The vibration plate 27 has a double structure in which an elastic film 32 such as a PPS film is laminated on a support plate 31 such as a stainless steel plate, and the support plate 31 is annularly etched at portions corresponding to the pressure chambers 23. An island portion 33 is formed in the ring.

  The vibrator unit 22 includes a piezoelectric vibrator 34 which is a kind of pressure generating element and a fixed plate 35. The piezoelectric vibrator 34 is formed with slit portions at a predetermined pitch corresponding to the pressure chambers 23 of the flow path unit 21 on one piezoelectric vibrator plate in which piezoelectric bodies and electrode layers are alternately laminated. Is formed in a comb-teeth shape. The fixed plate 35 is fixed to the base end portion of the comb-like vibrator. The vibrator unit 22 is inserted into the housing chamber 24 of the case 20 in a posture in which the tip of the piezoelectric vibrator 34 faces from the opening, and is attached to the case 20 by fixing the fixing plate 35 to the inner wall of the housing chamber 24. In this attached state, each tip of the piezoelectric vibrator 34 is fixed to the corresponding island portion 33 of the diaphragm 27.

  Each piezoelectric vibrator 34 expands and contracts in the longitudinal direction of the element perpendicular to the stacking direction by applying a potential difference between the opposing electrodes, and displaces the elastic film 32 that partitions the pressure chamber 23. That is, in the recording head 15, the piezoelectric vibrator 34 is contracted in the element longitudinal direction by charging, so that the elastic body film 32 is displaced and the pressure chamber 23 is expanded with the contraction. Further, since the piezoelectric vibrator 34 extends in the longitudinal direction of the element due to discharge, the elastic film 32 is pushed toward the nozzle plate 26 along with the expansion, and the elastic film 32 around the island portion 33 is deformed to deform the pressure chamber. 23 contracts. Then, since the pressure fluctuation occurs in the ink filled in the pressure chamber 23 in accordance with the volume change of the pressure chamber 23, the ink is ejected from the nozzle opening 16 by controlling the volume change of the pressure chamber 23. be able to.

  As described above, in the recording head 15 of the ink jet printer, the piezoelectric vibrator (pressure generating element) 34 is operated to cause a pressure fluctuation in the pressure chamber 23, thereby ejecting ink from the nozzle opening. Print text and images.

  Ink jet printers employ a method of printing dots having different sizes for the purpose of improving image quality. In this case, the dot size is changed by ejecting ink a plurality of times within one recording cycle. For example, when “small dots” are printed, ejection is performed once, when “medium dots” is performed, ejection is performed twice, and when “large dots” is performed, ejection is performed three times. In this case, four-gradation recording is possible including non-recording in which ink is not discharged.

  FIG. 3 is a view showing an example of a pulse waveform (ink ejection drive signal) for driving the pressure generating element in the recording head, and the pulses PS1, PS2, PS3 and PS4 shown in FIG. 3 are always generated. A pulse is selected according to a gradation value, and a target dot is formed by driving a pressure generating element.

  For example, when forming a “small dot (gradation value 2)”, only the third pulse (PS3) is selected. In the case of “medium dot (gradation value 3)”, the second pulse (PS2) and the fourth pulse (PS4) are selected. In the case of “large dot (gradation value 4)”, the first pulse (PS1), the third pulse (PS3), and the fourth pulse (PS4) are selected. The intervals between the pulses are set so that the pressure generating elements are driven at equal intervals regardless of whether large, medium, or small dots are formed. In the case of “non-recording (gradation value 1)”, no pulse is selected.

  FIG. 4 shows an example of a pulse waveform (ink ejection drive signal) applied to the pressure generating element when large, medium, and small dots are formed.

  Next, an example in which the present invention is applied to the configuration of the recording head shown in FIG. 2 and the ink jet printer using the driving method of the pressure generating element by the pulse shown in FIG. 3 will be described.

  FIG. 1 is a block diagram showing an example of a circuit configuration of an in-vehicle printer according to the present invention, and shows only a portion directly related to the present invention.

  In FIG. 1, reference numeral 1 is a signal switching switch (such as a semiconductor switch) that switches between an ink ejection driving signal (pressure generating element driving signal) and a constant voltage signal, and 2 is a positive / negative constant voltage switching that switches a positive / negative constant voltage signal. Switch (semiconductor switch or the like), 3 is a positive voltage constant voltage signal source, 4 is a negative voltage constant voltage signal source, and 5 is an impact sensor (impact detection) that detects an impact or vibration applied to the printer (or recording head). Means) 6 is a direction detector (direction detection means) for detecting the direction of impact or vibration, 7 is a level detector (level detection means) for determining whether the magnitude of impact or vibration is equal to or greater than a predetermined threshold, 8 is a decoder for selecting a pulse signal (see FIGS. 3 and 4) to be applied to the piezo element (pressure generating element) according to the gradation value (dot size), and 9 is each nozzle. Each switch (semiconductor switch, etc.) that is closed when a pulse signal is applied to the piezo element (pressure generating element) provided in 10 and 10 indicates each piezo element (pressure generating element) provided for each nozzle. Yes.

  In a normal use state, the signal selector switch 1 is in the state shown in FIG. 1, and selects the ink ejection drive signal (pressure generating element drive signal) a shown in FIG. The decoder 8 controls the opening and closing of each switch 9 according to the gradation value data and the print timing signal input from an external print control device (not shown), and applies it to each piezo element 10. A pulse signal (pulse signals PS1, PS2, PS3, PS4 shown in FIG. 3) is selected. As a result, large, medium, and small dots are selected and printed for each nozzle.

  Next, an operation when an impact or vibration is applied to the printer will be described. When an impact or vibration is applied to the printer, the impact sensor 5 detects the impact or vibration. In the level detector 7, the magnitude of the impact or vibration detected by the impact sensor 5 is a limit value that can hold a predetermined threshold, for example, a meniscus (see FIG. 5) of the ink liquid level at the nozzle opening of the recording head. Whether or not it exceeds the limit value, printing is stopped, the signal selector switch 1 is switched, and the constant voltage signal b is selected. The decoder 8 outputs a decode value (1111) that closes all the switches 9 and controls the constant voltage signal b to be applied to all the piezo elements 10.

  At the same time, the direction detector 6 detects the direction of impact or vibration and controls the positive / negative constant voltage changeover switch 2 to select the positive voltage constant voltage signal c or the negative voltage constant voltage signal d. In this case, when an impact is applied in the direction in which the ink is ejected, a voltage value (for example, a constant voltage signal d having a negative voltage) is selected so that the piezo element 10 is deformed in the direction in which the ink is returned into the head. When an impact is applied in the direction in which the ink is returned into the head and bubbles are mixed, a voltage value (for example, a positive constant voltage signal c) that deforms the piezo element 10 in the direction in which the ink is pushed out is selected.

  Thereafter, when the impact or vibration is subsided, the signal changeover switch 1 is switched again to select the ink ejection drive signal (pressure generating element drive signal) a, and printing is started again from the position where printing was stopped.

  As described above, in the present invention, the magnitude and direction of impact or vibration is detected, and a positive voltage or a negative voltage is applied to the piezo element 10 to eject ink from the nozzle openings and bubbles to the nozzle openings. Can be prevented, and printing failure due to impact or vibration can be prevented.

  Further, by setting the threshold value as a determination criterion in the level detector 7 based on “a limit value at which the meniscus formed by the ink liquid formed in the nozzle opening is not destroyed by impact or vibration”, the meniscus is protected and the nozzle opening It is possible to prevent air bubbles from entering. FIG. 5 is a diagram showing an example of a meniscus, and shows an example in which a meniscus M made of ink liquid is formed in the nozzle opening 16.

  In the example shown in FIG. 1, when the impact or vibration exceeds a predetermined threshold, the voltage applied to the piezo element 10 is a fixed voltage (constant voltage). A variable voltage can also be used depending on the magnitude of vibration.

  Although the embodiments of the present invention have been described above, the in-vehicle printer of the present invention is not limited to the above-described illustrated examples, and various modifications can be made without departing from the gist of the present invention. Of course.

  In the present invention, in an ink jet printer, the magnitude and direction of an impact or vibration applied to the printer is detected, and a positive voltage or a negative voltage is applied to a pressure generating element (for example, a piezoelectric vibrator such as a piezo element), whereby a nozzle This has the effect of preventing printing failure due to ink jumping out of the opening and mixing of bubbles into the nozzle opening.

  Therefore, the present invention can be applied to a control method for a vehicle-mounted printer, a vehicle-mounted printer, and the like.

The block diagram which shows the circuit structural example of the vehicle-mounted printer by this invention. FIG. 3 is a diagram illustrating an example of a recording head of an inkjet printer. FIG. 4 is a diagram illustrating an example of a pulse waveform for driving a pressure generating element in a recording head. The figure which shows the example of the pulse waveform in the case of forming each dot. The figure which shows the example of a meniscus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Signal changeover switch, 2 Positive / negative constant voltage changeover switch 3 Positive voltage constant voltage signal source, 4 Negative voltage constant voltage signal source 5 Impact sensor, 6 Direction detector, 7 Level detector 8 Decoder, 9 Switch, 10 Piezo element

Claims (4)

A control method for an ink jet type in-vehicle printer that performs recording by discharging ink from a nozzle opening due to pressure fluctuation of a pressure generating element in a recording head,
A procedure to detect the magnitude of impact or vibration acting on the printer;
A procedure to detect the direction of impact or vibration acting on the printer;
A step of driving the pressure generating element in a direction to cancel the force applied to the ink by the shock or vibration when the magnitude of the shock or vibration is a predetermined threshold value or more. Control method. The method for controlling an in-vehicle printer according to claim 1, wherein the threshold value is a limit value that can maintain a meniscus of an ink liquid level in a nozzle opening of a recording head. An ink-jet in-vehicle printer that performs recording by ejecting ink from a nozzle opening due to pressure fluctuation of a pressure generating element in a recording head,
An impact detection means for detecting an impact or vibration applied to the printer;
Direction detecting means for detecting the direction of the impact or vibration;
Level detection means for detecting whether the magnitude of the impact or vibration is equal to or greater than a predetermined threshold;
Pressure generating element control means for generating pressure in a direction to cancel the force applied to the ink by the impact or vibration when the magnitude of the impact or vibration is a predetermined threshold value or more. In-vehicle printer. The in-vehicle printer according to claim 3, wherein the threshold value is a limit value that can maintain a meniscus of the ink liquid level in the nozzle opening of the recording head.

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