Liquid ejection head cleaning method and control method, and liquid ejection apparatus
By circulating stop, wiping and pre-initial ejection steps in the cleaning method of the liquid ejection head, the problem of mixing and thickening of the mixed color recording liquid in the ejection port and the pressure chamber is solved, and more efficient maintenance and faster recording operation recovery is achieved, and recording quality is improved.
Patent Information
- Application Number
- JP2021029159
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2020-06-15
- Filing Date
- 2021-02-25
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2041-02-25
AI Technical Summary
During the cleaning and control process of the liquid ejection head, the mixed color recording liquid is easily mixed when flowing through the injection port or the pressure chamber, resulting in a decrease in recording quality. In the existing method, the recording liquid becomes thicker due to the evaporation of volatile components when the recording liquid cycle is stopped, making it difficult to perform pre-initial ejection, which increases maintenance time and recording liquid consumption.
The recording liquid is circulated by configuring a liquid supply path, a supply port, a pressure chamber, a recovery port and a recovery path, and the cleaning method includes a cycle stop, wiping and pre-initial ejection steps. The wipe step starts at one end of the liquid ejection head and proceeds along the ejection port. Use the moving wipe members to clean and eliminate the mixed color recording liquid. The pre-initial spray is performed immediately after the wipe is completed to prevent the recording liquid from becoming thicker.
It reduces the consumption of recording liquid during maintenance, shortens the time to stop circulation, quickly resumes recording operations, and effectively prevents color mixing and spray defects, improving recording quality.
Smart Images

Figure 0007654422000001 
Figure 0007654422000002 
Figure 0007654422000003
Abstract
Description
[Technical field]
[0001] The present invention relates to a cleaning method and control method for a liquid ejection head, and a liquid ejection apparatus. [Background technology]
[0002] In an inkjet recording device, which is a type of liquid ejection device, a recording liquid in which a solid component such as a coloring material is added to a volatile component such as water as a solvent is ejected from an ejection port of a liquid ejection head to the outside to perform recording. When the volatile component of the recording liquid exposed to the outside air through the ejection port volatilizes (evaporates) and the viscosity of the recording liquid located near the ejection port increases, the ejection characteristics of the recording liquid, for example, the accuracy of landing of droplets on a recording medium, may decrease, leading to a decrease in recording quality. In particular, a recording liquid containing a larger amount of solid components, which has been used in recent years for applications such as commercial printing for making albums, may experience a large increase in viscosity (thickening) due to the evaporation of the volatile components, and may not be able to maintain the ejection accuracy of the recording liquid (resulting in liquid ejection failure). As an example of a method for suppressing such an increase in viscosity of the recording liquid, Patent Document 1 proposes a method of constantly refreshing the recording liquid by circulating the recording liquid through the ejection port and pressure chamber, without allowing the recording liquid to stagnate in the ejection port and pressure chamber.
[0003] In addition, in order to remove the recording liquid adhering to the discharge port formation surface of the liquid discharge head and improve the discharge characteristics, various methods of wiping the discharge port formation surface are proposed in Patent Document 2. For example, there is a method of wiping the discharge port formation surface with a flexible plate-like member (rubber blade, etc.), a method of sucking while wiping with a flexible tubular member, a method of wiping with a sponge-like porous body or nonwoven fabric, and a method of sucking the recording liquid by pressing a porous body or nonwoven fabric against the discharge port by capillary force. These methods are called the blade wipe method, vacuum wipe method, web wipe method, tuck method, etc. However, in a so-called multi-color integrated head in which liquid discharge heads for discharging different colors and types of recording liquid are integrally configured, when the above-mentioned wiping is performed, a phenomenon (color mixing) occurs in which recording liquids of different colors (types) mix on the discharge port formation surface. If the mixed recording liquid is pushed into the pressure chamber from the discharge port by wiping, it becomes impossible to record the desired color thereafter. Therefore, after wiping and before printing, liquid ejection (preliminary ejection) that is not involved in printing is performed in order to discharge the mixed printing liquid to the outside. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] Special Publication No. 2014-510649 [Patent Document 2] Japanese Patent Application Publication No. Hei 2-202453 Summary of the Invention [Problem to be solved by the invention]
[0005] If wiping is performed while the recording liquid is circulating through the ejection port and pressure chamber as in the method described in Patent Document 1, the mixed recording liquid forced into the ejection port and pressure chamber by wiping will circulate. If this happens, the mixed recording liquid will spread throughout the entire flow path in the liquid ejection head, so that even if preliminary ejection is performed as in the method described in Patent Document 2, the mixed recording liquid cannot be discharged completely, and the desired color cannot be recorded, resulting in a significant decrease in recording quality. In order to prevent such a situation, it is possible to stop the circulation of the recording liquid during wiping, and resume the circulation of the recording liquid after wiping of the entire ejection port formation surface of the liquid ejection head and preliminary ejection are completed. However, even in the short time between wiping and preliminary ejection, the volatile components of the recording liquid near the ejection port volatilize, and the mixed recording liquid due to wiping becomes thicker. If the recording liquid becomes thicker, it becomes difficult to eject the mixed recording liquid due to preliminary ejection. In particular, in a line-type head in which the recording width of the liquid ejection head is the same length as the recording width of the recording medium, it takes a long time from the start to the completion of wiping. If the circulation of the recording liquid is stopped during this wiping, the viscosity of the recording liquid inside the ejection ports and pressure chambers will increase, especially in the areas wiped at the beginning of wiping, which may make it difficult to eject the recording liquid during preliminary ejection. In this case, in order to remove the thickened recording liquid from the pressure chamber, it becomes necessary to take measures such as increasing the number of preliminary ejections, lengthening the time for which the recording liquid is circulated again after the preliminary ejection has finished, etc. Such measures increase the consumption of recording liquid that does not contribute to recording, and lengthen the time required for so-called maintenance, from stopping the circulation of the recording liquid to wiping, preliminary ejection, and restarting the circulation. The present invention aims to provide a liquid ejection head cleaning method and control method, and a liquid ejection device, which consumes less recording liquid during maintenance, removes thickened recording liquid from the pressure chambers, and suppresses color mixing, ejection defects, and deterioration of recording quality. Another aim of the present invention is to provide a liquid ejection head cleaning method and control method, and a liquid ejection device, which can complete maintenance that stops the circulation of the recording liquid in a short time and quickly resume recording operations. [Means for solving the problem]
[0006] The present invention relates to The ink cartridge is configured to include a liquid supply path, a supply port, a pressure chamber, a recovery port, and a liquid recovery path, and is configured to circulate the recording liquid. The nozzle has a nozzle forming surface on which a plurality of nozzle rows each having a plurality of nozzles are formed. 、 A method for cleaning a liquid ejection head in which at least one of the ejection port arrays ejects a recording liquid different from that of the other ejection port arrays, comprising: The cleaning method includes a circulation stopping step of stopping circulation of the recording liquid in the liquid ejection head; a wiping step of wiping the ejection port surface, and a preliminary ejection step of preliminary ejecting the recording liquid from the ejection port that has been wiped; a circulation restarting step of restarting circulation of the recording liquid after the wiping step and the preliminary ejection step are performed; The wiping step are arranged from one end of the liquid ejection head to the other end. A wiping member is moved along the row of ejection ports. Yeah Iping This is what we do. The preliminary ejection step Following the movement of the wiping member, The discharge port forming surface The wiping member passes through all of the discharge ports. From the discharge port Sequential Pre-eject It is something that we do. It is characterized by: Effect of the Invention
[0007] According to the present invention, the consumption of recording liquid during maintenance is small, maintenance that stops the circulation of the recording liquid can be completed in a short time, the thickened recording liquid can be removed from the pressure chamber, and recording operations can be resumed quickly, while also suppressing color mixing, ejection defects, and deterioration of recording quality. [Brief description of the drawings]
[0008] [Figure 1] 1 is a schematic perspective view showing a main part of a liquid ejection apparatus including a liquid ejection head to which a cleaning method of the present invention is applied; [Diagram 2] 2 is a schematic perspective view of the liquid ejection head of the liquid ejection device shown in FIG. 1, as viewed from the ejection port formation surface side. [Diagram 3] 3 is a schematic perspective view showing a recording element substrate of the liquid ejection head shown in FIG. 2, with a portion cut away. [Figure 4] FIG. 4(a) is a schematic plan view of the main part of the liquid ejection head shown in FIGS. 2 and 3, and FIG. 4(b) is a cross-sectional view taken along line AA in FIG. 4(a). [Diagram 5] FIG. 2 is a schematic perspective view showing a cleaning mechanism of the liquid ejection head according to the first embodiment of the present invention. [Figure 6] FIG. 6(a) to FIG. 6(f) are schematic front views sequentially illustrating each step of the liquid ejection head cleaning method according to the first embodiment of the present invention. [Figure 7] Figure 7(a) is a schematic front view showing a part of a cleaning method for a liquid ejection head in a first embodiment of the present invention, Figure 7(b) is a cross-sectional view showing an enlarged view of region B in Figure 7(a), and Figure 7(c) is a cross-sectional view showing an enlarged view of region C in Figure 7(a). [Figure 8] FIG. 8(a) is a schematic front view showing a part of a method for cleaning a liquid ejection head according to a first embodiment of the present invention, and FIG. 8(b) is an enlarged cross-sectional view showing a region B of FIG. 8(a). [Figure 9] FIG. 9(a) is a schematic front view showing a liquid circulating state after the liquid ejection head cleaning method according to the first embodiment of the present invention, and FIG. 9(b) is an enlarged cross-sectional view showing region B of FIG. 9(a). [Figure 10] FIG. 11 is a schematic perspective view showing a cleaning mechanism of a liquid ejection head according to a second embodiment of the present invention. [Figure 11] FIG. 11(a) is a schematic front view showing a liquid ejection head cleaning mechanism of a third embodiment of the present invention, and FIG. 11(b) and FIG. 11(c) are schematic front views showing, in sequence, each step of a liquid ejection head cleaning method using the mechanism of FIG. 11(a). [Figure 12] FIGS. 12(a), 12(b) and 12(c) are schematic front views sequentially showing each step of a cleaning method performed using a liquid ejection head cleaning mechanism according to a fourth embodiment of the present invention. [Figure 13] 13(a), 13(b) and 13(c) are schematic front views sequentially showing each step of a cleaning method performed using a liquid ejection head cleaning mechanism according to a fifth embodiment of the present invention. [Figure 14] 11 is a graph showing the relationship between the elapsed time after wiping is completed and the ejection speed of droplets ejected from an ejection port. [Figure 15] 13 is a schematic front view showing one step of a cleaning method performed using a modified example of the cleaning mechanism for the liquid ejection head according to the fifth embodiment of the present invention. FIG. [Figure 16] 1 is a block diagram illustrating an example of a control system of a liquid ejection device to which the present invention is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the following description does not limit the scope of the present invention. The example described below is a so-called thermal type liquid ejection head that uses a heat generating element as an energy generating element (recording element) that generates energy for ejecting recording liquid. In a thermal type liquid ejection head, thermal energy is generated to generate bubbles in the recording liquid in a pressure chamber, and the recording liquid is ejected from the ejection port. However, the liquid ejection head to which the present invention can be applied is not limited to the thermal type, and the present invention can also be applied to liquid ejection heads that employ a piezo type using a piezoelectric element or various other liquid ejection methods.
[0010] [First embodiment] (Inkjet recording device) FIG. 1 is a schematic perspective view showing some of the components involved in recording of an inkjet recording device 10 (hereinafter also referred to as a recording device), which is an example of a liquid ejection device to which the present invention is applied and which performs recording by ejecting liquid ink. FIG. 2 is a schematic perspective view of a liquid ejection head 3 of the recording device 10 shown in FIG. 1. The recording device 10 includes a conveying section 1 for conveying a recording medium 2, a liquid ejection head 3 having a recording element substrate 4 shown in FIG. 2, a liquid supply mechanism described below, a cleaning mechanism 30 (see FIG. 5) for the liquid ejection head 3, an outer housing (not shown), a control mechanism 50 (see FIG. 16), and the like. The liquid ejection head 3 is a so-called line-type liquid ejection head 3 in which a plurality of recording element substrates 4 are arranged on a support member 60 in a direction substantially perpendicular to the conveying direction of the recording medium 2 (see FIG. 1) over a width equivalent to the recording width of the recording medium 2, as shown in FIG. 2. A wiring substrate (not shown) for transmitting power and ejection control signals is electrically connected to the liquid ejection head 3. The liquid supply mechanism is a mechanism in which a liquid supply means, which serves as a supply path for supplying the recording liquid (liquid ink) to the liquid ejection head 3, is fluidly connected to a main tank and a buffer tank (neither of which are shown in the figure). The liquid path in the liquid ejection head 3 to which the recording liquid is supplied from the liquid supply mechanism will be described later. The control mechanism 50 controls the driving of the liquid ejection head 3, the driving of each member of the conveying section 1, the driving of the cleaning mechanism 30, etc. The recording device 10 performs continuous recording in one pass by linking these components and conveying multiple recording media 2 continuously or intermittently. Note that the recording media 2 are not limited to cut paper, and may be continuous roll paper. The liquid ejection head 3 of this embodiment is capable of full-color printing using cyan (C), magenta (M), yellow (Y), and black (K) inks as the recording liquid.
[0011] 1, liquid connection parts 5 provided at both ends of the liquid ejection head 3 are parts that connect the supply paths of the recording device body (not shown) to the liquid paths of the liquid ejection head 3. As a result, the four colors of ink, CMYK, are supplied from the supply paths of the recording device body to the liquid ejection head 3, and the ink that has passed through the liquid paths in the liquid ejection head 3 is collected into the supply paths of the recording device body. In this way, the inks of each color circulate through the supply paths of the recording device body and the liquid paths of the liquid ejection head 3 (the supply pressure is adjusted midway by pressure adjustment mechanisms 6a, 6b, 6c, 6d provided in the head).
[0012] (Configuration of liquid ejection head) The configuration of the liquid ejection head 3 according to the first embodiment of the present invention will be described below. FIG. 2 is a schematic perspective view of the liquid ejection head 3 according to this embodiment. The liquid ejection head 3 of this embodiment is a line-type liquid ejection head in which 15 recording element substrates 4 capable of ejecting liquid ink of four colors, C, M, Y, and K, individually are arranged in a straight line. That is, 15 recording element substrates 4a to 4o are arranged in-line. It should be noted that the recording width can be increased by increasing the number of recording element substrates 4. As shown in FIG. 2, in addition to the recording element substrates 4a to 4o, the liquid ejection head 3 includes an electric wiring substrate 8 electrically connected to a wiring substrate (not shown) of the main body of the recording device via a flexible wiring substrate 7.
[0013] (Configuration of the recording element substrate) The configuration of the recording element substrate 4 of this embodiment will be described. FIG. 3 is a schematic perspective view of the recording element substrate 4 as viewed from the side where the ejection ports 9 are formed (the ejection port forming surface 11a side), with a part of the substrate being cut away. FIG. 4(a) is a schematic plan view showing an enlarged area P of FIG. 3, with each component being transparently superimposed. FIG. 4(b) is a schematic cross-sectional view cut along the line AA of FIG. 4(a). The recording element substrate 4 is configured by laminating a substrate 19 made of Si and an ejection port forming member 11 made of a photosensitive resin. As shown in FIG. 3, a plurality of ejection port arrays each consisting of a plurality of ejection ports 9 are formed on the ejection port forming surface 11a of the ejection port forming member 11 of the recording element substrate 4. Specifically, in this embodiment, four ejection port arrays 12M, 12C, 12Y, and 12K corresponding to four colors of ink (M, C, Y, and K) are formed. Hereinafter, the direction in which the ejection port arrays each consisting of a plurality of ejection ports 9 extend will be referred to as the "ejection port arrangement direction." In this manner, in this liquid ejection head 3, a plurality of recording element substrates 4 each having an ejection port formation surface 11a on which a plurality of ejection port arrays 12M, 12C, 12Y, and 12K each consisting of a plurality of ejection ports 9 are formed are arranged in a row.
[0014] As shown in FIG. 4(a), pressure chambers 14 partitioned by partition walls (flow path walls) 13 are provided at positions corresponding to the respective ejection ports 9. As shown in FIG. 4(b), heat generating elements (recording elements) 15, which are an example of energy generating elements that generate energy for ejecting the recording liquid, are disposed at positions corresponding to the respective pressure chambers 14 on the substrate 19. The heat generating elements 15 are electrically connected to electrical wiring (not shown) provided on the recording element substrate 4. The heat generating elements 15 generate thermal energy based on an ejection control signal (pulse signal) input from a control circuit of the recording device main body (not shown) via the electrical wiring substrate 8 and the flexible wiring substrate 7, and cause film boiling of the recording liquid. The pressure caused by this film boiling ejects the recording liquid from the ejection ports 9 to the outside. As shown in FIG. 3, a liquid supply path 16 is formed on one side of each ejection port array, and a liquid recovery path 17 is formed on the other side, and they extend along the ejection port array. The liquid supply path 16 and the liquid recovery path 17 are formed by grooves provided on the surface of the substrate 19 opposite to the surface on which the recording elements 15 are formed, and communicate with the pressure chambers 14 and the ejection ports 9 via the supply ports 18a and the recovery ports 18b, respectively. Between the liquid supply path 16 and the liquid recovery path 17, pressure adjustment mechanisms 6a to 6d (see FIG. 1) are provided which generate a pressure difference adjusted for each color.
[0015] 3, a cover plate 20 is laminated on the surface of the substrate 19 of the recording element substrate 4 opposite to the surface in contact with the ejection port forming member 11. The cover plate 20 is provided with a plurality of openings 21 that communicate with the liquid supply path 16 and the liquid recovery path 17. In the cover plate 20 of this embodiment, three openings 21 are provided for one liquid supply path 16, and two openings 21 are provided for one liquid recovery path 17.
[0016] Next, the flow of the recording liquid in the recording element substrate 4 will be described. Between the liquid supply path 16 and the liquid recovery path 17, a pressure difference is generated, which is adjusted for each color by the pressure adjustment mechanisms 6a to 6d (see FIG. 1). When the recording liquid is discharged from some of the discharge ports 9 of the liquid discharge head 3, the above-mentioned pressure difference causes the recording liquid in the liquid supply path 16 of the substrate 19 to flow to the liquid recovery path 17 via the supply port 18a, the pressure chamber 14, and the recovery port 18b in the non-discharge discharge port 9. That is, the recording liquid flows in the direction C in FIG. 3. This flow in the direction C allows the recording liquid, bubbles, foreign matter, etc., which have become thickened due to the volatilization of volatile components from the discharge port 9, to be collected in the liquid recovery path 17 in the discharge port 9 and the pressure chamber 14 that are not discharging the recording liquid. Since the discharge port 9 and the pressure chamber 14 are always supplied with refreshed recording liquid, the thickening of the recording liquid inside the discharge port 9 and the pressure chamber 14 can be suppressed. The recording liquid recovered in the liquid recovery path 17 is finally recovered in the supply path of the recording device body through the opening 21 of the cover plate 20. Such a flow of the recording liquid is referred to in this specification as the circulation (circulation flow) of the recording liquid.
[0017] (cleaning mechanism) FIG. 5 shows a cleaning mechanism 30 that comes into contact with the ejection port forming surface 11a of the ejection port forming member 11 of the recording element substrate 4 to clean the ejection port forming surface 11a. As shown in FIG. 5, the cleaning mechanism 30 has a base 32, an elastic tube 40a fixed to the base 32, a suction tube 33 connected to the elastic tube 40a, and a preliminary ejection receiver 35 arranged adjacent to the base 32. The elastic tube 40a is formed to have a size that can cover the multiple ejection ports 9 in the ejection port arrangement direction and covers all the ejection port arrays 12M, 12C, 12Y, and 12K in a direction intersecting the ejection port arrangement direction. In the wiping process, the open end of the elastic tube 40a is pressed against the ejection port forming surface 11a, and the base 32 is moved in the ejection port arrangement direction by the moving mechanism while operating a suction pump 34 (see FIG. 6(a) for example) connected to the elastic tube 40a via the suction tube 33. In this way, the elastic tube 40a is brought into sliding contact with the entire area of the ejection port forming surface 11a, and suction and wiping are performed simultaneously. This operation is called suction wiping. The elastic tube 40a is a tubular member that sucks the recording liquid from the ejection port 9 and wipes the ejection port forming surface 11a with its edge, and is a type of wiping member. By performing suction wiping, it is possible to suck and remove dust adhering to the entire ejection port forming surface 11a including the vicinity of the ejection port 9, solidified and attached recording liquid, air bubbles present inside the ejection port 9 and the pressure chamber 14, and thickened recording liquid. A cleaning mechanism 30 configured in this way is sometimes called a vacuum wiper.
[0018] When the vacuum wiper 30 performs suction wiping, the recording liquids of different colors and types sucked out from the discharge port 9 mix at the contact portion between the vacuum wiper 30 and the discharge port forming member 11 or in the vicinity thereof. A part of the mixed recording liquid (sometimes called mixed recording liquid) may infiltrate into the pressure chamber 14 from the discharge port 9. If the mixed recording liquid is circulated without being discharged from the discharge port 9 and the pressure chamber 14, the mixed recording liquid will flow out into the liquid recovery path 17 and spread throughout the circulation path of the recording liquid. If such color mixing occurs, it will not be possible to reproduce the intended color and the print quality will decrease, so it must be avoided. Conventionally, the circulation of the recording liquid is stopped during wiping, and after wiping is completed, preliminary discharge is performed to discharge the mixed recording liquid, and then the circulation of the recording liquid is resumed. Preliminary discharge is the discharge of liquid that does not contribute to recording before the original purpose of recording on the recording medium. Wiping takes time, and wiping of the line-type liquid ejection head 3 in particular takes a long time. For this reason, at the ejection port 9 where suction wiping was performed at the beginning of the wiping process, volatilization (evaporation) of the volatile components (e.g., water) contained in the recording liquid progresses, and the viscosity of the recording liquid in the vicinity of the ejection port 9 and inside the pressure chamber 14 increases. When the viscosity of the recording liquid increases, even if the recording element 15 is driven to generate energy, the viscous recording liquid cannot be ejected to the outside (liquid ejection failure occurs). In particular, the recording liquid in commercial printing and the like often has a composition with a water content of less than 71%, and when such a recording liquid is used, the tendency for the liquid to thicken is significant. When the water content of the recording liquid is less than 66%, the tendency is even more significant, and when the water content of the recording liquid is less than 60%, the tendency is even more significant. Also, when the content of solid components dispersed in the recording liquid is 7% or more, the tendency is also significant for the liquid to thicken. When the content of solid components is 10% or more, the tendency is even more significant.
[0019] Therefore, in this embodiment, as shown in Figs. 6(a) to 6(f), without waiting for the completion of wiping of the entire discharge port formation surface 11a across the multiple recording element substrates 4a to 4o of the liquid discharge head 3, preliminary discharge is sequentially performed from the portion where the vacuum wiper 30 has passed. This preliminary discharge process discharges the recording liquid from the discharge port 9 to the outside before the volatile components of the mixed recording liquid volatilize and the viscosity of the recording liquid in the vicinity of the discharge port 9 and inside the pressure chamber 14 increases, making it difficult to discharge the liquid. In other words, preliminary discharge is performed before liquid discharge failure occurs due to the increase in the viscosity of the recording liquid in the discharge port 9 that has already been wiped. An example of the specific timing of this wiping and preliminary discharge will be described below in order. Before the wiping and preliminary discharge operations are performed, the circulation operation of the recording liquid is stopped. Thereafter, as shown in Fig. 6(a), the elastic tube 40a of the vacuum wiper 30 starts wiping by suctioning while sliding against the first recording element substrate 4a of the liquid discharge head 3. Next, the vacuum wiper 30 moves in the direction A, and the elastic tube 40a passes the recording element substrate 4a. Then, the vacuum wiper 30 reaches the position shown in FIG. 6(b), that is, the position where the elastic tube 40a faces the second recording element substrate 4b, and while the vacuum wiper 30 is in sliding contact with and sucking the recording element substrate 4b, the preliminary ejection of the first recording element substrate 4a is started. This causes the mixed recording liquid to be discharged toward the preliminary ejection receiver 35 from the vicinity of the ejection port 9 of the recording element substrate 4a and the inside of the pressure chamber 14. After the wiping process of the second recording element substrate 4b and the preliminary ejection process of the first recording element substrate 4a are completed, the vacuum wiper 30 moves further in the direction A, as shown in FIG. 6(c). As shown in FIG. 6(d), the vacuum wiper 30 reaches the position where the elastic tube 40a faces the third recording element substrate 4c. Then, the elastic tube 40a sucks the third recording element substrate 4c while sliding against it, and performs preliminary ejection of the second recording element substrate 4b. In this way, suction wiping of the recording element substrate and preliminary ejection of the recording element substrate that has been suction wiped are performed in parallel. As shown in Fig. 6(e), the elastic tube 40a reaches the last recording element substrate 4o of the liquid ejection head 3 and sucks it while sliding against it, and performs preliminary ejection of the previous (upstream) recording element substrate 4n.Then, as shown in FIG. 6(f), the elastic tube 40a moves further and passes the last recording element substrate 4o of the liquid ejection head 3, and the preliminary ejection of the last recording element substrate 4o is performed. In this manner, the suction wiping and preliminary ejection are performed for all the recording element substrates 4a to 4o of the liquid ejection head 3, thereby performing the cleaning operation of the liquid ejection head 3 of this embodiment. In this embodiment, as shown in FIG. 6(a) to FIG. 6(f), preliminary ejection is sequentially performed from the recording element substrates through which the elastic tube 40a has passed, without waiting for the completion of the suction wiping of the entire surface of the ejection port formation surface 11a of the liquid ejection head 3. This allows the mixed recording liquid to be discharged to the outside from the ejection port 9 before the volatile components of the mixed recording liquid evaporate and the viscosity of the recording liquid in the vicinity of the ejection port 9 and inside the pressure chamber 14 increases. After the cleaning operation of the liquid ejection head 3 is completed, that is, after the preliminary ejection process is completed, the recording liquid is supplied to each pressure chamber 14 from the supply port 18a, and the recording liquid is collected from the pressure chamber 14 through the recovery port 18b. In this way, the circulation of the recording liquid is started, preparing for the next recording.
[0020] 7 to 9 are diagrams mainly showing the state around the ejection port 9 and the pressure chamber 14. FIG. 7(a) is a front view showing a state after the state shown in FIG. 6(d) in which suction wiping of a part of the third recording element substrate 4c is completed and preliminary ejection of the second recording element substrate 4b is being performed. FIG. 7(b) is an enlarged cross-sectional view of the region B in FIG. 7(a) and is a cross-sectional view showing the main part of the third recording element substrate 4c after suction wiping is completed and before preliminary ejection. FIG. 7(c) is an enlarged cross-sectional view of the region C in FIG. 7(a) and is a cross-sectional view showing the main part of the first recording element substrate 4a after suction wiping and preliminary ejection are completed. FIG. 8(a) is a front view showing a state after the state shown in FIG. 6(f) in which suction wiping and preliminary ejection of all recording element substrates 4a to 4o are completed. Fig. 8(b) is an enlarged cross-sectional view of region B in Fig. 8(a), showing the main part of the third recording element substrate 4c that has been left after suction wiping and preliminary ejection have been completed. Fig. 9(a) is a front view showing the state after the state shown in Fig. 8(a) where circulation of the recording liquid has started after suction wiping and preliminary ejection of all recording element substrates 4a to 4o have been completed. Fig. 9(b) is an enlarged cross-sectional view of region B in Fig. 9(a), showing the main part of the third recording element substrate 4c where circulation of the recording liquid has started.
[0021] As shown in FIG. 7(b), when the suction wiping is completed and the preliminary ejection is not performed, the mixed recording liquid L1 is present in the ejection port 9 and the pressure chamber 14. In the present invention, the mixed recording liquid L1 is discharged to the outside, that is, the mixed recording liquid L1 is not present around the ejection port 9 and the pressure chamber 14, as in the state shown in FIG. 7(c). If the mixed recording liquid L1 is left in this state until the preliminary ejection of the last recording element substrate 4o of the liquid ejection head 3 is completed, the volatile components of the recording liquid evaporate from the ejection port 9 and the viscosity increases. As a result, as shown in FIG. 8(b), the thickened recording liquid (concentrated recording liquid) L2 is present in the ejection port 9 and the pressure chamber 14. Therefore, the circulation of the recording liquid is started, and fresh recording liquid is supplied from the supply port 18a to the pressure chamber 14 and the ejection port 9. The thickened recording liquid L2 flows from the discharge port 9 and the pressure chamber 14 to the recovery port 17b, and is diluted with fresh recording liquid on the way thereto, decreasing its viscosity. In addition, since the mixed recording liquid L1 has already been discharged from the discharge port to the outside by the preliminary discharge, the mixed recording liquid does not flow out from the pressure chamber 14 and the discharge port 9 to the recovery port 18b even if the recording liquid is circulated. Therefore, as shown in FIG. 9B, the discharge port 9 and the pressure chamber 14 are in a state where the recording liquid is not mixed or thickened. According to this embodiment, by starting the circulation of the recording liquid after the cleaning operation (wiping and preliminary discharge), the pressure chamber 14 and the discharge port 9 are in a state where the recording liquid is not mixed or thickened, and the recording liquid of the desired color can be discharged, thereby achieving good recording quality.
[0022] As described above, according to this embodiment, the wiping member 40a is moved along the ejection port rows to wipe the multiple ejection port rows. Then, before wiping of the entire ejection port formation surface 11a across the multiple recording element substrates 4 is completed, preliminary ejection from the wiped ejection port 9 is started. In this manner, the wiping process and the preliminary ejection process are sequentially performed from the first recording element substrate 4a located at one end of the row of the recording element substrates 4 to the last recording element substrate 4o located at the other end. Before wiping of the entire ejection port formation surface 11a across all the recording element substrates 4 is completed, preliminary ejection from the ejection port 9 of the recording element substrate located upstream of the recording element substrate being wiped in the movement direction of the wiping member 40a is started. As a result, the consumption of recording liquid for maintenance is small, and maintenance for stopping the circulation of the recording liquid can be completed in a short time, and the thickened recording liquid can be removed from the pressure chamber, allowing the recording operation to be resumed promptly. This solves the problem of color mixing and thickening of the recording liquid discharged from the liquid discharge head 1 caused by suction wiping, etc., and allows for good liquid discharge in the next recording. This method is suitable when the water content of the recording liquid is less than 71%, more suitable when it is less than 66%, and even more suitable when it is less than 60%. This method is also suitable when the content of solid components dispersed in the recording liquid is 7% or more, and even more suitable when the content of solid components is 10% or more. In this embodiment, the recording element substrate during wiping and the recording element substrate during preliminary discharge are adjacent to each other in the moving direction of the wiping member, but are not limited to such a configuration. These operations are mainly controlled by a control mechanism 50 (see FIG. 16).
[0023] [Second embodiment] The second embodiment of the present invention will be described below. The same components and methods as those in the first embodiment are indicated by the same reference numerals, and the description may be omitted. The cleaning mechanism of this embodiment shown in FIG. 10 includes a blade wiper 37 in which a rubber blade 40b is attached to a base 32. A preliminary ejection receiver 35 is provided adjacent to the rubber blade 40b on the base 32. The rubber blade 40b is a flexible plate-like member that wipes the ejection port formation surface 11a with its edge, and is a type of wiping member. By pressing the rubber blade 40b shown in FIG. 10 against the recording element substrate 4 and sliding the surface of the recording element substrate 4, it is possible to wipe off the dust and solidified recording liquid adhering to the vicinity of the ejection port 9 (see FIG. 3). This cleaning mechanism performs each step (wiping and preliminary ejection) of the cleaning method substantially similar to the steps shown in FIG. 6(a) to FIG. 6(f), and sequentially cleans a plurality of recording element substrates 4.
[0024] When wiping is performed by the rubber blade 40b of the blade wiper 37, the recording liquids of different colors and types drawn from the ejection orifices 9 by surface tension and capillary force are mixed near the contact portion between the rubber blade 40b and the ejection orifice formation surface 11a. Then, a part of the mixed recording liquid infiltrates into the pressure chamber 14 from the ejection orifice 9. The recording liquid mixed by wiping and infiltrated into the pressure chamber 14 is discharged to the preliminary ejection receiver 35 by preliminary ejection performed at the same timing as in the first embodiment. That is, in this embodiment, too, the mixed recording liquid is discharged from the ejection orifices 9 by sequentially performing preliminary ejection from the recording element substrates 4 that the rubber blade 40b has passed, without waiting for the wiping of all the recording element substrates 4 of the liquid ejection head 3 to be completed. At this point, the recording liquid is not circulated, so the mixed recording liquid does not flow out to the recovery port 18b and can be discharged to the outside. Since the preliminary ejection is performed immediately after wiping, the volatile components of the mixed recording liquid can be discharged from the ejection port 9 and the pressure chamber 14 to the outside before the recording liquid thickens due to evaporation of the mixed recording liquid. Even if the recording liquid is left after wiping and preliminary ejection and thickened, the circulation of the recording liquid is started before the start of recording, and fresh recording liquid is supplied, and the thickened recording liquid is discharged to the recovery port 18b and diluted with the fresh recording liquid. Therefore, when the liquid is ejected again, good recording quality can be obtained. Furthermore, the consumption of the recording liquid for maintenance is small, and the maintenance for stopping the circulation of the recording liquid can be completed in a short time, the thickened recording liquid can be removed from the pressure chamber, and the recording operation can be resumed promptly.
[0025] [Third embodiment] The third embodiment of the present invention will be described below. The same configurations and methods as those of the first and second embodiments are indicated by the same reference numerals, and the description may be omitted. The cleaning mechanism of this embodiment shown in FIG. 11A is a so-called web wipe, which includes a nonwoven fabric 40c, fixed rollers 41a and 41b, and a moving roller 42. The nonwoven fabric 40c is a cloth-like member having liquid absorption properties, and is a type of wiping member. As shown in FIG. 11(a), the nonwoven fabric 40c is wound around the fixed roller 41a, and is configured to be wound around the fixed roller 41b via the moving roller 42. When wiping is performed, as shown in FIG. 11(a), the liquid ejection head and the cleaning mechanism are moved in advance so as to be positioned so as to face each other. Then, as shown in FIG. 11(b), the moving roller 42 is pressed against the recording element substrate 4, and moved so as to roll on the surface of the recording element substrate 4. In this way, by rubbing the nonwoven fabric 40c against the ejection-orifice forming surface 11a of the ejection orifices 9, it is possible to remove dust and solidified recording liquid adhering to the vicinity of the ejection orifices 9. Then, as shown in Fig. 11(c), without waiting for the completion of wiping of all the recording element substrates 4 of the liquid ejection head 3, preliminary ejection can be sequentially performed onto the nonwoven fabric 40c from the recording element substrates 4 that the moving roller 42 has passed. After wiping and preliminary ejection are performed on the entire ejection-orifice forming surface 11a, the soiled nonwoven fabric 40c is taken up by the fixed roller 41b, and a new portion of the nonwoven fabric 40c faces the ejection-orifice forming surface 11a and is prepared for the next wiping operation.
[0026] In this embodiment, the mixed recording liquid can be discharged to the outside without flowing out to the recovery port 18b. Since the preliminary ejection is performed immediately after wiping, the mixed recording liquid can be discharged to the outside from the ejection port 9 and the pressure chamber 14 before the volatile components of the mixed recording liquid evaporate and the recording liquid becomes thicker. Even if there is recording liquid that has been left after wiping and preliminary ejection and has become thicker, circulation of the recording liquid is started before the start of recording, fresh recording liquid is supplied, and the thickened recording liquid is caused to flow to the recovery port 18b and is diluted with the fresh recording liquid. Therefore, when liquid is ejected again, good recording quality can be obtained. In this embodiment, the preliminary ejection can be performed directly on the nonwoven fabric 40c, and there is no need to provide a preliminary ejection receiver.
[0027] In this embodiment, the nonwoven fabric 40c is used as the wiping member, but from the viewpoint of absorbing and recovering the recording liquid, it is also possible to use a wiping member made of, for example, a porous body having liquid-absorbency, although this is not shown in the drawings. When a porous body is used, its shape may be a plate shape similar to the rubber blade 40b shown in Fig. 10, or a sheet shape similar to the nonwoven fabric 40c shown in Fig. 11.
[0028] [Fourth embodiment] The fourth embodiment of the present invention will be described below. The same reference numerals are used to denote configurations and methods similar to those of the first to third embodiments, and descriptions thereof may be omitted. In the first to third embodiments, the wiping member 40 completely passes one recording element substrate and performs preliminary ejection of the recording element substrate that has been wiped at the timing when the wiping member 40 is wiping the next recording element substrate. The wiping member 40 here is a general term including the elastic tube 40a, the rubber blade 40b, the nonwoven fabric 40c, the porous body, and the like. In contrast, in this embodiment, as shown in FIG. 12, preliminary ejection is sequentially performed from the ejection port 9 immediately after the wiping member 40 has passed in one recording element substrate 4. For example, as shown in FIG. 12(a), while wiping the first recording element substrate 4a, preliminary ejection is performed for the ejection port 9 that the wiping member 40 of the recording element substrate 4a has passed. As shown in FIG. 12(b), when the wiping member 40 is wiping the next recording element substrate 4b, the recording liquid is preliminarily ejected from the ejection port 9 of the recording element substrate 4a through which the wiping member 40 has passed. At the same time, the recording liquid is preliminarily ejected from the ejection port 9 of the recording element substrate 4b through which the wiping member 40 has already passed during wiping. As shown in FIG. 12(c), the wiping member 40 and the preliminarily ejected receiver 35 move from one end of the liquid ejection head 3 to the other end. When the cleaning operation of all the recording element substrates 4 of the liquid ejection head 3 is completed, the circulation of the recording liquid is immediately resumed. That is, in this embodiment, the timing from the completion of the cleaning operation to the start of the liquid circulation can be further accelerated. In addition, in this embodiment, the mixed recording liquid can be discharged from the ejection port 9 to the outside more quickly, so that it is suitable for the case of using a recording liquid that is more likely to thicken.
[0029] In the first to third embodiments, the wiping member 40 and the preliminary ejection receiver 35 are each equal in size to each recording element substrate 4 in plan view. In contrast, in the present embodiment, the wiping member 40 and the preliminary ejection receiver 35 may each be smaller than each recording element substrate 4 in plan view, and the assembly of the wiping member 40 and the preliminary ejection receiver 35 may be large enough to be accommodated inside one recording element substrate 4 in plan view. This allows the cleaning mechanism to be made compact. The wiping member 40 in this embodiment may be any of an elastic tube 40a similar to the first embodiment, a rubber blade 40b similar to the second embodiment, a nonwoven fabric 40c similar to the third embodiment, or a porous body.
[0030] [Fifth embodiment] The fifth embodiment of the present invention will be described below. The same reference numerals are used to denote configurations and methods similar to those of the first to fourth embodiments, and descriptions thereof may be omitted. In this embodiment, the timing from the completion of wiping to the execution of preliminary ejection is maximized, taking into consideration the evaporation characteristics of the recording liquid used. This allows the distance between the wiping member 40 and the preliminary ejection receiver 35 to be greater than that of the first to fourth embodiments. Therefore, a preliminary ejection receiver 35 with a large volume can be used, and the case where a large amount of recording liquid is discharged by preliminary ejection can be handled. In this embodiment, as shown in FIG. 13(a), the wiping member 40 sequentially performs a wiping operation (wiping) starting from the first recording element substrate 4a. Then, as shown in FIG. 13(b), when the wiping member reaches, for example, the sixth recording element substrate 4f, preliminary ejection of the three recording element substrates 4a, 4b, and 4c is performed, and the discharged recording liquid is collected by the large preliminary ejection receiver 35.
[0031] The timing of the start of preliminary ejection from the ejection port 9 after wiping by the wiping member 40 is limited by the thickening state of the recording liquid used, which is determined by the characteristics of the recording liquid itself, environmental conditions, etc. The timing from the end of wiping to the start of preliminary ejection will be described below. FIG. 14 shows the relationship between the elapsed time t after the completion of wiping and the ejection speed vi of the droplets ejected from the ejection port 9. According to this, the ejection speed of the droplets is high immediately after wiping, but as time passes from wiping, the recording liquid becomes thicker and the ejection speed decreases. Then, after a certain amount of time has passed, an ejection speed suitable for ejecting the mixed recording liquid by preliminary ejection cannot be obtained, and the mixed recording liquid cannot be sufficiently ejected from the ejection port 9 and the pressure chamber 14. That is, liquid ejection failure occurs. The time until the minimum ejection speed (the limit line of the ejection speed) at which the mixed recording liquid can be sufficiently ejected by preliminary ejection after wiping is reached is t1. That is, if preliminary ejection is performed in each ejection port 9 at a timing before the time t1 has elapsed after wiping is completed, the recording liquid that has mixed and become viscous can be ejected to the outside of the liquid ejection head 3.
[0032] In this manner, in this embodiment, preliminary ejection is performed at a time t1 at the longest after wiping is completed. At this time, the relative position of the preliminary ejection receiver 35 that receives the preliminary ejected droplets with respect to the wiping member 40 is determined as follows. When the wiping member 40 moves at a moving speed vm, the maximum distance L (see FIG. 13(c)) from the position of the wiping member 40 to the position of the ejection port 9 where preliminary ejection is performed at that timing is expressed by the following formula. L≦vm×t1 (Formula 1) Therefore, the preliminary ejection receiver 35 may be configured to be located within a range of a distance L from the wiping member 40. From another perspective, the position of the rear end of the preliminary ejection receiver 35 that receives the preliminary ejection is located within the range of distance L that satisfies formula 1. Note that the time t1 differs depending on the composition of the recording liquid and the surrounding environment (temperature and humidity) of the liquid ejection head, so it is preferable to determine it by testing under the most severe assumed usage environment conditions. For example, if the speed vm of the wiping member 40 is 20 mm / s and the limit time t1 for good preliminary ejection is 1.5 seconds, L = vm × t1 = 30 mm. Therefore, the maximum distance between the wiping member 40 and the ejection port 9 at which preliminary ejection is performed at that timing is set to within 30 mm. In other words, if the maximum distance from the wiping member 40 to the rear end of the preliminary ejection receiver 35 is 30 mm and it is within a range of 30 mm from the wiping member 40, the preliminary ejection receiver 35 can be made larger. As long as this condition is satisfied, for example, as shown in Fig. 15, a preliminary ejection receiver 35 having the same size as one recording element substrate 4 can be disposed at a position a distance L away from the wiping member 40. In this case, the preliminary ejection receiver 35 is moved intermittently using the size of the recording element substrate 4 as a unit of movement. This is a configuration in which the wiping member 40 and the preliminary ejection receiver 35 are moved independently, and the distance L can be adjusted according to the characteristics of the recording liquid used and the environmental conditions, and the wiping member 40 and the preliminary ejection receiver 35 can be moved according to the distance L.
[0033] Various conditions in each embodiment described above can be controlled by a control mechanism 50 provided in the main body of the recording device 10 as shown in FIG. 16. The control mechanism 50 appropriately controls the timing and speed of the movement of the wiping member 40, the timing and speed of the movement of the preliminary ejection receiver 35, the region where the recording element 15 is operated to eject liquid (specification of the recording element substrate 4 where the preliminary ejection is performed), the ejection timing, and the like. In particular, the timing of the preliminary ejection and the timing of the movement of the preliminary ejection receiver are controlled so as to be synchronized. That is, the control mechanism 50 moves the wiping member 40 along the ejection port rows to wipe a plurality of ejection port rows simultaneously. Before wiping of the entire ejection port formation surface 11a of the main ejection head 3 is completed, the preliminary ejection of the recording liquid from the ejection ports 9 that have already been wiped is started. Then, the preliminary ejection receiver member 35 sequentially collects the liquid that is preliminary ejected and not used for recording in the order of preliminary ejection. In addition, it is preferable to appropriately control these conditions within a range that satisfies the above-mentioned formula 1 described as the fifth embodiment. In this manner, the movement of the wiping member 40 from one end of the liquid ejection head 3 toward the other end is controlled to sequentially perform the cleaning operation. After the cleaning operation is completed, the circulation of the recording liquid is promptly started. The control mechanism 50 stops the circulation flow of the recording liquid flowing from the supply port 18a through the pressure chamber 14 to the recovery port 18b during recording before wiping and preliminary ejection are performed, and resumes the circulation flow after wiping of all the ejection ports 9 and preliminary ejection of the recording liquid are completed. Then, the recording operation is performed to eject the recording liquid in response to the input of a recording signal.
[0034] According to the cleaning method of the present invention, the recording liquid is sequentially discharged from the discharge ports 9 before wiping of all the recording element substrates 4 of the liquid discharge head 3 is completed and before the mixed recording liquid forced into the inside of the discharge ports 9 and pressure chambers 14 of the liquid discharge head 3 thickens. This prevents the mixed recording liquid from circulating, and does not cause a decrease in recording quality in the subsequent liquid discharge. Note that the present invention is not limited to a configuration in which all discharge port rows discharge different colors or types of liquid, and is widely applicable to a configuration in which at least one discharge port row discharges a recording liquid different from the other discharge port rows. The present invention can also be applied to a configuration in which the liquid discharge head 3 has only one recording element substrate 4. In addition, according to the present invention, the consumption of recording liquid during maintenance is small, maintenance that stops the circulation of the recording liquid can be completed in a short time, the thickened recording liquid can be removed from the pressure chamber, and recording operations can be resumed quickly.
[0035] In the above, the liquid ejection head is described as being applied to a so-called multi-color integrated line head configuration. However, the cleaning method of the present invention can also be applied to a liquid ejection head that employs a method of circulating the recording liquid, for example, a monochromatic line-type liquid ejection head. In this case, there is no problem of color mixing, but the maintenance time can be shortened. It goes without saying that the cleaning method of the present invention can also be applied to a configuration in which multiple monochromatic line-type liquid ejection heads that eject liquids of different colors are arranged in parallel to enable color recording as a whole, and multiple liquid ejection heads are wiped at once. [Explanation of symbols]
[0036] 3 Liquid ejection head 4, 4a to 4o Recording element substrate 9 Discharge port 11a Discharge port forming surface 12M,12C,12Y,12K outlet row 40, 40a to 40c Wiping member
Claims
1. A method for cleaning a liquid ejection head which is configured to have a liquid supply path, a supply port, a pressure chamber, a recovery port, and a liquid recovery path so that a recording liquid can be circulated, and which has an ejection port forming surface on which a plurality of ejection port rows each consisting of a plurality of ejection ports are formed, at least one of the ejection port rows ejecting a recording liquid different from that of the other of the ejection port rows, comprising: the cleaning method includes a circulation stopping step of stopping circulation of the recording liquid in the liquid ejection head, a wiping step of wiping the ejection port formation surface, a preliminary ejection step of preliminary ejection of the recording liquid from the ejection port that has already been wiped, and a circulation resumption step of resuming circulation of the recording liquid after the wiping step and the preliminary ejection step are performed; the wiping step is a step of wiping the liquid ejection head by moving a wiping member along the ejection port row arranged from one end to the other end of the liquid ejection head; the preliminary ejection step is a step of sequentially ejecting preliminary ink from the ejection ports that have been passed by the wiping member, for all the ejection ports in the ejection port formation surface, following the movement of the wiping member; A method for cleaning a liquid ejection head, comprising:
2. The liquid ejection head is configured by arranging a plurality of recording element substrates in a row from one end to the other end of the liquid ejection head, the recording element substrates having an ejection port forming surface on which a plurality of ejection port rows each having a plurality of ejection ports are formed, 2. The method for cleaning a liquid ejection head according to claim 1, characterized in that, when, of the multiple arranged recording element substrates, the recording element substrate arranged on the one end side is defined as a first recording element substrate, and the recording element substrate arranged adjacent to the first recording element substrate on the other end side is defined as a second recording element substrate, after performing the wiping process on the first recording element substrate, preliminary ejection is performed from the ejection openings of the first recording element substrate while the wiping process is being performed on the second recording element substrate.
3. The liquid ejection head is configured by arranging a plurality of recording element substrates in a row from one end to the other end of the liquid ejection head, the recording element substrates having an ejection port forming surface on which a plurality of ejection port rows each having a plurality of ejection ports are formed, 2. The method for cleaning a liquid ejection head according to claim 1, characterized in that, when, among the multiple arranged recording element substrates, the recording element substrate arranged on the one end side is defined as a first recording element substrate, and the recording element substrate arranged adjacent to the first recording element substrate on the other end side is defined as a second recording element substrate, while the wiping process is being performed on the first recording element substrate, a preliminary ejection is performed from the ejection port of the first recording element substrate through which the wiping member has passed.
4. The liquid ejection head is configured by arranging a plurality of recording element substrates in a row from one end to the other end of the liquid ejection head, the recording element substrates having an ejection port forming surface on which a plurality of ejection port rows each having a plurality of ejection ports are formed, 2. The method for cleaning a liquid ejection head according to claim 1, characterized in that, when, among the multiple arranged recording element substrates, the recording element substrate arranged on the one end side is defined as a first recording element substrate, and the recording element substrate arranged adjacent to the first recording element substrate on the other end side is defined as a second recording element substrate, while the wiping process is being performed on the second recording element substrate, preliminary ejection is performed from the ejection openings of the first recording element substrate through which the wiping member has passed and the ejection openings of the second recording element substrate through which the wiping member has passed.
5. a moving speed vm of the wiping member, a time t1 from when wiping is performed until a liquid ejection failure occurs due to an increase in the viscosity of the recording liquid caused by volatilization of a volatile component at the ejection port where wiping is performed, and a distance L between the ejection port being wiped and the ejection port at which preliminary ejection is started, L≦vm×t1 5. The method for cleaning a liquid ejection head according to claim 1, wherein the following relationship is satisfied:
6. A liquid ejection head comprising a liquid supply path, a supply port, a pressure chamber, a recovery port, and a liquid recovery path, configured to circulate recording liquid, and comprising an ejection port forming surface on which a plurality of ejection port rows are formed, at least one of the ejection port rows ejecting a recording liquid different from that of the other ejection port rows; a wiping member that wipes the ejection port surface; a preliminary ejection receiving member for receiving the liquid ejected by the preliminary ejection from the ejection port after the wiping; a control mechanism for controlling each of the operations of circulating the recording liquid to the liquid ejection head, ejecting the recording liquid from the ejection openings, moving the wiping member, and moving the preliminary ejection receiving member, the control mechanism performs a circulation stop to stop the circulation of the recording liquid in the liquid ejection head; a wiping operation in which the wiping member moves from one end of the liquid ejection head toward the other end along the ejection port rows to simultaneously wipe the plurality of ejection port rows; a preliminary ejection operation to eject the recording liquid not used for recording from the wiped ejection ports; an operation of receiving the preliminary ejected recording liquid in the preliminary ejection receiving member; and a circulation restart operation to restart the circulation of the recording liquid after the wiping and the preliminary ejection are performed; the operation of receiving the preliminary ejection with the preliminary ejection receiving member is to move the preliminary ejection receiving member so as to face the ejection port from which the preliminary ejection is being performed in synchronization with the ejection of the recording liquid from all the ejection ports of the ejection port formation surface through which the wiping member has passed, following the movement of the wiping member; A liquid ejection device comprising:
Citation Information
Patent Citations
Cleaning of ink discharge hole and ink jet recording device using the same cleaning technique
JP1990202453A
Ink jet recorder
JP1995025026A
Ink jet recording method, ink jet recording apparatus, and recorded material
JP2012051124A
Inkjet recording device and maintenance method thereof
JP2013001070A
Inkjet recording device
JP2013180440A