JP3815770B2 - Inkjet recording apparatus and inkjet recording method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a block drive system for recording an image on a recording medium by dividing a plurality of ejection openings in a recording head into a plurality of blocks and shifting the drive timing for ejecting ink from the ejection openings for each block. The present invention relates to an ink jet recording apparatus and an ink jet recording method.
[0002]
[Prior art]
An ink jet recording apparatus (ink jet recording apparatus) can increase the recording speed by increasing the number of ink ejection nozzles in the recording head and shortening the driving cycle of the recording head. In such a printing apparatus, when all the nozzles are driven simultaneously, the power consumption temporarily increases, which is disadvantageous in securing the power supply capacity. As a countermeasure, there is a method of averaging the power consumption by adopting a block driving method in which the nozzle is driven by being divided into a plurality of blocks. In this block driving method, the nozzles for each of the divided blocks are driven according to a certain order, and all the nozzles are driven when the driving order is completed. In a serial type recording apparatus, such driving is repeated while the recording head performs one scan.
[0003]
[Problems to be solved by the invention]
In an ink jet recording apparatus, after ink is ejected from the nozzles of the recording head, the ink vibrates inside the recording head. This vibration affects ink ejection in the next cycle. That is, when the ink swells outward from the ejection port due to the vibration, the ink droplet ejected in the next cycle becomes larger than the standard ink droplet, and the ink is inward from the ejection port. In the case of depression, the ink droplet ejected in the next cycle becomes smaller than the standard ink droplet.
[0004]
As described above, the ink ejection in the next cycle is affected by the vibration, and as a result, the image quality of the recorded image is deteriorated. In addition, when the next ink is ejected after waiting for the vibration of the ink to converge so that the ink is not affected by the vibration in the next cycle, the speeding up of recording is impaired. .
[0005]
Conventionally, since the nozzles of each divided block are driven in a fixed fixed order, the vibration of the ink in the recording head may fluctuate greatly periodically, and the influence of the vibration is large. Therefore, it has been difficult to achieve both the prevention of the deterioration of the image quality of the recorded image and the high-speed recording.
[0006]
An object of the present invention is to provide an ink jet recording head and an ink jet recording method capable of efficiently suppressing vibration of ink in the recording head and achieving both prevention of image quality deterioration of a recorded image and high speed recording. It is in.
[0007]
[Means for Solving the Problems]
The inkjet recording apparatus of the present invention is an inkjet recording apparatus that performs recording on a recording medium using a recording head capable of ejecting ink from a plurality of ejection openings, wherein the plurality of ejection openings are divided into a plurality of blocks, and Drive means for shifting the drive timing for ejecting ink from a plurality of ejection openings in accordance with a predetermined order for each of the plurality of blocks; and change means for changing the order in which the drive means shifts the drive timing of the plurality of blocks; And the changing means makes a cycle of driving the plurality of blocks within a period for recording an image for one column on the recording medium, and a driving cycle for each period for recording the image for one column. The drive order of the plurality of blocks can be changed so as to generate different blocks .
[0008]
The inkjet recording method of the present invention is an inkjet recording method in which recording is performed on a recording medium using a recording head capable of ejecting ink from a plurality of ejection ports, wherein the plurality of ejection ports are divided into a plurality of blocks, and The drive timing for ejecting ink from a plurality of ejection ports is shifted in a predetermined order for each of the plurality of blocks, and the drive timing of the plurality of blocks is cycled within a period for recording an image for one column on the recording medium. And the drive order of the plurality of blocks is changed so that blocks having different drive cycles are generated for each period of recording the image for one column .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0010]
FIG. 1 is an exploded perspective view of a recording head applicable in the present invention, and FIG. 2 is a schematic cross-sectional view of the main part of the recording head. In the recording head 10 of this example, 11 is a substrate on which a plurality of liquid passage walls 12 are formed, 13 is a top plate, 14 is a plurality of discharge ports constituting a plurality of nozzles, and 15 is a plurality of discharge ports 14. A plurality of flow paths 16 and 16 are common liquid chambers that communicate with the plurality of flow paths 15 in common. In the case of this example, 256 discharge ports 14 are formed. A portion between the discharge port 14 and the common liquid chamber 16 is referred to as a “nozzle”. The ink for image recording is supplied into the common liquid chamber 16 through the supply pipe 17 from an ink supply unit (not shown). The ink in the common liquid chamber 16 is supplied into the flow path 15 by capillary action, and is stably held by forming a meniscus at the discharge port 14 at the tip of the flow path 15. Each of the flow paths 15 is provided with a heating element (hereinafter also referred to as “heater”) 18 as an electrothermal converter. By energizing the heating element 18 through the wiring 19 and generating thermal energy from the heating element 18, the ink in the flow path 15 is heated and foamed by film boiling. The ink in 15 is ejected from the ejection port 14 as an ink droplet I.
[0011]
FIG. 3 is a perspective view for explaining a schematic configuration of a recording apparatus to which the present invention is applicable. The recording apparatus 50 of this example is a serial scanning type recording apparatus, and a carriage 53 is guided by guide shafts 51 and 52 so as to be movable in the main scanning direction of an arrow A. The carriage 53 is reciprocated in the main scanning direction by a driving force transmission mechanism such as a carriage motor and a belt for transmitting the driving force. On the carriage 53, a recording head 10 (not shown in FIG. 3) and an ink tank 54 for supplying ink to the recording head 10 are mounted. The recording head 10 and the ink tank 54 may constitute an ink jet cartridge. The paper P as the recording medium is inserted from the insertion port 55 provided at the front end of the apparatus, and then the transport direction is reversed, and then the transport is performed by the feed roller 56 in the sub-scanning direction indicated by the arrow B. The recording apparatus 50 performs sub-scanning of the paper P by a distance corresponding to the recording operation in which the recording head 10 is moved in the main scanning direction and ink is ejected toward the print area of the paper P on the platen 57. Images are sequentially recorded on the paper P by repeating the transport operation for transporting in the direction.
[0012]
A recovery system unit (recovery processing means) 58 is provided at the left end in FIG. 3 in the movement region of the carriage 53 so as to face the surface on which the ejection port 15 of the recording head 10 mounted on the carriage 53 is formed. The recovery system unit 58 includes a cap capable of capping the ejection port 15 of the recording head 10 and a suction pump capable of introducing a negative pressure into the cap. The recovery unit 58 includes a cap that covers the ejection port 15. By introducing negative pressure, ink is sucked and discharged from the ejection port 15 and a recovery process (also referred to as “suction recovery process”) is performed to maintain a good ink ejection state of the recording head 10. Further, a recovery process (also referred to as “ejection recovery process”) is performed in order to maintain a good ink ejection state of the recording head 10 by ejecting ink not contributing to an image from the ejection port 15 toward the inside of the cap. You can also.
[0013]
FIG. 4 is a schematic block diagram of the control system of the recording apparatus to which the present invention is applicable. In FIG. 4, the CPU 100 executes control processing of the operation of the recording apparatus, data processing, and the like. The ROM 101 stores programs such as those processing procedures, and the RAM 102 is used as a work area for executing these processes. Ink is ejected from the recording head 10 when the CPU 100 supplies recording data and a driving signal to the head driver 10A. The CPU 100 controls the carriage motor 103 for driving the carriage 53 in the main scanning direction via the motor driver 103A, and the P.P. The F motor 104 is controlled via the motor driver 104A.
[0014]
FIG. 5 is a configuration diagram of a drive circuit that drives the recording head 10, and can be configured on the head driver 10 </ b> A or the substrate 11 of the recording head 10. FIG. 6 is a timing chart for explaining a conventional example of the drive timing of the recording head 10 by the drive circuit of FIG. 5 as a comparative example of the present invention.
[0015]
In the drive circuit of FIG. 5, a total of 256 heaters 18 in each of the 256 nozzles of the recording head 10 are driven by being divided into 16 blocks each having 16 blocks, each of which has 16 blocks. The heater 18 is driven. The HDATA signal as recording data is serially transferred to the recording head 10 in synchronization with the HCLK signal. The recording data (HDATA) is received by the 16-bit shift register 301 and then latched by the latch circuit 302 at the rising edge of the BG signal. The block to be driven is designated by a four-line block enable signal (BE signal), and the designation signal is developed by the decoder 303, and then the segment of the designated block to be driven is selected. The segments (seg0 to seg255) correspond to the heaters 18 in each of the 256 nozzles. In FIG. 5, the drive transistor (see FIG. 2) for each heater 18 is not shown. Only the segment specified by both the BE signal and the HDATA signal is driven by the drive signal (HE signal), and ink droplets are ejected from the corresponding nozzle.
[0016]
In the driving system of FIG. 6 as a comparative example of the present invention, the block designation signal designates 16 blocks starting from block 0 to block 15 in order, and the block starting from block 0 is the same in the next column. 16 blocks up to 15 were specified in order. For this reason, the nozzle drive cycle T0cyc is constant for the nozzles of all blocks. However, the constant drive cycle T0cyc for all the nozzles in this way induces periodic vibrations of the ink in the recording head 10, and the vibrations of other nozzles via the common liquid chamber 16. The discharge was also affected.
[0017]
According to the present invention, by changing the driving cycle of a specific nozzle at an arbitrary timing, the influence of vibration on the recording image quality is minimized without giving periodicity to ink vibration.
[0018]
FIG. 7 is a timing chart for explaining an example of drive timing of the recording head 10 by the drive circuit of FIG. 5 as an embodiment of the present invention.
[0019]
In this example, first, 16 blocks from block 0 to block 15 are sequentially designated and driven by the BE signal. In the next column thereafter, all 16 blocks are driven by designating and driving block 0 to block 15 in order by the BE signal and then driving by designating block 0. As a result, for the nozzles in block 0, the driving cycle is T0'cyc, and for the nozzles in blocks 1 to 15, the driving cycle is T1'cyc, and the nozzle driving interval varies depending on the block. Thereby, the vibration of the ink can be dispersed.
[0020]
As described above, various methods can be used as a method for changing the drive order of blocks.
[0021]
FIG. 8 is a circuit block diagram for explaining an example of a method for changing the drive order of blocks, and FIG. 9 is a timing chart for explaining drive timing of the circuit. The CLM_TRIG signal is a trigger signal output for each column, and the BL_TRIG signal is a trigger signal output when a block is switched. As described above, since it is necessary to drive 16 blocks in one column, 16 BL_TRIG signals are output at the trigger interval of the CLM_TRIG signal. Therefore, by counting up the BL_TRIG signal, a pre_BE signal similar to the conventional BE signal can be generated. Further, the base_BE signal generated by counting up the CLM_TRIG signal changes to 1, 2, 3,. By adding the pre_BE signal and the base_BE signal as described above, it is possible to output the I_BE signal as the BE signal in FIG. 7, that is, a block signal shifted by one block for each column.
[0022]
FIG. 10 is a circuit block diagram when the drive order of blocks is changed using a barrel shifter. FIG. 11 is a circuit block diagram in the case where the drive order of the blocks is stored in advance in the memory, the blocks are sequentially read, and the I_BE signal is generated by the BE generation block. As shown in FIG. 11, when the drive order of blocks is stored in a memory, ink vibrations can be dispersed by preparing a random drive order as the drive order.
[0023]
Further, when the recording head is not incorporated in the recording apparatus main body, by providing the recording head with vibration avoidance information unique to the recording head, high-precision control using the information becomes possible. For example, the recording head can be tested at the time of shipment, and the drive order of the blocks in FIG. 11 can be written in a nonvolatile memory mounted on the recording head. Further, it goes without saying that the present invention can be applied to a recording apparatus equipped with a plurality of recording heads such as a color printer. In that case, the order of block driving in each recording head can be individually changed.
[0024]
(Other embodiments)
The present invention can be applied to a full line type recording apparatus using a long recording head in addition to a serial scanning type recording apparatus. That is, the present invention is widely applied to a block drive type recording apparatus that divides a plurality of nozzles in a recording head into a plurality of blocks and drives the nozzles for each block regardless of the type of the recording apparatus. Can be applied.
[0025]
【The invention's effect】
As described above, the present invention divides a plurality of ejection ports of a recording head into a plurality of blocks, and changes the order of shifting when the drive timing for ejecting ink from these ejection ports is shifted for each block. As a result, it is possible to efficiently suppress periodic vibration of the ink in the recording head, and to achieve both prevention of image quality deterioration of the recorded image and higher recording speed.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part of a recording head applicable to the present invention.
FIG. 2 is a schematic cross-sectional view of a main part of the recording head of FIG.
FIG. 3 is a perspective view of a recording apparatus to which the present invention can be applied.
4 is a block configuration diagram of a control system of the recording apparatus of FIG. 3;
FIG. 5 is a schematic configuration diagram of a drive circuit for the recording head of FIG. 1;
FIG. 6 is a timing chart for explaining drive timing of a recording head as a comparative example of the present invention.
FIG. 7 is a timing chart for explaining an example of the drive timing of the recording head according to the present invention.
FIG. 8 is a block configuration diagram of a circuit for changing the block drive order using an adder.
FIG. 9 is a timing chart for explaining an example of changing the block driving order by the circuit of FIG. 8;
FIG. 10 is a block configuration diagram of a circuit for changing a block driving order using a barrel shifter.
FIG. 11 is a block configuration diagram of a circuit for changing a block driving order using a memory.
[Explanation of symbols]
10 Recording head 14 Discharge port 18 Heater (electrothermal converter)
100 CPU
101 ROM
102 RAM
P paper (recording medium)

Claims (11)

In an inkjet recording apparatus that records on a recording medium using a recording head capable of ejecting ink from a plurality of ejection openings.
Driving means for dividing the plurality of ejection openings into a plurality of blocks and shifting a drive timing for ejecting ink from the plurality of ejection openings according to a predetermined order for each of the plurality of blocks;
Change means capable of changing the order in which the drive means shifts the drive timing of the plurality of blocks;
Equipped with a,
The changing means makes a cycle of driving the plurality of blocks within a period for recording an image for one column on the recording medium, and a block having a different driving cycle for each period for recording the image for one column. The inkjet recording apparatus is characterized in that the drive order of the plurality of blocks can be changed so as to cause the problem . 2. The ink jet recording apparatus according to claim 1 , wherein the changing unit shifts the driving timing of the plurality of blocks by a predetermined number of blocks every time the image for one column is recorded. Storage means for storing information relating to the order of shifting the drive timing of the plurality of blocks;
The inkjet recording apparatus according to claim 1 , wherein the changing unit changes the order in which the driving timings of the plurality of blocks are shifted based on information stored in the storage unit. 4. The ink jet recording apparatus according to claim 3 , wherein the information stored in the storage unit is a parameter for setting an order of shifting the driving timing of the plurality of blocks. The inkjet recording apparatus according to claim 4 , wherein the parameter is a shift amount for shifting the drive timing of the plurality of blocks by a predetermined number of blocks. The inkjet recording apparatus according to claim 3 , wherein the storage unit is provided in the recording head. The inkjet recording apparatus according to claim 1, wherein an image is recorded using a plurality of the recording heads. The driving unit is configured to shift a driving time for ejecting ink from the plurality of ejection ports according to a predetermined order for each of the plurality of blocks, independently for each of the plurality of recording heads.
The inkjet recording apparatus according to claim 7 , wherein the changing unit is capable of changing an order in which the driving unit shifts a driving timing of the plurality of blocks independently for each of the plurality of recording heads. The ink jet recording apparatus according to claim 1 , wherein the recording head includes an electrothermal converter that generates thermal energy used to eject ink. Moving means for reciprocating the recording head in the main scanning direction;
Conveying means for conveying the recording medium in a sub-scanning direction intersecting the main scanning direction;
An ink jet recording apparatus according to claim 1, comprising: In an ink jet recording method for recording on a recording medium using a recording head capable of discharging ink from a plurality of ejection openings,
Dividing the plurality of ejection ports into a plurality of blocks, and shifting the drive timing for ejecting ink from the plurality of ejection ports according to a predetermined order for each of the plurality of blocks,
The drive timing of the plurality of blocks is cycled within a period for recording an image for one column on the recording medium, and blocks having different driving cycles are generated for each period for recording the image for one column. And changing the drive order of the plurality of blocks.

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