JP2006334882A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a waiting time generated by performing individual suction when a plurality of heads are sucked in. <P>SOLUTION: In this recording apparatus with a constitution wherein a plurality of caps are provided for the plurality of heads and which can individually or concurrently suck in the plurality of heads, the heads are concurrently sucked in, including the heads, the timers of which have not been put into a timeout state yet, among the relevant heads, when it is supposed that suction timers of the plurality of heads are put into a timeout state in which the times of the suction timers are close to one another. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus and a cleaning method thereof.

  In an ink jet recording apparatus, it is known that ejection failure occurs due to evaporation of components in the ink when left for a long period of time. In order to eliminate such a defect, attempts have been made to eliminate it by a method such as suction using a pump or wiping preliminary discharge. Among them, suction using a pump is an effective means for eliminating discharge defects, and is used particularly after a long pause. It may also be used to remove residual bubbles that have been ejected during the ejection operation referred to as dot count and have not disappeared.

  As for a cleaning method using a pump, a so-called timer cleaning method that recovers with the passage of time is disclosed in Japanese Patent Laid-Open No. 10-119311. Japanese Patent Application Laid-Open No. 10-006531 and Japanese Patent Application Laid-Open No. 06-198886 are disclosed as means for combining temperature detection with a timer. Japanese Patent Laid-Open No. 2001-232820 discloses an example of a configuration in which the number of times the power is turned on in software is measured and recovery is performed based on the number. A configuration in which cleaning is performed by these methods to prevent defective printing is generally used. A recording apparatus usually uses a plurality of heads for colorization.

  At present, a general recording apparatus generally has a plurality of heads such as 4 heads and 6 heads. When performing recovery operations for maintenance of these heads, a method of recovering all the heads with a single recovery means, a method of recovering each head individually with recovery means, and multiple heads As one unit, there is a method of having recovery means for each unit and performing recovery in each unit. When all the heads are recovered by a single recovery means, it is not necessary to have a timer for controlling the recovery means for each head, and a single timer is sufficient. On the other hand, when there are a plurality of recovery means and the recovery means recovers one or more heads, it is necessary to have a timer for each head or recovery means. Each timer operates individually and is reset when the head in charge of each recovery means recovers. For example, when a counter that counts dots of a specific head counts up and recovery is performed, the counter is reset and the timer is reset at the same time. At this time, other heads are recovered at the same time, and if the recovery means or head timer is reset, there will be no difference between the timers, but the other heads are recovered by counting up one head in this way. This is a waste of ink, and generally the recovery operation of the other heads is not performed at the same time, so that the timer is deviated. In this way, the next suction operation is performed with the individual timers deviated. On the other hand, in the conventional method, suction is performed individually for each head counted up.

As another conventional example, Patent Documents 5 to 9 can be cited.
Japanese Patent Laid-Open No. 10-119311 Japanese Patent Laid-Open No. 10-006531 Japanese Patent Laid-Open No. 06-198886 JP 2001-232820 A JP-A-7-68797 JP 2002-137417 A JP 2002-200775 A JP 2002-205416 A JP 2002-205417 A

  As described above, when recovery is performed with a timer for controlling the recovery system for each head or recovery means, recovery for each head or recovery system is performed individually, as described above. Depending on the state, there may occur a case where the timer of another head or the recovery means is timed up immediately after the suction by the timer of one head or the recovery means and the suction is performed again.

  In order to avoid such a problem, when the timer of one head or recovery means expires, the timers of other heads or recovery means are referred to at the same time, and if the difference is small, these are recovered simultaneously.

  By using the embodiment of the present invention, the time loss due to the sequential execution of a plurality of recovery operations is minimized, and further, the recovery operation is excessively performed by determining whether the difference between the timers is equal to or less than a specified value. It is possible to prevent personality. Further, it is possible to extend the life of the recovery means by reducing the extra load of recovery that occurs by performing the recovery operation a plurality of times.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  FIG. 10 shows the appearance of the printer used in the present invention. The recording apparatus used here is a so-called serial scan type recording apparatus, and forms an operation image by scanning the recording head in a direction (main operation direction) perpendicular to the feeding direction of the recording medium. First, an outline of the operation during printing will be described. First, a recording medium is conveyed by a paper feed roller 6 driven by a paper feed motor 5 through a gear. The carriage motor 3 is scanned in the direction orthogonal to the paper feed by the carriage motor 3 to print a fixed bandwidth, feed the paper, and print according to the next bandwidth. However, in the case of such serial scan printing, paper feed in one scan may not be performed if necessary, and paper feed may be performed after performing a plurality of scan prints. There has also been realized a method of printing the drawn data, feeding the paper around 1 / n band, and printing again to complete an image by a plurality of printing scans and paper feeding. In this embodiment, the carriage belt 4 is used to transmit the driving force from the carriage motor 3 to the carriage unit 2, but other driving methods such as a lead screw may be used instead of the carriage belt. The fed recording medium is guided between the paper feeding roller 6 and the pressure roller to the printing portion. At the time of printing, since the cap is applied to the recording head in the normal resting state, the cap is first opened and the carriage is set in a scan movable state so that scanning can be performed in the main operation direction in the case of a serial printer. Thereafter, when data for one scan is accumulated in the buffer, the carriage unit 2 is scanned by the carriage motor 3 to perform printing.

  As the water-soluble organic solvent used in the ink of the present invention, any water-soluble organic solvent that has been used in conventionally known inks can be used. Specifically, alkyl having 1 to 5 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, and n-pentanol. Alcohols; Amides such as dimethylformamide and dimethylacetamide; Ketones or ketoalcohols such as acetone and diacetone alcohol; Ethers such as tetrahydrofuran and dioxane; Diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene Oxyethylene or oxypropylene addition polymers such as glycol, polyethylene glycol, polypropylene glycol; ethylene glycol, propylene group Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, such as coal, trimethylene glycol, butylene glycol, 1,2,6-hexanetriol, hexylene glycol; thiodiglycol; glycerin; ethylene glycol monomethyl (or Lower alkyl ethers of polyhydric alcohols such as ethyl) ether, diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monomethyl (or ethyl) ether; triethylene glycol dimethyl (or ethyl) ether, tetraethylene glycol dimethyl (or ethyl) Lower dialkyl ethers of polyhydric alcohols such as ether; sulfolane, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like. The content of the water-soluble organic solvent as described above is generally in the range of 1 to 49%, preferably 2 to 30% by weight with respect to the total weight of the ink. The water-soluble organic solvents as described above can be used alone or as a mixture, but the most preferable liquid-medium composition in the case of having a medium is at least one water-soluble high-boiling organic solvent such as diethylene glycol, triethylene. It contains a polyhydric alcohol such as glycol or glycerin.

  FIG. 11 shows the data flow of the printer used in this embodiment. In FIG. 11, reference numeral 101 denotes a programmable peripheral interface (hereinafter referred to as PPI), which receives a command signal (command) and a recording information signal sent from a host computer (not shown) and transfers them to the MPU 102, as well as the console 106. And a signal from the home position sensor 107 for detecting that the carriage is at the home position. An MPU (microprocessing unit) 102 controls each part in the ink jet printer apparatus according to a control program stored in the control ROM 105. Reference numeral 103 denotes a RAM that stores received signals or is used as a work area for the MPU 102 and temporarily stores various data. A font generation ROM 104 stores pattern information such as characters and records corresponding to the code information, and outputs various pattern information corresponding to the input code information. Reference numeral 130 or 121 denotes a print buffer for storing data expanded by the ROM 104 or the like, and has a capacity of m rows. Reference numeral 105 denotes a control ROM in which processing procedures executed by the MPU 2 are stored. Each of these units is controlled by the MPU 102 via an address bus 117 and a data bus 118, respectively.

  Reference numeral 108 denotes a carriage motor that reciprocally scans the carriage on which the recording head 112 is mounted. Reference numeral 110 denotes a paper feed motor for transporting a recording material such as paper in a direction perpendicular to the moving direction of the carriage, and 113 denotes an ink discharge port (not shown) of a recording head 112 described later by driving a cap member. ), And a purge motor for operating the wiper to wipe off the ink on the head face by operating the wiper to block the ink discharge port from the outside air and prevent the nozzle from drying. 115 is a motor driver for driving the carriage motor 108, 116 is a motor driver for driving the paper feed motor 110, and 114 is a motor driver for driving the capping motor 113. The console 116 is provided with a keyboard switch and a display lamp. The home position sensor 107 is provided in the vicinity of the home position of the carriage, and detects that the carriage on which the recording head 112 is mounted has reached the home position. A sheet sensor 109 detects the presence or absence of a recording material such as recording paper, that is, whether or not the recording material is supplied to the recording unit. Reference numeral 112 denotes an ink jet recording head that discharges ink droplets by causing a change in state due to film boiling in ink using thermal energy. The recording head 112 has m (for example, 64) discharge ports (not shown). ), M discharge heaters (not shown) corresponding to each discharge port are provided. Reference numeral 111 denotes a driver for driving the discharge heater of the recording head 112 in accordance with the recording information signal. A power supply unit 124 supplies power to each of the above units, and includes an AC adapter and a battery as a drive power supply device.

  In the above configuration, the MPU 2 is connected to a host device such as a computer via the PPI 101, and processing procedures for commands and recording information signals sent from the host device and programs stored in the control ROM 106. The recording operation is controlled based on the recording information stored in the RAM 106.

  In a normal recording apparatus conventionally used in the field in which the present invention is used, when printing data is transmitted from the host 100 that transmits recording data via a parallel port, an infrared port, a network, or the like, The type of media that is recorded at the beginning of the media (types of media such as plain paper, OHP, and glossy paper, and special media such as transfer film, cardboard, and banner paper), media size (A4, A4 letter, A3, etc.) B4, B5, or envelopes, postcards), print quality (draft, high quality, medium quality, specific color emphasis, monochrome / color type, etc.), paper feed cassette (ASF, manual feed, bin 1, bin 2, etc.), A memo that is usually called a ROM is sent by sending a command describing whether or not an object is automatically identified and accepting that command on the main unit. Determining the ejection amount, the printing direction of the ink per print pass number and unit area at the time of multi-pass printing performs recording on the basis of the housing have been various data to over area (memory 1 122). In some cases, information such as whether or not to apply the treatment liquid is transmitted as a command. According to these pieces of information, the recording device reads the data necessary for recording from the ROM described above, and performs recording according to those data. In addition to the above, the data read from these ROMs is used for recording each pass. There are mask types used for recording, recording head drive conditions (for example, applied pulse shape and application time), droplet size, paper feed conditions, carriage speed, and the like.

  The ink tank used in this embodiment is molded by injection, blow, or the like using a resin such as PP or PE, and is assembled using techniques such as ultrasonic welding, thermal welding, adhesion, and fitting. Inside the tank, there is a type in which the exterior functions as an ink chamber as it is, a type having a bag filled with ink inside, a type in which a porous material is inserted inside to hold ink and simultaneously generate negative pressure, etc. . Further, when the tank is provided with a negative pressure mechanism, negative pressure may be generated by supporting the bag portion inside the tank in the expansion direction by a spring mechanism or the like provided inside or outside the bag.

  2 and 3 are external views of the head used in this embodiment, FIG. 4 is a sectional view of the head used in this embodiment, and FIG. 5 is an external view of the wiper. 4 is a cross-sectional view taken along planes A-A ′ and B-B ′ of the head shown in FIGS. 2 and 3. The width of the nozzle wiper 20 shown in FIG. 5- (2) is the same, but Bk. The width of the nozzle wiper 20 is made narrower than the width F of the chip in FIG. 4 and is smaller than the chip width of the corresponding head. This is because the chip of each color is slightly recessed from the TAB surface as shown in FIG. 4 in order to avoid contact of the head with the print medium, and the wiper enters the recessed surface to be wiped away. It is. The wiper shown in FIG. 5 is attached to a wiper holder 27 (not shown) using a wiper fixing bracket (not shown). The wiper is aligned with holes formed in the wipers 20, 21, and 22 and the wiper holder. This is done by fitting with the pin. The wipers 20, 21, 22 are driven by the purge motor 113 in the direction W shown in FIGS. 2, 3, and 5, and wipe the orifice and the TAB surface. When the wiping operation is completed, the carriage is retracted outside the wiping area, and the wiper is driven in the reverse direction to return to the position where wiping is started.

  In the head of FIG. In the chip, 640 nozzles are arranged at a density of about 245 nozzles per cm, and in the color chip, 1280 nozzles are arranged at a density of about 490 nozzles per cm for each color. In the head of FIG. 3, 1280 nozzles are arranged at a density of about 490 nozzles per cm for each color in all the chips. In FIG. 4, the ink advances and is supplied in the direction D from the supply port 23 and is guided to the ink liquid chamber 24 on the filter in the head. After that, the process proceeds in the direction of arrow E in the figure, and after dust and the like mixed by the filter 25 are filtered, it is guided to the ink liquid chamber 26 below the filter and guided to the nozzle for discharging the ink formed on the lower surface of the orifice plate. It is burned. 6 and 7 are enlarged views of the nozzle portion of the head shown in FIGS. 2 and 3 used in the present invention. The ink liquid chamber is formed by a heater board on which an orifice plate 31, a liquid chamber forming member 34, and a heater are mounted. The ink stored in this portion generates bubbles by the heating of the heater 33 and is pushed out of the orifice plate as the bubbles expand, and becomes spherical droplets by the interfacial tension with the air and flies toward the recording member.

The recording apparatus of the present invention is configured on the assumption of a so-called A4 size recording material. When the total number of dots at the time of printing is full on an A4 recording medium, the color is 1.26. The number of print dots of × 10 ⁸ dots is the maximum value. Similarly, Bk. The head has the maximum number of printable dots of 3.17 × 10 ⁷ dots. Regarding the dot count at the time of wiping, the number of dots counted by the dot counter in the recording apparatus is stored in the main body (memory 122, etc.), and it is determined whether or not a predetermined value has been reached after printing is completed. ing. In this embodiment, the determination of whether or not wiping is performed is configured to be performed at the end of each page. However, in the case of a plotter or large format printer having a large print area, it is configured to determine whether or not to perform wiping after each print scan. Is also possible. In addition, the ink mist adhering to the face surface as well as the dot count may fluctuate depending on the print duty.Therefore, the number of dots may be increased or decreased by adding a coefficient calculated based on the duty to the number of dots. Is possible.

  A normal printing sequence is shown in FIG. 8, and a sequence at the end of printing is shown in FIG. When printing is instructed in FIG. 8, a recovery S22 sequence before printing (details of FIG. 1 will be described later) is performed in Step 21 (hereinafter, Step ○ is referred to as S) as in S13, and other steps following S22 in FIG. Printing is performed. First, in order to obtain a printable state, it is confirmed whether or not the cap is put on by a sensor signal. If the cap is put on, the cap is opened (S32). Thereafter, paper feeding is performed (S23). If data for one scan is stored in the print buffer 121 (S24), preliminary ejection is performed (S25) and printing is performed (S26). If no print data is available, the process waits until the data is in the print buffer 121 (S27). If the print data is not complete, the process waits for a predetermined time (Tcap) in S28, and if the data is still not complete, the cap is performed (S33) and waits for further data to be prepared. However, if the preset time Tpreinj. Is exceeded within a certain time in the cap open state, preliminary ejection is performed at each set time to prevent ejection failure (S34). If the print data for one scan is complete during the print weight and printing is possible, preliminary ejection is performed immediately before printing (S34) and the printing operation is performed (S26). In this embodiment, preliminary ejection is performed every time before scanning, but it is also possible to select whether or not to perform preliminary ejection by a timer immediately before printing. After printing is completed, it is confirmed whether or not there is a paper discharge command (S30). When a paper discharge command is received, paper discharge is performed, and the printing operation ends.

  One form of this embodiment is shown in FIG. A set of a plurality of individual printing chips is referred to as A side and B side for convenience. Each unit is as shown in FIG. 2 and FIG. When an activation command such as soft-on or printing is issued in S1, the current time is acquired in S2, and the times (S3, S4) Ta and Tb at the time of the previous cleaning on the A side and B side are subsequently acquired. In S5 and S6, elapsed times Tna and Tnb from the previous cleaning on the A side and B side are calculated. Based on the result, in step S7, the A side Tna is first compared with the threshold value Tla for executing the cleaning. If the threshold value Tla is exceeded, the process proceeds to step S8 to determine the B side head. The threshold value Tlb is compared, and if Tnb exceeds Tlb, the process proceeds to the simultaneous cleaning in S10. On the other hand, if Tnb does not exceed Tlb, it is determined whether or not the difference between Ta and Tb is equal to or less than the specified value Tc as in this embodiment. If the difference is equal to or less than Tc, the process proceeds to S10, and simultaneous suction is performed. In S13, both timers are reset and the process ends. If Tna does not exceed Tla in S7, the process proceeds to S8 'and Tnb and Tlb are compared as in S8. If Tnb does not exceed Tlb, the recovery operation is not performed and the process ends. If Tnb exceeds Tlb, the difference between Tb and Ta is obtained in S9, and if it is less than the prescribed value Tc, simultaneous cleaning is performed in S10. In summary, the determination of each timer time difference (difference between Ta and Tb) is performed on either the A side or the B side (multiples possible) and the other (multiples possible) does not reach the timer. This is a case of (NO in S7, 8 in the figure). If both times up, the simultaneous suction sequence is executed and the process ends. Even if only one of them is timed up and the other is not timed up, if the difference between Ta and Tb is larger than Tc, it moves to the individual recovery sequence in the figure as in the normal suction operation, and either time Only the head that is up (S11 + S14 execution or S12 + S15 execution) performs the recovery operation. Note that the time used above may be based on a generally used absolute standard time, or may be a relative time based on an internal RTC.

  12 is the same as the embodiment of the present invention in FIG. 1 until the calculation of the cleaning interval in S6, which shows an example of a recovery sequence before printing that has been conventionally used. Thereafter, determination is made for each A side and B side, and when both have timed up, the A side and B side simultaneous cleaning in S10 is performed, and both timers are reset. When either the A side or the B side has timed up, unlike the case of the embodiment, no particular determination is performed, and the recovery operation is performed only for the head that has timed up.

Determination sequence described in the embodiment External view of the head used in the examples External view of the head used in the examples Sectional view of the head used in the examples Example of wiper configuration used in the examples Nozzle enlarged view Orifice enlarged view Print sequence Recovery sequence after printing External view of the recording apparatus used in Example 1 Data flow diagram of the recording apparatus used in Example 1 Conventional cleaning judgment sequence

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Purge unit 2 Carriage unit 3 Carriage motor 4 Carriage belt 5 Paper feed motor 6 Paper feed roller 7 Pressure roller 8 Eject roller 9 Recording head 10 Shaft 11 Black orifice plate 12 Cyan orifice plate 13 Magenta orifice plate 14 Yellow orifice plate 15 Light Cyan Orifice plate 16 Light Magenta Orifice plate 19 Supply port 20 Nozzle wiper for 1 chip 21 Nozzle wiper for 3 chip 22 Full surface wiper 23 Ink supply port 24 Ink liquid chamber on filter 25 Filter 26 Ink liquid chamber on filter 27 Wiper holder 28 Wiper Fixing bracket 29 Spacer 30 TAB surface 31 Orifice Rate 32 nozzle 33 heater 34 liquid chamber forming material 100 host 101 PPI
102 CPU
103 RAM
104 ROM for print data
106 Console 107 Home position sensor 108 Carriage motor 109 Sheet sensor 110 Conveyance motor 111 Head driver 112 Recording head 113 Purge motor 114-6 Motor driver 117 Address bus 118 Data bus 120 Power supply unit 121 Print buffer 122 Memory 1
123 Memory 2
124 Gate array 130 Print buffer 150 Data processing part 201 Main tank 202 Sub tank 203 Buffer chamber 204 Atmospheric side pin 205 Supply side pin 206 Tank rubber 207 Supply side tube 208 Supply joint 209 Conductive line 201 Memory

Claims (1)

  In an inkjet recording apparatus having a plurality of heads and a plurality of recovery means corresponding thereto, timers for measuring time for each of the plurality of heads, determination means for determining whether or not recovery is necessary based on a predetermined criterion for each of the plurality of heads, There is a means to determine whether or not the adjacent heads are sucked at the same time depending on whether or not the timers are close to each other. An ink jet recording apparatus characterized by being performed.

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