JP5328615B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus that prevents ink ejection failure.

  An ink jet recording apparatus records an image on a recording medium such as paper by ejecting ink droplets from a plurality of ejection ports of a recording head using an electrothermal transducer or an electromechanical transducer.

  When ink droplets are ejected from the recording head, droplets (mist) smaller than the main droplets are simultaneously ejected in addition to the main droplets. When this mist adheres to the recording head, it affects the subsequent ejection, causing non-ejection, color mixing, and the like, which may reduce the image quality. Therefore, conventionally, wiping to wipe the recording head at an appropriate timing, or preliminary ejection for ejecting ink that is not involved in the recording process from the recording head is performed, thereby preventing deterioration in image quality (for example, Patent Documents). 1).

JP 07-195708 A

  By the way, in recent years, there has been a growing demand for image robustness of printed matter as a use for posting a photograph-quality printed matter indoors or for a sign or display market. Therefore, an ink jet recording apparatus using a pigment ink that is superior in image fastness as compared with a dye ink has been developed. However, in terms of color reproduction range and saturation, it has not yet reached a level that can provide high image quality comparable to silver salt photography, plate-making printing, and the like.

  Therefore, it is conceivable to increase the saturation by increasing the pigment concentration of each ink. However, if this is done, the ink viscosity increases, and ink thickening is likely to occur due to long-term storage or temperature rise of the recording head accompanying ejection.

  In particular, when the mist adhering to the periphery of the ejection port is thickened / fixed, not only will the subsequent ejection be affected, but the ink will also be thickened / fixed to the wiping member. Therefore, the cause of ejection failure of the recording head cannot be removed by wiping, and it is difficult to maintain a good ink ejection state.

  Accordingly, the present invention has been made in view of such circumstances, and an object thereof is to provide an ink jet recording apparatus capable of preventing ink discharge failure as much as possible.

According to one aspect of the invention,
A recording head having a plurality of ejection openings for ejecting ink;
Wiping means for wiping the ejection surface provided with the plurality of ejection ports of the recording head;
When wiping is performed immediately after the preliminary ejection operation for recovering the ejection state of the recording head, more ink mist adheres to the ejection surface than when wiping is not performed immediately after the preliminary ejection operation. Thus, there is provided an ink jet recording apparatus comprising control means for controlling a preliminary ejection operation from the recording head .

  According to this, since a relatively large amount of ink mist adheres to the ejection surface at the time of preliminary ejection immediately before wiping, the ink fixed on the ejection surface can be redissolved by the ink mist. Since the re-dissolved ink has increased fluidity, if wiping is executed in that state, the fixed ink as a cause of ejection failure can be effectively removed from the ejection surface.

  On the other hand, when the preliminary ejection is performed other than immediately before wiping (for example, when preliminary ejection is performed immediately after wiping), the amount of ink mist adhering to the ejection surface is relatively reduced. Accordingly, it is possible to reduce the amount of ink mist adhering to the periphery of the ejection port due to the temperature rise of the recording head during recording, and to reduce the cause of ejection failure on the ejection surface. In this way, ink ejection defects can be prevented as much as possible.

  According to another aspect of the invention,
  A recording head having a plurality of ejection openings for ejecting ink;
  Wiping means for wiping the ejection surface provided with the plurality of ejection ports of the recording head;
  When wiping is performed immediately after the preliminary ejection operation for recovering the ejection state of the recording head, the recording head is driven at a higher frequency than when wiping is not performed immediately after the preliminary ejection operation. There is provided an ink jet recording apparatus comprising: a control unit that controls a preliminary discharge operation from the recording head.

  Preferably, the ink ejected from the recording head is a pigment ink. The pigment ink adhering to the ejection surface is dissolved by adhering ink mist. When the recording head performs a preliminary ejection operation, a cap member is provided at a position facing the ejection surface. The cap member is used for receiving pre-discharged ink.

Preferably, when wiping is performed immediately after the preliminary ejection operation for recovering the ejection state of the recording head, the cap member and the ejection surface are compared with a case where wiping is not performed immediately after the preliminary ejection operation. Is far away. This also causes a relatively large amount of ink mist to adhere to the ejection surface during preliminary ejection immediately before wiping, so that the ink fixed on the ejection surface is re-dissolved with ink mist, and subsequent wiping effectively eliminates the cause of ejection failure. Can be removed. On the other hand, when the preliminary ejection is executed except immediately before wiping, the amount of ink mist adhering to the ejection surface is relatively reduced, so that the amount of ink mist adhering to the periphery of the ejection port can be reduced. In this way, ink ejection defects can be prevented as much as possible.

  Preferably, the cap member at a position where the pre-discharged ink lands is provided with an absorber. The absorber is provided with a porous material.

  According to the present invention, an excellent effect that ink discharge failure can be prevented as much as possible is exhibited.

1 is a perspective view of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an ejection surface of a recording head. It is the schematic of a wiping apparatus and a cap. It is a block diagram which shows the structure of the control system of an inkjet recording device. It is a figure which shows the mode of an ink droplet division | segmentation. It is a general | schematic fragmentary sectional view which shows the state at the time of preliminary discharge execution, (a) is a case of a high frequency, (b) is a case of a low frequency. It is a flowchart for demonstrating preliminary discharge operation | movement. It is a graph which shows the result of an evaluation test. It is a general | schematic fragmentary sectional view which shows the state at the time of the preliminary discharge execution in another Example.

  Embodiments of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 is a perspective view of the ink jet recording apparatus according to the present embodiment, showing a state where a case cover is removed. The ink jet recording apparatus 1 includes a movable carriage 2 on which a recording head is mounted, a carriage motor M1 and a transmission mechanism 4 for reciprocating the carriage 2 in the scanning direction x. Further, a paper feed mechanism 5 for supplying a recording medium P such as paper and a recovery device (recovery means) 10 for performing recovery processing of the recording head are provided.

  Although the recording head does not appear in FIG. 1, it is integrally provided on the bottom surface of the carriage 2. A plurality of ink tanks (also referred to as ink cartridges) 6 are detachably mounted on the carriage 2. Ink in the ink cartridge 6 is supplied to the recording head. Below the recording head, the recording medium P is transported in the sub-scanning direction y with the platen placed on the platen. The recording medium P is transported by a transport motor (not shown) and a transport roller 7. The scanning direction x and the sub scanning direction y are perpendicular to each other.

  The recording head records an image on the recording medium P by ejecting ink based on the image signal. In synchronization with at least one movement of the carriage 2 on the forward path side (+ x side) and the backward path side (−x side), a drive signal based on the image signal is given to the recording head, whereby an image for one band is recorded on the recording medium. Record it. When the recording for one band is completed, the recording medium is conveyed by the width of one band and stopped. The carriage 2 is moved again, and the next one band is recorded. By alternately repeating such a recording operation and a conveying operation, an image is formed on the recording medium. The recording medium P after recording is discharged from the apparatus main body by the transport roller 7.

  The recording head is for color recording, and the carriage 2 contains a plurality of types of inks, that is, four inks each containing black (K), cyan (C), magenta (M), and yellow (Y). An ink cartridge 6 is mounted. These four ink cartridges are independently removable and replaceable.

  The black ink uses a pigment ink that can improve the image quality but has a higher viscosity than a general dye ink and is easily fixed. For other color inks, dye ink is used.

  FIG. 2 shows a bottom surface portion of the recording head 3 provided on the bottom surface portion of the carriage 2. As shown in the figure, the recording head 3 is provided with a plurality of ejection ports (also referred to as nozzles) 31 for ejecting ink. These ejection ports 31 are aligned in a row along the sub-scanning direction y for each ink color, and form four nozzle rows 32. The surface where the outlets of the discharge ports 31 are opened is the discharge surface 33 of the recording head 3. During the recording operation, the ejection port 31 and the ejection surface 33 are positioned above the recording medium P and face the recording medium P downward.

  32Y is a yellow nozzle row composed of nozzles 31 for discharging yellow ink. Similarly, 32M is a magenta nozzle row, 32C is a cyan nozzle row, and 32K is a black nozzle row. In each nozzle row 32, the nozzles 31 are arranged at a density of D nozzles per inch, that is, Ddpi. The nozzle rows 32 are separated from each other in the scanning direction x, and are arranged in parallel to the sub-scanning direction y.

  Although not shown, each nozzle 31 communicates with the corresponding ink tank 6 via an ink path, and the vicinity of the nozzle 31 is always filled with ink by the supply of ink from the ink tank 6. The recording head 3 is provided with an electrothermal conversion element, that is, a heater for each nozzle 31. When a driving voltage or driving pulse is applied to the heater, bubbles are generated in the ink by the heat energy generated by the heater. Then, the ink generated in the nozzle 31 is pushed out by a predetermined amount by this bubble generation pressure, and ink is ejected. In the present embodiment, the recording head that ejects ink by such a bubble jet (registered trademark) system is used, but a recording head that ejects ink by another ejection method such as a piezo system may be used. Further, the recording head may be a separate housing for each ink color and each nozzle row.

  Returning to FIG. 1, the ink jet recording apparatus is provided with a recovery device (recovery means) 10 for recovering the ink ejection state of the recording head. The recovery device 10 includes a wiping device 12 (wiping means) for wiping (wiping) the ejection surface of the recording head. Further, the recovery device 10 includes preliminary ejection means for ejecting ink that is not involved in the recording process from the ejection port of the recording head (this is called preliminary ejection). Further, the recovery device 10 includes a cap 11 as a receiving means for receiving the pre-discharged ink. The wiping device 12 and the cap 11 are positioned below the home position of the carriage 2 where no recording operation is performed in the scanning direction x.

  FIG. 3 schematically shows the wiping device 12 and the cap 11. The wiping device 12 includes a wiping blade 41 made of rubber or the like, and a base member 42 that supports the wiping blade 41, and can reciprocate in the sub-scanning direction y. During the wiping operation, the wiping blade 41 reciprocates in the sub-scanning direction y, and wipes the ejection surface 33 of the recording head 3 stationary at the home position.

  The cap 11 can move close to and away from the ejection surface 33 of the recording head 3 that is stationary at the home position, and specifically can be raised and lowered. As shown in detail in FIG. 6, the cap 11 has a rectangular frame-shaped contact member 51 that can be in close contact with the ejection surface 33 outside the four nozzle rows 32, and a shallow dish shape in which the contact member 51 is attached to the upper end. The cap main body 52 and the absorber 53 accommodated in the cap main body 52 are provided. For example, the contact member 51 is made of an elastic body such as rubber, and the absorber 53 is made of a porous material such as sponge. The cap 11 is connected to a suction pump (not shown) that sucks the ink preliminarily ejected to the absorber 53 and guides it to a waste tank.

  FIG. 3A shows a state when the preliminary discharge is executed. At this time, the cap 11 is positioned at a predetermined interval directly below the ejection surface 33 of the recording head 3, and the ink droplet IK is preliminarily ejected to the absorber 53 of the cap 11. The cap 11 is in a position slightly raised from its home position. The wiping device 12 is stationary at the home position as shown in the figure, and is out of the space between the discharge surface 33 and the cap 11. By this preliminary discharge, it is possible to discharge and remove thickened ink, bubbles, and the like in each discharge port and ink path.

  FIG. 3B shows a state when wiping is executed. At this time, the cap 11 is returned to the lower home position, and the wiping device 12 is reciprocated a predetermined number of times in the sub-scanning direction y between the ejection surface 33 and the cap 11. During this reciprocation, the wiping blade 41 wipes and cleans the discharge surface 33. By this wiping, it is possible to wipe off ink, dust and the like adhering to the ejection surface 33.

  Note that there is also suction recovery as a recovery process executed by the recovery device 10. In this method, the suction pump is operated in a state where the cap 11 is in close contact with the ejection surface 33, and ink is forcibly sucked from the ejection port 31. This suction recovery can refresh the ink in each ejection port and prevent clogging of the ejection port. In this way, a recovery process for properly maintaining or recovering the ink ejection state of the recording head is appropriately executed.

  On the other hand, when the recording operation is not performed, the cap 11 is raised and is in close contact with the ejection surface 33. This protects the recording head and prevents ink from evaporating and drying from the ejection port 31.

  FIG. 4 shows the configuration of the control system of the ink jet recording apparatus. The CPU 500 executes control of each part of the apparatus and data processing via the main bus line 505. That is, the CPU 500 controls data processing, head driving, and carriage driving via the following units in accordance with a program stored in the ROM 501. The RAM 502 is used as a work area for data processing by the CPU 500. In addition to these memories, there are storage means such as a hard disk. The image input unit 503 has an interface with the host device, and temporarily holds an image input from the host device. The image signal processing unit 504 executes data processing such as color conversion and binarization.

  The operation unit 506 includes a key and the like, thereby enabling input by the operator. A recovery system control circuit 507 controls recovery operations such as preliminary ejection and wiping in accordance with a recovery processing program stored in the RAM 502. The recovery system motor 508 drives the wiping device 12, the cap 11, the suction pump 511, and the like during the recovery process. The head drive control circuit 515 individually controls the heater 513 for each ejection port of the recording head 3 to cause the recording head 3 to eject ink for normal recording and preliminary ejection. Further, the carriage drive control circuit 516 and the paper feed control circuit 517 similarly control carriage movement and paper feed, respectively, according to the program.

  The recording head 3 is provided with a heat retaining heater for keeping the ink temperature in the recording head 3 at a predetermined temperature, and a thermistor 512 for detecting the ink temperature in the recording head. The head temperature control circuit 514 controls the heat retaining heater based on the detection signal from the thermistor 512.

  Next, an example relating to the recovery processing of this embodiment will be described. In the recording head described below (see FIG. 2), the pitch between the nozzles 31 of each nozzle row 32 is about 42.4 μm, and the number of nozzles is 128. The length of each nozzle row 32 in the sub-scanning direction y is 5.42 mm. Further, regarding the positional relationship in the scanning direction x between the black nozzle row 32K and the yellow nozzle row 32Y, the black nozzle row 32K is upstream in the scanning direction (printing area side), and the yellow nozzle row 32Y is downstream in the scanning direction ( Home position side). The distance between the black nozzle row 32K and the yellow nozzle row 32Y is 3.0 mm, and the intervals between the yellow-magenta, magenta-cyan, and cyan-black nozzle rows in the scanning direction x are equally 1.0 mm.

  Usually, the ink droplets ejected from the ejection port 31 are not ejected as a single ink droplet, but are divided into a plurality of ink droplets after ejection. The largest ink droplet among multiple ink droplets is the main droplet, the smaller than the main droplet following the main droplet ejection direction is a satellite, and other finer ink droplets with a smaller ejection speed are mist or ink. Call it a mist. This phenomenon always occurs not only in the recording operation but also in the preliminary ejection operation.

  FIG. 5 shows how ink droplets are divided. Reference numeral 301 denotes ink, 302 denotes ink immediately after ejection, 303 denotes a meniscus, 304 denotes main droplets, 305 denotes satellites, and 306 denotes mist.

  In FIG. 5A, ink discharge from the nozzle 31 is started. Immediately after the start of ejection, the ink 302 is continuously ejected from the nozzle 31. Thereafter, in FIG. 5B, the meniscus 303 generated due to the contraction of the bubbles moves backward, and the ink 301 moves to the inside of the recording head. As the ink 301 moves, the ejected ink 302 is separated from the ink 301 inside the recording head, and a velocity distribution is generated in the ejected ink 302. In FIG. 5C, the ink having the velocity distribution is divided, and the main droplet 304 having the largest volume and velocity, the satellite 305 having a smaller volume and velocity than the main droplet 304, and the lower cap having the smaller volume and velocity reach the lower cap. Hard mist 306 is generated.

  In this embodiment, pigment ink is used as the black ink, and dye ink is used as the other color ink (cyan, magenta, yellow). Therefore, the black ink that has increased in viscosity due to being left for a long time or the temperature rise of the recording head tends to adhere to the periphery of the discharge port 31 for black ink or the wiping blade 41.

  Therefore, in this embodiment, when the preliminary discharge is performed immediately before wiping when executing the recovery process, more ink mist 306 adheres to the discharge surface 33 than when preliminary discharge is performed other than immediately before wiping. Then, the recording head 3 is driven. Here, “when preliminary ejection is performed other than immediately before wiping” means, for example, when preliminary ejection is performed immediately after wiping or when only preliminary ejection is performed without performing wiping. When both wiping and preliminary discharge are executed, the other is executed immediately after the end of one, and both are executed continuously.

  Specifically, when the preliminary ejection is performed immediately before wiping, the recording head 3 is driven at a higher frequency than when the preliminary ejection is performed other than just before wiping. In this embodiment, the recording head 3 is driven at a driving frequency of 10 kHz when preliminary ejection is performed immediately before wiping, and the recording head 3 is driven at a driving frequency of 5 kHz when preliminary ejection is performed other than immediately before wiping. Here, “driving the recording head” means applying a driving voltage or a driving pulse to all heaters corresponding to all nozzles of the recording head. The frequency or driving frequency means the number of driving voltages or driving pulses applied per second. If there is no ejection failure, the number of ink droplets equal to the frequency is ejected per second.

  FIG. 6A shows the state of the ink droplet IK when preliminary ejection is executed at a high frequency. In this case, the mist MS rises due to the airflow generated by the preliminary discharge. At that time, the airflows generated by ejection from the nozzle rows 32 collide with each other, the airflow in the upward direction (+ z direction) increases, and the amount of mist reaching the entire ejection surface 33 of the recording head increases. The reached mist adheres to the black ink fixed on the ejection surface 33 and re-dissolves the fixed black ink, thereby improving the fluidity of the fixed black ink. For this reason, wiping immediately after that facilitates wiping off the fixed black ink and facilitates removal of the cause of ejection failure. Further, the ink fixed to the wiping blade 41 can be re-dissolved at the time of wiping by the mist adhering to the ejection surface 33, and the viscosity increase / fixation of the ink on the wiping blade 41 can be suppressed. In this way, it is possible to prevent ink ejection defects as much as possible.

  On the other hand, FIG. 6B shows the state of the ink droplet IK when preliminary ejection is executed at a low frequency. In this case, although the mist MS rises due to the airflow generated by the preliminary discharge from each nozzle row 32, the ascending airflow is relatively weak and tends to fly horizontally along the upper surface of the absorber 53 of the cap 11. Accordingly, almost no mist reaches the discharge surface 33 and most of the mist stays on the upper surface of the absorber 53. Therefore, re-dissolution of the fixed black ink by mist cannot be expected, but the mist is prevented from adhering to the discharge surface 33 itself, and the black ink is thickened and fixed on the discharge surface 33 due to the temperature rise of the head during the subsequent recording. The possibility of causing a discharge failure can be reduced. This also makes it possible to prevent ink discharge defects as much as possible.

  In each of the examples shown in FIGS. 6A and 6B, the distance L between the ejection surface 33 and the absorber 53 of the cap 11 is set to 3 mm. It is said to be a distance.

  FIG. 7 is a flowchart for explaining a series of steps executed by the CPU 500 when the preliminary ejection is executed. First, when the preliminary ejection operation is started in step S101, the CPU 500 checks the wipe flag stored in the RAM 502 in step S102, and determines in step S103 whether or not it is just before executing the wiping. The CPU 500 determines that the wiping is performed immediately before the wiping flag is turned on, and determines that the wiping is not performed immediately before the wiping is performed when the wipe flag is not turned on (when the wipe flag is turned off). The preliminary discharge execution condition and the wiping execution condition are determined in advance. For example, when the ink jet recording apparatus is turned on, preliminary ejection and wiping are continuously executed in this order, or these are continuously executed in the reverse order, depending on the off time before being turned on. Only one of these is executed.

  When the CPU 500 determines in step S103 that it is immediately before wiping, the CPU 500 selects the preliminary ejection drive condition A stored in the ROM 501 in step S104. In this case, the CPU 500 sets the drive frequency of the recording head to 10 kHz, which is a high frequency.

  On the other hand, when the CPU 500 determines in step S103 that it is not immediately before wiping, the CPU 500 selects the preliminary ejection driving condition B stored in the ROM 501 in step S105. In this case, the CPU 500 sets the drive frequency of the recording head to 5 kHz, which is a low frequency.

  When the preliminary ejection driving condition is selected in this way, in step S106, the CPU 500 drives the heater 513 of the recording head via the head driving control circuit 515, and executes preliminary ejection according to the selected preliminary ejection driving condition. In step S107, the preliminary ejection operation ends.

  FIG. 8 shows the results of an evaluation test showing the effect of this example. In this evaluation test, 500 sheets of 100% duty were continuously recorded on A4 size paper, and a nozzle check pattern was recorded for every 100 sheets, thereby measuring the number of non-ejection nozzles in the black ink nozzle row. The recording mode is 6 passes in the so-called multi-pass method. The drive frequency during recording is 10 kHz.

  First, a sequence is performed in which 500 nozzles are preliminarily ejected at a driving frequency of 5 kHz, then one sheet is recorded, and then wiping is performed immediately after 500 nozzles are preliminarily ejected at a predetermined driving frequency. , Repeated for 500 sheets. The drive frequency of the preliminary ejection that is performed after recording one sheet and immediately before wiping is 10 kHz in the case of this embodiment and 5 kHz in the case of the comparative example.

  In the case of this example, as a result, it was confirmed that a non-ejection nozzle was not generated during printing of 500 sheets, and a highly reliable recovery process was performed. On the other hand, in the comparative example, during the printing of 500 sheets, the black ink staying around the ejection port started to thicken, and the performance for removing the ejection failure factor was lowered. For this reason, three non-ejection nozzles were generated at the time of about 300 sheets, and a total of six non-ejection nozzles were generated at the end of printing 500 sheets.

  As described above, when the preliminary ejection is performed immediately before wiping, the recording head is driven so that more ink mist is adhered than when preliminary ejection is performed other than just before wiping. Therefore, mist can be attached to the ejection surface, particularly around the ejection port, and the fixed ink can be redissolved to increase its fluidity. Then, it is possible to sufficiently remove the cause of ejection failure by subsequent wiping.

  Further, when the preliminary discharge is executed except immediately before wiping, the amount of ink mist adhering to the discharge surface, particularly around the discharge port, can be relatively reduced. Therefore, it is possible to prevent ink thickening and sticking on the ejection surface due to head temperature rise or the like, and it is possible to prevent ejection failure.

  Note that the frequency in the preliminary ejection immediately before and after the wiping is not limited to 10 kHz and 5 kHz, and can be set to an arbitrary value. Further, these frequencies may be changed according to the recording mode, the recording image width, the head temperature, and the like.

  In this embodiment, the drive frequency is controlled in order to control the amount of mist adhering to the discharge surface, but the total number of preliminary discharges itself is controlled, and the drive energy or drive pulse applied to the heater is controlled. It is also possible to adopt a method of doing so.

  Next, another embodiment will be described. In this other embodiment, when performing the preparatory ejection immediately before wiping when performing the recovery process, more ink mist adheres to the ejection surface than when performing preliminary ejection other than just before wiping. The distance with respect to the discharge surface 33 of the cap 11 is adjusted.

  Specifically, when the preliminary discharge is performed immediately before wiping, the discharge surface 33 of the cap 11 is positioned farther from the discharge surface 33 than when the preliminary discharge is performed other than immediately before wiping. The distance to is adjusted. For example, when the preliminary ejection is executed immediately before wiping, the cap 11 is set so that the distance L between the absorber 53 of the cap 11 and the ejection surface 33 of the recording head 3 is 3 mm, as shown in FIG. The height is adjusted or controlled. Further, when the preliminary discharge is executed except immediately before wiping, the height of the cap 11 is set so that the distance L between the absorber 53 of the cap 11 and the discharge surface 33 of the recording head 3 is 1 mm, as shown in FIG. Is adjusted or controlled.

  As shown in FIG. 6A, when the cap 11 is positioned distal from the discharge surface 33, a relatively large amount of mist that does not reach the absorber 53 of the cap 11 is generated. The generated mist rises due to the air flow generated by the preliminary discharge from each nozzle row 32, and therefore adheres to the entire periphery of the discharge port 31 on the discharge surface 33.

  On the other hand, when the cap 11 is positioned proximal to the ejection surface 33 as shown in FIG. 9, most of the ink droplets reach the absorber 53 of the cap 11 and the generation of mist is suppressed. Further, since the air flow generated by the preliminary discharge from each nozzle row 32 tends to go straight downward, the mist rise is suppressed and the mist is prevented from adhering to the periphery of the discharge port 31.

  In this manner, as in the above-described embodiment, when the preliminary ejection immediately before wiping is performed, the fixed black ink on the ejection surface 33 is redissolved by mist, and wiping by wiping immediately after wiping can be promoted. Further, when the preliminary discharge is performed other than immediately before wiping, it is possible to prevent the mist from adhering to the discharge surface 33 itself. In either case, it is possible to prevent ink discharge defects as much as possible.

  In both the examples shown in FIGS. 6A and 9, the driving frequency is 10 kHz, which is the driving frequency on the high frequency side in the above-described embodiment.

  In other examples, the same evaluation test as in the above example was performed. As a result, no ejection failure nozzles were generated even after 500 sheets were printed, and a highly reliable recovery process was performed. confirmed. In addition, unnecessary mist was not scattered around the cap 11 and internal contamination could be suppressed.

  The distance between the cap 11 and the ejection surface 33 is not limited to 3 mm and 1 mm, and any distance can be selected. These distances may be changed according to the recording mode, the recording image width, the recording head temperature, and the like. Furthermore, instead of adjusting or changing the height position of the cap 11, a configuration in which the position of the recording head 3 in the scanning direction or the position of the recording head 3 in the height direction is adjusted or changed if possible.

  Although the embodiment of the present invention has been described in detail above, various other embodiments of the present invention are conceivable. The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 3 Recording head 10 Recovery device 11 Cap 12 Wiping device 31 Discharge port 33 Discharge surface MS Ink mist L Distance

Claims (9)

A recording head having a plurality of ejection openings for ejecting ink;
Wiping means for wiping the ejection surface provided with the plurality of ejection ports of the recording head;
When wiping is performed immediately after the preliminary ejection operation for recovering the ejection state of the recording head, more ink mist adheres to the ejection surface than when wiping is not performed immediately after the preliminary ejection operation. An ink jet recording apparatus comprising: control means for controlling a preliminary ejection operation from the recording head as described above .   A recording head having a plurality of ejection openings for ejecting ink;
  Wiping means for wiping the ejection surface provided with the plurality of ejection ports of the recording head;
  When wiping is performed immediately after the preliminary ejection operation for recovering the ejection state of the recording head, the recording head is driven at a higher frequency than when wiping is not performed immediately after the preliminary ejection operation. An ink jet recording apparatus comprising: control means for controlling a preliminary ejection operation from the recording head.   The ink jet recording apparatus according to claim 1, wherein the ink ejected from the recording head is a pigment ink.   4. The ink jet recording apparatus according to claim 3, wherein the pigment ink fixed to the ejection surface is dissolved by adhering ink mist.   The inkjet recording apparatus according to claim 1, wherein a cap member is provided at a position facing the ejection surface when the recording head performs a preliminary ejection operation. .   The inkjet recording apparatus according to claim 5, wherein the cap member is used to receive pre-discharged ink.   When wiping is performed immediately after the preliminary ejection operation for recovering the ejection state of the recording head, the distance between the cap member and the ejection surface is larger than when wiping is not performed immediately after the preliminary ejection operation. The inkjet recording apparatus according to claim 5, wherein the distance is far.   8. The ink jet recording apparatus according to claim 5, wherein the cap member at a position where the pre-discharged ink is landed is provided with an absorber.   The inkjet recording apparatus according to claim 8, wherein the absorber is made of a porous material.

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