Liquid discharge device, method for discharging liquid and control program

Abstract

To sufficiently clean and moisturize a suction cap in a liquid discharge device.SOLUTION: A liquid discharge device including a head and performing a prescribed treatment with liquid that is discharged by the head includes: a suction part for sucking the head; a first cleaning part for cleaning the suction part by injecting cleaning fluid within one hour after the suction part sucks the head; and a second cleaning part for cleaning the suction part by injecting cleaning fluid into the suction part every second time that is set on the basis of temperature and humidity.SELECTED DRAWING: Figure 14

Description

[Technical field]

[0001] The present invention relates to a liquid ejection apparatus, a liquid ejection method, and a control program. [Background technology]

[0002] 2. Description of the Related Art There are known techniques for performing various processes by ejecting liquid, specifically, techniques for image forming apparatuses that use ink as the liquid and perform a process for forming an image on a recording medium such as paper, and the like.

[0003] An image forming apparatus having a head that ejects ink is provided with a suction cap that sucks ink from the head. When ink remains in the ink for a long time, it thickens and adversely affects the suction by the suction cap or the ejection by the head. For this reason, the ink is sucked by the suction cap. On the other hand, if ink remains in the suction cap, the suction performance decreases. Therefore, a technique is known that washes the suction cap to prevent the suction performance of the suction cap from decreasing (for example, see Patent Document 1, etc.). Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional technology, the suction cap is often not sufficiently cleaned and moisturized. As a result, dried ink clogs various places, causing problems. Therefore, the conventional technology has a problem that the suction cap cannot be sufficiently cleaned and moisturized.

[0005] SUMMARY OF THE DISCLOSURE In view of the above, an object of the present invention is to thoroughly clean and moisturize a suction cap in a liquid ejection device. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, a liquid ejection apparatus includes: A liquid ejection device including a head, the liquid being ejected by the head for performing a predetermined process, A suction unit that sucks the head; a first cleaning unit that injects a cleaning solution to clean the suction unit within one hour after the suction unit starts suction; a second cleaning unit that injects the cleaning liquid into the suction unit and cleans the suction unit every second time period that is set based on temperature and humidity; Equipped with. Effect of the Invention

[0007] According to the present invention, the suction cap of the liquid ejection device can be thoroughly cleaned and moisturized. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram (side view) illustrating an example of a liquid ejection device. [Diagram 2] FIG. 1 is a diagram (plan view) illustrating an example of a liquid ejection device. [Diagram 3] 1A and 1B are diagrams illustrating an example of a carriage 103. [Figure 4] 13 is a diagram showing an example (part 1) of the arrangement of a head cleaning unit 171 and a carriage 103. FIG. [Diagram 5] 13 is a diagram showing an example (part 2) of the arrangement of the head cleaning unit 171 and the carriage 103. FIG. [Figure 6] 13 is a diagram showing an example (part 3) of the arrangement of the head cleaning unit 171 and the carriage 103. FIG. [Figure 7] FIG. 4 is a diagram illustrating an example of a suction unit. [Figure 8] FIG. 13 is a diagram showing an example (part 1) of injection of a cleaning solution. [Figure 9] FIG. 13 is a diagram showing an example (part 2) of injection of a cleaning solution. [Figure 10] FIG. 13 is a diagram showing an example (part 3) of injection of a cleaning solution. [Figure 11] FIG. 13 is a diagram showing an example (part 4) of injection of a cleaning solution. [Figure 12] FIG. 13 is a diagram showing an example of remaining ink. [Figure 13] FIG. 13 is a diagram showing an example of setting a cleaning frequency. [Figure 14] FIG. 13 is a diagram illustrating an example of the overall process. [Figure 15] FIG. 13 is a diagram showing an example of sealing the exhaust port. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, specific examples will be described with reference to the accompanying drawings. Note that the embodiment is not limited to the specific examples described below.

[0010] [Example of liquid ejection device] FIG. 1 is a diagram (side view) showing an example of a liquid ejection device. FIG. 2 is a diagram (plan view) showing an example of a liquid ejection device. The liquid ejection device is, for example, an image forming apparatus 10 as described below. That is, in the following example, the liquid is ink for forming an image. Also, in the following example, the recording medium to which the liquid adheres is paper 112.

[0011] The image forming apparatus 10 has a carriage 103 supported by a guide rod 101, which is a guide member mounted horizontally on side panels installed on the left and right, and a guide rail 102 so that the carriage 103 can slide freely in the main scanning direction, and is moved in the main scanning direction by a main scanning motor 104 via a timing belt 105.

[0012] The carriage 103 includes rows of nozzles that eject ink of four colors, for example, yellow (Y), cyan (C), magenta (M), and black (Bk). The carriage 103 also includes four print heads 107 and a cleaning head 201 that cleans the suction cap 173 with cleaning liquid.

[0013] The nozzle rows of the print head 107 are arranged on the carriage 103 such that the longitudinal direction of the nozzle rows is perpendicular to the main scanning direction of the carriage 103 .

[0014] The inkjet head constituting the recording head 107 includes a piezoelectric actuator such as a piezoelectric element, a thermal actuator that utilizes a phase change caused by film boiling of a liquid using an electrothermal conversion element such as a heating resistor, a shape memory alloy actuator that uses a metal phase change caused by a change in temperature, or an electrostatic actuator that uses electrostatic force.

[0015] The carriage 103 also includes sub-tanks 108 for each color in order to supply ink of each color to the recording head 107. Ink is supplied to the sub-tanks 108 from a main tank (hereinafter referred to as an "ink cartridge 12") via an ink supply tube 14.

[0016] The image forming apparatus 10 integrally includes a sub-tank 108 and a recording head 107. However, the recording head 107 and the sub-tank 108 may be separate. Furthermore, the ink cartridge 12 and the recording head 107 may be integrated without using a sub-tank.

[0017] Meanwhile, the paper feed cassette 110 has papers 112 stacked on a pressure plate 111. A paper feed roller 113 is provided to separate and transport the papers 112 one by one from the pressure plate 111. A separation pad 114 is provided at a position opposite the paper feed roller 113.

[0018] A conveyor belt 121 is provided for electrostatically attracting and conveying the paper 112. Also provided is a counter roller 122 for pinching the paper 112 sent via a guide 115 between the conveyor belt 121 and conveying it.

[0019] A conveying guide 123 is provided to change the direction of the paper 112 so that the paper 112 follows the conveying belt 121. A tip pressure roller 125 is provided on the pressing member 124 on the conveying belt 121 side. A charging roller 126 is also provided to charge the surface of the conveying belt 121.

[0020] The conveyor belt 121 is an endless belt and is stretched between a conveyor roller 127 and a tension roller 128.

[0021] A sub-scanning motor 131 rotates a timing belt 132 and a timing roller 133. Next, the timing belt 132 and the timing roller 133 rotate the transport roller 127. Then, when the transport roller 127 rotates, the transport belt 121 rotates in the sub-scanning direction. Note that a guide member 129 is provided on the rear side of the transport belt 121 in correspondence with an image forming area where the recording head 107 forms an image.

[0022] A slit disk 134 is provided on the shaft of the transport roller 127. Further, a sensor 135 is provided to detect the slits of the slit disk 134. The slit disk 134 and the sensor 135 constitute a first encoder 136.

[0023] The charging roller 126 is in contact with the surface layer of the conveyor belt 121. The charging roller 126 is disposed so as to rotate following the rotation of the conveyor belt 121. The charging roller 126 applies a pressure of 2.5 N to both ends of the shaft.

[0024] An encoder scale 142 having slits formed therein is provided on the rear side of the carriage 103. An encoder sensor 143 detects the slits of the encoder scale 142. For example, the encoder sensor 143 is a transmissive photosensor or the like. The encoder scale 142 and the encoder sensor 143 constitute a second encoder 144 that detects the position of the carriage 103 in the main scanning direction relative to the home position.

[0025] In order to discharge the paper 112, the image forming apparatus 10 is provided with a separation claw 16 that separates the paper 112 from the conveyor belt 121, a paper discharge roller 152, a paper discharge roller 153, and a paper discharge tray 154 that stocks the paper 112 to be discharged.

[0026] A double-sided paper feed unit 161 is detachably attached to the rear of the image forming apparatus 10. The double-sided paper feed unit 161 takes in the paper 112 returned by the reverse rotation of the conveyor belt 121, turns it over, and feeds it again between the counter roller 122 and the conveyor belt 121.

[0027] The paper 112 is separated and fed one by one, and the paper 112 fed upward is guided by a guide 115. Next, the paper 112 is sandwiched between a conveyor belt 121 and a counter roller 122 and conveyed. Next, the leading edge of the paper 112 is guided by a conveyor guide 123, and is pressed against the conveyor belt 121 by a leading edge pressure roller 125, after which the conveying direction is changed by 90°.

[0028] The control circuit applies a voltage from the high-voltage power supply to the charging roller 126 so that positive and negative outputs are alternately repeated. By such control, the conveyor belt 121 is charged with a charging voltage pattern, i.e., positive and negative voltages are alternately charged in a belt shape of a predetermined width in the sub-scanning direction which is the rotation direction.

[0029] When the paper 112 is conveyed onto the conveyor belt 121 that is alternately positively and negatively charged, the paper 112 is electrostatically attracted to the conveyor belt 121. After being attracted, the paper 112 is conveyed in the sub-scanning direction by the circular movement of the conveyor belt 121.

[0030] Meanwhile, the image forming apparatus 10 drives the recording head 107 in response to an image signal while moving the carriage 103. The recording head 107 then forms an image for one line by ejecting ink onto the paper 112. After the image is formed, the paper 112 is transported a predetermined distance, and the recording head 107 forms an image for the next line.

[0031] When the image forming apparatus 10 receives a recording end signal or a signal indicating that the rear end of the paper 112 has reached the image forming area, the image forming apparatus 10 ends image formation and ejects the paper 112 onto the paper ejection tray 154 .

[0032] In the case of double-sided printing, after completing image formation on the front side (i.e., the side on which an image is formed first), image forming apparatus 10 reverses the rotation of conveyor belt 121. Then, sheet 112 is conveyed into double-sided paper feed unit 161 and sheet 112 is turned over. In this way, a state is created in which image formation is possible on the back side, and image forming apparatus 10 conveys sheet 112 between counter roller 122 and conveyor belt 121 again. After conveyance, image forming apparatus 10 performs timing control to form an image on the back side of sheet 112, and then discharges the sheet to discharge tray 154.

[0033] A head cleaning unit 171 that cleans the nozzle surface is installed at a position away from the paper 112 in the scanning direction (X-axis direction) of the carriage 103. Specifically, the head cleaning unit 171 is installed with a suction cap 173, a recording head moisture cap 172, a cleaning head moisture cap 204, and a wiper blade 174.

[0034] 3 is a diagram showing an example of the carriage 103. Specifically, the carriage 103 is mounted on a guide rod 101 via a carriage guide 106.

[0035] The carriage 103 includes a recording head 107 and a cleaning head 201 .

[0036] The recording head 107 includes ink ejection nozzles 211 that eject ink. An image is formed by ejecting ink from the ink ejection nozzles 211 onto a sheet of paper 112.

[0037] The cleaning head 201 includes a cleaning nozzle 202 that flushes a cleaning liquid. Note that the cleaning nozzle 202 only needs to be able to flush the cleaning liquid, and does not need to be able to flush liquid like the ink ejection nozzle 211. The cleaning nozzle 202 may have a lower diameter precision than the ink ejection nozzle 211, and may have a larger nozzle diameter than the ink ejection nozzle 211.

[0038] [Example of equipment configuration used for cleaning] 4 to 6 are diagrams showing examples of the arrangement of the head cleaning unit 171 and the carriage 103. Below, an example in which the first cleaning unit and the second cleaning unit are realized by the head cleaning unit 171 will be described.

[0039] However, the first cleaning unit and the second cleaning unit may be realized by separate dedicated hardware instead of being realized by a common hardware. Also, the first cleaning unit and the second cleaning unit may be realized by an injection device or the like that injects the cleaning liquid into the suction cap 173 inside or outside the image forming apparatus 10.

[0040] The carriage 103 has a sub-tank 108 that temporarily stores ink to be supplied to the print head 107 , and a cleaning liquid sub-tank 203 that temporarily stores cleaning liquid to be supplied to the cleaning head 201 .

[0041] On the other hand, the head cleaning unit 171 is provided in an area outside the image forming area. The head cleaning unit 171 includes a suction cap 173, a suction mechanism 205, a recording head moisture cap 172, a cleaning head moisture cap 204, a wiper blade 174, and an absorber 206.

[0042] The suction cap 173 sucks ink or cleaning liquid from the ink ejection nozzles 211 and the cleaning nozzles 202 .

[0043] The suction mechanism 205 sucks the liquid present in the suction cap 173 through the suction path 212. For example, the suction mechanism 205 is a pump.

[0044] The print head moisture retaining cap 172 retains moisture on the nozzle surface of the print head 107 to prevent the nozzles from becoming clogged due to drying.

[0045] The cleaning head moisture retaining cap 204 keeps the nozzle surface of the cleaning head 201 moist, thereby preventing the nozzles from becoming clogged due to drying.

[0046] The wiper blade 174 wipes the nozzle faces of the ink ejection nozzles 211 and the cleaning nozzles 202 to remove any liquid remaining on the nozzle faces.

[0047] The absorbent body 206 absorbs the liquid wiped by the wiper blade 174 .

[0048] In this example, there is one suction cap 173, but one may be provided for each print head moisture cap 172. Furthermore, if the volatility of the ink or cleaning liquid is low, the print head moisture cap 172 and cleaning head moisture cap 204 may not be necessary.

[0049] 4 shows the image forming apparatus 10 in a standby state, a cleaning state, etc. For example, the nozzle surface of the ink ejection nozzles 211 of the recording head 107 is sealed by a suction cap 173 corresponding to the ink ejection nozzles 211 and a recording head moisture retention cap 172.

[0050] The cleaning nozzle 202 of the cleaning head 201 is sealed by a cleaning head moisture retaining cap 204 .

[0051] The above-mentioned configuration prevents the nozzle surfaces of the ink ejection nozzles 211 and cleaning nozzles 202 from drying. In addition, the suction mechanism 205 is operated with the nozzle surface sealed to create a negative pressure inside the suction cap 173. Then, the ink ejection nozzles 211 suck up the ink inside the recording head 107a to perform head cleaning.

[0052] Next, the carriage 103 is moved, and the print heads 107b, 107c, and 107d are sucked by the suction cap 173. In this manner, the print heads 107a to 107d are cleaned.

[0053] During cleaning, ink may remain inside the suction cap 173. When the suction cap 173 is opened to the atmosphere, the ink remaining inside the suction cap 173 tends to dry out and accumulate. This drying is more noticeable when ink containing a high solid content and a highly viscous pigment is used. In addition, water-based disperse dyes and the like may also have poor resolubility.

[0054] Problems can easily arise when an ink whose fluidity changes (for example, water-based ink) loses its fluidity. Specifically, the fluidity of an ink is lost due to "1: Easy to lose fluidity (synonymous with easy to thicken or dry out)", "2: Low fluidity to begin with (synonymous with high viscosity)", and "3: Poor resolubility (once fluidity is lost, it is difficult to return to the original state)". Of these, "3: Poor resolubility" is particularly problematic. In other words, adding water after the fluidity has been lost has little effect if the resolubility is poor.

[0055] Fig. 5 shows a state in which the image forming apparatus 10 cleans the suction cap 173. As shown in Fig. 5, in a state in which the cleaning nozzle 202 of the cleaning head 201 is sealed with the suction cap 173, the suction mechanism 205 is operated.

[0056] When the cleaning liquid flows into the suction cap 173, the ink remaining in the suction cap 173 is washed away and cleaned. In this cleaning, the suction cap 173 sucks the cleaning nozzle 202.

[0057] When the cleaning nozzle 202 and the ink discharge nozzle 211 are sucked together, ink and cleaning liquid may flow into the suction cap 173, decreasing the efficiency of cleaning the suction cap 173. Therefore, the suction cap 173 can efficiently clean the ink inside the suction cap 173 by restricting suction to the cleaning nozzle 202.

[0058] It is also preferable to suction the cleaning nozzles 202 successively after suctioning the ink ejection nozzles 211. The suction cap 173 is installed in a position outside the image formation area. Therefore, when the carriage 103 is in a position facing the suction cap 173, the cleaning nozzles 202 of the carriage 103 are located farther from the paper 112 than the ink ejection nozzles 211.

[0059] The ink remaining in the suction cap 173 will dry out and solidify over time due to exposure to the atmosphere, making it difficult to clean. Therefore, if the cleaning liquid is quickly sucked up by the suction cap 173 after the ink is sucked up by the suction cap 173, a significant cleaning effect can be obtained.

[0060] Furthermore, by locating the cleaning nozzles 202 at a position away from the ink ejection nozzles 211, the suction operation of the print head 107, the cleaning operation of the suction cap 173, and the printing operation can be performed in a series of operations. Specifically, the operations can be performed in the moving direction of the carriage 103, that is, in the order of Figures 4, 5, and 6. In this way, unnecessary movement of the carriage 103 can be reduced when cleaning the suction cap 173, and the productivity of the image forming apparatus 10 can be improved.

[0061] 6 shows a state in which the image forming apparatus 10 forms an image on paper 112. Specifically, the carriage 103 reciprocates along the guide rod 101. During the reciprocating movement, the recording head 107 ejects ink to form an image on the paper 112.

[0062] The hardware configuration and operation procedure are not limited to those described above. That is, the liquid ejection device may include hardware other than those described above. Furthermore, the liquid ejection device may achieve cleaning using a procedure or hardware different from those described above.

[0063] [Example of suction part] 7 is a diagram showing an example of a suction unit. Specifically, the nozzles of the print head 107 come into contact with the opening 301 of the suction cap 173. Then, the print head 107 is brought into contact with the opening 301 and sealed, and then the suction mechanism 205 performs suction. In this way, when the suction mechanism 205 performs suction, a negative pressure is created inside the suction cap 173, and ink can be sucked from the print head 107. When the ink is sucked, it is discharged from the discharge port 303. In this way, maintenance of the print head 107 is performed.

[0064] In addition, ink may enter the suction cap 173 due to “idle ejection” in which the print head 107 ejects ink onto the suction cap 173 .

[0065] An absorber 302 may be provided inside the suction cap 173. By providing the absorber 302, it is possible to prevent ink from flying and turning into mist due to idle ejection, which can soil the machine body, or adhere to the nozzles and cause ejection defects.

[0066] Furthermore, when the image forming apparatus 10 is in a standby state, the recording head 107 may be capped. In this state, if the absorber 302 contains moisture such as ink, the nozzles can be kept moist.

[0067] [Cleaning example] 8 to 11 are diagrams showing examples of cleaning. Below, the state inside the suction cap 173 shown in Fig. 7 will be explained using schematic diagrams. In the following explanation, "ink components 304" are typically indicated by black circles, and "cleaning liquid components 305" are typically indicated by white circles.

[0068] Fig. 8 is a diagram showing an example (part 1) of injection of a cleaning liquid. Hereinafter, an example will be described in which a cleaning liquid is injected into the suction cap 173 in the state shown in Fig. 8 to perform cleaning. Therefore, when the inside of the suction cap 173 is cleaned with a cleaning liquid, the state changes in the order of Fig. 8, Fig. 9, Fig. 10, and Fig. 11.

[0069] After the recording head 107 is sucked, the recording head 107 is decapped. Next, the image forming apparatus 10 performs "idle suction" after decap. "Idle suction" is an operation in which suction is performed in a state in which the recording head 107 is not in contact with the suction cap 173. By such "idle suction", ink is discharged from the suction cap 173.

[0070] Even when idle suction is performed, ink components 304 remain inside the suction cap 173, as shown in Fig. 8. In particular, in a configuration in which the absorber 302 is provided, a large amount of ink components 304 tend to remain inside the suction cap 173 because the absorber 302 absorbs the ink.

[0071] Furthermore, if the ink has low resolubility, once the ink dries, even if moisture (including ink) enters the suction cap 173, the dried ink may not liquefy and may accumulate.

[0072] Fig. 9 is a diagram showing a second example of injection of cleaning liquid. Fig. 9 shows a state in which cleaning liquid is injected into the suction cap 173 in the state shown in Fig. 8, and the suction cap 173 is further cleaned. The ink component 304 inside the suction cap 173 is reduced compared to the state shown in Fig. 8. Furthermore, when cleaning liquid is injected, the cleaning liquid component 305 inside the suction cap 173 increases, and the cleaning liquid component 305 cleans the inside of the suction cap 173.

[0073] Fig. 10 is a diagram showing a third example of injection of a cleaning liquid, in which a cleaning liquid is injected into the suction cap 173 in the state shown in Fig. 9, and the suction cap 173 is further washed.

[0074] Fig. 11 is a diagram showing a fourth example of injection of a cleaning liquid, in which a cleaning liquid is injected into the suction cap 173 in the state shown in Fig. 10, and the suction cap 173 is further washed.

[0075] As described above, when the suction cap 173 is washed, the ink components 304 are diluted or discharged from within the suction cap 173, and thus are reduced.

[0076] Ink components 304 are easily discharged if they are washed before they dry, that is, before the water in ink components 304 evaporates. Therefore, washing is performed within a predetermined time after the suction unit performs suction (hereinafter, the time from suction to washing is referred to as the "first time"). The first time is a time that is set in advance. Moreover, washing performed within the first hour is referred to as the "first washing".

[0077] That is, it is desirable to perform the first cleaning as soon as possible after suction (including dry suction) has been performed. Therefore, it is desirable to set the first time period based on the specifications of the device and the like, so that the first cleaning can be performed as short as possible. It is also desirable to set the first time period taking into consideration the temperature and humidity. Specifically, the first time period is set to about several minutes.

[0078] Fig. 12 is a diagram showing an example of remaining ink. Even after the first cleaning, as shown in Fig. 12, there are cases where ink components 304 are not completely discharged and remain in the suction cap 173. If drying proceeds with the ink components 304 remaining in the suction cap 173 in this way, the ink components 304 will solidify in the suction cap 173.

[0079] In particular, when an image is formed, the toner is in a decapped state, and therefore drying is likely to proceed. Also, the higher the temperature or the lower the humidity, the faster the evaporation rate, and therefore the more the toner dries.

[0080] Therefore, the image forming apparatus 10 performs a cleaning (hereinafter referred to as a "second cleaning") in addition to the first cleaning. The second cleaning is a cleaning that is performed periodically at predetermined time intervals (hereinafter, the cycle for performing the second cleaning is referred to as a "second time").

[0081] Fig. 13 is a diagram showing an example of how the cleaning frequency is set. For example, the second cleaning is performed according to a weighting coefficient determined by a table for determining the cleaning frequency shown in Fig. 13 (hereinafter simply referred to as "the table").

[0082] In the table, the horizontal axis is "humidity h" and the vertical axis is "temperature t." Therefore, when temperature and humidity conditions are acquired by sensors such as a thermometer and a hygrometer, the weighting coefficients are determined by the table. The weighting coefficients entered in the table are set in advance.

[0083] The weighting factor corresponds to the length of the second time period, so that the larger the weighting factor, the shorter the second time period is set, and the shorter the second time period, the more frequently the second cleaning is performed.

[0084] The weighting coefficient is set to a higher value as the temperature increases. For example, when the humidity is "humidity h is less than 10%" and the temperature t is less than 10°C, the weighting coefficient is "0.25." On the other hand, when the humidity is "humidity h is less than 10%" and the temperature t is equal to or greater than 40°C and less than 45°C, the weighting coefficient is "1.5." In this way, even under the same humidity conditions, the weighting coefficient becomes larger if the temperature is higher. Therefore, the higher the temperature, the shorter the second time is determined to be, and the more frequently the second cleaning is performed.

[0085] The weighting coefficient is set to a higher value as the humidity becomes lower. For example, when "temperature t is 30° C. or higher and lower than 35° C." and "humidity h is less than 10%", the weighting coefficient is "1". On the other hand, when "temperature t is 30° C. or higher and lower than 35° C." and "humidity h is 90% or higher", the weighting coefficient is "0.25". In this way, even under the same temperature conditions, the weighting coefficient becomes larger if the humidity is low. Therefore, the lower the humidity, the shorter the second time is determined and the more frequently the second cleaning is performed.

[0086] Alternatively, the weighting coefficient may be added every hour, and the second cleaning may be performed when the added value reaches a threshold value. For example, in the decapped state, the temperature and humidity are acquired every minute. The weighting coefficient is determined based on the acquired temperature and humidity.

[0087] For example, the threshold value is preset to "100." If "temperature t is 37°C" and "humidity h is 25%, the weighting coefficient is determined to be "1." Therefore, under these conditions and settings, if the decap state continues for "100 minutes," the second cleaning is executed.

[0088] Similarly, if "temperature t is 27°C" and "humidity h is 25%, the weighting coefficient is determined to be "0.5." Therefore, under these conditions and settings, if the decap state continues for "200 minutes," the second cleaning is performed.

[0089] As described above, it is desirable to determine the second time so that it is shorter as the temperature and humidity conditions result in a faster evaporation rate. Under temperature and humidity conditions such as high temperature or low humidity, where the evaporation rate is fast, the ink tends to dry out. Therefore, under temperature and humidity conditions where the evaporation rate is fast, it is desirable to perform cleaning more frequently. In this way, when the second cleaning is performed based on the temperature and humidity conditions, the suction cap 173 can be sufficiently cleaned and moisturized.

[0090] The weighting coefficients are not limited to the values ​​and trends shown in Fig. 13. In other words, the weighting coefficients may be set to different values ​​depending on the drying time, decap time, time for ink to accumulate, amount of water evaporation, device, type of liquid, etc. Depending on the type of ink, the ease of re-dissolving or drying may differ. Also, the weighting coefficients may be calculated and determined based on a formula or the like instead of a table.

[0091] When one suction cap 173 corresponds to multiple heads, cleaning may be performed for each head. On the other hand, when one suction cap 173 corresponds to multiple heads, cleaning may be performed after the last head has been used.

[0092] [Overall processing example] 14 is a diagram showing an example of the overall process. For example, the overall process is a process in which steps S1401 to S1402 related to the first cleaning and steps S1403 to S1404 related to the second cleaning are executed in parallel.

[0093] In step S1401, the image forming apparatus 10 determines whether or not suction has been performed. If suction has been performed (YES in step S1401), the image forming apparatus 10 proceeds to step S1402. On the other hand, if suction has not been performed (NO in step S1401), the image forming apparatus 10 repeats step S1401.

[0094] In step S1402, the image forming apparatus 10 performs a first cleaning procedure in which a first cleaning is performed within a first hour.

[0095] It should be noted that the image forming apparatus 10 may perform other operations as long as the first cleaning is performed within the first hour. For example, operations other than the first cleaning, such as ink suction or blank ejection, may be performed consecutively in a short period of time. Specifically, in a head cleaning operation, ink suction, wiping of the head nozzle surface, and blank ejection may be set as one set of operations. If the time required to perform the first cleaning plus this set of operations all falls within the first hour, it is desirable for the image forming apparatus 10 to perform the first cleaning after completing the series of operations in one set.

[0096] On the other hand, if the operation of filling the cap with ink is intermittent and an interval of the first time or more elapses between cleaning operations, it is desirable for the image forming apparatus 10 to perform the first cleaning each time.

[0097] In step S1403, the image forming apparatus 10 determines the second time based on the temperature and humidity.

[0098] In step S1404, the image forming apparatus 10 performs a second cleaning procedure in which a second cleaning is performed every second time determined in step S1403.

[0099] For example, the second cleaning checks the temperature and humidity periodically (preset in advance, for example, every minute) during decap, and adds the weighting coefficient shown in Fig. 13. Then, when the total value of the weighting coefficient exceeds a threshold, the second cleaning is performed and the total value is reset. The total value may also be reset when the first cleaning is performed.

[0100] Step S1404 is repeatedly executed for each second time period determined in step S1403.

[0101] As described above, if suction is performed in step S1402, the first cleaning is performed within the first hour. Meanwhile, separately from the first cleaning, the second cleaning is performed periodically in steps S1403 and S1404.

[0102] The first cleaning is performed immediately after ink enters the suction cap 173 by suction. In other words, the first cleaning is performed before the ink dries inside the suction cap 173 and becomes difficult to discharge. Therefore, the first cleaning is performed to rinse and wash away the ink with cleaning liquid while the ink is in a liquid state and has high fluidity.

[0103] In this way, when both the first cleaning and the second cleaning are performed, the cleaning is performed periodically and at a timing when the liquid is likely to flow, so that the image forming apparatus 10 can sufficiently clean the suction cap 173. Furthermore, since the cleaning liquid is periodically injected by the second cleaning in addition to the first cleaning, the image forming apparatus 10 can sufficiently moisturize the inside of the suction cap 173.

[0104] Note that cleaning may be performed after an idle discharge or the like is performed. Cleaning may also be performed multiple times. Furthermore, when performing cleaning multiple times, it is desirable to use a small amount of cleaning liquid for the first cleaning, and a large amount of cleaning liquid for the second and subsequent cleanings. In this way, by starting with a small amount of cleaning liquid and then increasing the amount, it is possible to prevent cleaning liquid contaminated by cleaning from reaching the upper surface of the suction cap 173.

[0105] Also, the time from when the cleaning liquid is injected for cleaning to when the cleaning liquid is discharged (hereinafter referred to as "wait time") may be set. Depending on the type of ink, it may take time for the components to peel off from the suction cap 173. Therefore, if there is a wait time, more ink can be discharged.

[0106] When injecting a cleaning liquid for cleaning, the outlet 303 may be sealed and a certain amount of cleaning liquid may be stored in the suction cap 173 before the cleaning liquid is discharged. In other words, it is desirable to inject the cleaning liquid until it reaches the entire inside of the suction cap 173.

[0107] In particular, when there are few injection ports for injecting the cleaning liquid, or in a configuration in which the absorbent body 302 is provided, it is desirable to inject a sufficient amount of cleaning liquid until the cleaning liquid reaches the entire inside of the suction cap 173.

[0108] [Modification of sealing the exhaust port 303] After cleaning the suction unit in the first cleaning or the second cleaning, the image forming apparatus 10 preferably closes one of the discharge paths to fill the inside of the cap with cleaning liquid and prevent the inside of the cap from drying out. Specifically, it is preferable to further include a sealing mechanism that seals the discharge side by squeezing the tube with a tubing pump, for example. Alternatively, a sealing mechanism that seals the discharge path by attaching an electromagnetic valve or the like to one of the discharge paths may be used.

[0109] The sealing mechanism may be the following: Note that the following lid or the like may be used in combination to seal the waste liquid.

[0110] Fig. 15 is a diagram showing an example of sealing the exhaust port. Compared to Fig. 7, Fig. 15 is different in that the exhaust port 303 is sealed by a sealing mechanism 306.

[0111] After the image forming apparatus 10 has cleaned the suction unit in the first cleaning or the second cleaning, it is preferable that the cleaning liquid be discharged from the discharge port 303 and the discharge port 303 be sealed by the sealing mechanism 306 .

[0112] For example, when the suction path 212 is a tube, the sealing mechanism is configured to crush the tube to make it difficult for waste liquid to flow. However, the sealing mechanism only needs to be able to prevent discharge. The sealing mechanism 306 may be, for example, a valve, a lid, or a throttle mechanism. The sealing mechanism 306 is sealed or opened by an actuator or manually.

[0113] When the discharge port 303 is sealed by the sealing mechanism 306, the cleaning liquid can be held within the suction cap 173. Therefore, when the discharge port 303 is sealed by the sealing mechanism 306, the image forming apparatus 10 can keep the inside of the suction cap 173 moist.

[0114] Furthermore, when the discharge port 303 is capped with the sealing mechanism 306 sealed, the nozzle surface of the print head 107 can also be kept moist.

[0115] However, it is desirable to seal the discharge port 303 with the sealing mechanism 306 after cleaning and discharge. If the discharge port 303 is sealed when there is a large amount of ink components 304 inside the suction cap 173, the cleaning liquid containing a large amount of ink components 304 may reach the upper surface of the suction cap 173, and the ink components 304 may dry near the upper surface of the suction cap 173. Therefore, if the sealing mechanism 306 seals the discharge port 303 after cleaning and discharge, i.e., when there is a small amount of ink components 304 inside the suction cap 173, it is possible to prevent the ink components 304 from remaining near the upper surface of the suction cap 173.

[0116] Furthermore, it is preferable that the cleaning liquid is injected while the discharge port 303 is sealed by the sealing mechanism 306. When the cleaning liquid is injected while the discharge port 303 is sealed by the sealing mechanism 306, the cleaning liquid can be held within the suction cap 173. Therefore, when the cleaning liquid is injected while the discharge port 303 is sealed by the sealing mechanism 306, the image forming apparatus 10 can keep the inside of the suction cap 173 moist.

[0117] Note that a process of draining the cleaning liquid may be performed before sealing. The remaining amount of cleaning liquid in the suction cap 173 varies depending on the dry state, etc. Therefore, the cleaning liquid is drained once and the remaining amount is reset, and then the cap is sealed and the cleaning liquid is injected. In this manner, it is possible to prevent the cleaning liquid in the suction cap 173 from overflowing from the cap, without measuring the remaining amount of cleaning liquid in the suction cap 173 or varying the amount of cleaning liquid injected.

[0118] [Modification of the third cleaning section] It is preferable to further include a third cleaning unit that injects cleaning liquid to clean the suction unit (hereinafter referred to as "third cleaning") when there is a state transition such as power operation, transition to a sleep state, or recovery from a sleep state. For example, the third cleaning unit is realized by a head cleaning unit 171 or the like.

[0119] The power operation is, for example, an operation in which the user presses a power switch to switch the power of the entire image forming apparatus 10 to "ON" or "OFF."

[0120] The sleep state is a state in which part of the image forming apparatus 10 is stopped. For example, if no command is given to the image forming apparatus 10 for a certain period of time, the image forming apparatus 10 transitions to the sleep state. On the other hand, if a command is input to the image forming apparatus 10 in the sleep state, the image forming apparatus 10 returns from the sleep state to a state in which processing such as image formation can be executed.

[0121] In addition, the state transition may include a transition from a sleep state or a state in which a process can be executed to another mode if there is a mode other than the sleep state or the state in which a process can be executed.

[0122] It is desirable to cap the image forming apparatus 10 before the state transition. However, even if the image forming apparatus 10 is capped, evaporation of moisture often occurs. Therefore, when the image forming apparatus 10 transitions to the state, the image forming apparatus 10 performs the third cleaning.

[0123] In this way, when cleaning is performed during state transition, the ink components 304 remain in the suction cap 173 and can be prevented from drying.

[0124] In addition, even when the third cleaning is performed, the image forming apparatus 10 can keep the inside of the suction cap 173 moist by sealing the discharge port 303 with the sealing mechanism 306 after the cleaning is performed, and injecting cleaning liquid after sealing the discharge port 303 with the sealing mechanism 306.

[0125] [Modification of injection route] The cleaning liquid may be injected from a point other than the opening 301. For example, a path for injecting the cleaning liquid (hereinafter simply referred to as an "injection path") may be formed in the suction cap 173. In this manner, in a configuration with an injection path, the cleaning liquid can be injected into the suction cap 173 regardless of the capping or decapping state. Furthermore, if there are multiple injection paths, the cleaning liquid can be dispersed so that it is not injected unevenly.

[0126] [About caps and decaps] "Capping" refers to a process of closing the top of the suction cap 173 (opening 301 in FIG. 7) to put the suction cap 173 in a sealed state. For example, capping refers to a process of moving the recording head 107 so that the recording head 107 abuts against the opening 301. In the capped state, the nozzle surface of the recording head 107 abuts against the opening 301, so that the nozzle surface of the recording head 107 is moisturized and protected. However, capping may be performed by closing with an object other than the recording head 107.

[0127] "Decapping" is a process of opening the top of the suction cap 173. In the decapped state, the opening 301 is open, so that moisture is likely to evaporate.

[0128] [Other embodiments] The image forming apparatus 10 performs printing, for example, in commercial printing. However, the image forming apparatus 10 may be used for purposes other than commercial printing. For example, the image forming apparatus 10 may be a copy machine, an MFP, a printer, or the like.

[0129] In the present application, the liquid is not particularly limited as long as it has a viscosity or surface tension that allows it to be ejected from the head, but it is preferable that the viscosity of the liquid becomes 30 mPa s or less when heated or cooled at room temperature and normal pressure.

[0130] More specifically, for example, the liquids include solutions, suspensions, or emulsions containing solvents such as water or organic solvents, colorants such as dyes or pigments, functional materials such as polymerizable compounds, resins, or surfactants, biocompatible materials such as DNA, amino acids, proteins, or calcium, edible materials such as natural dyes, etc. These can be used, for example, as inkjet inks, surface treatment liquids, components of electronic elements or light-emitting elements, liquids for forming electronic circuit resist patterns, or material liquids for three-dimensional modeling.

[0131] The head is equipped with a piezoelectric actuator (e.g., a stacked piezoelectric element and a thin-film piezoelectric element, etc.) as an energy generation source for ejecting liquid, a thermal actuator that uses an electrothermal conversion element such as a heating resistor, an electrostatic actuator having a vibration plate and an opposing electrode, etc.

[0132] Furthermore, the term "liquid ejection device" includes not only devices capable of ejecting liquid onto an object onto which the liquid can adhere, but also devices that eject liquid into air or liquid. This "liquid ejection device" may also include means for feeding, transporting, or discharging the object onto which the liquid can adhere, as well as other pre-processing devices or post-processing devices.

[0133] For example, as a "liquid ejection device," an image forming device that ejects ink to form an image on paper may be a three-dimensional modeling device (also called a "three-dimensional modeling device") that ejects modeling liquid onto a powder layer formed by layering powder in order to form a three-dimensional object (also called a "three-dimensional object").

[0134] Furthermore, the "liquid ejection device" is not limited to one that visualizes images such as characters or figures by ejecting liquid. For example, the "liquid ejection device" may be one that forms a pattern that does not have meaning in itself, or one that forms a three-dimensional image.

[0135] The above-mentioned "object to which liquid can adhere" means a medium to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks, or to which the liquid adheres and penetrates, etc. For example, the medium is a recording medium such as paper, recording paper, film, or cloth, an electronic board, an electronic component such as a piezoelectric element, a powder layer, an organ model, or a test cell, and unless otherwise specified, includes all objects to which liquid can adhere.

[0136] Furthermore, the material of the above-mentioned "object to which liquid can adhere" may be anything to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, or ceramics.

[0137] The liquid ejection method according to the present invention may include processes other than those described above. The liquid ejection method also includes a method in which some of the processes are performed by a process or operation of an external device.

[0138] The liquid ejection method described above may be realized by a program (including firmware and equivalents to a program; hereinafter simply referred to as a "program") that executes the processes exemplified above or processes equivalent to the processes described above.

[0139] That is, the above-mentioned liquid ejection method may be realized by a program written in a programming language etc., so that a command is issued to the liquid ejection device to obtain a predetermined result. Note that the program may be configured so that part of the processing is executed by hardware such as an IC (Integrated Circuit).

[0140] The control program causes the liquid ejection device to execute the above-described processes and the like by cooperating with the arithmetic device, control device, storage device, etc. of the liquid ejection device. In other words, the control program is loaded into the main storage device, etc., and issues commands to the arithmetic device to perform calculations and operate the liquid ejection device.

[0141] The control program may also be provided via a computer-readable recording medium or a telecommunications line such as a network.

[0142] For example, aspects of the present invention are as follows.

[0143] <1> A liquid ejection device including a head, the liquid being ejected by the head for performing a predetermined process, A suction unit that sucks the head; a first cleaning unit that injects a cleaning solution to clean the suction unit within one hour after the suction unit starts suction; a second cleaning unit that injects the cleaning liquid into the suction unit and cleans the suction unit every second time period that is set based on temperature and humidity; The liquid ejection device includes:

[0144] <2> The second cleaning section includes: The second time is determined to be shorter as the evaporation rate of the liquid increases under temperature and humidity conditions based on the temperature and humidity. the above <1> The liquid ejection apparatus according to claim 1,

[0145] <3> After the first cleaning unit cleans the suction unit, the cleaning liquid is discharged from the outlet, and the outlet is sealed. the above <1> or <2> The liquid ejection apparatus according to claim 1,

[0146] <4> After sealing the outlet, the cleaning liquid is injected into the suction part. the above <3> The liquid ejection apparatus according to claim 1,

[0147] <5> After the second cleaning unit cleans the suction unit, the cleaning liquid is discharged from the outlet, and the outlet is sealed. the above <1> ~ <4> The liquid ejection apparatus according to any one of the above items.

[0148] <6> After sealing the outlet, the cleaning liquid is injected into the suction part. the above <5> The liquid ejection apparatus according to claim 1,

[0149] <7> The apparatus further includes a third cleaning unit that injects the cleaning liquid to clean the suction unit when a power supply operation, a transition to a sleep state, or a transition from the sleep state occurs. the above <1> ~ <6> The liquid ejection apparatus according to any one of the above items.

[0150] <8> the liquid is ink, The head ejects the ink onto a recording medium, the predetermined process is a process for forming an image on the recording medium, the suction unit is a suction cap that caps the head, The first cleaning unit performs the first cleaning when the suction unit performs suction, The second cleaning unit periodically performs the second cleaning based on the second time determined according to a weighting coefficient determined in a table according to the temperature and the humidity. the above <1> ~ <7> The liquid ejection apparatus according to any one of the above items.

[0151] The present invention is not limited to the above-mentioned embodiments. Therefore, the present invention can be modified or modified without departing from the technical gist of the invention. Therefore, all technical matters included in the technical ideas described in the claims are the subject of the present invention. The above-mentioned embodiments are preferred examples. Those skilled in the art can realize various modifications from the disclosed contents, and such modifications are included in the technical scope described in the claims. [Explanation of symbols]

[0152] 10: Image forming device 107: Recording head 171: Head cleaning unit 173: Suction cap 205: Suction mechanism 206: Absorbent 211: Ink ejection nozzle 212: Suction path 301: Opening 302: Absorbent 303: Outlet 304: Ink components 305: Cleaning solution components 306: Sealing mechanism h:Humidity t :Temperature [Prior art documents] [Patent documents]

[0153] [Patent Document 1] JP 2007-296779 A

Claims

1. A liquid ejection device including a head, the liquid being ejected by the head for performing a predetermined process, A suction unit that sucks the head; a first cleaning unit that injects a cleaning liquid to clean the suction unit within a first hour after the suction unit starts suction; a second cleaning unit that injects the cleaning liquid into the suction unit and cleans the suction unit every second time period that is set based on temperature and humidity; A liquid ejection device comprising:

2. The second cleaning section includes: The second time is determined to be shorter as the evaporation rate of the liquid increases under temperature and humidity conditions based on the temperature and humidity. The liquid ejection device according to claim 1 .

3. After the first cleaning unit cleans the suction unit, the cleaning liquid is discharged from the discharge port, and the discharge port is sealed. The liquid ejection device according to claim 1 .

4. After sealing the outlet, the cleaning liquid is injected into the suction part. The liquid ejection device according to claim 3 .

5. After the second cleaning unit cleans the suction unit, the cleaning liquid is discharged from the discharge port, and the discharge port is sealed. The liquid ejection device according to claim 1 .

6. After sealing the outlet, the cleaning liquid is injected into the suction part. The liquid ejection device according to claim 5 .

7. The apparatus further includes a third cleaning unit that injects the cleaning liquid to clean the suction unit when a power supply operation, a transition to a sleep state, or a transition from the sleep state occurs. The liquid ejection device according to claim 1 .

8. the liquid is ink, The head ejects the ink onto a recording medium, the predetermined process is a process for forming an image on the recording medium, the suction unit is a suction cap that caps the head, The first cleaning unit performs a first cleaning when the suction unit performs suction, The second cleaning unit periodically performs the second cleaning based on the second time determined according to a weighting coefficient determined in a table according to the temperature and the humidity. The liquid ejection device according to claim 1 .

9. Head and a suction unit that sucks the head; A liquid ejection method in which a liquid ejection device performs a predetermined process using the liquid ejected by the head, a first washing step of injecting a washing solution to wash the suction unit within a first hour after the suction unit starts suction; a second cleaning step of injecting the cleaning solution into the suction part to clean the suction part every second time period that is set based on temperature and humidity; A liquid ejection method comprising:

10. A control program for causing a liquid ejection apparatus to execute the liquid ejection method according to claim 9.

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