JP3713882B2 - Inkjet head control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inkjet head control device of an inkjet recording apparatus that prints by ejecting ink.
[0002]
[Prior art]
A communication device such as a facsimile device and an information processing device such as a personal computer usually have a recording device capable of recording these data on paper so as to record data consisting of characters and figures as visual information. In this recording device, various printing methods such as impact method, thermal method, ink jet method, etc. are adopted, but in recent years, ink jet method that is excellent in quietness and can print on paper of various materials is adopted. The ink jet recording apparatus which attracts attention has attracted attention.
[0003]
The above-described inkjet recording apparatus includes an inkjet head having a plurality of channels for ejecting ink droplets on a sheet so as to print characters and figures on the sheet, and an inkjet that drives and controls the inkjet head based on print data. A head control device. Ink jet heads are usually formed by forming a flow path wall of an ink flow path communicating with nozzles from a polarized piezoelectric material and forming electrodes on the wall surface. Conventionally, when the print data instructs ink ejection, the inkjet head control device applies a pulsed print pulse voltage to the corresponding channel electrode to generate an electric field on the flow path wall, By changing the volume of the ink flow path by deforming the path wall, ink droplets are ejected from the nozzles by increasing or decreasing the ink pressure.
[0004]
[Problems to be solved by the invention]
However, in the configuration in which the flow path wall is deformed at an arbitrary time interval based on the print data and ink droplets are ejected as in the conventional case, the piezoelectric member forming the flow path wall vibrates due to the reaction after deformation. Therefore, depending on the next injection timing, vibration due to the previous injection may remain, and the phase of vibration and the start of deformation may be discontinuous. If the phase of vibration and the start of deformation become discontinuous, the flow path wall (piezoelectric member) cannot be deformed at a normal speed or amount, and the ejection amount of ink droplets becomes unstable. This results in a decrease in print quality such as ink droplets splashing on the paper (splashing).
[0005]
Therefore, the present invention intends to provide an ink jet head control device capable of eliminating vibration after deformation of a piezoelectric member forming a flow path wall so that good print quality can always be obtained. .
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the invention of claim 1 applies the printing pulse voltage to the piezoelectric member based on the printing data, and increases or decreases the volume of the ink flow path by deformation of the piezoelectric member. An inkjet head control device that ejects ink droplets from nozzles communicated with a flow path, wherein predetermined print data and print data to be printed next are input, and the former print data indicates ejection of ink droplets, when the latter print data indicates a non-ejection of ink drops after a former print data, and outputs the added stop pulse data for dissipating the vibration generated by the printing pulse voltage, the former and the latter when the print data indicates a both ejection of ink droplets, a print control means for outputting the former and latter print data without outputting the stop pulse data , The data determination unit is inputted the print data and the stop pulse data output by, and a head drive unit that outputs a printing pulse voltages and a stop pulse voltage on the basis of the print data and the stop pulse data to said piezoelectric member It is characterized by having.
[0007]
As a result, after the piezoelectric member is deformed by the printing pulse voltage, if vibration due to the deformation remains in the piezoelectric member, this vibration may adversely affect the amount of deformation at the next deformation of the piezoelectric member. However, according to the above configuration, since the vibration of the piezoelectric member can be eliminated, the piezoelectric member can always be deformed with a constant deformation amount, and the printing quality can be improved.
[0008]
A second aspect of the present invention is the ink jet head control apparatus according to the first aspect, wherein the print control means determines the predetermined print data and a latch circuit that holds the next print data, and each print data. And determining means.
[0009]
Thereby, the print control means determines each print data held in the latch circuit and outputs stop pulse data.
[0010]
Invention 請 Motomeko 3, an inkjet head control apparatus according to claim 1 or 2, wherein the head drive unit, and characterized by outputting the stop pulse voltage at the timing when the opposite phase of the vibration To do. As a result, the vibration can be reliably eliminated by applying the stop pulse voltage at a timing that is in the opposite phase of the vibration.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS. The ink jet head control apparatus according to the present embodiment is mounted on an ink jet recording apparatus built in or connected to a communication apparatus such as a facsimile apparatus or an information processing apparatus such as a personal computer. As shown in FIG. 3, the ink jet recording apparatus includes a printer controller 17, a print buffer 18, a head drive unit 19, and a CR motor drive unit 20. The head drive unit 19 and the CR motor drive unit 20 are respectively connected to a print head 21 and a CR motor 22 that are inkjet heads. The print head 21 is provided with, for example, 64 channels of nozzles for ejecting ink, and each nozzle is connected to an ink flow path having a side wall made of a piezoelectric material subjected to polarization treatment. An electrode for generating an electric field is formed in the side wall surface of the ink flow path, and a print pulse voltage for deforming the side wall and a stop pulse voltage for eliminating vibration after deformation are applied to the electrodes. As described above, a head drive unit 19 described later is connected.
[0012]
As shown in FIG. 4, the print head 21 is fixed to the carriage 23 so that the direction of ink ejection relative to the paper 25 is a predetermined angle. A guide shaft 24 horizontally disposed in the main scanning direction is movably inserted into the carriage 23, and a scanning belt 26 driven by a CR motor 22 is connected to the carriage 23. A CR that drives the scanning belt 26 is connected to the carriage 23. The motor 22 moves the carriage 23 forward and backward along the guide shaft 24 in the main scanning direction, thereby main-scanning the print head 21 while maintaining the distance between the print head 21 and the paper 25 constant. .
[0013]
An encoder element 27 made of a non-contact sensor such as an optical type or a magnetic type is provided on the lower surface of the carriage 23. In the detection direction of the encoder element 27, timing slits 28 having a large number of slit portions 28a at equal intervals are provided in parallel to the guide shaft 24. The encoder element 27 together with the carriage 23 is in the main scanning direction. When the movement is performed, the slit portion 28a of the timing slit 28 is detected and output as an encoder signal.
[0014]
The encoder signal is input to the printer controller 17 as shown in FIG. The printer controller 17 includes a print timing generation unit 34, a buffer control unit 35, a CPU unit 38, and an I / F control unit 42. The print timing generation unit 34, the buffer control unit 35, and the I / F control unit 42 constitute an ASIC unit integrally formed by a hard logic circuit such as an ASIC (Application Specific Integrated Circuit). ing.
[0015]
The print timing generation unit 34 constituting the ASIC unit forms a print timing signal (print clock) based on the encoder signal, and outputs the print timing signal to the buffer control unit 35 and the print control unit 43. It is like that. The buffer control unit 35 includes a DMA controller and an address generator (not shown). The buffer control unit 35 stores the print data input via the I / F unit 16 in the print buffer 18 and the print buffer 18. A read process for reading the print data at a predetermined timing and outputting the print data to the print control unit 43 is executed.
[0016]
The print data stored in the print buffer 18 is output to the print controller 43 as shown in FIG. The print control unit 43 manages the input / output of print data and sets the voltage application timing of the head drive unit 19, and print data and stop pulse data from the buffer control unit 35 to the head drive unit 19. And a data processing unit 2 for outputting. The data processing unit 2 has a data selector 4, a 4-bit shift register unit 3, a stop pulse generation unit 5, and a parallel / serial conversion unit 6 connected in this order from the buffer control unit 35 side. The 4-bit shift register unit 3 has 64-bit shift registers 3 a corresponding to the number of channels of the print head 21 for 64 channels. The data selector 4 disposed between the 4-bit shift register unit 3 and the buffer control unit 35 receives the print data of each channel from the print buffer 18 input via the buffer control unit 35 as the 4-bit shift register unit 3. Each shift register 3a is distributed in 4-bit units.
[0017]
The 4-bit shift register unit 3 is connected to a stop pulse generation unit 5 that generates stop pulse data based on print data. The stop pulse generation unit 5 includes data determination units 5a for 64 channels, and each data determination unit 5a is connected to each shift register 3a of the above-described 4-bit shift register unit 3, and each shift register The print data is input in 1-bit units from 3a.
[0018]
As shown in FIG. 2, the data determination unit 5 a includes a first latch circuit 7 that stores print data to be used as the next (n-th) print data, and the print data stored in the first latch circuit 7. The second latch circuit 8 for storing the next (n + 1) th print data is connected in parallel. The first latch circuit 7 is connected to one input terminal of a two-input AND circuit 10, and the second latch circuit 8 is connected to the other input terminal of the AND circuit 10 via a knot circuit 11. . The AND circuit 10 receives the stop pulse data “1” only when the print data “1” from the first latch circuit 7 and the print data “0” from the second latch circuit 8 are input. Is output. The print data “1” indicates ink droplet ejection, “0” indicates ink droplet ejection prohibition, the stop pulse data “1” indicates application of a stop pulse voltage, and “0” indicates The prohibition of application of stop pulse voltage shall be indicated.
[0019]
The AND circuit 10 is connected to one input terminal of the 2-input switching circuit 9. Further, the above-described first latch circuit 7 is connected to the other switching terminal of the switching circuit 9. Then, the switching circuit 9 to which the stop pulse data from the AND circuit 10 and the print data from the first latch circuit 7 are inputted respectively switches both data in approximately half the cycle of the print timing signal (print clock). However, the data is output to the parallel-serial conversion unit 6. In addition, as shown in FIG. 1, the parallel-serial conversion unit 6 serially transfers these data to the head drive unit 19 at the input timing of the transfer clock when print data and stop pulse data of all channels are input. It is like that.
[0020]
The head drive unit 19 to which print data and stop pulse data are serially transferred as described above has a serial-parallel conversion circuit 12 that sequentially takes in each data at the input timing of the transfer clock and performs parallel conversion. The serial-parallel conversion circuit 12 is connected to a flip-flop (F / F) circuit 13, and the flip-flop circuit 13 holds and updates the data content of the serial-parallel conversion circuit 12 based on the head strobe signal. ing. The flip-flop circuit 13 is connected to a driver circuit 15 including a transistor or the like via an AND circuit 14, and the AND circuit 14 receives data of the flip-flop circuit 13 every time an H level fire signal is input. The contents are output to the driver circuit 15, and a print pulse voltage and a stop pulse voltage are output from the driver circuit 15 to each channel of the print head 21. The fire signal is composed of a print pulse that becomes H level in the same cycle as the print timing signal, and a stop pulse that becomes H level between the output of the print pulses, and the stop pulse consists of a piezoelectric member after printing. The optimum pulse width for eliminating the vibration of the side wall and the output timing that is in the opposite phase of the vibration are set.
[0021]
The operation of the inkjet head control device in the above configuration will be described.
[0022]
First, when a communication device such as a facsimile device receives print data or an information processing device such as a personal computer outputs print data, an ink jet recording device built in or connected to the communication device or information processing device is used. When the print data is input, as shown in FIG. 3, the print data is input to the buffer control unit 35 via the I / F unit 16 and the like, and then the CPU unit 38 instructs to write the print data. The buffer control unit 35 stores the result in the print buffer 18.
[0023]
When storage of print data in the print buffer 18 is performed for one band (64 channels), the buffer control unit 35 is instructed to perform a reading process by the CPU unit 38 when the carriage 23 starts moving, and FIG. As shown, the print data stored in the print buffer 18 is read in units of 4 bits and output to the print control unit 43. The print data input to the print control unit 43 is stored while being distributed by the data selector 4 to each shift register 3 a of the 4-bit shift register unit 3.
[0024]
When the print data is stored in all the shift registers 3a, the print data of each shift register 3a is output to each data determination unit 5a of the stop pulse generation unit 5 in 1-bit units. Here, the following operation will be described by focusing on a specific channel (for example, 0 channel). As shown in FIG. 5A, print data (b0 “1”, b1 “) is stored in the shift register 3a in units of 4 bits. 1 ”, b2“ 0 ”, b3“ 1 ”) (b4“ 0 ”, b5“ 1 ”, b6“ 1 ”, b7“ 1 ”) are sequentially stored, 1 bit from the shift register 3a The print data b0 “1”, b1 “1”, b2 “0”, b3 “1”,... Are output to the data determination unit 5 a of the stop pulse generation unit 5 in units.
[0025]
When these print data b0 “1”, b1 “1”, b2 “0”, b3 “1”,... Are sequentially input to the data determination unit 5a, for example, the first print data b0 “1” is input. Is output while being held in the first latch circuit 7, the second print data b 1 “1” is stored as the next output data in the first latch circuit 7 and is held in the second latch circuit 8. Is output. Thereafter, when the third print data b2 “0” is input to the data determination unit 5a, the first latch circuit 7 stores the third print data b2 “0” as well as the third print data b2 “0”. The second print data b1 “1” is output. The second latch circuit 8 outputs the third print data b2 “0” while holding it.
[0026]
When the n-th print data b0 “1” is output from the first latch circuit 7 in this way, the print data b0 “1” is input to one input terminal of the AND circuit 10 and the switching circuit 9. The When the print data b0 “1” is output from the first latch circuit 7, the (n + 1) th print data b1 “1” is output from the second latch circuit 8, and this print data b1 “1” is output from the knot circuit. 11 is input to the other input terminal of the AND circuit 10. As a result, as shown in FIG. 5B, the print data b0 “1” and the print data b1 “0” inverted by the knot circuit 11 are input to the AND circuit 10, whereby these data b0 “ Stop pulse data a0 “0” obtained by ANDing 1 ”and b1“ 0 ”is output to the other input terminal of the switching circuit 9. After this, as shown in FIG. 5C, the switching circuit 9 switches the print data b0 “1” from the first latch circuit 7 and the stop pulse data a0 “0” from the AND circuit 10 while switching in parallel. The data is output to the serial conversion unit 6.
[0027]
A series of operations in the data determination unit 5a as described above are sequentially performed every time print data b0 “1”, b1 “1”, b2 “0”, b3 “1”,. When these print data b0 “1”... And stop pulse data a0 “0”... Are input to the parallel-serial conversion unit 6, the data of all channels are sent from the head control unit 1 as shown in FIG. The data is serially transferred to the serial / parallel conversion circuit 12 of the head drive unit 19 in synchronization with the transfer clock.
[0028]
The data of all channels input to the serial / parallel conversion circuit 12 are output in parallel to the flip-flop circuit 13. The data of all the channels input to the flip-flop circuit 13 is taken in based on the head strobe signal so as to synchronize with the print pulse and stop pulse of the fire signal, and then held in one of the AND circuits 14. Output to the input terminal. At this time, the fire signal from the head control unit 1 is input to the other input terminal of the AND circuit 14, and the fire signal includes an H level print pulse and an H level stop pulse having the same cycle as the print timing signal. Alternately. Accordingly, as shown in FIG. 5D, when the print data b0 “1”, b1 “1”, b2 “0”, b3 “1”,. An output signal obtained by ANDing the data and the print signal of the fire signal is output to the driver circuit 15, while the stop pulse data a0 “0”, a1 “1”, a2 “0”, a3 “1”,. Is input to the AND circuit 14, an output signal obtained by ANDing these data and the stop pulse of the fire signal is output to the driver circuit 15.
[0029]
As a result, as shown in FIG. 5E, when the data content is “1” such as the print data b0 and the stop pulse data a1, the driver circuit 15 is driven, so that the print pulse voltage and the stop pulse are driven. A pulse voltage is output to a predetermined channel of the print head 21. Then, as shown in FIG. 5F, when the print pulse voltage is input to the print head 21, the side wall (piezoelectric member) of the ink flow path in the predetermined channel is deformed by the application of the print pulse voltage. A droplet is ejected and printing is performed. On the other hand, when the stop pulse voltage is input to the print head 21, the stop pulse voltage is applied at a timing that is opposite to the vibration generated by the deformation of the side wall (piezoelectric member), thereby eliminating the side wall vibration. Therefore, the influence of vibration when the side wall is deformed by the next application of the printing pulse voltage is eliminated.
[0030]
As described above, the ink jet head control apparatus according to the present embodiment applies a print pulse voltage to a piezoelectric member (side wall) based on print data as shown in FIG. Ink droplets are ejected from the nozzles communicating with the ink flow path by increasing or decreasing the volume of the ink. The print pulse voltage for ejection is applied to the piezoelectric member to cause deformation, and then the deformation is caused by the deformation. A print control unit 43 (stop pulse control means) is provided that can apply a stop pulse voltage that eliminates vibration to the piezoelectric member. The stop pulse voltage may be applied every time the piezoelectric member is deformed by the printing pulse voltage, or is applied only when the vibration after deformation is considered to adversely affect printing quality. You may come to be.
[0031]
Thereby, after the piezoelectric member is deformed by the printing pulse voltage, if vibration due to the deformation remains in the piezoelectric member, this vibration may adversely affect the amount of deformation at the next deformation, According to the above configuration, in the case of adverse effects, the vibration of the piezoelectric member can be eliminated by the stop pulse voltage, and the piezoelectric member can always be deformed with a constant deformation amount. Therefore, since the piezoelectric member is not deformed at a normal speed and amount, problems such as ink droplet scattering (occurrence of splashing) that occurs when the ejection amount of the ink droplet becomes unstable can be prevented. Printing quality can be improved.
[0032]
In the present embodiment, the print control unit 43 (stop pulse control means) determines whether or not the print data alternately indicates “1” indicating ejection of ink droplets and “0” indicating ejection prohibition. A data determination unit 5a (determination means) that determines whether or not “1” and “0” are alternately instructed by the data determination unit 5a. It is configured to let you. In this embodiment, by connecting the two-stage latch circuits 7 and 8 in parallel, when the print data indicates “0” following “1”, the print data is “1” and “0”. "3", but when the print data indicates "1", "0" and "1" in succession by connecting three stages of latch circuits in parallel Only the stop pulse voltage may be output.
[0033]
As a result, the vibration of the piezoelectric member disappears due to the stop pulse voltage when the ink droplet ejection and the ejection prohibition, which are most adversely affected by the deformation of the piezoelectric member at the next deformation, are alternately performed. Therefore, it is possible to improve the printing quality by always deforming the piezoelectric member with a constant deformation amount.
[0034]
In the present embodiment, the print control unit 43 (stop pulse control means) outputs a fire signal that applies a stop pulse voltage at a timing that is in reverse phase of the vibration caused by the deformation of the piezoelectric member. (Application timing setting means). As a result, the vibration can be reliably eliminated by applying the stop pulse voltage at a timing that is in the opposite phase of the vibration.
[0035]
【The invention's effect】
According to the first aspect of the present invention, a printing pulse voltage is applied to the piezoelectric member based on the printing data, and the volume of the ink flow path is increased or decreased by deformation of the piezoelectric member, so that the ink from the nozzle communicating with the ink flow path An inkjet head control device that ejects droplets, wherein predetermined print data and print data to be printed next are input, the former print data indicates ejection of ink droplets, and the latter print data indicates ink droplets when showing the non-injection, after the former print data, and the stop pulse data by adding the output for dissipating the vibration generated by the printing pulse voltage, the former and the latter printing data are both drop ejection when the indicating includes print control means for outputting the former and latter print data without outputting the stop pulse data, the data determination unit is output It said print data and the stop pulse data is input, is configured to have a head driving unit that outputs a printing pulse voltages and a stop pulse voltage on the basis of the print data and the stop pulse data to said piezoelectric member.
[0036]
As a result, after the piezoelectric member is deformed by the printing pulse voltage, if vibration due to the deformation remains in the piezoelectric member, this vibration may adversely affect the amount of deformation at the next deformation of the piezoelectric member. However, according to the above configuration, since the vibration of the piezoelectric member can be eliminated, the piezoelectric member can be always deformed with a constant deformation amount, and the print quality can be improved. .
[Brief description of the drawings]
FIG. 1 is a block diagram of an inkjet head control device.
FIG. 2 is a circuit diagram of a data determination unit.
FIG. 3 is a block diagram of an ink jet recording apparatus.
FIG. 4 is a perspective view of a main part of the ink jet recording apparatus.
FIG. 5 is an explanatory diagram illustrating an operation state of the inkjet head control device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Head control part 2 Data processing part 3 4-bit shift register part 3a Shift register 4 Data selector 5 Stop pulse generation part 5a Data judgment part 6 Parallel serial conversion part 7 1st latch circuit 8 2nd latch circuit 9 Switching circuit 10 AND circuit DESCRIPTION OF SYMBOLS 11 Knot circuit 12 Serial parallel conversion circuit 13 Flip-flop circuit 14 AND circuit 15 Driver circuit 16 I / F part 17 Printer controller 18 Print buffer 19 Head drive part 21 Print head 22 CR motor 23 Carriage 25 Paper

Claims (3)

Ink jet head control for ejecting ink droplets from nozzles communicating with the ink flow path by applying a print pulse voltage to the piezoelectric member based on the print data and increasing or decreasing the volume of the ink flow path by deformation of the piezoelectric member A device,
Print data and is input to be printed and the next predetermined print data, the former printing data indicates the ejection of ink droplets, when the latter print data indicates a non-ejection of ink droplets, the former printing data After that, stop pulse data for eliminating the vibration caused by the print pulse voltage is added and output. When both the former and latter print data indicate ejection of ink droplets, the stop pulse data is output. Print control means for outputting the former and the latter print data ,
The print data and stop pulse data output by the data determination unit are input, and a head drive unit that outputs a print pulse voltage and a stop pulse voltage to the piezoelectric member based on the print data and stop pulse data;
An inkjet head control device comprising: The print control means includes
2. The ink jet head control apparatus according to claim 1, further comprising: a latch circuit that holds the predetermined print data and the next print data; and a determination unit that determines each print data. The head drive unit is
The ink jet head control device according to claim 1 or 2, characterized in that outputs the stop pulse voltage at the timing when the opposite phase of the vibration.

Images