JP2011178080A - Inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet printer which can make a printer head and a carriage compact while suppressing effects of variation of a capacity value of a circuit with which an ejection driving source is connected. <P>SOLUTION: The ink jet printer includes the printer head 60 which has an ejection actuator comprised of a capacitive element that repeats charging and discharging on the basis of a driving waveform signal to make the ink ejected from nozzles and which is configured to eject the ink to a printing medium according to the driving waveform signal inputted to the ejection driving source; a CPU which forms nozzle selecting data on the basis of printing data for performing printing by the printer head 60; a driving waveform generating circuit 121 which generates the driving waveform signal; and a capacity value adjusting part 130 which is provided as a separate body from the printer head 60 and adjusts the capacity value of the circuit with which the ejection actuator is connected on the basis of the number of nozzles selected by the nozzle selecting data so that the driving waveform for driving the ejection actuator becomes constant. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a printer head having a nozzle for discharging ink and a discharge drive source, and controls the discharge waveform applied by the discharge control device to the discharge drive source, whereby ink having a particle size corresponding to the discharge waveform is printed on the print medium. The present invention relates to an ink jet printer that performs predetermined printing on a printing medium by discharging the ink to a printing medium.

  An ink jet printer is a printing target in which fine particles of ink are ejected from nozzles onto a printing medium while a printer head (also called an ink jet head or an ink jet printer head: IJP head) is moved relative to the printing medium from front to back and from side to side. It is an apparatus that prints information such as characters, figures, patterns, and photographs on the surface. This ink jet printer is provided with a printer head having a number of nozzles and ejection drive sources such as piezoelectric elements arranged in a line at a fine pitch in the front-rear direction, and each ejection drive source is moved while moving the printer head left and right. By controlling the drive waveform applied to the nozzle and ejecting ink having a particle diameter corresponding to the drive waveform from the nozzle, desired information can be printed in the belt-like print region.

  In the ink jet printer as described above, it is well known that a capacitive element such as a piezo element is used as an ejection drive source, but the number and types of nozzles that eject ink differ depending on the type of print data. When the ink discharge rate (ratio of nozzles that discharge ink with respect to all nozzles) changes and the electric capacity of the circuit to which the discharge drive source is connected varies, an event may occur in which the drive waveform is deformed. In view of this, an ink jet printer in which the occurrence of the above-described event is suppressed by separately providing a dummy capacitive load and keeping the electric capacity of the entire circuit constant is known (see, for example, Patent Documents 1 and 2). ).

JP 11-320872 A JP 2007-203493 A

  However, in the ink jet printer as described above, since the dummy capacitive load is built in the printer head and directly connected to the COM line, the substrate for arranging the dummy capacitive load is provided. Is required to be provided on the printer head or a carriage as a moving body thereof, and the printer head and the carriage cannot be reduced in size.

  The present invention has been made in view of such problems, and an ink jet capable of reducing the size of a printer head and a carriage while suppressing the influence of fluctuations in the capacitance value of a circuit to which an ejection drive source is connected. An object is to provide a printer.

  In order to achieve the above object, an ink jet printer according to the present invention includes a capacitive element that is provided corresponding to a nozzle that ejects ink and that performs charging and discharging based on an input of a driving waveform signal. A discharge drive source (for example, the discharge actuator 65 in the embodiment) that discharges ink from the nozzles by vibrating along with the printer head that discharges ink from the nozzles to print on the print medium, and prints by the printer head A nozzle selection unit (for example, the CPU 102 in the embodiment) that selects a nozzle to eject ink based on print data to be applied, and a discharge waveform corresponding to the nozzle selected by the nozzle selection unit by generating a drive waveform signal A drive waveform signal output unit that outputs a drive waveform signal to a source (for example, in the embodiment) Dynamic waveform generating circuit 121) and a power storage unit (for example, capacitive dummy load 135 (1) in the embodiment) that is electrically connected to the ejection drive source via the drive waveform output unit and stores electric power (for example) ), A switch for turning on / off the electrical connection between the power storage unit and the ejection drive source (for example, the switching element 137 (1) (n) in the embodiment), and the number of nozzles selected by the nozzle selection unit A switch switching unit (for example, the selection circuit 133 in the embodiment) for switching on / off of the switch so that the waveform of the drive waveform signal remains constant even if the voltage changes, a power storage unit, a switch, and a switch The switching unit is provided separately from the printer head.

  The ink jet printer further includes a waveform signal amplifying unit (for example, the amplifier circuit 122 in the embodiment) that amplifies the driving waveform signal output from the driving waveform signal output unit, and the storage unit is connected via the waveform signal amplifying unit. It is preferable to be electrically connected to the ejection drive source.

  According to the inkjet printer according to the present invention configured as described above, by providing the storage unit, the switch, and the switch switching unit in the circuit to which the ejection drive source is connected, according to the print data (selection status of the nozzle), Since the electric capacity of the circuit can be changed, it is possible to suppress the occurrence of a problem that the drive waveform is disturbed. Since the power storage unit, the switch, and the switch switching unit are provided separately from the printer head, the printer head and the carriage can be reduced in size, and the degree of freedom for the placement location of the substrate on which the power storage unit and the like are installed is increased. be able to.

  In addition, a waveform signal amplifying unit is provided, and the power storage unit is electrically connected to the ejection drive source via the waveform signal amplifying unit, whereby the electric capacity of the power storage unit can be reduced, and a plurality of power storage units are provided. In this case, it is possible to reduce the influence of device errors between the power storage units.

It is the perspective view which looked at the printer apparatus to which this invention is applied from diagonally forward. It is the perspective view which looked at the said printer apparatus from diagonally back. It is a front view which shows the principal part structure of the apparatus main body which comprises the said printer apparatus. It is a perspective view which shows typically the outline structure of the printer head in the said printer apparatus about the nozzle row of 1 row. It is a block diagram which shows the system configuration | structure of the control unit in the said printer apparatus. It is a block diagram which shows the relationship between the inkjet head drive circuit and printer head in the said control unit.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. As an example of an inkjet printer to which the present invention is applied, a perspective view of a printer device P of a type in which one of XY two axes moves the print medium and the other one moves the printer head is viewed obliquely from the front and obliquely rear. FIG. 1 and FIG. 2 are perspective views as viewed from above, respectively, and FIG. 3 shows the configuration of the main part of the apparatus main body 1 in this printer apparatus P. First, referring to these drawings, the entire printer apparatus P is shown. The configuration will be described. In the following description, directions indicated by arrows F, R, and U added in FIG. 1 will be referred to as “front”, “right”, and “upward”, respectively.

  The printer device P is a device that performs a predetermined operation such as printing on a sheet-like print medium M such as a tarpaulin or a vinyl chloride sheet that is generally called a medium. An apparatus main body 1, a support portion 2 that supports the apparatus main body 1 at a height at which work can be easily performed, a delivery mechanism 3 that is provided on the rear side of the support portion 2 and that feeds a printing medium M wound in a roll shape, And a take-up mechanism 4 that is provided on the front side of the support unit 2 and winds up the print medium M that has been printed.

  The apparatus main body 1 includes a body 10 serving as a mounting base for each mechanism, a platen 20 that supports the print medium M, and a medium moving mechanism 30 (see FIG. 3) that moves the print medium M supported by the platen 20 back and forth. The carriage 40 is located above the platen 20 and is supported movably to the left and right along the upper surface of the print medium M, and holds a printer head 60 to be described later. The carriage 40 is supported by the platen 20 with respect to the print medium M. A carriage moving mechanism 50 (see FIG. 3) that moves left and right and a control unit 100 that controls the operation of each part of the printer apparatus P are provided.

  As shown in FIG. 3, the body 10 includes a lower frame 11L provided with a platen 20 and a feed roller of the media moving mechanism 30, and an upper frame 11U provided with a support structure for the pinch roller 31 and the carriage 40 of the media moving mechanism 30. A medium insertion portion 15 having a horizontally long window shape through which the print medium M can be inserted forward and backward is formed between the upper frame 11U and the lower frame 11L.

  The carriage 40 is supported on a guide rail 45 attached to the upper frame 11 </ b> U so as to be movable left and right via a slide block (not shown), and is driven by a carriage moving mechanism 50. The carriage moving mechanism 50 is wound around a drive pulley 51 and a driven pulley 52 provided near the left and right side ends of the guide rail 45, a servo motor 53 that rotates the drive pulley 51, and the drive pulley 51 and the driven pulley 52. The carriage 40 is configured to be connected and fixed to the timing belt 55. The rotation of the servo motor 53 is controlled by the control unit 100, and the carriage 40 is moved to the left and right by a feed amount corresponding to a drive control signal output from the control unit 100 to the servo motor 53.

  In this way, the printer head 60 that ejects ink is provided on the carriage 40 that is moved relative to the print medium M in the front-rear and left-right directions. As shown in FIG. 4, the printer head 60 includes a nozzle 61, a pressure chamber 62, an ink supply chamber 63, an individual supply path 64, and a discharge actuator 65. A number of nozzles 61 are provided side by side, and pressure chambers 62, 62, 62,... Are partitioned and formed above the pressure chambers 62, 62, 62,. An ink supply chamber 63 is formed through the individual supply paths 64, 64, 64. The ink supply chamber 63 is supplied with liquid ink from an ink cartridge 70 (see FIG. 2) via a tube and an infusion pump (not shown), and the ink supply chamber 63 and the pressure chamber 62 are filled with liquid ink. Thus, the liquid ink is ejected from the nozzle 61 by the operation of the ejection actuator 65.

  The discharge actuator 65 is provided corresponding to each of the nozzle 61 and the pressure chamber 62. As the discharge actuator 65, a piezoelectric element used as a pressure vibrator can be used. The discharge actuator 65 is a capacitive element that repeats charging and discharging based on the input of a drive signal COM (pulse signal), which will be described later, but a plurality of discharge actuators 65 are connected in parallel to form a so-called capacitive load. is doing. Upon receiving the drive signal COM, the discharge actuator 65 is deformed in the pressure chamber 62 in accordance with the waveform.

  Specifically, when a charging pulse (waveform in which the potential increases) of the waveform of the drive signal COM is applied to the discharge actuator 65, the discharge actuator 65 bends in a direction contracting from the pressure chamber 62, Since the pressure is reduced, ink is sucked from the nozzle 61 into the pressure chamber 62. On the other hand, when a discharge pulse (waveform in which the potential decreases) of the waveform of the drive signal COM is applied to the discharge actuator 65, the discharge actuator 65 bends in the direction of bulging into the pressure chamber 62, and the pressure chamber 62 Therefore, the ink particles are ejected outward from the nozzle 61 (in the direction opposite to the pressure chamber 62). In this way, the ejection actuator 65 repeatedly charges and discharges in response to the drive signal COM, and vibrates with the charge and discharge, whereby the ink suction from the nozzle 61 and the ink ejection from the nozzle 61 are performed.

  The control unit 100 is provided to comprehensively control the operation of the printer apparatus P, and includes a control unit 101, a movement control block 110, and an inkjet head drive circuit 120 as shown in FIG. The The control unit 101 includes a CPU 102, a ROM 103, and a RAM 104. The CPU 102 executes various processes such as a printing process. The ROM 103 is provided for storing various programs executed by the CPU 102, and is composed of a nonvolatile semiconductor memory. The RAM 104 includes a volatile memory that temporarily stores print data input from the outside to the control unit 100 via an input interface (not shown), or various data when executing print processing based on the print data. Is done.

  The movement control block 110 outputs a drive control signal to a media feed motor (not shown) of the media moving mechanism 30 and a servo motor 53 of the carriage moving mechanism 50 based on the processing of the CPU 102. The motor rotates at a rotation amount corresponding to the drive control signal. As a result, the print medium M is transported back and forth by a predetermined feed amount, and the carriage 40 moves left and right by the predetermined feed amount.

  The inkjet head drive circuit 120 is a circuit that generates the drive signal COM to the ejection actuator 65. As shown in FIG. 6, the drive waveform generation circuit 121, the amplifier circuit 122, the interface 129, and the capacitance value adjustment unit. 130. Drive waveform data generated by the CPU 102 and obtained from the ROM 103 or RAM 104 is input to the drive waveform generation circuit 121. The drive waveform generation circuit 121 generates a pulsed drive waveform signal for driving the ejection actuator 65 from the input drive waveform data. The amplification circuit 122 amplifies the drive waveform signal generated from the drive waveform generation circuit 121 to such an extent that the ejection actuator 65 can be driven, and generates the pulse-shaped drive signal COM described above. The interface 129 is provided for transmitting and receiving signals between the control unit 100 and the printer head 60, and the drive signal COM is output to the discharge actuator 65 via the interface 129.

  The ROM 103 or the RAM 104 stores nozzle selection data that is data of the nozzles 61 that eject ink generated by the CPU 102 based on print data input by a user operation or the like. This nozzle selection data is output to the printer head 60 by the CPU 102 via the interface 129 and also to the selection circuit 133 described later. When nozzle selection data is input to the printer head 60, a drive signal COM is input to the ejection actuator 65 corresponding to the nozzle 61 selected by the nozzle selection data, and the ejection actuator 65 vibrates to cause ink from the nozzle 61 to vibrate. Discharge or suction is performed.

  By the way, with respect to the drive signal COM input to the ejection actuator 65, when the ink ejection rate (ratio of the nozzles 61 that eject ink with respect to the total number of nozzles 61) changes, the number of connected ejection actuators 65 that are capacitive loads is connected. Changes, and the capacitance value of the COM line changes accordingly. When the capacitance value changes in this way, the discharge actuators 65 that are capacitive loads are connected in parallel, so the waveform of the drive signal COM changes. And when the said capacitance value is large, what is called a low-pass filter is comprised and a high frequency component is removed from the waveform of the drive signal COM. As described above, when the waveform of the drive signal COM changes, there arises a problem that variations in ink ejection speed and the like occur and a good image cannot be obtained. Therefore, in order to cope with this problem, the printer apparatus P of the present embodiment includes the capacitance value adjustment unit 130, and by changing the capacitance value of the circuit using the capacitance value adjustment unit 130, the waveform of the drive signal COM. It is possible to eliminate the above disturbance and solve the above problem.

  Further, in the printer apparatus P of the present embodiment, the capacitance value adjusting unit 130 is not a COM line through which the drive signal COM passes, that is, by being provided separately from the carriage 40 and at a position away from the carriage 40, An effect such as reducing the weight of the carriage 40 can be obtained. As shown in FIG. 6, the capacitance value adjustment unit 130 includes a selection circuit 133, capacitive dummy loads 135 (1)... (N), and switching elements 137 (1). (N is a natural number of 2 or more). The capacitive dummy loads 135 (1)... (N) and the switching elements 137 (1). One of these capacitive dummy loads 135 (1)... (N) is grounded, and the other is connected in series to the switching elements 137 (1).

  The selection circuit 133 includes capacity value detection means (not shown), and can detect the total capacity value of the ejection actuator 65 based on the input nozzle selection data. As this capacitance value detecting means, for example, a NOT circuit that inverts and outputs nozzle selection data, and the number of nozzles 61 that do not eject ink are counted based on an inversion signal of nozzle selection data obtained through this NOT circuit. A counter can be used. The selection circuit 133 detects the number of nozzles 61 that are not selected based on the input nozzle selection data, selects the switching elements 137 (1)... (N) to be turned on (or off), and Change the capacitance value. In this way, the capacitance value of the circuit can be changed to make the waveform of the drive signal COM constant, and the problem that a good image cannot be obtained due to the disturbance of the waveform of the drive signal COM can be solved.

  As the selection circuit 133 that operates as described above, for example, an FPGA (Field Programmable Gate Array) that can incorporate a program in advance in the RAM 104 or the like can be used. When an FPGA is used, the nozzle selection data is previously stored in the RAM 104 or the like. The selection pattern of the corresponding switching elements 137 (1)... (N) can be stored, and the circuit (configuration) can be arbitrarily changed. Further, the selection pattern of the switching elements 137 (1)... (N) corresponding to the nozzle selection data by the selection circuit 133 differs depending on the number of capacitive dummy loads 135 (n) and the characteristics of the printer head 60. Considering this point, the selection pattern by the selection circuit 133 can be stored in the RAM 104 or the like in advance or can be changed as appropriate.

  As described above, in the printer device P according to the present embodiment, the capacitance value adjustment unit 130 including the selection circuit 133 and the capacitive dummy loads 135 (1)... (N) is connected to the COM line separately from the carriage 40. The capacitance value of the capacitive dummy loads 135 (1)... (N) can be further reduced from the above, for example, the capacitance value of the device, etc. Even if there is an error, the error can be reduced.

  In addition, since the capacitance value adjusting unit 130 is provided at a position away from the carriage 40 as described above, the degree of freedom in arranging the substrate on which the capacitance value adjusting unit 130 is arranged is increased, and the printer head 60 and its The effect that the carriage 40 which is a moving body can be reduced in weight can be obtained.

  In the above-described embodiment, as an inkjet printer to which the present invention can be applied, a type in which one of the XY two axes moves the print medium and the other one moves the printer head 60 is exemplified. However, the present invention can also be applied to other types of ink jet printers. For example, a table movement type in which the print medium is fixedly held on the table and the table is moved, and a head movement type in which the X-axis carriage and the Y-axis carriage move in the X and Y directions with respect to the table holding the print medium. The same effect can be applied to an inkjet printer such as the above, and the same effect can be obtained.

P Printer device (inkjet printer)
60 Printer head 61 Nozzle 65 Discharge actuator (Discharge drive source)
102 CPU (nozzle selection unit)
121 Drive waveform generation circuit (drive waveform signal output unit)
122 Amplifier circuit (drive waveform signal output unit, waveform signal amplification unit)
133 Selection circuit (switch switching unit)
135 Capacitive dummy load (power storage unit)
137 Switching element (switch)

Claims (2)

An ejection drive that is provided corresponding to a nozzle that ejects ink, and that is composed of a capacitive element that charges and discharges based on an input of a drive waveform signal, and that ejects ink from the nozzle by vibrating with the charge and discharge. A printer head for printing on a print medium by discharging ink from the nozzles;
A nozzle selection unit that selects a nozzle for ejecting ink based on print data for printing by the printer head;
A drive waveform signal output unit that generates the drive waveform signal and outputs the drive waveform signal to an ejection drive source corresponding to the nozzle selected by the nozzle selection unit;
A power storage unit that is electrically connected to the ejection drive source via the drive waveform output unit and stores electric power;
A switch for turning on / off electrical connection between the power storage unit and the ejection drive source;
A switch switching unit that switches on / off the switch so that the waveform of the drive waveform signal is constant even if the number of nozzles selected by the nozzle selection unit is changed,
The power storage unit, the switch, and the switch switching unit are provided separately from the printer head. A waveform signal amplifier for amplifying the drive waveform signal output by the drive waveform signal output unit;
The inkjet printer according to claim 1, wherein the power storage unit is electrically connected to the ejection drive source through the waveform signal amplifier.

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