Printing apparatus and maintenance method

Abstract

The present invention provides a printing device that can perform maintenance operations appropriate to the humidity of the environment in which the device is installed, suppressing unnecessary ink consumption while stably ejecting ink. [Solution] The device comprises a head that ejects ink, a circulation path through which a temperature-controlled liquid circulates via the inside of the head, a liquid supply unit that delivers the temperature-controlled liquid, a temperature detection unit that detects the head temperature or a correlation temperature correlated with the head temperature, a temperature control unit that controls the head temperature or the correlation temperature, and an environmental humidity sensor that detects the humidity of the environment in which the device is installed. After the device is started up, the temperature detection unit detects the head temperature or the correlation temperature. If the head temperature or the correlation temperature is below a threshold temperature, a heating waveform is applied to the head to raise the head temperature or the correlation temperature to the threshold temperature, and then maintenance is performed. The type of maintenance after the application of the heating waveform is changed according to the humidity of the environment in which the device is installed, thereby enabling both suppression of ink consumption and stable ink ejection.

Description

Technical Field

[0001] The present invention relates to a printing apparatus and a maintenance method.

Background Art

[0002] In a head that discharges a liquid, as the temperature of a heat-generating member such as a head drive substrate including a pressure generating means such as a piezoelectric element for discharging the liquid, a driving IC (driver IC) such as a switching circuit, and a power amplifier section that is disposed near the head and generates a driving waveform to drive the piezoelectric element increases, the liquid temperature rises and the discharge characteristics fluctuate.

[0003] On the other hand, when the environmental temperature is low and lower than the value of the head temperature, the ink thickens and it becomes difficult to discharge stably. Therefore, for example, in Patent Document 1, a technique is disclosed in which a path through which a temperature control liquid passes is provided in the head, and the temperature control liquid is sent to a heater in the case of heating or a radiator or a chiller in the case of cooling to perform temperature adjustment, and the temperature of the head is kept within a certain range. Further, a technique of applying a heating waveform to the head to raise the head temperature instead of using a heater as a heating means is already known.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a low-humidity environment, the moisture in the ink near the meniscus easily evaporates, and the discharge property easily deteriorates. Since the influence of the external humidity cannot be completely ignored, when the installation environment humidity of the apparatus is low, the problem that the thickening of the ink after the application of the heating waveform is accelerated and the discharge property deteriorates has not been solved.

[0005] An object of the present invention is to provide a printing apparatus capable of performing a maintenance operation suitable for the installation environment humidity of the apparatus, suppressing unnecessary ink consumption, and stably discharging the ink.

Means for Solving the Problems

[0006] The printing apparatus of the present invention, as a means for solving the problem, The print head that ejects ink, A circulation path through which the temperature-controlled liquid circulates via the inside of the head, A liquid delivery unit that delivers the temperature-controlled liquid, A temperature detection unit that detects the head temperature or a correlated temperature that correlates with the head temperature, A temperature control unit that controls the head temperature or the correlation temperature, The device is equipped with an ambient humidity sensor that detects the humidity of the environment in which the device is installed, After the device is started up, the temperature sensing unit detects the head temperature or the correlation temperature, If the head temperature or the correlation temperature is below the threshold temperature, a heating waveform is applied to the head, and after controlling the head temperature or the correlation temperature to the threshold temperature, a maintenance operation is performed. The type of maintenance operation after the application of the heating waveform is changed according to the humidity of the installation environment. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a printing apparatus that can perform maintenance operations suitable for the humidity of the environment in which the apparatus is installed, suppress unnecessary ink consumption, and stably eject ink. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram illustrating a printing apparatus according to one embodiment of the present invention. [Figure 2] Figure 2 is a plan view illustrating the head unit, which constitutes the ejection unit of a printing apparatus according to one embodiment of the present invention, as seen from the nozzle side. [Figure 3] Figure 3 is a cross-sectional diagram illustrating an example of a head in the short direction (direction perpendicular to the nozzle arrangement direction). [Figure 4] Figure 4 is a plan view illustrating the temperature-controlled liquid flow path along line AA in Figure 3. [Figure 5]Figure 5 is a block diagram illustrating the ink supply system and the temperature control solution circulation system in a printing apparatus according to one embodiment of the present invention. [Figure 6] Figure 6 is a block diagram illustrating the parts related to temperature control of the ink in the print head and maintenance operations before and after temperature control. [Figure 7] Figure 7 is a flowchart illustrating an example of maintenance operations performed by a printing apparatus according to one embodiment of the present invention. [Figure 8] Figure 8 is a flowchart illustrating another example of maintenance operations performed by a printing apparatus according to one embodiment of the present invention. [Figure 9] Figure 9 is a table showing the effect of the printing device's condition and the type of maintenance operation on ink ejection performance. [Figure 10] Figure 10 is a schematic diagram illustrating an example of a temperature-controlled fluid circulation system for multiple head units. [Figure 11] Figure 11 is a schematic diagram illustrating the connection relationship between the temperature-controlled fluid supply manifold, the temperature-controlled fluid recovery manifold, and the head. [Figure 12] Figure 12 is an explanatory diagram showing an example of the configuration of the head unit and the circulation path of the temperature-controlled liquid in a printing apparatus according to one embodiment of the present invention. [Figure 13] Figure 13 is a plan view illustrating an example of the configuration of a printing apparatus according to one embodiment of the present invention. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. First, the configuration of the printing apparatus of the present invention will be described with reference to Figure 1. Figure 1 is a schematic diagram illustrating a printing apparatus according to one embodiment of the present invention.

[0010] The printing apparatus 1 includes a loading unit 10 for loading a sheet material P, a pre-treatment unit 20, a printing unit 30, a drying unit 40, an unloading unit 50, and a reversing mechanism unit 60. The printing apparatus 1 applies a pre-treatment liquid (coats) to the sheet material P supplied (loaded) from the loading unit 10 as needed by the pre-treatment unit 20 which is a pre-treatment means, applies ink by the printing unit 30 to perform required printing, dries the ink adhering to the sheet material P by the drying unit 40, and then discharges the sheet material P to the unloading unit 50.

[0011] The loading unit 10 includes a loading tray 11 (lower loading tray 11A and upper loading tray 11B) for accommodating a plurality of sheet materials P, and a feeding device 12 (12A, 12B) for separating and feeding out the sheet materials P one by one from the loading tray 11, and supplies the sheet material P to the pre-treatment unit 20.

[0012] The pre-treatment unit 20 includes, for example, an application unit 21 which is a treatment liquid application means for applying a treatment liquid having an effect of aggregating the coloring material of the ink and preventing back printing to the printing surface of the sheet material P.

[0013] The printing unit 30 includes a drum 31 which is a carrying member (rotating body) for carrying the sheet material P on its circumferential surface and rotating, and an ink discharge unit 32 for discharging ink toward the sheet material P carried on the drum 31.

[0014] Also, the printing unit 30 includes a transfer cylinder 34 for receiving the sheet material P sent from the pre-treatment unit 20 and transferring the sheet material P between it and the drum 31, and a delivery cylinder 35 for receiving the sheet material P conveyed by the drum 31 and delivering it to the drying unit 40.

[0015] The sheet material P conveyed from the pre-treatment unit 20 to the printing unit 30 is gripped at its tip by a gripping means (sheet gripper) provided on the transfer cylinder 34 and conveyed as the transfer cylinder 34 rotates. The sheet material P conveyed by the transfer cylinder 34 is delivered to the drum 31 at the opposing position to the drum 31.

[0016] A gripping means (sheet gripper) is also provided on the surface of the drum 31, and the tip of the sheet material P is gripped by the gripping means (sheet gripper). Multiple suction holes are formed dispersed on the surface of the drum 31, and the suction means generates a suction airflow directed inward from the required suction holes of the drum 31.

[0017] The sheet material P, which has been transferred from the transfer drum 34 to the drum 31, is then gripped at the tip by the sheet gripper and attached to the drum 31 by the suction airflow from the suction means, and is conveyed as the drum 31 rotates.

[0018] The ink ejection unit 32 is equipped with ejection units 33 (33A to 33D), which are ink ejection means. For example, ejection unit 33A ejects cyan (C) ink, ejection unit 33B ejects magenta (M) ink, ejection unit 33C ejects yellow (Y) ink, and ejection unit 33D ejects black (K) ink. In addition, ejection units that eject special inks such as white and gold (silver) can also be used.

[0019] Each ejection unit 33 of the ink ejection unit 32 is controlled by a drive signal corresponding to the print information. When the sheet material P supported on the drum 31 passes through the area facing the ink ejection unit 32, ink of each color is ejected from the ejection unit 33, and an image corresponding to the print information is printed.

[0020] The drying unit 40 dries the ink that has adhered to the sheet material P in the printing unit 30. This causes the water and other liquid components in the ink to evaporate, fixing the colorants contained in the ink onto the sheet material P, and also suppressing curling of the sheet material P.

[0021] The reversal mechanism 60 is a mechanism that reverses the sheet material P in a switchback manner when performing double-sided printing on the sheet material P that has passed through the drying section 40, and the reversed sheet material P is sent back upstream of the transfer cylinder 34 through the transport path 61 of the printing section 30.

[0022] The discharge unit 50 is equipped with a discharge tray 51 on which multiple sheet materials P are loaded. The sheet materials P transported from the drying unit 40 are sequentially stacked and held on the discharge tray 51.

[0023] Next, an example of a head unit constituting the ejection unit will be described with reference to Figure 2. Figure 2 is a plan view of a head unit constituting the ejection unit of a printing apparatus according to one embodiment of the present invention, as seen from the nozzle side.

[0024] The head unit 300 consists of multiple ink ejection heads 100 arranged in a staggered pattern on a head mounting member 302.

[0025] Each head 100 has multiple rows of nozzles (four rows are used as an example here, but it is not limited to four rows) in which multiple nozzles 104 for ejecting ink are arranged.

[0026] Next, an example of head 100 will be described with reference to Figures 3 and 4. Figure 3 is a cross-sectional diagram of an example of head in the short direction (direction perpendicular to the nozzle arrangement direction), and Figure 4 is a plan view of the temperature-controlled liquid flow path along line AA in Figure 3.

[0027] The head 100 is constructed by sequentially stacking a nozzle plate 101 on which a nozzle 104 is formed, a flow path plate 102 that forms a flow path such as a pressure chamber 106 leading to the nozzle 104, and a diaphragm 103 that forms the wall surface of the pressure chamber 106. The head 100 also has a piezoelectric actuator 111 as a means of generating pressure and a frame member 120 that also serves as a common flow path member.

[0028] The piezoelectric actuator 111 has a plurality of columnar piezoelectric elements 112 fixed on a base member 113, and the piezoelectric elements 112 are joined to a diaphragm 103. In addition, wiring members 115 such as a flexible wiring board are connected to the piezoelectric elements 112.

[0029] The frame member 120, which also serves as a common flow channel member, forms a common supply channel 110 that supplies ink to be discharged into the pressure chamber 106.

[0030] A temperature-controlled liquid flow path member 131 is joined to this frame member 120 to form a temperature-controlled liquid flow path 130 within the head 100 through which a temperature-controlled liquid (liquid with adjusted temperature) flows. The temperature-controlled liquid flow path member 131 has a temperature-controlled liquid supply port 132 for supplying temperature-controlled liquid to the temperature-controlled liquid flow path 130 and a temperature-controlled liquid recovery port 133 for recovering the temperature-controlled liquid to the outside.

[0031] As a result, within the print head 100, the common supply channel 110, which is the ink flow path, and the temperature-controlled liquid channel 130 are thermally coupled. In addition, the frame member 120, which also serves as the housing of the print head 100, forms the wall surface of the temperature-controlled liquid channel 130 and is thermally coupled to the temperature-controlled liquid channel 130.

[0032] The temperature-controlled liquid flow channel member 131 has a case member 150 and a lid member 151 stacked on top of it in sequence.

[0033] Next, the ink supply system and the temperature-controlled liquid circulation system will be described with reference to Figure 5. Figure 5 is a block diagram illustrating the ink supply system and temperature-controlled liquid circulation system in a printing apparatus according to one embodiment of the present invention.

[0034] A printing apparatus according to one embodiment of the present invention includes, as an ink supply system, an ink tank 401 for storing ink to be supplied to the head 100, and an ink supply manifold 402 for distributing the ink supplied from the ink tank 401 to a plurality of heads 100. The ink supply manifold 402 and each head 100 are connected by a supply path 403 such as a supply tube.

[0035] A printing apparatus according to one embodiment of the present invention includes, as a temperature-controlled liquid circulation system, a temperature-controlled liquid tank 501 which is a storage tank for storing temperature-controlled liquid 510, a liquid supply pump 502 which is a liquid supply unit for supplying temperature-controlled liquid 510, a radiator 511 which is a cooling means for cooling temperature-controlled liquid 510, a temperature-controlled liquid supply manifold 505 which distributes and supplies temperature-controlled liquid 510 to each head 100, and a temperature-controlled liquid recovery manifold 506 which recovers temperature-controlled liquid 510 from each head 100.

[0036] The temperature-controlled liquid supply manifold 505 and the temperature-controlled liquid supply port 132 of each head 100 are connected by a supply path 513 such as a supply tube, and the temperature-controlled liquid recovery port 133 of each head 100 and the temperature-controlled liquid recovery manifold 506 are connected by a recovery path 514 such as a recovery tube.

[0037] By driving the liquid transfer pump 502, the temperature-controlled liquid 510 stored in the temperature-controlled liquid tank 501 circulates through a circulation path 500 that, starting from the temperature-controlled liquid tank 501, sequentially passes through the liquid transfer pump 502, the radiator 511 as a cooling means, the temperature-controlled liquid supply manifold 505, each head 100, and the temperature-controlled liquid recovery manifold 506 before returning to the temperature-controlled liquid tank 501.

[0038] In this configured system, the temperature-controlled fluid 510 is pumped up from the temperature-controlled fluid tank 501 by the fluid transfer pump 502, passes through the radiator 511, and is distributed to each head 100 from the temperature-controlled fluid supply manifold 505.

[0039] Then, the temperature-controlled liquid flows through the temperature-controlled liquid passage 130 of each head 100, cooling the frame member 120 of each head 100. After passing through each head 100, the temperature-controlled liquid is collected in the temperature-controlled liquid recovery manifold 506 and returned to the temperature-controlled liquid tank 501.

[0040] Meanwhile, ink is supplied from the ink tank 401 to the ink supply manifold 402 and distributed to each head 100.

[0041] Next, the temperature control and maintenance operations for the ink in the print head will be explained with reference to Figure 6. Figure 6 is a block diagram illustrating the parts related to the temperature control of the ink in the print head and the maintenance operations before and after temperature control.

[0042] The temperature control unit 801 controls the head temperature or a correlated temperature that correlates with the head temperature by controlling the fan 511a of the radiator 511, the head drive unit 821, the maintenance unit 870, etc., based on the detection results input by sensors, etc.

[0043] The temperature sensing unit 810 includes an ambient temperature sensor 811, a radiator inlet temperature sensor 812, a radiator outlet temperature sensor 813, and a head temperature sensor 822.

[0044] The ambient temperature sensor 811 detects the ambient temperature T5 of the radiator 511 and inputs the detection result to the temperature control unit 801. Note that the radiator 511 is located outside the device to avoid the effects of temperature rise inside the device, and the ambient temperature (ambient temperature) T5 of the radiator 511 is the same as the ambient temperature of the printing device 1.

[0045] The radiator inlet temperature sensor 812 detects the temperature of the conditioned fluid at the inlet of the radiator 511 (hereinafter referred to as the inlet temperature) T1 and inputs the detection result to the temperature control unit 801. The radiator outlet temperature sensor 813 detects the temperature of the conditioned fluid at the outlet of the radiator 511 (hereinafter referred to as the outlet temperature) T2 and inputs the detection result to the temperature control unit 801.

[0046] The head temperature sensor 822 detects the temperature T3 of the head 100 and inputs the detection result to the temperature control unit 801. Here, since the ink temperature and the head temperature are correlated, the head temperature sensor 822 may also directly detect the ink temperature T4 inside the head 100.

[0047] Furthermore, since the inlet temperature T1 and outlet temperature T2 are correlated with the head temperature T3, the inlet temperature T1 or outlet temperature T2 may be input to the temperature control unit 801 as the correlated temperature, and the temperature control unit 801 may control the correlated temperature.

[0048] The fan speed sensor 814 detects the rotation speed of the fan 511a of the radiator 511 and inputs the detection result to the temperature control unit 801. The temperature control unit 801 then controls the rotation drive of the fan 511a of the radiator 511 based on the detection results of each sensor.

[0049] The idle time timer 850 counts the time the device is left idle without printing and inputs the count result to the temperature control unit 801.

[0050] The ambient humidity sensor 860 detects the ambient humidity of the device's installation environment and inputs the detection result to the temperature control unit 801. The ambient humidity sensor 860 is located outside the device to avoid the influence of relative humidity fluctuations caused by temperature changes inside the device, and the humidity detection result is the same as the ambient humidity of the printing device 1.

[0051] Next, head temperature control, including temperature control of the temperature-controlled liquid by the temperature control unit, and head maintenance control before and after temperature control will be explained with reference to Figures 7 to 9.

[0052] Figure 7 is a flowchart illustrating an example of maintenance operations performed by a printing apparatus according to one embodiment of the present invention. After the apparatus is started up or after a print command is received, the head temperature sensor 822 detects the head temperature T3. When the head temperature T3 is less than the threshold temperature T0, the temperature control unit 801 applies a heating waveform to the piezoelectric element 112 of the head 100 via the head drive unit 821, controlling the pressure generating element of the head 100 to the extent that ink is not ejected. The heating waveform is a waveform that is outside the resonance point of the pressure chamber 106 of the head 100 and drives the piezoelectric element 112 to the extent that ink is not ejected.

[0053] When the heating waveform is applied, the head temperature T3 and ink temperature T4 rise (head heating mode). The head heating mode is performed with the nozzle surface of head 100 capped to suppress the thickening of the meniscus.

[0054] Temperature detection is performed at regular intervals (e.g., every second), and if the head temperature T3 is equal to or greater than the threshold temperature T0, the application of the heating waveform is terminated.

[0055] During the temperature control described above, even in the capping state, the influence of external humidity cannot be completely ignored. When the ambient humidity is low, the water in the ink near the meniscus evaporates, accelerating the thickening of the ink after the heating waveform is applied, which tends to worsen the ejection performance. Therefore, by performing a maintenance operation after the heating waveform is applied, the ink ejection performance can be restored. Furthermore, by changing the type of maintenance operation after the heating waveform is applied according to the ambient humidity of the installation environment, ink consumption during the maintenance operation can be reduced.

[0056] Maintenance operations include suction cleaning, which removes thickened ink by suction, and dry ejection, which removes thickened ink by dry ejection. Suction cleaning consumes a lot of ink and takes a long time to remove the thickened ink, but it has the advantage of high performance in removing thickened ink. On the other hand, dry ejection has the advantage of low ink consumption, although it has lower performance in removing thickened ink.

[0057] Therefore, by performing a suction cleaning operation if the ambient humidity H1 is less than the threshold humidity H0, and performing an empty ejection operation if the humidity is H0 or higher, it is possible to suppress unnecessary ink consumption while maintaining a stable ink ejection state.

[0058] Figure 8 is a flowchart illustrating another example of maintenance operations performed by a printing apparatus according to one embodiment of the present invention. If the apparatus is left idle for a long period of time without printing, the ink will thicken. If a heating waveform is applied while the thickened ink is present, the ink will oscillate, further accelerating the thickening process. As a result, even if maintenance operations are performed after the heating waveform is applied, the ink ejection performance may not be fully restored. Therefore, as shown in Figure 8, by performing maintenance operations before applying the heating waveform to remove the thickened ink, the ink ejection performance can be reliably restored by the maintenance operations performed after the heating waveform is applied.

[0059] Maintenance operations before applying a heating waveform may be controlled based on the time the device has been left idle without printing. For example, if the idle time t1 counted by the idle time timer 850 is greater than or equal to the threshold time t0, a suction cleaning operation may be performed, and if the idle time t1 is less than the threshold time t0, an empty discharge operation may be performed. Alternatively, maintenance operations may not be performed if the idle time t1 is less than the threshold time t0.

[0060] Furthermore, the number of droplets dispensed during the dry-dispensing operation can be made variable, and the number of droplets dispensed during the dry-dispensing operation can be changed according to the ambient humidity H1 and the standing time t1. This allows for the restoration of ink dispensing performance while suppressing unnecessary ink consumption during the dry-dispensing operation.

[0061] As shown in Figures 7 and 8, temperature detection may be performed not only when the device is started up, but also when a print command is received. By performing temperature detection immediately before printing, even if the device is left idle for a long time after starting up due to paper loading or other reasons in a low ambient temperature, causing the head temperature to drop, maintenance operations can be performed as needed to reliably restore ink ejection performance.

[0062] Although the heating effect will be reduced, a micro-drive waveform used to suppress ink viscosity buildup in the print head when not in use during printing may be used as the heating waveform. In this case, there is no need to add a new waveform, and memory consumption can be reduced.

[0063] Regarding the temperature reference, if the liquid transfer pump 502 is driven when the heating waveform is applied, the inlet temperature T1 or outlet temperature T2 may be referenced with the fan 511a stopped, and detected and controlled as a correlated temperature.

[0064] In this case, the entire circulation path of the temperature-controlled fluid is heated, resulting in a large heat capacity. Although it takes longer for the head to heat up, once heated, the large heat capacity means it cools down slowly and the temperature can be maintained stably.

[0065] When the head temperature T3 is equal to or greater than the threshold temperature T0, the pump operation of the liquid transfer pump 502 is started, and the operation of the fan 511a is started to circulate and cool the temperature-controlled liquid 510. In this case as well, the temperature of the head 100 is not raised by the heating waveform.

[0066] Figure 9 is a table showing the effect of different maintenance operations and the condition of the printing device on ink ejection performance. The evaluation method for ink ejection performance is as follows. [Evaluation Method] After printing for one hour at an ejection frequency of 60 kHz, the number of nozzles that exhibited ejection abnormalities (missed prints, bent prints, etc.) was checked. A rating of ○ was given if the number of nozzles with ejection abnormalities per head was less than 3, and a rating of × was given if it was 3 or more. However, if a missing print occurred in an adjacent nozzle, it was also given a × rating even if the number was less than 3.

[0067] As shown in Figure 9(a), if the ambient humidity is 40-50%RH, the ink ejection performance can be restored by the dry ejection operation. On the other hand, if the ambient humidity is 20-30%RH, the dry ejection operation does not sufficiently restore the ink ejection performance, so the ink ejection performance can be sufficiently restored by performing a suction cleaning operation instead.

[0068] As shown in Figure 9(b), there are no problems with ink ejection immediately after the suction cleaning operation. However, if the printer is left overnight without printing, the ink viscosity increases, reducing ink ejection and degrading print quality. Therefore, even after being left for a long time, performing a maintenance operation before the temperature rises due to the application of a heating waveform can remove the thickened ink and restore ink ejection.

[0069] Next, an example of a temperature-controlled fluid circulation system for multiple head units will be described with reference to Figure 10. Figure 10 is an explanatory diagram used for this explanation.

[0070] Here, a temperature-controlled fluid supply manifold 505 (505A to 505D) and a temperature-controlled fluid recovery manifold 506 (506A to 506D) are provided to accommodate multiple head units 300 (300A to 300D) including multiple heads 100.

[0071] Furthermore, a common temperature-controlled fluid tank 501 is provided, and temperature-controlled fluid 510 is branched and supplied from the common temperature-controlled fluid tank 501 to the temperature-controlled fluid supply manifold 505 (505A to 505D) via the fluid transfer pumps 502 (502A to 502D) and the radiators 511 (511A to 511D).

[0072] Meanwhile, the temperature-controlled fluid 510 that has passed through the head unit 300 is recovered by the temperature-controlled fluid recovery manifolds 506 (506A to 506D), and then aggregated into two groups, temperature-controlled fluid recovery manifolds 506A and 506B, and temperature-controlled fluid recovery manifolds 506C and 506D, before being returned to the temperature-controlled fluid tank 501.

[0073] Therefore, the circulation path 500A is a path that returns to the temperature-controlled fluid tank 501 via the fluid transfer pump 502A, radiator 511A, temperature-controlled fluid supply manifold 505A, head unit 300A, and temperature-controlled fluid recovery manifold 506A.

[0074] Similarly, the circulation path 500B is a route that returns to the temperature-controlled fluid tank 501 via the fluid transfer pump 502B, radiator 511B, temperature-controlled fluid supply manifold 505B, head unit 300B, and temperature-controlled fluid recovery manifold 506B.

[0075] The circulation path 500C is a route that goes from the temperature-controlled fluid tank 501, through the fluid transfer pump 502C, radiator 511C, temperature-controlled fluid supply manifold 505C, head unit 300C, and temperature-controlled fluid recovery manifold 506C, before returning to the temperature-controlled fluid tank 501.

[0076] The circulation path 500D is a route that goes from the temperature-controlled fluid tank 501, through the fluid transfer pump 502D, radiator 511D, temperature-controlled fluid supply manifold 505D, head unit 300D, and temperature-controlled fluid recovery manifold 506D, before returning to the temperature-controlled fluid tank 501.

[0077] In this configuration, radiators 511 are connected in parallel to each head unit 300.

[0078] In this example, four radiators 511 are connected in parallel, but it is also possible to arrange multiple radiators in series, parallel, or a combination of series and parallel connections for each head unit.

[0079] Next, the connection relationship between the temperature-controlled liquid supply manifold and the temperature-controlled liquid recovery manifold and the head will be explained with reference to Figure 11. Figure 11 is a schematic diagram used for this explanation.

[0080] From the first outlet port from the upstream end of the liquid flow path 551 of the temperature-controlled liquid supply manifold 505, the fluid is connected via the head 100 to the upstream inlet of the liquid flow path 561 of the temperature-controlled liquid recovery manifold 506. Similarly, from the second outlet port from the upstream end of the liquid flow path 551, the fluid is connected via the head 100 to the second inlet from the upstream end of the liquid flow path 561 of the temperature-controlled liquid recovery manifold 506. Then, from the downstream outlet port of the liquid flow path 551, the fluid is connected via the head 100 to the downstream inlet of the liquid flow path 561 of the temperature-controlled liquid recovery manifold 506.

[0081] By using this connection configuration, the flow path configuration of the temperature-controlled liquid passing through all heads 100 is standardized, the pressure loss in the flow path of the temperature-controlled liquid passing through each head becomes equal, and the flow rate and velocity become the same, so that the temperature of all heads can be adjusted uniformly.

[0082] In this case, it is preferable that the temperature-controlled liquid recovery manifold 506 be made of the same material and of the same length as the temperature-controlled liquid supply manifold 505. For example, by using an aluminum extruded material such as A6063 and manufacturing the temperature-controlled liquid supply manifold 505 and the temperature-controlled liquid recovery manifold 506 by extrusion molding, manufacturing costs can be reduced.

[0083] Next, the configuration of a printing apparatus according to one embodiment of the present invention will be described with reference to Figures 12 and 13.

[0084] Figure 12 is an explanatory diagram showing an example of the configuration of the head unit and the circulation path of the temperature-controlled liquid in a printing apparatus according to one embodiment of the present invention.

[0085] The head unit 300 consists of two sets of liquid-discharging heads (dual heads) 100, 100 arranged in a staggered pattern.

[0086] Then, the temperature-controlled liquid is supplied from the temperature-controlled liquid supply manifold 505 to the temperature-controlled liquid supply port 132 of one of the two sets of heads 100, and the temperature-controlled liquid that has passed through the frame member 120 of the one head 100 is recovered from the temperature-controlled liquid recovery port 133. The temperature-controlled liquid recovered from one head 100 is supplied to the temperature-controlled liquid supply port 132 of the other head 100, and the temperature-controlled liquid that has passed through the frame member 120 of the other head 100 is recovered from the temperature-controlled liquid recovery port 133.

[0087] The temperature-controlled liquid recovered from the temperature-controlled liquid recovery port 133 of the other head 100 is collected in the temperature-controlled liquid recovery manifold 506.

[0088] Figure 13 is a plan view illustrating an example of the configuration of a printing apparatus according to one embodiment of the present invention.

[0089] Printing apparatus 1 is a serial type printing apparatus. The carriage 1003 is held so as to be able to reciprocate in the main scanning direction by guide members such as guide member 1001 which is stretched across the left and right side plates 1010A and 1010B. The carriage 1003 then reciprocates in the main scanning direction via a timing belt 1008 stretched between a drive pulley 1006 and a driven pulley 1007, driven by the main scanning motor 1005.

[0090] This carriage 1003 is equipped with four ink ejection units 1004. Each ink ejection unit 1004 integrates a print head (ink ejection head) 100 and a sub-tank 1035.

[0091] Each sub-tank 1035 has a tank section that contains ink of each color to be supplied to each head 100.

[0092] The main body of the device has a cartridge holder 1051 on which replaceable main tanks 1050 (1050a to 1050f) containing ink of each color are mounted. A liquid supply pump unit 1052 is provided in this cartridge holder 1051, and the liquid supply pump unit 1052 supplies ink of each color from the main tank 1050 to each sub-tank 1035 via supply tubes (also called ink supply paths) 1056 for each color.

[0093] On the other hand, to transport the sheet material P, the system is equipped with a conveyor belt 1012, which is a conveying means for adsorbing the sheet material P and transporting it at a position opposite the head 100. This conveyor belt 1012 is an endless belt and is stretched between the conveyor roller 1013 and the tension roller 1014. The conveyor belt 1012 adsorbs the sheet material P by electrostatic attraction or air suction.

[0094] Then, the conveyor belt 1012 moves in a circular motion in the sub-scanning direction as the conveyor rollers 1013 are rotationally driven by the sub-scanning motor 1016 via the timing belt 1017 and timing pulley 1018.

[0095] Furthermore, a head maintenance device 1020, which is a maintenance and recovery mechanism for maintaining and recovering the head 100, is positioned on one side of the carriage 1003 in the main scanning direction, next to the conveyor belt 1012.

[0096] The head maintenance device 1020 consists of, for example, a suction cap 1021 that also serves as a moisturizing cap for capping the nozzle surface of the head 100 (the surface on which the nozzle 104 is formed), three moisturizing caps 1022, and a wiper 1023 for wiping the nozzle surface.

[0097] Furthermore, an encoder scale 1123 with a predetermined pattern is stretched between the side plates along the main scanning direction of the carriage 1003, and the carriage 1003 is equipped with an encoder sensor 1124 consisting of a transmissive photosensor that reads the pattern on the encoder scale 1123. These encoder scales 1123 and encoder sensors 1124 constitute a linear encoder (main scanning encoder) 1122 that detects the movement of the carriage 1003.

[0098] Furthermore, a code wheel 1125 is attached to the shaft of the conveyor roller 1013, and an encoder sensor 1126 consisting of a transmissive photosensor that detects the pattern formed on the code wheel 1125 is provided. These code wheel 1125 and encoder sensor 1126 constitute a rotary encoder (sub-scan encoder) that detects the amount of movement and position of the conveyor belt 1012.

[0099] In the apparatus configured in this way, the sheet material P is fed onto the conveyor belt 1012, picked up, and transported in the sub-scanning direction by the circumferential movement of the conveyor belt 1012.

[0100] Therefore, by moving the carriage 1003 in the main scanning direction and driving the head 100 in accordance with the image signal, ink is ejected onto the stationary sheet material P to record one line. After transporting a predetermined amount of sheet material P, the next line is recorded.

[0101] Upon receiving a recording completion signal or a signal indicating that the rear end of the sheet material P has reached the recording area, the recording operation is terminated and the sheet material P is ejected to the output tray.

[0102] The present invention can also be applied to a serial ink ejection device according to this embodiment.

[0103] In this application, the ejected ink is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head, but it is preferable that its viscosity becomes 30 mPa·s or less at room temperature and atmospheric pressure, or when heated or cooled.

[0104] The term "print head" includes those that use piezoelectric actuators (multilayer piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a diaphragm and a counter electrode as energy sources for ejecting ink.

[0105] "Printing apparatus" may include means for feeding, transporting, and ejecting ink-coated materials, as well as pre-processing equipment, post-processing equipment, etc.

[0106] Furthermore, the term "printing device" is not limited to those that visualize meaningful images such as characters or figures using ejected ink. For example, it also includes devices that form patterns that do not have meaning in themselves, or devices that create three-dimensional images.

[0107] The term "materials to which ink can adhere" above refers to materials to which ink can adhere, at least temporarily, including materials to which ink adheres and hardens, or materials to which ink penetrates. Specific examples include recording media such as paper, recording paper, film, and cloth; electronic components such as electronic circuit boards and piezoelectric elements; powder layers; organ models; and test cells. Unless otherwise specified, it includes all materials to which ink can adhere.

[0108] The materials referred to as "materials to which ink can adhere" above include paper, thread, fibers, fabrics, leather, metal, plastic, glass, wood, ceramics, etc., as long as ink can adhere to them, even temporarily.

[0109] Furthermore, the term "printing apparatus" includes devices in which the ink ejection head and the material to which ink can adhere move relative to each other, but is not limited to these. Specific examples include serial-type devices that move the ink ejection head, and line-type devices that do not move the ink ejection head.

[0110] Other types of "printing equipment" include processing liquid coating devices that dispense processing liquid onto the surface of paper for purposes such as modifying the paper surface, and spray granulation devices that granulate fine particles of raw materials by spraying a compositional solution, in which raw materials are dispersed in a solution, through a nozzle.

[0111] In this application, the terms image formation, recording, printing, copying, printing, and shaping are all considered synonymous.

[0112] The embodiments of the present invention are, for example, as follows.

[0113] <1> The print head that ejects ink, A circulation path through which the temperature-controlled liquid circulates via the inside of the head, A liquid delivery unit that delivers the temperature-controlled liquid, A temperature detection unit that detects the head temperature or a correlated temperature that correlates with the head temperature, A temperature control unit that controls the head temperature or the correlation temperature, The device is equipped with an ambient humidity sensor that detects the humidity of the environment in which the device is installed, After the device is started up, the temperature sensing unit detects the head temperature or the correlation temperature, The printing apparatus is characterized in that, if the head temperature or the correlation temperature is below a threshold temperature, a heating waveform is applied to the head, and after performing control to raise the head temperature or the correlation temperature to the threshold temperature, a maintenance operation is performed, and the type of maintenance operation after the application of the heating waveform is changed according to the humidity of the installation environment.

[0114] <2> When the humidity of the installation environment is below the threshold humidity, a suction cleaning operation is performed as a maintenance operation after the application of the heating waveform. <1> This is the printing device described in [reference].

[0115] <3> When the humidity of the installation environment is equal to or greater than the threshold humidity, an air discharge operation is performed as a maintenance operation after the heating waveform is applied. <1> from <2> It is a printing apparatus as described in any one of the items.

[0116] <4> It also includes an idle time timer that counts the amount of time the device is left idle without printing. When the printing device has been left idle for a period of time equal to or greater than a threshold time, a suction cleaning operation is performed as a maintenance operation before applying the heating waveform. <1> from <3> It is a printing apparatus as described in any one of the items.

[0117] <5> When the idle time of the printing apparatus is less than the threshold time, a dry ejection operation is performed as a maintenance operation before applying the heating waveform. <4> This is the printing device described in [reference].

[0118] <6> The number of drops dispensed during the air discharge operation is changed according to the humidity of the installation environment. <3> from <5> It is a printing apparatus as described in any one of the items.

[0119] <7> The maintenance operation is characterized by applying a heating waveform to the head immediately before the start of printing, controlling the head temperature or the correlation temperature to rise to the threshold temperature, and then performing the maintenance operation. <1> from <6> It is a printing apparatus as described in any one of the items.

[0120] <8> The print head that ejects ink, A circulation path through which the temperature-controlled liquid circulates via the inside of the head, A liquid delivery unit that delivers the temperature-controlled liquid, A temperature detection unit that detects the head temperature or a correlated temperature that correlates with the head temperature, A temperature control unit that controls the head temperature or the correlation temperature, An environmental humidity sensor that detects the humidity of the environment in which the device is installed, A maintenance method for a printing apparatus, which includes a timer that counts the time the apparatus is left idle without printing, After the device is started up, the temperature sensing unit detects the head temperature or the correlation temperature, The maintenance method is characterized in that, if the head temperature or the correlation temperature is below a threshold temperature, a heating waveform is applied to the head, and after controlling the head temperature or the correlation temperature to rise to the threshold temperature, a maintenance operation is performed, and the type of maintenance operation after the application of the heating waveform is changed according to the humidity of the installation environment.

[0121] The aforementioned <1> from <7> The printing apparatus described above, <8> The maintenance method described above can solve the aforementioned problems in the conventional method and achieve the objectives of the present invention. [Explanation of symbols]

[0122] 1 Printing device 100 print heads (ink ejection heads) 500 Circulation Routes 502 Liquid delivery unit (liquid delivery pump) 510 Temperature-controlled liquid 801 Temperature Control Unit 810 Temperature detection unit 850 Timer (for idle time) 860 Environmental Humidity Sensor [Prior art documents] [Patent Documents]

[0123] [Patent Document 1] Japanese Patent Publication No. 2021-146545

Claims

1. The print head that ejects ink, A circulation path through which the temperature-controlled liquid circulates via the inside of the head, A liquid delivery unit that delivers the temperature-controlled liquid, A temperature detection unit that detects the head temperature or a correlated temperature that correlates with the head temperature, A temperature control unit that controls the head temperature or the correlation temperature, The device is equipped with an ambient humidity sensor that detects the humidity of the environment in which the device is installed, After the device is started up, the temperature sensing unit detects the head temperature or the correlation temperature, A printing apparatus characterized in that, if the head temperature or the correlation temperature is below a threshold temperature, a heating waveform is applied to the head, and after performing control to raise the head temperature or the correlation temperature to the threshold temperature, a maintenance operation is performed, and the type of maintenance operation after the application of the heating waveform is changed according to the humidity of the installation environment.

2. The printing apparatus according to claim 1, characterized in that when the humidity of the installation environment is below a threshold humidity, a suction cleaning operation is performed as a maintenance operation after the application of a heating waveform.

3. The printing apparatus according to claim 1, characterized in that when the humidity of the installation environment is equal to or greater than the threshold humidity, an empty ejection operation is performed as a maintenance operation after the application of a heating waveform.

4. It also includes an idle time timer that counts the amount of time the device is left idle without printing. The printing apparatus according to claim 1, characterized in that when the idle time of the printing apparatus exceeds a threshold time, a suction cleaning operation is performed as a maintenance operation before applying a heating waveform.

5. The printing apparatus according to claim 4, characterized in that when the idle time of the printing apparatus is less than the threshold time, an empty ejection operation is performed as a maintenance operation before applying a heating waveform.

6. The printing apparatus according to claim 3 or 5, characterized in that the number of drops of the air dispensing operation is changed according to the humidity of the installation environment.

7. The printing apparatus according to claim 1, characterized in that a heating waveform is applied to the head immediately before the start of printing, and after performing control to raise the head temperature or the correlation temperature to the threshold temperature, a maintenance operation is performed.

8. The print head that ejects ink, A circulation path through which the temperature-controlled liquid circulates via the inside of the head, A liquid delivery unit that delivers the temperature-controlled liquid, A temperature detection unit that detects the head temperature or a correlated temperature that correlates with the head temperature, A temperature control unit that controls the head temperature or the correlation temperature, A maintenance method for a printing apparatus that includes an environmental humidity sensor for detecting the humidity of the environment in which the apparatus is installed, After the device is started up, the temperature sensing unit detects the head temperature or the correlation temperature, A maintenance method characterized in that, if the head temperature or the correlation temperature is below a threshold temperature, a heating waveform is applied to the head, and after performing control to raise the head temperature or the correlation temperature to the threshold temperature, a maintenance operation is performed, and the type of maintenance operation after the application of the heating waveform is changed according to the humidity of the installation environment.

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