JP2008100480A - Inkjet recorder and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink thickening inspection method which is low-cost, simple, and highly reliable. <P>SOLUTION: The inkjet recorder, performing printing by discharging ink from a print head 416, has an ink supplier 600 for supplying the print head 416 with ink, a pressure adjustment pump 605 for adjusting ink pressure in the print head, a heater for adjusting an ink temperature in the print head, a head recovery means for performing a recovery operation for discharging ink from the print head, a CPU for performing the test printing which shows that a predetermined pattern is printed by changing the ink pressure after the recovery operation and enables changes in the printing operation based on the ink information acquired by the test print. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to measures for increasing the viscosity of ink for inkjet recording.

In a conventional ink jet recording apparatus, a hard surface such as electric conductivity and pressure is inspected for a viscosity change (thickening) due to ink evaporation or the like (for example, Patent Document 1).
Japanese Patent Laid-Open No. 7-17924

  However, the conventional inspection method involves an increase in cost, apparatus size, and the like, and a low-cost, simple and reliable ink thickening inspection method is desired.

  In view of the above problems, the present invention provides an ink jet recording apparatus that performs a printing operation by ejecting ink from a recording head, the ink supplying means supplying ink to the recording head, and the pressure of the ink in the recording head Pressure adjusting means for adjusting the temperature, temperature adjusting means for adjusting the temperature of ink in the recording head, head recovery means for executing a recovery operation for discharging ink from the recording head, and after the recovery operation, Control means for executing a test print operation for printing a predetermined pattern by changing the pressure, and changing the print operation based on ink information obtained by the test print.

  The present invention includes an ink supply unit that supplies ink to a recording head, a pressure adjusting unit that adjusts the pressure of ink in the recording head, a temperature adjusting unit that adjusts the temperature of ink in the recording head, and the recording A head recovery means for performing a recovery operation for discharging ink from the head, and a method for controlling an ink jet recording apparatus that performs a printing operation by discharging ink from the recording head, and after the recovery operation, A test print operation for printing a predetermined pattern by changing the pressure of the ink is executed, and the print operation is changed based on ink information obtained by the test print.

  According to the present invention, it is possible to perform a low-cost, simple, and reliable ink thickening test without adding a new configuration, and to change to a printing operation according to the test result.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  The following embodiments are examples as means for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the apparatus to which the present invention is applied and various conditions without departing from the spirit of the present invention. The present invention is not limited to the following embodiments.

  The present invention can also be achieved by storing a software program for realizing a test print mode, which will be described later, in a storage medium, reading the program code from the storage medium, and executing it by an apparatus constituting the system. Needless to say. That is, the present invention can also be applied to a program for causing a computer to execute a conveyance abnormality detection flow described later, a recording medium for storing the program, and the like.

[Mechanical structure]
FIG. 1 is a side perspective view showing a mechanical configuration of an ink jet recording apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, an inkjet recording apparatus 500 is supplied with a label sheet 501 wound in, for example, a roll and temporarily attached with a plurality of labels, and is fixed by a conveyance belt 502 driven by a conveyance motor 413. Transported at speed.

  Each label leading edge of the label sheet 501 is detected by the leading edge detection sensor 414, and printing is performed by passing each label below the plurality of print heads 416K to 416Y based on the detection position.

  For printing, for example, a black print head 416K, a cyan print head 416C, a magenta print head 416M, and a yellow print head 416Y are used to perform color printing with a total of four colors of ink.

  The print heads 416K to 416Y for each color are line heads having a print width corresponding to the maximum width of the label paper 501 used, for example.

  Below the ink jet recording apparatus 500, ink cartridges 504K to 504Y and sub tanks 503K to 503Y corresponding to the print heads 416K to 416Y of the respective colors are mounted.

  Under the print heads 416K to 416Y, capping mechanisms 506K to 506Y are provided corresponding to the print heads.

  Although six capping mechanisms are shown in FIG. 1, for example, light cyan, light magenta, or a special color ink may be added, and is provided as a spare at that time.

  As will be described later, the ink cartridges 504K to 504Y, the sub tanks 503K to 503Y, the print heads 416K to 416Y, and the capping mechanisms 506K to 506Y are connected by independent ink tubes for each ink.

  FIG. 2 is a block diagram showing an electrical configuration of the ink jet recording apparatus 500 of the present embodiment.

  As shown in FIG. 2, the print data transmitted from the host computer 400 is received by the interface controller 402 of the inkjet recording apparatus 500.

  The interface controller 402 also receives a command for instructing the number, type, size, and the like of a recording medium, for example, a label.

  A CPU (central processing unit) 401 is an arithmetic processing unit that controls the entire apparatus, such as analysis of commands received by the interface controller 402, reception of print data, printing operation, and handling of a recording medium.

  After analyzing the received command, the CPU 401 renders the image data of each color component of the print data by developing a bitmap on the image memory 404.

  As an operation process before printing, the CPU 401 mutually drives a capping motor (not shown) and a head motor (not shown) via an input / output port (I / O) 408, a motor drive unit 410, and print heads 416K to 416Y. Is moved from the capping position (standby position) to the print position (not shown).

  Also, the label paper is continuously transported by driving a paper feed motor (not shown) and a transport motor 413 for feeding the label paper as a recording medium substantially simultaneously with the movement of the print heads 416K to 416Y.

  In order to determine the print timing of the label paper conveyed at a constant speed, the leading edge detection (TOF) sensor 414 detects the leading edge of the label.

  In synchronism with the conveyance of the label paper by the conveyance motor 413, the CPU 401 sequentially reads the corresponding color image data from the image memory 404 and transfers it to the corresponding print heads 416K to 416Y via the print head control circuit 409 to perform color printing. .

  The CPU 401 executes programs such as sequence change processing stored in the program ROM 403. This program is, for example, a program corresponding to the procedure shown in the flowchart of FIG.

  A test print pattern (FIGS. 8 and 9) for viscosity inspection is also developed from the program ROM 403. A work RAM 405 is used as a working memory.

  The EEPROM 406 stores device-specific parameters such as storage of the time when the previous recovery operation was executed, correction values for fine adjustment (registration) of the print positions in the width and the conveyance direction between the print heads, for example. This is a rewritable nonvolatile memory.

  Further, the CPU 401 supplies the pressure pump motor 411 and the sub pump motor 412 to an input / output circuit (I / O) 408 at the time of supplying ink to the print heads 416K to 416Y or at the time of recovery operation for discharging ink from the print heads 416K to 416Y. Control is performed via the motor drive unit 410.

  Next, with reference to FIG. 3, the ink supply device 600 incorporated in the ink jet recording apparatus 500 will be described.

  FIG. 3 is a schematic diagram showing an ink supply device 600 incorporated in the ink jet recording apparatus 500.

  In FIG. 3, the ink supply device 600 is provided in the print head 416 for each color, and supplies ink to each print head 416 and recovers the print head.

  The ink supply device 600 includes an ink cartridge 504 that is detachable from the recording apparatus main body, and a sub tank 503 disposed in the middle of an ink supply path 604 that connects the ink cartridge 504 and the print heads 416K to 416Y. A print head 416 is disposed at the bottom.

  The sub tank 503 and the print head 416 are connected (connected) by the two ink flow paths 608 and 614 via the filter 610.

  The sub tank 503 is fixed to the frame of the recording apparatus main body, and some of the ink flow paths 608 and 614 are made of a flexible tube. As a result, the print head 416 is movable.

  A cleaning pump 615 for cleaning the print head 416 and a standby valve 616 for opening and closing the ink channel 614 at a predetermined timing are attached to the ink channel 614.

  On the other hand, a pressure valve 609 that opens and closes the ink channel 608 at a predetermined timing is attached to the ink channel 608.

  A pressure detection sensor 607 for detecting the ink pressure in the ink flow path 608 is attached between the pressure valve 609 and the pressure adjustment pump 605 in the ink flow path 608.

  Inside the sub tank 503, a pressure adjusting pump 605 for applying an appropriate pressure to the multiple nozzles 618 of the print head 416 is disposed.

  The pressure adjusting pump 605 is located slightly above the bottom surface of the sub tank 503 and is separated from the bottom surface by a predetermined distance.

  The pressure adjustment pump 605 is immersed in the ink stored in the sub tank 503. A drive unit 602 for driving the pressure adjusting pump 605 is disposed above the sub tank 503, and the drive unit 602 is controlled by the CPU 401 (see FIG. 2).

  In addition, an atmosphere release valve 601 for setting the internal pressure of the sub tank 503 to atmospheric pressure is fixed to the upper wall of the sub tank 503.

  By opening the atmosphere release valve 601, the internal pressure of the sub tank 503 becomes equal to the atmospheric pressure.

  Further, the sub tank 503 is provided with a well-known liquid level detection sensor 417 for detecting the liquid level of ink (stored ink) stored in the sub tank 503.

  When the liquid level detection sensor 417 detects that the ink level in the sub tank 503 has become a certain level or less, the supply pump 603 starts operating, and ink is sucked from the ink cartridge 504 and supplied to the sub tank 503. The

  On the other hand, when the liquid level detection sensor 417 detects that the ink level in the sub tank 503 has reached a predetermined upper limit level, the supply pump 603 stops and the supply of ink is stopped.

  Further, the print head 416 and the ink cartridge 504 are connected via a recycle pump 611 and a recycle filter 612, and the ink forcibly discharged from the face 619 of the print head 416 at the time of cleaning is trapped by the cap 617, and the ink cartridge 504 The recycling method to return to is adopted.

  A detection sensor (not shown) for detecting the presence or absence of ink in the ink cartridge 504 is attached to the ink cartridge 504.

  An air release valve 606 for setting the internal pressure of the ink cartridge 504 to atmospheric pressure is attached to an air flow path that is connected when the ink cartridge 504 is attached to the recording apparatus main body.

  Next, a method for adjusting the pressure in the print head 416 by the pressure adjusting pump 605 will be described with reference to FIGS.

  4 is an enlarged view showing the sub-tank and the print head in detail, FIG. 5 is a top view showing the blades of the pressure adjusting pump, and FIG. 6 is a view showing the rotational speed of the blades shown in FIG. 5 and the pressure acting on the ink in the print head. It is a figure which shows a relationship.

  As shown in FIG. 4, the pressurizing valve 609, the standby valve 616, and the air release valve 601 are electromagnetic valves that block the ink flow path 608 by a valve sheet 703 integrated with a solenoid plunger 702. However, the present invention is not limited to these, and other methods may be adopted.

  If there is no means for controlling the negative pressure, a positive pressure corresponding to the water head difference h shown in the figure is applied in the vicinity of the nozzle (discharge port), so that not only a meniscus is formed, but also the ink drops. Even concerns arise.

  At the time of printing, it is necessary to apply an appropriate negative pressure to the print head 416 (ink discharge port of the print head 416 = pressure to form an ink meniscus at the nozzle outlet).

  In this case, the pressurization valve 609 and the atmosphere release valve 601 are in an open state, and the standby valve 616 is in a sealed state.

  By driving the pressure adjustment pump 605 in this state, the blade 801 of the pressure adjustment pump 605 rotates in the direction of arrow A in FIG. 5, and the ink receives a centrifugal force from the center C of the blade 801 along the blade surface 802. .

  That is, since the central portion of the rotation shaft of the pressure adjusting pump 605 (the peripheral portion of the center C) is relatively negative pressure, negative pressure is applied to the print head 416 from the suction port 701 of the sub tank 503 via the ink flow path 608. can do.

  The suction port 701 is formed on the bottom wall of the sub-tank 503, and the pressure adjustment pump 605 is disposed above the suction port 701 at a predetermined distance.

  Note that the rotation speed of the blade 801 is controlled by the CPU 401 (see FIG. 2).

  As described above, the pressure adjusting pump 605 sucks the ink in the print head 416 from the ink flow path 608 by the centrifugal force generated when the pressure adjusting pump 605 is driven to rotate the blade 801 in the arrow A direction. As a result of trying to suck into the sub tank 503 via the port 701 (almost never actually sucked), negative pressure is applied to the ink in the print head 416 (pressure lower than the atmospheric pressure around the outside of the ink ejection port). Thus, an ink meniscus is formed at the ink discharge port.

  When the pressure adjustment pump 605 is driven so that the blade 801 rotates in the direction opposite to the arrow A, the ink in the sub tank 503 acts so as to be pushed out from the suction port 701. A positive pressure (a pressure higher than the atmospheric pressure around the outside of the ink discharge port) is applied to the ink. As a result, ink is discharged from the ink discharge port.

  As shown in FIG. 6, the magnitude of the negative pressure generated by the pressure adjustment pump 605 varies according to the number of rotations when the blade 801 of the pressure adjustment pump 605 rotates in the direction of arrow A in FIG.

  As the blade 801 rotates faster in the direction of arrow A (the greater the number of revolutions per unit time), the greater negative pressure is generated, so that the ink in the print head 416 is sucked into the sub tank 503 with a strong force. The negative pressure acting on the ink in the print head 416 (in the nozzle 618) increases.

  Conversely, as the blade 801 rotates slower in the direction of the arrow C (the smaller the number of rotations per unit time), only a smaller negative pressure is generated, so the ink in the print head 416 will be sucked into the sub tank 503 with a weak force. Accordingly, the negative pressure acting on the ink in the print head 416 is reduced.

  That is, the magnitude of the negative pressure applied to the print head 416 can be controlled according to the number of rotations of the pressure adjustment pump 605, so that the ink flow path 608 can be printed with the ink flow path 608 open by driving the pressure adjustment pump 605. The pressure in the head 416 is adjusted.

  By the way, as the pressure adjusting pump 605, it is desirable to use a pump generally classified as a turbo type.

  Examples of the turbo-type pump include the centrifugal pump type, diagonal flow type, and axial flow type employed in this example.

  Since these can generate pressure without blocking (closing) the ink flow path (liquid flow path), the ink can move the pump in accordance with the differential pressure.

  For example, when ink is ejected from the print head 416, the ink is reduced in the print head 416, and the pressure between the print head 416 and the pressure adjustment pump (centrifugal pump) 605 is reduced.

  In this case, the ink in the sub tank 503 is supplied to the print head 416 via the ink flow path 608. On the other hand, when a piston pump classified as a so-called positive displacement type is used as the pressure adjustment pump 605, it is necessary to shut off the ink flow path 608 in order to pump ink, so that the ink is connected to the piston pump. In addition to being unable to move freely, the outside air is easily sucked from the ink discharge port of the nozzle 618 of the print head 416.

  A large number of nozzles 618 for discharging ink are formed in the print head 416 side by side.

  The large number of nozzles 618 are connected (communicated) with a common liquid chamber 620 in which ink is stored.

  The common liquid chamber 620 is connected to the sub tank 503 (see FIG. 4), and ink is supplied from the sub tank 503 to the common liquid chamber 620.

  Therefore, by changing the rotation speed of the pressure adjusting pump 605, the magnitude of the negative pressure applied to the print head 416, that is, the magnitude of the negative pressure acting on the ink in the nozzle 618 can be changed.

  Next, the test print mode will be described with reference to FIG.

  In FIG. 7, when the test print mode is started by the timer of the user or the apparatus, the ink in the head flow path is held at a predetermined temperature simultaneously with the head recovery operation (S300) (S301).

  Thereafter, a test print (S302) is performed, and the test print information is acquired by the user or the image reading apparatus (S303).

  Here, it is determined whether or not the test pattern has been completely printed (S304). If it is complete (FIG. 8), the test print mode is terminated. Here, when the viscosity of the ink is increased, the ink cannot withstand negative pressure and non-ejection occurs.

  If the test pattern is not printed completely and there is no ejection (Fig. 9), the information obtained from the test print can be used to print to the specified negative pressure (for example, 40mmaq), which exceeds the thickening limit of the main unit. (S305). If printing cannot be performed, ink replacement for that color is performed (S308), and the process returns to S300.

  If the test pattern is not printed completely and there is no discharge (NO in S304), and if printing is possible up to the specified negative pressure (YES in S305), the user can obtain information such as ink viscosity for each color obtained from the test print. Alternatively, it is input from the image reading apparatus (S306) and collated with the information stored in the program ROM 403 to change the print sequence and the recovery sequence (S307).

  The change in the print sequence is, for example, a change in the ink discharge amount (to keep the ink discharge amount constant), and the change in the recovery sequence is, for example, a change in the ink circulation time. Based on the viscosity information and the like, the number of revolutions and operating time of the pump and the heater power (heater drive pulse width) of the print head are changed.

  When normal printing is possible only up to a specified negative pressure (for example, 60 mmaq), for example, the ink circulation time, the pump operation time, the heater power is doubled, and the pump speed is halved.

  FIG. 8 shows an example of a test pattern at a normal time, and FIG. 9 shows an example of a test pattern at the time of thickening.

  In FIG. 8, reference numeral 100 denotes test print output paper, and scale examples 101 and 102Y to 102K indicating the water head pressure indicate test print patterns of respective colors. FIG. 9 shows an example of a print pattern 200 when ink is not ejected due to thickening.

  Next, the ink replacement in S308 of FIG. 7 will be described.

  In FIG. 3, the valve 621 in the flow path leading from the sub tank 503 to the waste ink tank 505 is opened, and ink is discharged to the waste ink tank 505 by the head pressure of the sub tank 503 and the waste ink tank 505. Next, the ink cartridge 504 is replaced, the ink in the ink cartridge 504 is supplied to the sub tank 503 by the supply pump 603, and the ink in the sub tank 503 is replaced.

  In addition, there are various recovery operations such as a wiping operation of the face 619 of the print head by a wiper blade (not shown) and ink circulation between the sub tank 503 and the print head 416, but details are omitted.

  Further, although the present embodiment has been described with reference to an ink recycling apparatus that seems to have a particularly large amount of evaporation, it can also be applied to a non-recycling apparatus.

[Description of effects]
The change in the print sequence enables stable ejection corresponding to the change in ink viscosity by adjusting the ink temperature in the flow path of the print head 416.

  The change in the print sequence enables stable ejection corresponding to the change in ink viscosity by adjusting the ejection energy of the print head 416.

  The change in the print sequence enables stable discharge corresponding to the change in ink viscosity by adjusting the discharge interval (time) of the print head 416.

  The recovery sequence can be changed by adjusting the amount of ink circulating in the flow path of the print head 416 so that stable recovery and printing corresponding to the change in ink viscosity can be performed.

  The recovery sequence can be changed by adjusting the time during which the ink circulates in the flow path of the print head 416, thereby enabling stable recovery and printing corresponding to the change in the viscosity of the ink.

  The recovery sequence can be changed by adjusting the internal pressure of the flow path when the ink circulates in the flow path of the print head 416, so that stable recovery and printing corresponding to the change in the viscosity of the ink can be performed.

  Even if the control described above is applied to a system constituted by a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), it is applied to an apparatus (for example, a copying machine, a facsimile machine, etc.) comprising a single device. You may apply.

  In addition, in the ink ejection method described above, a storage medium in which a program code of software that realizes the function is recorded is supplied to the system or apparatus, and the computer (or CPU or MPU) of the system or apparatus is stored in the storage medium. Needless to say, this can also be achieved by reading and executing the program code.

  In this case, the program code itself read from the storage medium realizes the above function.

  As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like is used. be able to.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but an OS (operating system) operating on the computer based on the instruction of the program code is actually used. A case where part or all of the processing is performed and the functions of the above-described embodiments are realized by the processing is also included.

  Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. This includes a case where the CPU or the like provided in the board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

1 is a side perspective view showing a mechanical configuration of an ink jet recording apparatus according to an embodiment of the present invention. 1 is a block diagram illustrating an electrical configuration of an ink jet recording apparatus according to an embodiment. It is a schematic diagram which shows the ink supply apparatus integrated in the inkjet recording device. It is an enlarged view showing a sub tank and a print head in detail. It is a top view which shows the blade | wing of a pressure adjustment pump. FIG. 6 is a diagram showing the relationship between the rotational speed of the blade shown in FIG. 5 and the pressure acting on the ink in the print head. It is a flowchart which shows operation | movement of a test print mode. It is a figure which shows the example of a test pattern at the time of normal. It is a figure which shows the example of a test pattern at the time of thickening.

Explanation of symbols

400 host computer
401 CPU (Central processing unit)
402 interface controller
403 program ROM
404 image memory
405 Work RAM
406 EEPROM
407 A / D converter
408 I / O
409 Printhead control circuit
410 Motor drive
411 Pressure pump / motor
412 Sub pump / motor
413 Conveyor motor
414 Label tip detection sensor
415 Operation panel
416 print head
417 Ink detection sensor
500 recorder
501 label paper
502 Conveyor belt
503 Sub tank
504 ink cartridge
505 Waste ink tank for ink replacement
506 Capping mechanism
600 Ink supply device
601 Atmospheric release valve
602 drive unit
603 supply pump
604 Ink supply path
605 pressure regulating pump
606 Atmospheric release valve
607 Pressure sensor
608 Ink channel
609 Pressure valve
610 Filter
611 Recycling pump
612 Recycling filter
614 Ink channel
615 Cleaning pump
616 Standby valve
617 cap
618 nozzle
619 Face
620 Common liquid chamber
621 Waste ink tank valve
701 Suction port
702 Plunger
703 Valve seat
801 feathers
802 feathers

Claims (8)

An inkjet recording apparatus that performs a printing operation by discharging ink from a recording head,
Ink supply means for supplying ink to the recording head;
Pressure adjusting means for adjusting the pressure of the ink in the recording head;
Temperature adjusting means for adjusting the temperature of the ink in the recording head;
Head recovery means for executing a recovery operation for discharging ink from the recording head;
Control means for executing a test print operation for printing a predetermined pattern by changing the pressure of the ink after the recovery operation, and changing the print operation based on ink information obtained by the test print. An ink jet recording apparatus.   2. The ink jet recording apparatus according to claim 1, wherein the test print operation is executed with the temperature of the ink made constant by the temperature adjusting unit.   The control means executes an ink replacement operation for replacing ink in the recording head by the ink supply means when a pressure at which a print error has occurred is less than a predetermined pressure as a result of the test printing. Item 3. The ink jet recording apparatus according to Item 1 or 2.   4. The ink jet recording apparatus according to claim 1, wherein the ink information includes information on pressure and viscosity of ink in the recording head. The ink includes at least yellow, magenta, cyan, and black colors,
The ink jet recording apparatus according to claim 1, wherein the test print is executed for each color of ink. Means for inputting the ink information;
Means for reading ink information from the test print pattern;
The inkjet recording apparatus according to claim 1, further comprising a unit that displays the ink information.   The inkjet recording apparatus according to claim 1, further comprising a unit that returns the ink discharged from the recording head to the ink supply unit. Ink supply means for supplying ink to the recording head;
Pressure adjusting means for adjusting the pressure of the ink in the recording head;
Temperature adjusting means for adjusting the temperature of the ink in the recording head;
A head recovery means for performing a recovery operation for discharging ink from the recording head, and a method for controlling an ink jet recording apparatus that performs a printing operation by discharging ink from the recording head,
After the recovery operation, a test print operation is performed in which a predetermined pattern is printed by changing the pressure of the ink, and the print operation is changed based on ink information obtained by the test print. .

Images