Patent Application
20240092101
The present invention relates to an inkjet printing apparatus, and more particularly to a head replacement method in the inkjet printing apparatus.
Conventionally, there is known an inkjet printing apparatus that ejects ink onto a printing medium (base material) such as printing paper by heat or pressure to print on a printing medium. The inkjet printing apparatus includes a head unit including a plurality of heads (print heads) having many nozzles that eject ink. The plurality of heads constituting the head unit are held on one head holding plate. One head unit includes, for example, five heads. In this case, the five heads are held on one head holding plate.
A typical inkjet printing apparatus for color printing is provided with at least a head unit for cyan (C) color, a head unit for magenta (M) color, a head unit for yellow (Y) color, and a head unit for black (K) color. In this manner, the head unit is typically provided for each color. An ink supply mechanism (ink circulation system) for supplying ink to each of the plurality of heads constituting the head unit is provided for each color. The ink supply mechanism is provided with a supply tank that stores ink to be supplied to the head and a collection tank that stores ink collected from the head. Ink flows from the supply tank to the collection tank via the head according to a difference (differential pressure) between the air pressure in the supply tank and the air pressure in the collection tank. Note that the present description focuses on an inkjet printing apparatus where pipes constituting the ink supply mechanism and pipes in the head form a circulation flow path through which ink circulates. When printing is performed on a printing medium, the ink circulates through the circulation flow path.
With respect to the inkjet printing apparatus as described above, ink ejection failure may occur due to solidification (drying) of ink caused by non-use for a long period of time, or other reasons. When printing is performed in a state where ink ejection failure has occurred, high-quality printed matter cannot be obtained. Therefore, cleaning or flushing is performed as a countermeasure against ink ejection failure. However, even when cleaning or flushing is performed, ink ejection failure may not be resolved sufficiently. In such a case, the head in which the ink ejection failure occurs is replaced. The head may be replaced for reasons except for ink ejection failure. Typically, a new head unit is provided by a printing apparatus manufacturer or the like with its interior filled with a liquid such as a cleaning solution.
Head replacement is usually manually performed by a user of the inkjet printing apparatus. That is, head replacement is not performed by a manufacturer operator who is familiar with the structure and the like of the inkjet printing apparatus. For this reason, during head replacement, the connection between the pipe constituting the ink supply mechanism and the pipe in the head (hereinafter simply referred to as “pipe connection”) may not be made properly. In the following description, with respect to the pipe connection, the connection between the pipe for supplying the ink from the supply tank to the head and the pipe in the head is referred to as a “supply-side pipe connection”, and the connection between the pipe for collecting the ink from the head to the collection tank and the pipe in the head is referred to as a “collection-side pipe connection”.
After head replacement, the air pressure in the supply tank is set to a high positive pressure, whereby the cleaning solution in the head after replacement (new head) is naturally discharged to the head cleaning cap. However, when there is an abnormality in the supply-side pipe connection after head replacement, the cleaning solution is not discharged to the head cleaning cap, and the cleaning solution is mixed with the ink when the ink circulation in the circulation flow path is resumed. As a result, printing failure occurs, and the need to remove ink in the circulation flow path arises. Furthermore, when there is an abnormality in the collection-side pipe connection after head replacement, negative pressure is not suitably applied to the head when the ink circulation in the circulation flow path is resumed, and a meniscus is not normally formed in each nozzle. As a result, when printing is performed, ink unexpectedly falls from each nozzle onto the printing medium, so-called “ink spillage”.
Japanese Laid-Open Patent Publication No. 2005-297279 discloses a technique for preventing damage to a head due to a pipe connection abnormality (failure). According to this technique, the head is provided with an inspection unit that inspects whether print data in a data latch unit is being updated normally or not. Then, when the inspection unit detects that the update of the print data has stopped, the printing operation stops, and an error signal is outputted.
However, according to the technique disclosed in Japanese Laid-Open Patent Publication No. 2005-297279, an abnormality in the pipe connection cannot be detected unless printing is actually performed on a printing medium after head replacement. Therefore, when there is an abnormality in the pipe connection, the printing medium and the ink are wasted.
Therefore, an object of the present invention is to provide a head replacement method capable of detecting an abnormality in pipe connection without performing printing, regarding an inkjet printing apparatus.
One aspect of the present invention is directed to a head replacement method for replacing a replacement target head that is at least one of a plurality of heads in an inkjet printing apparatus including
With such a configuration, after the end of the replacement of the head by the user, it is determined whether the pipe connection, including the connection between the ink discharge pipe and the collection branch pipe and the connection between the ink inflow pipe and the supply branch pipe, is properly made based on the ink liquid level position in at least one of the collection tank and the supply tank. Even when the ink circulation in the circulation flow path is started, when there is an abnormality in the pipe connection, the ink liquid level position does not change, so that it is possible to detect an abnormality in the pipe connection without performing printing on the printing medium. As above, it is possible to provide a head replacement method capable of detecting an abnormality in pipe connection without performing printing, regarding an inkjet printing apparatus.
Another aspect of the present invention is directed to an inkjet printing apparatus including:
Still another aspect of the present invention is directed to a non-transitory computer-readable recording medium on which a head replacement support program is recorded, the head replacement support program causing a computer included in a controller to execute, in an inkjet printing apparatus including a plurality of heads each configured to eject ink toward a printing medium, an ink supply mechanism configured to supply ink to each of the plurality of heads, and the controller configured to control operations of the plurality of heads and the ink supply mechanism:
These and other objects, features, modes, and advantageous effects of the present invention will become more apparent from the following detailed description of the present invention with reference to the accompanying drawings.
An embodiment of the present invention will be described below with reference to the accompanying drawings.
The print controller 100 controls the operation of the printer body 200 having the configuration as above. When an instruction command for printing output is given to the print controller 100, the print controller 100 controls the operation of the printer body 200 so that the printing paper PA is conveyed from the paper feeding unit 21 to the paper winding unit 29. Then, first, the printing unit 24 performs printing on the printing paper PA, next, the drying unit 26 dries the printing paper PA, and finally, the imaging unit 27 captures a printed image. When necessary, the cleaning mechanism 25 cleans the printing unit 24.
In the above configuration, a circulation flow path is formed through which ink circulates in the order of “supply tank 52—supply pipe 53—supply branch pipe 531—head 240—collection branch pipe 541—collection pipe 54—collection tank 51—recirculation pipe 55—supply tank 52”.
The body 241 includes an internal tank (not shown). The base plate 242 includes a flow path for ink flowing from the ink inflow pipe 246 to the internal tank and a flow path for ink flowing from the internal tank to the ink discharge pipe 244. The body 241 is also provided with many nozzles exposed to the back surface side of the base plate 242. A cavity in which ink is stored is provided between each nozzle and the internal tank, and a piezoelectric element is provided in the cavity. In such a configuration, when a drive signal having a predetermined drive waveform is applied to the piezoelectric element, the piezoelectric element is deformed based on the drive signal. As a result, ink is pushed out of the cavity, and ink is ejected from the nozzle.
The configuration and operation of the cleaning mechanism 25 will be described with reference to
The cleaning mechanism 25 includes a cap unit 251 including a plurality of caps 252 and a wiper unit 253 including a wiper 254. When cleaning is performed, as shown in
The auxiliary storage device 121 stores a print control program (a program for controlling the execution of a printing process by the printer body 200) 18. The print control program 18 includes, as a subprogram, a head replacement support program 19 for supporting the replacement of the head 240 by a user. The CPU 111 reads the print control program 18 stored in the auxiliary storage device 121 into the memory 112 and executes the program to achieve various functions of the print controller 100. The memory 112 includes a random-access memory (RAM) and a read-only memory (ROM). The memory 112 functions as a work area for the CPU 111 to execute the print control program 18 stored in the auxiliary storage device 121. Note that the print control program 18 is provided by being stored into the computer-readable recording medium (non-transitory recording medium). That is, for example, the user purchases the optical disc 5 as the recording medium of the print control program 18, inserts the optical disc 5 into the optical disc drive 122, reads the print control program 18 from the optical disc 5, and installs the print control program 18 in the auxiliary storage device 121.
Before the description of a procedure for head replacement in the present embodiment, a basic flow of head replacement will be described. Here, attention is paid to the state and the like of each component in a case where head replacement is normally performed without any abnormality occurring in the conventional procedure. In
The state of the ink supply mechanism when ink is circulating normally in the circulation flow path before head replacement is as shown in
The ink circulation in the circulation flow path is stopped prior to the actual replacement of an old head with a new head. The state of the ink supply mechanism when the ink circulation in the circulation flow path is stopped is as shown in
In a state where the ink circulation in the circulation flow path is stopped, the work of actually replacing the old head with the new head is performed. At this time, first, a drive signal wire (communication cable) is removed from the communication connector 243 (cf.
Thereafter, the supply control valve 531 corresponding to the new head is set to the open state, and the second pressure adjustment mechanism 522 greatly increases the air pressure in the supply tank 52 (large pressure is applied to the inside of the supply tank 52). As a result, the ink in the supply tank 52 flows to the new head 240 via the supply pipe 53 and the supply branch pipe 530, and the cleaning solution in the new head 240 is discharged to the head cleaning cap 252. In this manner, cleaning (pressurized purging) is performed. The state of the ink supply mechanism at this time is as shown in
Next, the supply control valve 531 corresponding to the new head is set to the closed state, and the second pressure adjustment mechanism 522 opens the supply tank 52 to the atmosphere. The state of the ink supply mechanism at this time is as shown in
After the supply tank 52 is opened to the atmosphere, all the supply control valves 531 including the supply control valve 531 that corresponds to the new head, all the collection control valves 541 including the collection control valve 541 that corresponds to the new head, and the return control valve 552 are set to the open state, and the pump 551 is set to the operating state. The first pressure adjustment mechanism 512 sets the air pressure in the collection tank 51 to the negative pressure, and the second pressure adjustment mechanism 522 sets the air pressure in the supply tank 52 to the positive pressure. As above, the ink circulation in the circulation flow path is resumed. The state of the ink supply mechanism at this time is as shown in
Based on the above, the head replacement processing (a series of processing related to head replacement including the work of actually replacing an old head with a new head) in the present embodiment will be described.
The control unit 150 sequentially performs the determination as to whether head replacement is necessary, and the identification of the replacement target head when head replacement is necessary, based on the imaging result of the printed image by the imaging unit 27 and the like. When head replacement is required, the control unit 150 starts the head replacement processing. First, a single circulation of ink to the replacement target head is performed (step S100). Specifically, circulation of ink is performed while setting only the valve corresponding to the replacement target head among the supply control valves 531(1) to 531(5) and the collection control valves 541(1) to 541(5) to the open state. For example, when the head 240(3) is the replacement target head, as shown in
Next, the first ink liquid level position and the second ink liquid level position are continuously checked in a state where the single circulation of ink to the replacement target head is performed, and it is determined whether there is a change in both the first ink liquid level position and the second ink liquid level position (step S110). As a result, when there is a change in both the first ink liquid level position and the second ink liquid level position, the processing proceeds to step S300, and when there is no change in at least one of the first ink liquid level position and the second ink liquid level position, the processing proceeds to step S200.
In step S200, ink is circulated to the non-replacement target head. Specifically, circulation of ink is performed while setting only the valve corresponding to the replacement target head among the supply control valves 531(1) to 531(5) and the collection control valves 541(1) to 541(5) to the closed state.
Next, the first ink liquid level position and the second ink liquid level position are checked in a state where the circulation of ink to the non-replacement target head is performed, and it is determined whether there is a change in both the first ink liquid level position and the second ink liquid level position (step S210). As a result, when there is a change in both the first ink liquid level position and the second ink liquid level position, it is determined that there is an abnormality in the valve corresponding to the replacement target head (step S220), and when there is no change in at least one of the first ink liquid level position and the second ink liquid level position, it is determined that there is an abnormality in the liquid level sensor (step S230). When it is determined in step S220 or step S230 that an abnormality has occurred, the device in which the abnormality has occurred is repaired or replaced by a service person or the like, and then the processing is performed again from step S100. In step S220, the determination is performed as follows in detail. When there is no change in the first ink liquid level position in step S110, it is determined that there is an abnormality in the collection control valve 541 corresponding to the replacement target head, and when there is no change in the second ink liquid level position in step S110, it is determined that there is an abnormality in the supply control valve 531 corresponding to the replacement target head. Further, in step S230, the determination is performed as follows in detail. When there is no change in the first ink liquid level position in step S110, it is determined that there is an abnormality in the first liquid level sensor 511. When there is no change in the second ink liquid level position in step S110, it is determined that there is an abnormality in the second liquid level sensor 521.
In step S300, the ink circulation in the circulation flow path is stopped. Specifically, the supply control valves 531(1) to 531(5), the collection control valves 541(1) to 541(5), and the return control valve 552 are set to the closed state, and the pump 551 is set to the stopped state, whereby the ink circulation in the circulation flow path is stopped.
Thereafter, a head replacement screen 600 as shown in
After the display of the head replacement screen, the user performs head replacement work (step S320). That is, the user performs the work of actually removing the old head from the head unit 2 and attach the new head to the head unit 2.
In the present embodiment, a pipe removal step is achieved by step S12, a head removal step is achieved by step S13, a head attachment step is achieved by step S14, and a pipe connection step is achieved by step S15.
After the user performs the head replacement work as described above, the user presses the above-described Complete button 610 included in the head replacement screen 600 (cf.
After the complete button 610 is pressed, the second pressure adjustment mechanism 522 opens the supply tank 52 to the atmosphere. Then, the ink liquid level position (second ink liquid level position) of the supply tank 52 in the state of being open to the atmosphere is detected by the second liquid level sensor 521, and the detected ink liquid level position is stored (step S340). At this time, the supply control valves 531(1) to 531(5), the collection control valves 541(1) to 541(5), and the return control valve 552 are set to the closed state.
Next, the new head is cleaned (step S350). In step S350, first, the cleaning mechanism 25 moves from the away position to the home position. Then, after only the supply control valve 531 corresponding to the new head is set to the open state, the second pressure adjustment mechanism 522 greatly increases the air pressure in the supply tank 52 (large pressure is applied to the inside of the supply tank 52). As a result, ink flows from the supply tank 52 to the new head, and the cleaning solution in the new head is discharged to the cap 252 covering the new head. Note that the new head may be cleaned by the first pressure adjustment mechanism 512 greatly increasing the air pressure in the collection tank 51 while setting only the collection control valve 531 corresponding to the new head to the open state. Although the cleaning solution in the new head is discharged to the cap 252 by pressurized purging in the present embodiment, the present invention is not limited thereto, and the cleaning solution in the new head may be discharged to the cap 252 by suction purging using a suction pump connected to the cap 252.
Next, the supply control valve 531 corresponding to the new head is set to the closed state, and thereafter, the second pressure adjustment mechanism 522 opens the supply tank 52 to the atmosphere. Then, the ink liquid level position (second ink liquid level position) of the supply tank 52 in the state of being open to the atmosphere is detected by the second liquid level sensor 521 (step S360).
Next, it is determined whether the ink liquid level position detected in step S360 has changed from the ink liquid level position stored in step S340 (step S370). More specifically, it is determined whether the ink liquid level position detected in step S360 is lower than the ink liquid level position stored in step S340. As a result, when the ink liquid level position detected in step S360 is lower than the ink liquid level position stored in step S340, the processing proceeds to step S400. When the ink liquid level position detected in step S360 is not lower than the ink liquid level position stored in step S340, the processing proceeds to step S600. When no abnormality has occurred, the ink liquid level position detected in step S360 is lower than the ink liquid level position stored in step S340.
In step S400, the single circulation of ink to the new head is performed (step S400). Specifically, circulation of ink is performed while setting only the valve corresponding to the new head among the supply control valves 531(1) to 531(5) and the collection control valves 541(1) to 541(5) to the open state. At this time, the air pressure in the collection tank 51 is set to the negative pressure, the air pressure in the supply tank 52 is set to the positive pressure, the return control valve 552 is set to the open state, and the pump 551 is set to the operating state.
Thereafter, the first ink liquid level position is continuously checked in a state where the single circulation of ink to the new head is performed, and it is determined whether there is a change in the first ink liquid level position (step S410). As a result, when there is a change in the first ink liquid level position, it is determined that the head replacement has been performed normally (step S500), and the head replacement processing ends. On the other hand, when there is no change in the first ink liquid level position, the processing proceeds to step S600.
In step S600, as in step S200, ink is circulated to the non-replacement target head. Next, the first ink liquid level position and the second ink liquid level position are checked in a state where the circulation of ink to the non-replacement target head is performed, and it is determined whether there is a change in both the first ink liquid level position and the second ink liquid level position (step S610). As a result, when there is a change in both the first ink liquid level position and the second ink liquid level position, the processing proceeds to step S700. On the other hand, when there is no change in at least one of the first ink liquid level position and the second ink liquid level position, it is determined that there is an abnormality in the liquid level sensor (step S800), and the head replacement processing ends temporarily. At this time, after a service person or the like repairs or replaces the liquid level sensor in which the abnormality has occurred, for example, the processing is performed again from step S340. In step S800, the determination is performed as follows in detail. When there is no change in the first ink liquid level position in step S410, it is determined that there is an abnormality in the first liquid level sensor 511. When there is no change in the second ink liquid level position in step S370, it is determined that there is an abnormality in the second liquid level sensor 521.
In step S700, it is determined that there is an abnormality in the pipe connection. Specifically, when there is no change in the first ink liquid level position in step S410, it is determined that there is an abnormality in the connection between the ink discharge pipe 244 and the collection branch pipe 540 via the first non-spill 245 for the new head. When there is no change in the second ink liquid level position in step S370, it is determined that there is an abnormality in the connection between the ink inflow pipe 246 and the supply branch pipe 530 via the second non-spill 247 for the new head.
Thereafter, a pipe connection promotion screen 700 as shown in
After the display of the pipe connection promotion screen 700, the user redoes the pipe connection (the connection between the ink discharge pipe 244 and the collection branch pipe 540 via the first non-spill 245 and the connection between the ink inflow pipe 246 and the supply branch pipe 530 via the second non-spill 247 with respect to the new head) (step S720).
After the user redoes the pipe connection, the user presses the above-described complete button 710 included in the pipe connection promotion screen 700 (cf.
After step S730 ends, the processing returns to step S340 or step S400. In this regard, when there is no change in the second ink liquid level position in step S370, the processing returns to step S340, and when there is no change in the first ink liquid level position in step S410, the processing returns to step S400.
Note that the determination results in steps S500, S600, and S700 are displayed on the display unit 123 of the print controller 100. That is, a determination result as to whether the pipe connection has been made properly is displayed on the display unit 123. Therefore, the user can quickly grasp whether the pipe connection has been made properly after head replacement.
In the present embodiment, an ink liquid level position pre-checking step is achieved by steps S100 and S110, a liquid level sensor inspection step is achieved by steps S200 and S210, a message output step is achieved by step S310, a replacement completion reception step is achieved by step S330, a supply-side connection state determination step is achieved by steps S340, S350, S360, and S370, an ink circulation start step is achieved by step S400, and a connection state determination step is achieved by steps S410, S500, S600, S610, S700, and S800. A second ink liquid level position storage step is achieved by step S340, a pressurization step is achieved by step S350, a second ink liquid level position checking step is achieved by step S360 and step S370, a first ink liquid level position checking step is achieved by step S410, and an ink liquid level position rechecking step is achieved by step S600 and step S610.
According to the present embodiment, after the user finishes the replacement of the head 240, it is determined whether the pipe connection, including the connection between the ink discharge pipe 244 and the collection branch pipe 540 and the connection between the ink inflow pipe 246 and the supply branch pipe 530, has been made properly based on the ink liquid level position (the height of the ink liquid level) in the collection tank 51 and the supply tank 52. Even when the ink circulation in the circulation flow path is started, when there is an abnormality in the pipe connection, the ink liquid level position does not change. Therefore, with the configuration of the present embodiment, it is possible to detect an abnormality in the pipe connection without performing printing on the printing medium. Since an abnormality in the pipe connection can be detected before printing on the printing medium, wasteful consumption of ink and printing media is reduced. Thus, it is possible to contribute to the achievement of the Sustainable Development Goals (SDGs). As described above, according to the present embodiment, it is possible to provide a head replacement method capable of detecting an abnormality in pipe connection without performing printing regarding an inkjet printing apparatus. In addition, according to the present embodiment, when an abnormality occurs due to head replacement, it is possible to quickly identify the cause of the abnormality (defective portion). Specifically, it is possible to identify which of the following has an abnormality: the connection between the ink discharge pipe 244 and the collection branch pipe 540, the connection between the ink inflow pipe 246 and the supply branch pipe 530, the first liquid level sensor 511, the second liquid level sensor 521, the collection control valve 541, and the supply control valve 542.
Modifications of the above embodiment will be described below.
In step S400, the single circulation of ink to the new head is performed. Then, the first ink liquid level position is continuously checked in a state where the single circulation of ink to the new head is performed, and it is determined whether there is a change in the first ink liquid level position (step S410). As a result, when there is a change in the first ink liquid level position, it is determined that the head replacement has been performed normally (step S500), and the head replacement processing ends. On the other hand, when there is no change in the first ink liquid level position, it is determined that there is some abnormality (step S415), and the head replacement processing ends temporarily.
When it is determined in step S375 or step S415 that there is any abnormality, the head replacement processing is performed again from an appropriate step after a service person or the like identifies the cause of the abnormality and takes measures (e.g., repairs or replaces equipment).
In the present modification, a message output step is achieved by step S310, a replacement completion reception step is achieved by step S330, a supply-side connection state determination step is achieved by steps S340, S350, S360, and S370, an ink circulation start step is achieved by step S400, and a connection state determination step is achieved by steps S410, S415, and S500. A second ink liquid level position storage step is achieved by step S340, a pressurization step is achieved by step S350, a second ink liquid level position checking step is achieved by step S360 and step S370, and a first ink liquid level position checking step is achieved by step S410.
As described above, in the present modification, the processes of steps S100 to S230 in the above embodiment (cf.
According to the present modification, it is not possible to quickly identify the cause of an abnormality that has occurred at the time of head replacement, but it is possible to determine whether the head replacement has been performed normally without performing printing.
In the present modification, an ink liquid level position pre-checking step is achieved by steps S100 and S110, a message output step is achieved by step S310, a replacement completion reception step is achieved by step S330, a supply-side connection state determination step is achieved by steps S340, S350, S360, and S370, an ink circulation start step is achieved by step S400, and a connection state determination step is achieved by steps S410, S415, and S500. A second ink liquid level position storage step is achieved by step S340, a pressurization step is achieved by step S350, a second ink liquid level position checking step is achieved by step S360 and step S370, and a first ink liquid level position checking step is achieved by step S410.
As above, in the present modification, the processes of steps S600 to S800 in the above embodiment (cf.
According to the present modification, when the abnormality occurs after the replacement of the head, the possibility that the cause of the abnormality is the valve can be eliminated. In addition, as in the first modification, it is not possible to quickly identify the cause of an abnormality that has occurred at the time of head replacement, but it is possible to determine whether the head replacement has been performed normally without performing printing.
The present invention is not limited to the above embodiment (including the modifications), and various modifications can be made without departing from the gist of the present invention. For example, although one head is replaced at a time in the above embodiment (including the modifications), the present invention is also established even when a plurality of (e.g., two) heads are replaced at a time. In this case, the plurality of heads are the “replacement target heads” in the present invention. Further, for example, although the configuration of the inkjet printing apparatus 10 that performs color printing has been exemplified in the above embodiment, the present invention can also be applied to a case where an inkjet printing apparatus that performs monochrome printing is adopted.
Although the present invention has been described in detail above, the above description is illustrative in all aspects and is not restrictive. It is understood that numerous other modifications and variations can be devised without departing from the scope of the present invention.
This application is an application claiming priority based on Japanese Patent Application No. 2022-147034 entitled “Head Replacement Method, Inkjet Printing Apparatus, and Head Replacement Support Program” filed on Sep. 15, 2022, and the contents of which are herein incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-147034 | Sep 2022 | JP | national |
