JP3992216B2 - Ink jet recording apparatus and recovery system cleaning method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ink jet recording apparatus that forms an image on a recording medium by ejecting ink from nozzles formed on a recording head.
[0002]
[Prior art]
As one type of output device such as a computer or a workstation, an ink jet type recording device that forms an image on a recording medium such as recording paper by discharging ink is known. The ink jet recording apparatus usually includes a recording head on which nozzles for ejecting ink are formed, a carriage that carries the recording head and reciprocates in a predetermined direction, and a direction orthogonal to the predetermined direction (recording medium conveyance direction). And a recording medium conveying device for conveying the recording medium.
[0003]
When forming an image on the recording paper, the recording paper being transported by the recording medium transport device is temporarily stopped, and the carriage is reciprocated in the predetermined direction, while the nozzle is based on the image signal including the image information. Ink is ejected, and an image for one band is formed on an image forming area on the recording paper facing the nozzle outlet (ink ejection port). Thereafter, the recording paper is transported by a width corresponding to one band, stopped, and again, the ink is ejected from the nozzles based on the image signal while reciprocating the carriage in the predetermined direction, thereby forming a new image forming area on the recording paper. 1 band image is formed. By repeating such an operation, the entire image is formed on the recording paper.
[0004]
In such an ink jet recording apparatus, since recording is performed by directly ejecting ink (recording liquid) from the recording head, it is necessary to maintain the recording head in a state in which ink can always be ejected. Various special operations that are not found in the device are required:
[0005]
"Suction"
Gas is mixed as bubbles in the supply path for supplying ink to the nozzles, which are the ink ejection holes, and in the ink reservoir (common liquid chamber) in the vicinity of the nozzles. When the bubbles become a certain size, the supply of ink to the nozzles is hindered. May not be discharged. As a countermeasure, suction is an operation of sucking and removing ink and bubbles up to the common liquid chamber by applying a negative pressure to the nozzle surface. Further, suction is also performed to remove ink accumulated in the cap by preliminary ejection in a state in which the cap described later is removed from the head. (The suction described in the present invention is the latter suction.)
[0006]
"Wiping"
Ink may not be ejected normally due to an object (paper dust, ink, etc.) adhering to the surface (face surface) on which the nozzle is placed, which hinders ink ejection. In order to remove this, flexibility such as rubber The operation of wiping the face surface with the blade member is wiping. A means for performing wiping is called a wiper.
[0007]
"Preliminary discharge"
During image formation, not all of the nozzles eject ink. Therefore, for the nozzles that are not ejected, the drying of the ink proceeds and it may become impossible to eject. In order to improve the image defect, preliminary ejection is an operation for ejecting ink to a portion other than the recording paper every predetermined time and preventing the ink from drying. Also called “preliminary discharge”.
[0008]
"Capping"
Capping is the operation of covering the face surface with a cap to prevent the ink in the nozzles from drying during the non-printing time. In order to prevent drying, the cap contains an absorbent body soaked with suction ink to some extent.
[0009]
[Problems to be solved by the invention]
By the way, the preliminary ejection during printing is generally executed little by little by time management, so that a small amount of ink is accumulated in the cap for a relatively long time. Even if the operation of sucking the accumulated ink is performed, if there is not a sufficient ink layer inside the absorber in the cap, the air is sucked, so that the ink remains in the cap. For this reason, the ink in the cap and the suction pump thickens and adheres to the ink flow path leading to the cap, the suction pump, and the waste ink tank.
[0010]
Also, the ink fixed to the suction pump or ink flow path is re-dissolved to some extent by the suction operation and discharged into the waste ink tank, but eventually the ink flow path may be blocked or the pump may be damaged. There is a risk that the ink discharged into the cap overflows. This problem is particularly noticeable because pigment inks and the like often have improved water resistance and are difficult to redissolve.
[0011]
The present invention has been made in this background, and an object thereof is to prevent ink sticking in a recovery system and to make it possible to satisfactorily perform a suction operation and a preliminary discharge operation, and a recovery system thereof. It is to provide a cleaning method.
[0012]
[Means for Solving the Problems]
A recovery system cleaning method of the present invention is a recovery system cleaning method for an ink jet recording apparatus that records ink on a recording paper by discharging ink droplets from nozzles of a recording head, and the amount of discharged ink performs a suction operation at a predetermined time. A pre-ejection operation is performed on the cap until a predetermined amount to be executed, and then an ink suction operation in the cap is performed.
[0013]
According to another aspect, the recovery system cleaning method of the present invention is a recovery system cleaning method for an ink jet recording apparatus that records on recording paper by discharging ink droplets from nozzles of a recording head,
[0014]
At a predetermined time, a preliminary ejection operation is performed with a second ink ejection amount that is greater than the first ink ejection amount during the preliminary ejection operation for preventing the nozzle from drying, and then the ink suction operation within the cap is performed. It is characterized by doing.
[0015]
The predetermined time is, for example, before printing by the recording head is completed and the recording head is sealed with a cap.
[0016]
During the preliminary ejection operation at the predetermined time point, for example, the preliminary ejection operation is performed on the cap until the ink in the cap is almost full.
[0017]
The predetermined time point may be before printing by the recording head is started. In this case, the suction operation is preferably performed to the extent that ink remains in the ink flow path.
[0018]
According to still another aspect, the recovery system cleaning method of the present invention is a recovery system cleaning method for an ink jet recording apparatus that performs recording on recording paper by ejecting ink droplets from nozzles of the recording head. During printing, every time a predetermined time elapses, printing is temporarily interrupted and a preliminary ejection operation is performed. When the amount of ink in the cap that receives the preliminary ejection exceeds a predetermined amount, the ink suction operation in the cap is performed. It is characterized by performing.
[0019]
An ink jet recording apparatus according to the present invention includes a recording head that records ink on recording paper by ejecting ink droplets from nozzles, a cap for preventing drying of the nozzles, and the ink jet recording head when not printing. Preliminary ejection means that discharges ink droplets from the nozzles to eliminate printing defects, ink suction means that communicates with the cap, and the amount of ink ejected at a predetermined time becomes a predetermined amount for performing the suction operation And a controller that performs preliminary ejection on the cap until the ink is discharged, and then performs an ink suction operation in the cap.
[0020]
In this apparatus, for example, after the ink is preliminarily ejected until the cap is almost full before the start of printing and / or after the end of printing, the ink suction means performs an ink suction operation in the cap.
[0021]
According to such a method and apparatus of the present invention, a recovery system can be obtained by flowing a certain amount of ink through the ink flow path at least before printing and at the end of printing without significantly changing the configuration of the conventional recovery unit. The ink is prevented from sticking in each part. In addition, the ink flowed before printing re-dissolves the fixed ink in the ink flow path for the time during printing, and the fixed ink generated by long-term storage is eliminated by flowing the redissolved ink at the end of printing. As a result, good output can be guaranteed over a long period of time. As a result, it is possible to perform the suction operation and the preliminary discharge operation satisfactorily over a long period of time, and it is possible to maintain good image quality.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0023]
A plotter as an example of the ink jet recording apparatus of the present invention will be described with reference to FIG. FIG. 1 is a perspective view showing a schematic external configuration of a plotter.
[0024]
The plotter 10 includes a platen 14 on which the recording paper 12 conveyed in the direction of arrow A is placed. Two scanning rails (guide rails) 16 are spanned above the platen 14 in parallel to the platen 14. A carriage 20 that reciprocates in the directions of arrows B and C (direction orthogonal to the direction of arrow A) by a motor (not shown) and a belt 18 is attached to the scanning rail 16 via a slide bearing (not shown). Yes.
[0025]
On the carriage 20, four recording heads 22K (black), 22C (cyan), 22M (magenta), and 22Y (yellow) having ink discharge ports (nozzle outlets: not shown) for discharging ink are mounted. Yes. An image forming area having a bandwidth substantially corresponding to the nozzle row width is assumed on the recording paper 12 in front of the ink discharge port. Ink is ejected from the ink ejection port to this image forming area, whereby an image for one band is formed in this portion.
[0026]
At a position away from the image forming area at one end of the movable range of the carriage 20, ink is forcibly sucked from the nozzles, and the ink supply path and nozzles formed on the recording head 22 are cleaned to form a recording head. A recovery device 30 that restores the 22 ink discharge states to the initial discharge state is disposed. The recovery device 30 includes four rubber caps 32K, 32C, 32M, and 32Y that detachably cover the outlets of the nozzles of the four recording heads 22K, 22C, 22M, and 22Y. One end of a tube (not shown) is connected to each cap 32K, 32C, 32M, 32Y, and the other end of the tube is connected to a suction pump (not shown). The four caps 32K, 32C, 32M, and 32Y are fixed to the cap base 32.
[0027]
In forming an image on the recording paper 12 such as roll paper, the recording paper 12 is placed on the platen 14, and a conveyance roller 24 that exposes a part of the outer peripheral surface from the opening formed in the platen 14; The recording paper 12 is conveyed by rotating the conveying roller 24 by a motor (not shown) while the recording paper 12 is sandwiched by the pinch rollers 26 that press both ends of the recording paper 12 from above.
[0028]
On the other hand, the carriage 20 is reciprocated above the recording paper 12 in the directions of arrows B and C, and an image including image information transmitted from the head control unit 130 (see FIG. 3) to the recording heads 22K, 22C, 22M, and 22Y. Ink is ejected from the nozzles based on the signal, and an image is formed in an image forming area of one band of the recording paper 12. During the image forming operation, when it becomes necessary to suck ink from the nozzles in order to clean the nozzles, the carriage 20 is moved above the recovery device 30 to execute a predetermined recovery operation. When the image formation is completed, a cutter (not shown) mounted on the carriage 20 is ejected to a predetermined position, and the recording paper 12 is cut into a predetermined size.
[0029]
FIG. 2 is a schematic diagram of the cap 32K and the corresponding pump 34 for one ink (for example, black) of the recovery device 30 shown in FIG. One end of the ink flow path 33a is connected to the bottom surface of the cap 32K, and the pump 34 is connected to the other end. Further, one end of another ink flow path 33 b is connected to the bottom surface of the pump 34. The other end of the ink flow path 33b is led to a waste ink tank (not shown).
[0030]
FIG. 3 is a block diagram showing a schematic configuration of the control hardware of the inkjet plotter described above. The image data transferred from the host computer is temporarily held in the reception buffer 121 of the recording apparatus. Conversely, data for confirming whether or not the data has been correctly transferred and data indicating the operating state of the recording apparatus are transferred from the recording apparatus to the host computer. The data held in the reception buffer 121 is transferred to the memory unit 123 and temporarily stored under the management of the control unit 122 having a CPU or the like.
[0031]
The drive control unit 124 controls the drive of the carriage motor for moving the carriage, the conveyance motor for conveying the recording material, and the like according to a command from the control unit 122, and the drive unit 125 for recovery operations such as suction and wiping. Control the drive. The sensor control unit 126 sends a signal output from the sensor unit 127 including various sensors and switches (SW) for detecting environmental temperature, humidity, and the like to the CPU in the control unit 122.
[0032]
The head control unit 130 controls driving of the recording heads 22K, 22C, 22M, and 22Y according to a command from the image processing unit 221 of the control unit 122. In addition, temperature information indicating the state of each recording head is transmitted to the control unit 122.
[0033]
FIG. 4 is a flowchart of the printing operation of the inkjet plotter according to the first embodiment of the present invention. This process is executed individually for each recording head. This operation is started when image data is input. First, a preliminary ejection count for counting the number of preliminary ejections is started (S1). That is, the preliminary discharge count value Tt is set to zero. Next, the cap is separated from the head (S2), and preliminary ejection before printing on the cap is performed only for a predetermined T1 (S3). At this time, Tt is increased by T1. Next, a wiping operation before printing is performed (S4), and preliminary ejection after wiping is performed again for T2 (S5). At this time, Tt is increased by T2.
[0034]
After these operations are completed, the printing operation is started (S6). Therefore, time counting is started (S7), and the subsequent printing time is managed. Printing is continued (S9) until a predetermined printing time (for example, 10 seconds) elapses (S8, No). Every time a predetermined printing time elapses (S8, Yes), printing is stopped, the head is moved onto the cap, and preliminary ejection for a predetermined T3 times is performed in order to prevent the ink in the nozzles from drying. S11). At this time, Tt is increased by T3. Further, the time count is reset (S12). Next, when the pre-discharge count value (pre-discharge meter) exceeds a predetermined number (S13, Yes), suction by a suction pump is performed (S14). The predetermined number set in advance is, for example, a number at which the ink in the cap becomes almost full, and is 1500 in this case. After this suction, the ink in the cap becomes empty, so Tt is reset to 0 (S15). If Tt is less than or equal to the predetermined number in step S13, the process returns to step S7 to continue printing.
[0035]
When printing is completed (S10, Yes), the amount of the current preliminary discharge count Tt that is less than 1500 shots, that is, (1500-Tt) is calculated (S16). Thereafter, preliminary ejection is performed on the cap by this calculated amount (S17). Thereafter, ink is sucked with a pump to cause the cap and the ink flow path to flow with ink (S18). Thereafter, the head is capped (S19), and the operation of FIG. 4 ends.
[0036]
By configuring and operating in this way, each time a single image is formed, the remaining ink in the cap can be discharged neatly, so that thickened ink is not accumulated in the ink flow path and the suction pump, It can be kept clean.
[0037]
FIG. 5 is a flowchart of the printing operation of the ink jet plotter according to the second embodiment of the present invention. The configuration of the main body is as shown in FIGS. The operations in S21 to S40 in FIG. 5 are basically similar to S1 to S19 in FIG. 4, and only the differences will be described.
[0038]
In the process of FIG. 5, the pre-printing preliminary discharge (S23) performed after the cap is turned off before printing is quantitatively different from the process of FIG. That is, in the present embodiment, 1500 preliminary discharges are performed (S23). These 1500 shots are the maximum amount of ink that can be stored in the cap. Thereafter, the suction pump operation is executed (S24). The operation amount of the suction pump sucks the entire amount of ink in the cap, but a part (for example, almost half) of the sucked ink stays in each part of the recovery system such as the ink flow path and the suction pump. . In this way, by keeping non-thickening ink in each part of the recovery system that tends to thicken by drying, it is possible to prevent sticking due to ink drying and to deal with (for example, redissolve) thickened ink when left unattended. be able to. Further, when the printing is completed, these inks are flushed out from the respective parts of the recovery system, so that each part of the recovery system can be kept clean.
[0039]
The printing operations of the first and second embodiments described above may be executed at each printing operation and / or at a predetermined timing. The predetermined timing includes, for example, every predetermined number of output sheets, every predetermined time, at the time of head replacement, and at the time of ink tank replacement.
[0040]
【The invention's effect】
As described above, in the ink jet recording apparatus according to the present invention, after the printing is finished, the ink without thickening is discharged to the preliminary discharge during the printing by flowing the ink through the recovery system such as the ink flow path and the suction pump. Ink can flow cleanly. Alternatively, the ink having no viscosity is distributed to each part of the ink flow path and the suction pump recovery system before the start of printing, whereby the thickened ink can be dissolved again and discharged at the end of printing. As a result, the ink does not stick to each part of the recovery system, the life of the recovery part can be extended, and a good image can be obtained. The present invention is particularly suitable when applied to an ink jet recording apparatus employing a pigment ink.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a schematic external configuration of an inkjet plotter according to an embodiment of the present invention.
FIG. 2 is a schematic diagram of a cap and corresponding pump for one ink of the recovery device shown in FIG. 1;
FIG. 3 is a block diagram showing a schematic configuration of control hardware of the inkjet plotter shown in FIG. 1;
FIG. 4 is a flowchart of a printing operation of the ink jet plotter according to the first embodiment of the present invention.
FIG. 5 is a flowchart of a printing operation of an ink jet plotter according to a second embodiment of the present invention.
[Explanation of symbols]
10 Plotter 20 Carriage 22K, 22C, 22M, 22Y Recording head 30 Recovery device 32 Cap base 32K, 32C, 32M, 32Y Cap

Claims (8)

A recovery system cleaning method for an ink jet recording apparatus that records on recording paper by discharging ink droplets from nozzles of a recording head,
Preliminary ejection is performed at least before the start of printing, the ink preliminarily ejected from the nozzles of the recording head is counted in the cap that stores waste ink, and when the counted value reaches a predetermined count value, Execute the suction operation of the ink ejected to reset the count value,
After completion of printing, when performing the suction operation of the ink ejected into the cap is ejected difference of the ink to a predetermined count value which defines said counted count value previously continuously in the cap, then the A recovery system cleaning method, wherein the ink suction operation in the cap is executed.   The recovery system cleaning method according to claim 1, wherein the suction operation is performed before printing by the recording head is completed and the recording head is sealed with a cap.   The recovery system cleaning method according to claim 1, wherein the predetermined count value corresponds to an amount at which the cap is almost full.   The preliminary ejection is also performed during printing, and the preliminary ejection during printing is performed by temporarily interrupting printing every time a predetermined time elapses, and the counted value counted is the predetermined predetermined count value. The recovery system cleaning method according to claim 1, wherein when the pressure reaches the value, a suction operation of the ink discharged into the cap is executed to reset the count value. A recovery system cleaning method for an ink jet recording apparatus that records on recording paper by discharging ink droplets from nozzles of a recording head,
A recovery system cleaning method, wherein the suction operation for sucking waste ink from the cap is performed to the extent that ink is discharged from the cap but ink remains in the ink flow path before printing is started.   6. The recovery system cleaning method according to claim 5, wherein the suction operation for sucking the waste ink from the cap is performed until the ink is discharged from the ink flow path downstream from the cap after the end of printing. A recording head that records ink on recording paper by ejecting ink droplets from nozzles;
A cap for preventing drying of the nozzle;
Preliminary ejection means for discharging the ink droplets from the nozzles so that the ink jet recording head is opposed to the cap at the time of non-printing to eliminate printing defects;
Ink suction means for communicating with the cap and sucking ink in the cap;
Counting means for counting ink ejected from the nozzle to the cap;
Preliminary ejection is performed at least before the start of printing, the ink preliminarily ejected from the nozzles of the recording head is counted in the cap that stores waste ink, and when the counted value reaches a predetermined count value, When the suction operation of the ink discharged into the cap is executed after the printing is completed , the count value is reset before the suction operation. And a control means for continuously ejecting ink of a difference between a predetermined count value and a predetermined count value to the cap, and then performing an ink suction operation in the cap;
An ink jet recording apparatus comprising:   The predetermined predetermined count value corresponds to an amount that the cap is almost full, and after printing is completed, a preliminary ink ejection operation is performed until the cap is almost full, and then the ink suction means performs the inside of the cap. 8. The ink jet recording apparatus according to claim 7, wherein the ink suction operation is performed.

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