JP2006334869A - Device and method for controlling inkjet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a user to select low-gradation printing, and to shorten time required for the low-gradation printing, when the printing can be done with a low gradation as in the case of text data printing and test printing. <P>SOLUTION: A drive pulse depending on dot pattern data (gradient) of a pixel is selected from a drive waveform signal which is composed of a combination of a plurality of drive pulses, and fed to a piezoelectric element (actuator) which is provided in an inkjet head, so that an ink droplet can be ejected from an inkjet nozzle. In this case, the desired number of the gradations can be selected from among the plurality of numbers of the gradations, and only the piezoelectric-element driving pulse necessary for the number of the gradations is selected depending on the selected number of the gradations, so that the drive waveform signal, which is composed of the combination of the drive pulses depending on each gradient of the number of the gradations, can be generated and output. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention controls an ink jet printer that prints predetermined characters and images by ejecting fine particles (ink droplets) of liquid ink of a plurality of colors from nozzles and forming minute ink dots on a print medium, for example. The present invention relates to an apparatus and a control method.

Such an inkjet printer is generally inexpensive and can easily obtain a high-quality color printed matter. Accordingly, along with the widespread use of personal computers and digital cameras, it has become widespread not only in offices but also in general users.
In general, such an ink jet printer reciprocates in a direction intersecting a print medium conveyance direction with a moving body called a carriage or the like that is integrally provided with an ink cartridge and an ink discharge head (generally called an ink jet head). However, by ejecting fine particles of liquid ink from the nozzles of the inkjet head, a large number of minute ink dots are formed on the print medium, thereby drawing a predetermined character or image and creating a desired printed matter. It has become. The carriage is equipped with ink cartridges of four colors (black, yellow, magenta, cyan) and inkjet heads for each color, so that not only monochrome printing but also full color printing combining the colors can be easily performed. (Furthermore, 6 colors, 7 colors, or 8 colors in which light cyan, light magenta, and the like are added to each of these colors have been put into practical use).

 By the way, in this type of ink jet printer, higher gradation is required. The gradation is a state of density of each color included in a so-called pixel represented by ink dots, and the size of the ink dot corresponding to the color density of each pixel is called gradation, and can be expressed by ink dots. The number of furniture is called the number of gradations. High gradation means that the number of gradations is large. In order to change the gradation, for example, it is necessary to change a drive signal to an actuator provided in the ink jet head. For example, when the actuator is a piezo element (piezoelectric element), the displacement (strain) of the actuator (more precisely, the diaphragm) increases as the voltage value applied to the actuator increases. The gradation of dots can be changed.

Therefore, in Patent Document 1 listed below, a drive waveform signal is created by combining drive signals corresponding to each gradation degree of achievable number of gradations, and this is generated for each pixel, that is, for each actuator provided in the inkjet head. The drive signal is selected from the drive waveform signal according to the gradation of the ink dot to be formed, and the drive signal is supplied to the actuator to eject the ink droplet. The gradation degree of the ink dots to be achieved is achieved.
Japanese Patent Laid-Open No. 2003-1824

 However, in the control apparatus and control method for an ink jet printer described in Patent Document 1, a drive waveform signal is created by combining drive signals corresponding to each gradation of achievable number of gradations, and this is generated as an actuator for an ink jet head. Since the output is performed every time, the printing cycle of each pixel is limited by the length of the drive waveform signal (required output time). For example, when the number of gradations that can be achieved is 8 gradations, the length of the drive waveform signal obtained by combining the drive signals of 8 gradation levels becomes the printing cycle of each pixel. However, there are cases where the user does not require a high gradation such as simple text data. In such a case, the drive waveform signal may be used even though a low gradation such as four gradations or two gradations may be used. Therefore, there is a problem in that the printing period of the same size print medium is the same regardless of the high gradation and the low gradation.

  The present invention has been made paying attention to the above-mentioned problems, and an ink jet that can shorten the time required for printing when low gradation drawing is possible while drawing high gradation is possible. It is an object of the present invention to provide a printer control device and a control method.

  [Invention 1] In order to solve the above-mentioned problem, an ink jet printer control device according to Invention 1 selects a drive signal corresponding to the gradation of a pixel from a drive waveform signal composed of a combination of a plurality of drive signals, and the drive signal. In a control apparatus for an inkjet printer that supplies ink to an actuator provided in an inkjet head and ejects ink droplets from inkjet nozzles, a gradation number selection unit that can select a desired gradation number from a plurality of gradation numbers; According to the number of gradations selected by the gradation number selection means, only the actuator drive signal required for the number of gradations is selected, and a drive waveform comprising a combination of drive signals corresponding to the respective gradation levels of the number of gradations And a drive waveform signal generating means for generating a signal.

 [Invention 2] In addition, the ink jet printer control method of the invention 2 selects a drive signal corresponding to the gradation of a pixel from a drive waveform signal composed of a combination of a plurality of drive signals, and the drive signal is provided in the inkjet head. In a control method of an ink jet printer that supplies ink to an actuator and ejects ink droplets from an ink jet nozzle, a desired number of gradations can be selected from a plurality of gradations, and the selected number of gradations can be selected. Only the actuator drive signal required for the number of gradations is selected, and a drive waveform signal composed of a combination of drive signals corresponding to each gradation degree of the number of gradations is created.

  The ink jet head referred to in these inventions refers to an ink ejection head used in, for example, an ink jet printer, and fine ink droplets are ejected from a nozzle by a known electrostatic method, piezo method, film boiling ink jet method, or the like. Treated as a generic term for forming round ink dots on a print medium. The gradation is the density state of each color contained in the pixel represented by the ink dot. The ink dot size corresponding to the color density of each pixel is defined as the gradation and expressed by the ink dot. The number of gradation levels that can be defined is defined as the number of gradations. Accordingly, high gradation means that the number of gradations is large, and low gradation means that the number of gradations is small.

 According to the control apparatus and control method for an ink jet printer according to the present invention, a drive signal corresponding to the gradation level of a pixel is selected from a drive waveform signal composed of a combination of a plurality of drive signals, and the drive signal is provided in the ink jet head. When supplying ink to an actuator and ejecting ink droplets from an inkjet nozzle, a desired number of gradations can be selected from a plurality of gradations, and the number of gradations is determined according to the selected number of gradations. For example, the user can select only the actuator drive signal necessary for the number of gradations and create a drive waveform signal composed of a combination of drive signals corresponding to the number of gradations. When it is determined that gradation drawing is sufficient, it is possible to shorten the time required for printing by shortening the length of the drive waveform signal.

Next, a first embodiment of a control apparatus and control method for an inkjet printer of the present invention will be described with reference to the drawings.
FIG. 1 shows an inkjet printer 2 of this embodiment and a host computer 1 for driving the inkjet printer 2. The host computer 1 can be any computer system including a personal computer. In addition, the inkjet printer 2 according to this embodiment includes an inkjet head that reciprocates in the width direction of the print medium and feeds the print medium in the longitudinal direction while reciprocally moving a carriage that is integrally provided with an ink cartridge and an inkjet head. By discharging fine particles (ink droplets) of the liquid ink from the nozzles 21 to form minute ink dots on the print medium, a predetermined printed matter is drawn on the print medium to create a desired printed matter. This is a so-called multi-pass inkjet printer. The reciprocating direction of the carriage is also referred to as the main scanning direction, and the paper feeding direction of the printing medium is also referred to as the sub-scanning direction.

  In the host computer 1, an image processing circuit 23 is constructed by software, for example, and performs image processing of the captured image data. In the present embodiment, the user can select the number of gradations for image processing for the host computer 1, and the image processing circuit 23 selects the number of gradations for image data in accordance with the selected number of gradations. Image processing is performed, and dot pattern data corresponding to the print pixel is created and output to the inkjet printer 2 together with the selected number of gradations. Incidentally, the dot pattern data includes a gradation level for each print pixel and actuator drive pulse selection information corresponding to the selected number of gradations, as will be described later. The number of gradations that can be selected is 8 gradations, 4 gradations, or 2 gradations.

  The inkjet printer 2 includes a carriage mechanism 22 that moves the carriage and a control circuit 20. The inkjet printer 2 controls the speed of the carriage mechanism 22 using an encoder signal from the carriage mechanism 22, The drive signal to the actuator of the inkjet head 21 is generated and output according to the dot pattern data and the number of gradations.

  Ink jet heads include, for example, nozzles that exclusively discharge black (K) ink, nozzles that exclusively discharge yellow (Y) ink, nozzles that exclusively discharge magenta (M) ink, and cyan (C) ink. Are arranged in the sub-scanning direction, the liquid is ejected from each nozzle of the inkjet head 21, the carriage is moved in the main scanning direction, and the print medium is moved in the sub-scanning direction (paper feed direction). By moving, for example, color image data can be printed on the print medium. In this embodiment, 180 nozzles are provided for each color.

  As a method for ejecting ink from each nozzle of the ink jet head, there are an electrostatic method, a piezo method, a film boiling ink jet method, and the like. In the electrostatic method, when a drive signal is given to the electrostatic gap, which is an actuator, the diaphragm in the cavity is displaced to cause a pressure change in the cavity, and the ink droplet is ejected from the nozzle by the pressure change. is there. In the piezo method, when a drive signal is given to a piezo element (piezoelectric element) that is an actuator, the diaphragm in the cavity is displaced to cause a pressure change in the cavity, and the ink drop is ejected from the nozzle by the pressure change. Is. In the film boiling ink jet method, there is a micro heater in the cavity, the ink is instantaneously heated to 300 ° C. or more, the ink becomes a film boiling state, bubbles are generated, and the ink droplet is ejected from the nozzle by the pressure change. Is. Although any ink discharge method can be applied to the present invention, a piezo method is employed in the present embodiment.

  FIG. 2 shows further details of the control circuit 20, the inkjet head 21, and the carriage mechanism 22. The control circuit 20 includes a central processing circuit (CPU) 24 that performs arithmetic processing, a memory 25 that includes ROM, RAM, and the like, a D / A converter 26 that converts a digital signal into analog, and a D / A converter 26. Is provided with a drive waveform signal generation circuit 27 for generating a drive waveform signal for driving the piezoelectric element 32 as an actuator in accordance with the output of. In addition, a shift register 28, a register 29, and a decoder processing unit 30 are configured in the inkjet head 21 by a microcomputer and a program, and a drive waveform from the drive waveform signal generating circuit 27 is output from the decoder processing unit 30. Among the signals, a switch circuit 31 that selects a necessary drive signal and a piezoelectric element 32 that is an actuator for ejecting ink droplets are provided. The carriage mechanism 22 includes a carriage drive circuit 33 for driving the carriage 34. The dot pattern data is input to the shift register 28 of the inkjet head 21, the LAT signal output from the CPU 24 is input to the register 29 and the decoder processing unit 30, and the number of gradations and the CH signal output from the CPU 24 are also the decoder processing unit. 30. The dot pattern data includes dot pattern data itself and information for selecting a drive signal (hereinafter also referred to as drive pulse).

  FIG. 3 shows further details of the decoder processing unit 30 (the register 29 is omitted). The decoder processing unit 30 is also actually constructed by a microcomputer and a program. The decoder processing unit 30 stores the first to third latches 36 to 38 for storing dot pattern data, the fourth latch 39 for storing drive pulse selection information, and the dot pattern data stored in the shift register 28. The data storage control unit 35 that plays a role of storing the drive pulse selection information in the fourth latch 39 in each of the first to third latches 36 to 38, and the dot pattern stored in the first to third latches 36 to 38 A decoder 41 that outputs an open / close signal of the switch circuit 31 based on data and a control logic 40 that outputs a reference signal to the switch circuit 31 based on drive pulse selection information stored in a fourth latch are provided.

  For example, as shown in FIG. 12, when the number of selected gradations is 8 gradations, the dot pattern data for each pixel is assumed to form ink dots having the gradations 0 to 7. That is, information of 8 gradations, that is, 3 bits is required for each nozzle. In this embodiment, since 180 nozzles are provided for each color, there is 3 bits × 180 dots, that is, 540 bits of dot pattern data for any one of the four colors described above. On the other hand, when the selected number of gradations is 8 gradations, in order to output the ink dots having the above-described gradations 0 to 7, a drive signal (driving) to the piezo element as an actuator is output. Pulse) must be selected from pulse 0 to pulse 7. As information for selecting this pulse, when the number of gradations is 8 gradations, 8 bits of information for 8 gradations, that is, 64 bits are required. Accordingly, the dot pattern data is 604 bits in total.

  On the other hand, as shown in FIG. 13, for example, when the selected number of gradations is four, ink dots having the sizes of gradation 0, gradation 1, gradation 3, and gradation 6 are added. To be formed. In this case, since the dot pattern data may be 2 bits for each nozzle, the dot pattern data is 2 bits × 180 nozzles, that is, 360 bits. On the other hand, the pulse selection information corresponds to 4 bits × 4 gradations, that is, 16 bits in accordance with the number of gradations 4, and all the dot pattern data is 376 bits. Similarly, as shown in FIG. 14, for example, when the selected number of gradations is two gradations, ink dots having gradations 0 and 6 are formed, and the dot pattern data is 1 bit × 180 nozzles, that is, 180 bits, pulse selection information is 2 bits × 2 gradations, that is, 4 bits, and all dot pattern data is 184 bits.

  As shown in FIG. 4a, the shift register 28 has a maximum of 604 bits D0 to D603 in accordance with the case where the selected number of gradations is 8 gradations. If the selected number of gradations is 8, as shown in FIG. 4b, pulse selection information is stored in D0 to D63, lower bits of the dot pattern data are stored in D64 to D243, and D244 to D423 are displayed. The middle bit of the dot pattern data is stored, and the upper bits of the dot pattern data are stored in D424 to D603, respectively. On the other hand, when the number of selected gradations is 4, as shown in FIG. 4c, pulse selection information is stored in D0 to D15, lower bits of the dot pattern data are stored in D16 to D195, and D196 to D196. The upper bits of the dot pattern data are stored in D375. When the selected number of gradations is 2, as shown in FIG. 4d, pulse selection information is stored in D0 to D3, and all bits of the dot pattern data are stored in D4 to D183. .

  The data storage control unit 35 performs the arithmetic processing of FIG. 5 on the shift register 28 and stores the data stored in D0 to D603 of the shift register 28 in the first to fourth latches 36 to 39 again. . In this calculation process, first, the number of gradations N is input in step S1, and then it is determined in step S2 how many gradations N are present. If the number of gradations N is 2, that is, two gradations. In step S3, if the number of gradations N is 4, that is, 4 gradations, the process proceeds to step S5. If the number of gradations N is 8, that is, 8 gradations, the process proceeds to step S7. To do.

  In step S3, the pulse selection information stored in D0 to D3 of the shift register 28 and the dot pattern data stored in D4 to D183 are read. Next, in step S4, the pulse selection information for D0 to D3 is read as the fourth. The dot pattern data of D4 to D183 is stored in the latch 39 in the first latch 36, and the Hi level signal of logical value “1” is stored in the second latch 37 and the third latch 38.

  In step S5, the pulse selection information stored in D0 to D15 of the shift register 28 and the dot pattern data stored in D16 to D375 are read. Next, in step S6, the pulse selection information of D0 to D15 is read as the fourth. The dot pattern data of D16 to D195 is stored in the first latch 36, the dot pattern data of D196 to D375 is stored in the second latch 37 in the latch 39, and the high level of the logical value “1” is stored in the third latch 38. Store the signal.

  In step S7, the pulse selection information stored in D0 to D63 of the shift register 28 and the dot pattern data stored in D64 to D603 are read. Next, in step S8, the pulse selection information of D0 to D63 is read as the fourth. In the latch 39, the dot pattern data of D64 to D243 is stored in the first latch 36, the dot pattern data of D244 to D423 is stored in the second latch 37, and the dot pattern data of D424 to D603 is stored in the third latch 38, respectively.

  FIG. 6 is a block diagram showing details of the control logic 40 and the decoder 41. The CH signal is output at a period corresponding to the drive pulse length of the piezoelectric element 32 as an actuator, and the LAT signal is output every time the CH signal is output for the selected number of gradations. When the LAT signal is output, the CH signal is not output. Therefore, when the selected number of gradations is 8, as shown in FIG. 7, the output of q7 becomes Hi level simultaneously with the rise of the LAT signal, and q7 becomes simultaneous with the rise of the next CH signal. When the output becomes Lo level, the output of q6 becomes Hi level. At the same time when the next CH signal rises, the output of q6 becomes Lo level and at the same time the output of q5 becomes Hi level, and at the same time when the next CH signal rises. The output of q5 becomes Lo level and the output of q4 becomes Hi level. At the same time when the next CH signal rises, the output of q4 becomes Lo level and the output of q3 becomes Hi level, and the next CH signal rises. At the same time, the output of q3 becomes the Lo level and the output of q2 becomes the Hi level. At the same time when the next CH signal rises, the output of q2 becomes the Lo level and the output of q1. Becomes the Hi level, the output of q1 becomes the Lo level simultaneously with the rise of the next CH signal, the output of q0 becomes the Hi level, and the output of q0 becomes the Lo level simultaneously with the rise of the next LAT signal, and q7 Becomes the Hi level, and this is sequentially repeated.

  When the selected number of gradations is 4, as shown in FIG. 8, the output of q3 becomes Hi level simultaneously with the rise of the LAT signal, and q3 becomes simultaneous with the rise of the next CH signal. When the output becomes Lo level, the output of q2 becomes Hi level. At the same time when the next CH signal rises, the output of q2 becomes Lo level and at the same time the output of q1 becomes Hi level, and at the same time when the next CH signal rises. The output of q1 becomes Lo level and the output of q0 becomes Hi level. At the rise of the next LAT signal, the output of q0 becomes Lo level and the output of q3 becomes Hi level, and this is sequentially repeated. When the selected number of gradations is two gradations, as shown in FIG. 9, the output of q1 becomes Hi level simultaneously with the rise of the LAT signal, and q1 simultaneously with the rise of the next CH signal. When the output becomes Lo level, the output of q0 becomes Hi level, and simultaneously with the rise of the next LAT signal, the output of q0 becomes Lo level and the output of q1 becomes Hi level, and this is repeated sequentially.

  When the outputs of q0 to q7 and the dot pattern data stored in the first to third latches 36 to 38 are both at the Hi level, the output of the decoder 41 is also at the Hi level. That is, the corresponding switch in the switch circuit 31 is closed according to the gradation level in the dot pattern data stored corresponding to each nozzle, and a drive pulse corresponding to the gradation level is selected from the drive waveform signal described later. Thus, a drive pulse is output to the piezoelectric element 32 which is an actuator.

  In the memory 25 of the control circuit 20 in FIG. 2, drive pulse data of the piezoelectric element 32 that is an actuator is stored. This drive pulse data is composed of digital data of voltage values such as 0 V, 0 V, 1 V, 2 V, 3 V, 3 V,. For example, the drive pulse 0 data corresponding to gradation 0 shown in FIG. 12 is hexadecimal addresses 0000 0000H to 0FFF FFFFH, and the drive pulse 1 data corresponding to gradation 1 is addresses 1000 0000H to 1FFF as shown in FIG. In FFFFH, drive pulse 2 data corresponding to gradation 2 is address 2000 0000H to 2FFF FFFFH, drive pulse 3 data corresponding to gradation 3 is address 3000 0000H to 3FFF FFFFH, and drive pulse 4 data corresponding to gradation 4 is address. 4000 0000H to 4FFF FFFFH, drive pulse 5 data equivalent to gradation 5 is address 5000 0000H to 5FFF FFFFH, drive pulse 6 data equivalent to gradation 6 is drive pulse equivalent to gradation 7 and address 6000 0000H to 6FFF FFFFH 7 Data is stored in addresses 7000 0000H to 7FFF FFFFH, respectively.

  Therefore, for example, when addresses 0000 0000H to 7FFF FFFFH are sequentially accessed at predetermined sampling periods and the stored drive pulse data is read, for example, as shown in FIG. The drive pulse 7 corresponding to 7 is formed in order, converted into analog by the D / A converter 26 and amplified and output by the drive waveform signal generation circuit 27 to be a drive waveform signal.

  Next, the arithmetic processing of FIG. 11 performed in the CPU 24 in order to change the way of accessing the memory 25 by the selected number of gradations will be described. In this arithmetic processing, first, in step S11, it is determined how many gradations the selected gradation number is. If the selected gradation number is two gradations, the process proceeds to step S12 and is selected. If the number of gradations is 4 gradations, the process proceeds to step S17. If the selected number of gradations is 8 gradations, the process proceeds to step S26.

In step S12, it is determined whether or not the LAT signal is output. If the LAT signal is output, the process proceeds to step S13. If not, the process waits.
In step S13, for example, the driving pulse 0 data corresponding to the gradation 0 is sequentially accessed as the first driving pulse data for two gradations, and the address of the first driving pulse data for two gradations is sequentially accessed, and then the process proceeds to step S14. Transition.

In step S14, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S15. If not, the process waits.
In step S15, for example, the driving pulse 6 data corresponding to gradation 6 is sequentially accessed as the second driving pulse data for two gradations, and the address of the second driving pulse data for two gradations is sequentially accessed, and then step S16 is performed. Transition.

In step S16, it is determined whether or not the output of all the dot pattern data is completed. When the output of all the dot pattern data is completed, the process returns to the main program. Otherwise, the process proceeds to step S12. .
On the other hand, in step S17, it is determined whether or not the LAT signal is output. If the LAT signal is output, the process proceeds to step S18, and if not, the process waits.

In step S18, for example, the driving pulse 0 data corresponding to gradation 0 is sequentially accessed as the first driving pulse data for four gradations, and the address of the first driving pulse data for four gradations is sequentially accessed. Transition.
In step S19, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S20. If not, the process waits.

In step S20, for example, the driving pulse 1 data corresponding to gradation 1 is sequentially accessed as the second driving pulse data for four gradations, and the address of the second driving pulse data for four gradations is sequentially accessed. Transition.
In step S21, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S22. If not, the process waits.

In step S22, for example, the driving pulse 3 data corresponding to the gradation 3 is sequentially accessed as the third driving pulse data for four gradations, and the address of the third driving pulse data for four gradations is sequentially accessed, and then the process proceeds to step S23. Transition.
In step S23, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S24. If not, the process waits.

In step S24, for example, the driving pulse 6 data corresponding to gradation 6 is accessed as the fourth driving pulse data for four gradations in advance, and the address of the fourth driving pulse data for four gradations is sequentially accessed, and then step S25 is performed. Transition.
In step S25, it is determined whether or not output of all dot pattern data has been completed. If output of all dot pattern data has been completed, the process returns to the main program; otherwise, the process proceeds to step S17. .

In step S26, it is determined whether or not the LAT signal is output. If the LAT signal is output, the process proceeds to step S27. If not, the process waits.
In step S27, for example, drive pulse 0 data corresponding to gradation 0 is sequentially accessed as preset first drive pulse data for 8 gradations, and the address of the first drive pulse data for 8 gradations is sequentially accessed, and then step S28 is performed. Transition.

In step S28, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S29, and if not, the process waits.
In step S29, for example, the driving pulse 1 data corresponding to the gradation 1 is sequentially accessed as the second driving pulse data for 8 gradations, and the address of the second driving pulse data for 8 gradations is sequentially accessed. Transition.

In step S30, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S31. If not, the process waits.
In step S31, for example, the driving pulse 2 data corresponding to the gradation 2 is set as preset third driving pulse data for 8 gradations, and the address of the third driving pulse data for 8 gradations is sequentially accessed, and then the process proceeds to step S32. Transition.

In step S32, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S33, and if not, the process waits.
In step S33, for example, the driving pulse 3 data corresponding to the gradation 3 is accessed as the fourth driving pulse data for 8 gradations in advance, and the address of the fourth driving pulse data for 8 gradations is sequentially accessed, and then the process proceeds to step S34. Transition.

In step S34, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S35, and if not, the process waits.
In step S35, for example, the driving pulse 4 data corresponding to the gradation 4 is sequentially accessed as the preset fifth driving pulse data for 8 gradations, and the address of the fifth driving pulse data for 8 gradations is sequentially accessed. Transition.

In step S36, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S37, and if not, the process waits.
In step S37, for example, the driving pulse 5 data corresponding to gradation 5 is used as preset sixth driving pulse data for 8 gradations, and the address of the sixth driving pulse data for 8 gradations is sequentially accessed. Transition.

In step S38, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S39. If not, the process waits.
In step S39, for example, drive pulse 6 data corresponding to gradation 6 is used as preset seventh gradation drive pulse data for eight gradations, and the address of the seventh gradation drive pulse data for eight gradations is sequentially accessed. Transition.

In step S40, it is determined whether or not a CH signal is output. If a CH signal is output, the process proceeds to step S41, and if not, the process waits.
In step S41, for example, drive pulse 7 data corresponding to gradation 7 is sequentially accessed as preset eighth drive pulse data for eight gradations, and the address of the eighth drive pulse data for eight gradations is sequentially accessed, and then step S42 is performed. Transition.

In step S25, it is determined whether or not output of all dot pattern data has been completed. If output of all dot pattern data has been completed, the process returns to the main program; otherwise, the process proceeds to step S17. .
According to this arithmetic processing, for example, when the selected number of gradations is 8 gradations, as shown in FIG. 12, drive pulse 0 data, drive pulse 1 data, drive pulse 2 data, drive pulse 3 data , Drive pulse 4 data, drive pulse 5 data, drive pulse 6 data, and drive pulse 7 data are sequentially read, so that gradation 0, gradation 1, gradation 2, gradation 3, gradation 4, gradation 5 A drive waveform signal composed of a combination of drive pulses for generating ink dots corresponding to gradation 6 and gradation 7 is generated and output. Of these, if only the corresponding dot pattern data drive signal is selected and supplied to the piezoelectric element 32 as an actuator, ink dots corresponding to the dot pattern data can be formed.

  On the other hand, for example, when the selected number of gradations is 4, as shown in FIG. 13, drive pulse 0 data, drive pulse 1 data, drive pulse 3 data, and drive pulse 6 data are sequentially read. As a result, a drive waveform signal composed of a combination of ink dot generation drive pulses corresponding to gradation 0, gradation 1, gradation 3, and gradation 6 is generated and output. For example, when the selected number of gradations is two gradations, the driving pulse 0 data and the driving pulse 6 data are sequentially read as shown in FIG. A drive waveform signal composed of a combination of drive pulses for generating ink dots is generated and output.

  Assuming that the length of the drive waveform signal is the printing cycle TA, printing is performed when the selected number of gradations is 4 to the printing cycle TA when the selected number of gradations is 8. The period TA is about half of that, and the printing period TA when the selected number of gradations is 2 is about half of that. Thus, when the printing cycle TA is shortened, it is possible to shorten the time required for printing on the same size printing medium.

  Therefore, in the control apparatus and control method of the ink jet printer according to the present embodiment, the user can select a low gradation, such as text data or test printing, and the selected number of gradations. Therefore, only the drive pulses required for the number of gradations are selected, and a drive waveform signal consisting of a combination of drive pulses corresponding to the respective gradation levels is generated, enabling high gradation drawing. On the other hand, if the user determines that drawing with low gradation is acceptable, it is possible to shorten the time required for printing by shortening the length of the drive waveform signal.

  In the above-described embodiment, three types of gradations of 8 gradations, 4 gradations, and 2 gradations can be selected. However, the number of gradations that can be selected is not limited to this. The number of gradations such as gradations and 3 gradations can be selected. However, since 5 gradations are larger than 4 gradations, that is, 2 bits, the dot pattern data requires 3 bits, which is the same as 8 gradations. For example, 3 gradations are 2 gradations, that is, 1 bit. Since it is larger, the dot pattern data requires 2 bits, the same as 4 gradations.

Moreover, in the said embodiment, although only the piezo system was explained in full detail as an inkjet system, an inkjet system is not limited to this. In other words, the present invention can be applied to any actuator, that is, an ink jet system, as long as it generates a drive waveform signal by combining drive signals corresponding to each gradation level of a multi-gradation and supplies it to the actuator. It is.
In each of the above embodiments, only an example in which the ink jet printer of the present invention is applied to a so-called multi-pass ink jet printer has been described in detail. However, the ink jet printer of the present invention can be applied to various types including a line head ink jet printer. It can be applied to a type of inkjet printer.

1 is a configuration diagram of a printing system showing an embodiment of an inkjet printer of the present invention. FIG. 2 is a system configuration diagram of the ink jet printer of FIG. 1. FIG. 3 is a system configuration diagram of a decoder processing unit in FIG. 2. It is explanatory drawing of the shift register of FIG. It is a flowchart of the arithmetic processing performed in the data storage control part of FIG. It is explanatory drawing which made the decoder and control logic of FIG. 3 into a block diagram. It is explanatory drawing of the signal for a drive pulse at the time of 8 gradation selection output from the control block of FIG. It is explanatory drawing of the signal for a drive pulse selection at the time of 4 gradation selection output from the control block of FIG. FIG. 7 is an explanatory diagram of a drive pulse selection signal output from the control block of FIG. 6 when two gradations are selected. FIG. 3 is an explanatory diagram of drive pulse data and its address stored in the memory of FIG. 2. 3 is a flowchart showing a memory access calculation process performed by the CPU of FIG. 2. It is explanatory drawing of the drive waveform signal at the time of 8 gradation selection produced | generated and output by the arithmetic processing of FIG. It is explanatory drawing of the drive waveform signal at the time of 4 gradation selection produced | generated and output by the arithmetic processing of FIG. It is explanatory drawing of the drive waveform signal at the time of 2 gradation selection produced | generated and output by the arithmetic processing of FIG.

Explanation of symbols

  1 is a host computer, 2 is an inkjet printer, 20 is a control circuit, 21 is an inkjet head, 22 is a carriage mechanism, 23 is an image processing circuit, 24 is a CPU, 25 is a memory, 27 is a drive waveform signal generation circuit, and 28 is a shift Register, 30 is a decoder processing unit, 31 is a switch circuit, 32 is a piezoelectric element (actuator)

Claims (2)

  Ink jet that selects a drive signal corresponding to the gradation of a pixel from drive waveform signals composed of a combination of a plurality of drive signals, supplies the drive signal to an actuator provided in the ink jet head, and ejects ink droplets from the ink jet nozzle. In the printer control apparatus, a gradation number selection unit that can select a desired number of gradations from a plurality of gradation numbers, and the gradation number according to the number of gradations selected by the gradation number selection unit. Control of an ink jet printer comprising drive waveform signal generating means for selecting only a necessary actuator drive signal and generating a drive waveform signal composed of a combination of drive signals corresponding to each gradation degree of the number of gradations apparatus.   Ink jet that selects a drive signal corresponding to the gradation of a pixel from drive waveform signals composed of a combination of a plurality of drive signals, supplies the drive signal to an actuator provided in the ink jet head, and ejects ink droplets from the ink jet nozzle. In the printer control method, a desired number of gradations can be selected from a plurality of gradation numbers, and only the actuator drive signal necessary for the gradation number is selected according to the selected gradation number. A control method for an ink jet printer, comprising: generating a drive waveform signal composed of a combination of drive signals corresponding to each gradation of the number of gradations.

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