Liquid feeding apparatus, image forming apparatus, and diagnosis method for liquid feeding apparatus

Abstract

To diagnose a deterioration level of at least one of a filter and a pump accurately with a simple structure.SOLUTION: A liquid feeding apparatus includes: a flow path part including a pump that feeds a liquid from a first reservoir to a second reservoir, and a filter that collects foreign matters from the liquid fed; and a diagnosis part which acquires a numerical value related to a liquid feed amount of the liquid fed to the second reservoir by driving the pump with at least one second set value different from a first set value related to a normally used driving force, and diagnoses a deterioration level of at least one of the pump and the filter based on the numerical value.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid feeding device, an image forming apparatus, and a method for diagnosing a liquid feeding device.

Background Art

[0002] In an inkjet type image forming apparatus, ink is supplied to an inkjet head using a liquid feeding device. When a component constituting the liquid feeding device fails, the image forming apparatus stops, resulting in a significant printing pause time.

[0003] For example, when a filter that is disposed in a flow path for supplying ink and collects foreign matter becomes clogged, a sufficient ink supply amount cannot be obtained, an ink supply error may occur, and the image forming apparatus may stop.

[0004] Therefore, if the degree of clogging of the filter can be monitored and information such as filter replacement recommendation information can be notified to the user before an ink supply error occurs due to the clogging of the filter, the image forming apparatus can be prevented from stopping by replacing the filter before the error occurs.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In order to diagnose the degree of clogging of the filter, a method of measuring the ink supply amount from the flow path having the filter can be considered. However, when the pump for supplying ink deteriorates, for example, when a leak occurs in the valve portion of the pump due to the adhesion of deposits, the ink supply amount decreases. Therefore, it is difficult to diagnose only the degree of clogging of the filter by this method.

[0007] As a method for diagnosing the degree of clogging of a filter, Patent Document 1 discloses a method of measuring the respective ink supply amounts in two flow paths, a flow path through the filter and a flow path not through the filter. However, this method causes an increase in the size and cost of the apparatus.

[0008] An object of the present invention is to provide a liquid feeding device, an image forming apparatus, and a diagnosis method for a liquid feeding device that can accurately diagnose the degree of deterioration of at least one of a filter and a pump with a simple configuration.

Means for Solving the Problems

[0009] The liquid feeding device according to the present invention includes a flow path section having a pump for feeding a liquid from a first storage section to a second storage section, and a filter for collecting foreign matters from the liquid to be fed, a diagnosis section that drives the pump with at least one second set value different from a first set value regarding a driving force for normal use, acquires a numerical value regarding a liquid feeding amount fed to the second storage section, and diagnoses the degree of deterioration of at least one of the pump and the filter based on the numerical value, and is provided with.

[0010] The image forming apparatus according to the present invention includes a first storage section and a second storage section for storing ink, the above-described liquid feeding device for feeding the ink, and an image forming section for forming an image using the ink supplied from the second storage section. and is provided with.

[0011] The diagnosis method for a liquid feeding device according to the present invention is a diagnosis method for a liquid feeding device including a flow path section having a pump for feeding a liquid from a first storage section to a second storage section, and a filter for collecting foreign matters from the liquid to be fed, Drive the pump with at least one second set value different from the first set value regarding the driving force usually used, obtain a numerical value regarding the liquid feeding amount fed to the second storage section, and diagnose the degree of deterioration of at least one of the pump and the filter based on the numerical value.

Effect of the Invention

[0012] According to the present invention, with a simple configuration, the degree of deterioration of at least one of the filter and the pump can be accurately diagnosed.

Brief Description of the Drawings

[0013]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] [Image Forming Apparatus] FIG. 1 is a schematic diagram showing an example of an ink supply unit 40 and an inkjet printer 100 according to the present embodiment. FIG. 2 is a block diagram showing a main part of the control system of the inkjet printer 100 shown in FIG. 1.

[0016] As shown in FIG. 2, the inkjet printer 100 (image forming apparatus in the present invention) includes a conveyance unit 10, a supply unit 20, a discharge unit 30, an ink supply unit 40, a head module 50, an operation display unit 70, an input / output interface 80, a control unit 90, and the like.

[0017] The conveying unit 10 conveys the recording medium M (see FIG. 1). The conveying unit 10 is composed of, for example, a conveying belt, a conveying drum, etc. The recording medium M supplied from the supply unit 20 is conveyed to the head module 50 by the conveying operation of the conveying unit 10. Thereafter, the recording medium M on which an image is formed by the head module 50 is conveyed to the discharging unit 30 by the conveying operation of the conveying unit 10.

[0018] As the recording medium M, various media capable of fixing the ink ejected from the inkjet head (not shown) of the head module 50 can be used. The recording medium M is, for example, a medium such as sheet-like paper, cloth, resin, etc. Note that the recording medium M is not limited to a sheet-like medium, and may be a medium such as roll-like paper, cloth, resin, etc.

[0019] The supply unit 20 accommodates the recording medium M and supplies the recording medium M to the conveying unit 10. The supply unit 20 has, for example, a storage unit for accommodating the recording medium M, and belts, rollers, etc. for conveying the recording medium M to the conveying unit 10.

[0020] The discharging unit 30 accommodates the recording medium M discharged from the conveying unit 10. The discharging unit 30 has, for example, belts, rollers, etc. for conveying the recording medium M from the conveying unit 10, and a storage unit for accommodating the recording medium M after image formation.

[0021] The ink supply unit 40 (liquid feeding device in the present invention) is a device that supplies ink I (liquid in the present invention) to the head module 50. The ink supply unit 40 includes a main ink storage unit 400, a main liquid feeding unit 410, a first ink storage unit 420, a sub liquid feeding unit 430, a second ink storage unit 440, a pressure adjustment unit 450, a head supply path 461, a circulation unit 470, etc.

[0022] The main ink storage unit 400 stores the ink I to be fed to the first ink storage unit 420. The main ink storage unit 400 has a main tank 401 for storing the ink I.

[0023] The main tank 401 stores Ink I, and when the stored Ink I approaches empty, Ink I is replenished by the user or service technician.

[0024] The main liquid supply section 410 supplies the Ink I stored in the main tank 401 to the first ink storage section 420 (the first sub-tank 421 described later). The main liquid supply section 410 includes a main supply path 411, a supply pump 412, a supply valve 413, etc. The supply pump 412 and the supply valve 413 are arranged in this order from the upstream side to the downstream side in the liquid supply direction.

[0025] One end of the main supply path 411 on the upstream side in the liquid supply direction is arranged inside the main tank 401, and the end on the downstream side in the liquid supply direction is connected to the side surface of the first sub-tank 421, serving as a flow path from the main tank 401 to the first sub-tank 421.

[0026] The supply pump 412 is a pump that supplies Ink I from the main tank 401 to the first sub-tank 421. The supply valve 413 opens and closes the main supply path 411.

[0027] When the control unit 90 detects, by means of a liquid level sensor 422 described later, that the liquid level of Ink I in the first sub-tank 421 is at the lower limit, it controls the supply pump 412 and the supply valve 413 to supply Ink I from the main tank 401 to the first sub-tank 421.

[0028] The first ink storage section 420 (the first storage section in the present invention) stores Ink I to be supplied to the second ink storage section 440. The first ink storage section 420 includes a first sub-tank 421 that stores Ink I, a liquid level sensor 422, etc.

[0029] The first sub-tank 421 stores Ink I and is normally in an open-to-atmosphere state (0 kPa).

[0030] The liquid level sensor 422 measures the liquid level height of the ink I stored in the first sub-tank 421. As the liquid level sensor 422, any sensor can be used as long as it can measure the liquid level height of the ink I. For example, sensors such as magnetic type, optical type, and capacitance type are applicable.

[0031] The sub-feed unit 430 (flow path unit in the present invention) feeds the ink I stored in the first sub-tank 421 to the second ink storage unit 440 (second sub-tank 441). The sub-feed unit 430 includes a sub-supply path 431, a filter 432, a feed pump 433, a feed valve 434, etc. The filter 432, the feed pump 433, and the feed valve 434 are arranged in this order from the upstream side to the downstream side in the feed direction.

[0032] The sub-supply path 431 connects the first sub-tank 421 and the second sub-tank 441 and serves as a flow path from the first sub-tank 421 to the second sub-tank 441. The filter 432 filters the ink I to be fed and collects foreign matters. Note that a degassing module for degassing the ink I may be provided together with the filter 432.

[0033] The feed pump 433 is a pump that feeds the ink I from the first sub-tank 421 to the second sub-tank 441. Here, as an example, a feed pump 433 with a minimum pump duty setting of 20% is used. However, as long as the ink I feeding operation can be guaranteed, a feed pump with a different minimum value may be used. The feed valve 434 opens and closes the sub-supply path 431. For example, when feeding the ink I from the first sub-tank 421 to the second sub-tank 441, the feed valve 434 opens, and when feeding the ink I from the second sub-tank 441 to the head module 50, the feed valve 434 closes.

[0034] When the control unit 90 detects that the liquid level of the ink I in the second sub-tank 441 is at the lower limit by the liquid level sensor 445 described later, it controls the feed pump 433 and the feed valve 434 to feed the ink I from the first sub-tank 421 to the second sub-tank 441.

[0035] The second ink storage unit 440 (the second storage unit in the present invention) stores the ink I to be fed to the head module 50. The second ink storage unit 440 includes a second sub-tank 441 that stores the ink I, an air flow path 442, a back pressure valve 443, a back pressure pump 444, a liquid level sensor 445, and the like.

[0036] The second sub-tank 441 is connected to the first sub-tank 421 via the sub-supply path 431 and is connected to the head module 50 via the head supply path 461.

[0037] One end of the air flow path 442 is connected to the upper part of the second sub-tank 441 (above the upper limit of the ink I stored inside), and the other end is open to the atmosphere. The back pressure valve 443 adjusts its opening / closing amount to adjust the amount of air flowing through the air flow path 442. The back pressure pump 444 sucks the air in the second sub-tank 441 via the air flow path 442 and the back pressure valve 443, and reduces the air pressure (back pressure) in the second sub-tank 441.

[0038] A pressure detection unit (not shown) for detecting the internal air pressure is provided in the second sub-tank 441. The control unit 90 controls the back pressure valve 443 and the back pressure pump 444 based on the air pressure detected by the pressure detection unit so that the air pressure in the second sub-tank 441 becomes a predetermined pressure.

[0039] During printing, the control unit 90 controls the air pressure in the second sub-tank 441 to form an appropriate meniscus so that the ink I is appropriately ejected from the nozzles by the ejection operation of the inkjet heads of the head module 50. For example, as shown in FIG. 1, the air pressure is controlled to -3 kPa.

[0040] The liquid level sensor 445 measures the liquid level height of the ink I stored in the second sub-tank 441. As the liquid level sensor 445, any sensor can be used as long as it can measure the liquid level height of the ink I. For example, sensors such as magnetic, optical, and capacitance sensors are applicable.

[0041] The pressure adjustment unit 450 adjusts the air pressure inside the first sub-tank 421 or vents the first sub-tank 421 and the second sub-tank 441 to the atmosphere. The pressure adjustment unit 450 includes a first atmosphere release passage 451, a first atmosphere release valve 452, a pressure adjustment passage 453, a pneumatic pump 454, a pressure adjustment valve 455, a second atmosphere release passage 456, and a second atmosphere release valve 457.

[0042] One end of the first atmosphere release passage 451 is connected to the upper part of the first sub-tank 421 (above the upper limit of the ink I stored therein), and the other end is open to the atmosphere. The first atmosphere release valve 452 opens and closes the first atmosphere release passage 451.

[0043] The control unit 90 controls the first atmosphere release valve 452 to open and close the first atmosphere release passage 451, thereby venting the first sub-tank 421 to the atmosphere or sealing the first sub-tank 421.

[0044] One end of the pressure adjustment passage 453 is connected to one end side of the first atmosphere release passage 451, that is, to the upper part of the first sub-tank 421 (above the upper limit of the ink I stored therein), and the other end is open to the atmosphere. The pneumatic pump 454 adjusts the air pressure (back pressure) inside the first sub-tank 421 or the second sub-tank 441 via the pressure adjustment passage 453. The pressure adjustment valve 455 adjusts the amount of air flowing through the air flow passage 442 that flows through the pressure adjustment passage 453.

[0045] The control unit 90 closes the first atmosphere release valve 452 and the second atmosphere release valve 457, and controls the pneumatic pump 454 and the pressure adjustment valve 455 to adjust the air pressure (back pressure) inside the first sub-tank 421.

[0046] One end of the second atmosphere release passage 456 is connected to the upper part of the second sub-tank 441 (above the upper limit of the ink I stored therein), and the other end is connected to the pressure adjustment passage 453. The second atmosphere release valve 457 opens and closes the second atmosphere release passage 456.

[0047] The control unit 90 controls the pressure regulating valve 455 and the second atmosphere release valve 457 to open the pressure regulating passage 453 and the second atmosphere release passage 456, thereby releasing the second sub-tank 441 to the atmosphere. Further, the control unit 90 controls the second atmosphere release valve 457 to close the second atmosphere release passage 456, thereby sealing the second sub-tank 441.

[0048] Also, the control unit 90 closes the pressure regulating valve 455, opens the first atmosphere release valve 452 and the second atmosphere release valve 457, and controls the air pump 454 to adjust the air pressure (back pressure) in the second sub-tank 441.

[0049] The head supply passage 461 is a supply passage having one end connected to the bottom of the second sub-tank 441 and the other end connected to the head module 50, and supplies the ink in the second sub-tank 441 to the head module 50.

[0050] The circulation unit 470 circulates the ink I in the head module 50 and causes it to flow back to the first sub-tank 421. The circulation unit 470 includes a circulation passage 471 and a circulation valve 472.

[0051] One end of the circulation passage 471 is connected to the head module 50, and the other end is connected to the first sub-tank 421. The circulation valve 472 opens and closes the circulation passage 471.

[0052] The control unit 90 controls the circulation valve 472 to open and close the circulation passage 471, thereby circulating the ink I in the head module 50 and causing it to flow back to the first sub-tank 421 or stopping the reflux.

[0053] For example, the circulation unit 470 is used for an ink circulation operation performed when air bubbles enter the inkjet head in the head module 50. When air bubbles enter the inkjet head, the control unit 90 stops the printing operation, opens the liquid supply valve 434 and the circulation valve 472, closes the back pressure valve 443 and the second atmosphere release path 456, and drives the liquid supply pump 433 to increase the air pressure in the second sub-tank 441. With the increased air pressure, the ink I containing air bubbles in the inkjet head is circulated to the first sub-tank 421 to extrude the air bubbles in the inkjet head.

[0054] Here, as an example, the back pressure valve 443, the first atmosphere release valve 452, and the pressure adjustment valve 455 are normally open valves that close by control (supply of a predetermined drive voltage) from the control unit 90. Also, the other supply valve 413, the liquid supply valve 434, the second atmosphere release valve 457, and the circulation valve 472 are normally closed valves that open by control (supply of a predetermined drive voltage) from the control unit 90.

[0055] The head module 50 (the image forming unit in the present invention) has devices and members necessary for image formation such as an inkjet head. The head module 50 discharges the ink I supplied from the ink supply unit 40 (the second ink storage unit 440) from the nozzles of the inkjet head to form an image on the recording medium M.

[0056] If the nozzles of the inkjet head are clogged, the control unit 90 closes the back pressure valve 443 and the pressure adjustment valve 455, opens the second atmosphere release valve 457, and drives the pneumatic pump 454 to increase the air pressure in the second sub-tank 441. With the increased air pressure, the ink I in the nozzles is forcibly discharged to extrude the clogging in the nozzles.

[0057] In addition, in FIG. 1, for the sake of simplicity of the figure, the ink supply unit 40 and the head module 50 for one color are illustrated, but the ink supply unit 40 and the head module 50 are arranged according to the number of colors to be used. For example, when using four colors of yellow (Y), magenta (M), cyan (C), and black (K), the ink supply unit 40 and the head module 50 for four colors are arranged.

[0058] The operation display unit 70 is, for example, a flat panel display such as a liquid crystal with a touch panel or an organic EL (Electro Luminescence). The operation display unit 70 displays an operation menu for the user, information regarding image data, various states of the inkjet printer 100, and the like. Further, the operation display unit 70 includes a plurality of keys and accepts various input operations of the user.

[0059] The input / output interface 80 mediates the transmission and reception of data between the external device 200 and the control unit 90. The input / output interface 80 is configured by, for example, any of various serial interfaces, various parallel interfaces, or a combination thereof.

[0060] The external device 200 is, for example, a personal computer, a facsimile device, or the like, and supplies a print job, image data, etc. to the control unit 90 via the input / output interface 80.

[0061] The control unit 90 includes a CPU (Central Processing Unit) 91, a RAM (Random Access Memory) 92, a ROM (Read Only Memory) 93, a storage unit 94, and the like.

[0062] The CPU 91 reads out various control programs and setting data stored in the ROM 93, stores them in the RAM 92, and executes the programs to perform various arithmetic processes. For example, based on the image data received from the input / output interface 80, the control unit 90 generates a drive signal for the image to be formed and outputs it to the head module 50.

[0063] The RAM 92 provides a working memory space for the CPU 91 and stores temporary data. Note that the RAM 92 may include a non-volatile memory.

[0064] The ROM 93 stores various control programs and setting data executed by the CPU 91. Note that instead of the ROM 93, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

[0065] The storage unit 94 stores print jobs input from the external device 200 and image data related to the print jobs via the input / output interface 80. As the storage unit 94, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may be used in combination.

[0066] To the control unit 90, a conveyance unit 10, a supply unit 20, a discharge unit 30, an ink supply unit 40, a head module 50, an operation display unit 70, an input / output interface 80, etc. are respectively connected. The control unit 90 comprehensively controls the overall operation of the inkjet printer 100. The conveyance unit 10, the supply unit 20, the discharge unit 30, the ink supply unit 40, the head module 50, the operation display unit 70, the input / output interface 80, etc. are controlled by the control unit 90 to execute predetermined processes.

[0067] With the above configuration, the inkjet printer 100 supplies the recording medium M from the supply unit 20 to the conveyance unit 10, forms an image on the recording medium M conveyed to the conveyance unit 10 with the head module 50, and conveys the recording medium M on which the image is formed to the discharge unit 30.

[0068] Incidentally, in the inkjet printer 100 having the above-described configuration, in order to diagnose the degree of clogging of the filter 432, a method of measuring the supply amount of the ink I from the sub-supply path 431 having the filter 432 can be considered. However, even when the liquid feed pump 433 that supplies the ink I deteriorates, since the supply amount of the ink I decreases, it is difficult to diagnose only the degree of clogging of the filter 432 by this method.

[0069] Therefore, in the present embodiment, the ink supply unit 40 includes a diagnostic unit described below. The diagnostic unit drives the liquid feed pump 433 with at least one second set value different from the first set value regarding the driving force for normal use, and acquires a numerical value regarding the liquid feed amount fed to the second ink storage unit 440. Then, the diagnostic unit diagnoses the degree of deterioration (degree of deterioration) of at least one of the liquid feed pump 433 and the filter 432 based on the acquired numerical value.

[0070] Hereinafter, pump duty is used as the first and second set values regarding the driving force for driving the liquid feed pump 433, but any other set value such as the number of rotations may be used as long as it is a set value regarding the driving force. Further, hereinafter, the liquid feed amount or the liquid level rise width described later is used as the numerical value regarding the liquid feed amount, but any value proportional to the liquid feed amount such as the liquid feed speed may be used.

[0071] Also, here, the control unit 90 has a configuration that also serves as the diagnostic unit in the ink supply unit 40, but another control unit or the like that functions as the diagnostic unit may be provided in the ink supply unit 40 separately from the control unit 90.

[0072] Regarding the above-described diagnostic unit, first, with reference to FIG. 3, the relationship between the pump duty of the liquid feed pump 433 and the liquid feed amount for feeding the ink I will be described. FIG. 3 is a graph showing the relationship between the pump duty of the liquid feed pump 433 and the liquid feed amount for feeding the ink I.

[0073] As shown in FIG. 3, the liquid feeding amount of the liquid feeding pump 433 for feeding the ink I increases as the pump duty (%) of the liquid feeding pump 433 increases. In FIG. 3, the liquid feeding amount of the ink I when the pump duty is 40% used during printing is set to 100, and the liquid feeding amount with respect to the pump duty is graphed. In the present embodiment, based on the pump duty used during printing (the first set value in the present invention), the pump duty during pump diagnosis (the second set value in the present invention) and the pump duty during filter diagnosis (the second set value in the present invention) are set.

[0074] Here, as an example, the pump duty during pump diagnosis is set to 20% and the pump duty during filter diagnosis is set to 100%. However, the pump duty during pump diagnosis may be lower and the pump duty during filter diagnosis may be higher than the reference pump duty.

[0075] [Setting of Pump Duty] The setting of the pump duty will be described with reference to FIGS. 4A to 5D. First, with reference to FIGS. 4A to 4D, the reason for increasing the pump duty during filter diagnosis with respect to the reference pump duty will be explained.

[0076] FIGS. 4A to 4D are graphs showing the relationship between the filter degradation degree and the liquid feeding amount of the ink I. FIG. 4A is a graph when the pump duty of the liquid feeding pump 433 is 20%. FIG. 4B is a graph when the pump duty of the liquid feeding pump 433 is 40%. FIG. 4C is a graph when the pump duty of the liquid feeding pump 433 is 70%. FIG. 4D is a graph when the pump duty of the liquid feeding pump 433 is 100%.

[0077] In FIGS. 4A to 4D, with the ink delivery volume of ink I being set to 100 when the filter 432 and the liquid delivery pump 433 are new, the ink delivery volume of ink I with respect to the filter degradation degree is graphed. Also, in FIGS. 4A to 4D, the state when the filter 432 is new is set as the filter degradation degree 0 (0%), and the state where the filter 432 needs to be replaced (for example, the state where the reference ink delivery volume cannot be obtained) is set as the filter degradation degree 10 (100%). Further, in FIGS. 4A to 4D, when the liquid delivery pump 433 is new, when it is 40% degraded, and when replacement is necessary are indicated by a solid line, a dashed line, and a one-dot chain line, respectively.

[0078] Referring to FIG. 4A, when the pump duty of the liquid delivery pump 433 is 20%, the change amount (slope) of the ink delivery volume of ink I with respect to the filter degradation degree is smaller than in FIGS. 4B to 4D, regardless of whether the liquid delivery pump 433 is new, 40% degraded, or needs to be replaced.

[0079] Referring also to FIGS. 4B to 4D, as the pump duty increases, the change amount of the ink delivery volume of ink I with respect to the filter degradation degree becomes larger, regardless of whether the liquid delivery pump 433 is new, 40% degraded, or needs to be replaced.

[0080] For example, in FIGS. 4A to 4D, regarding the change amount of the ink delivery volume of ink I with respect to the filter degradation degree when the liquid delivery pump 433 is new, let the change amounts from the filter degradation degree 0 to the filter degradation degree 10 be Cf1 to Cf4, respectively. In this case, Cf1 < Cf2 < Cf3 < Cf4, and when the pump duty of the liquid delivery pump 433 is 100%, the change amount of the ink delivery volume of ink I with respect to the filter degradation degree is the largest.

[0081] Thus, when diagnosing the filter degradation degree, a relatively large pump duty for which the change amount of the ink delivery volume of ink I with respect to the filter degradation degree becomes large is desirable, and 100%, which is the maximum value of the pump duty, is most desirable.

[0082] Also, when the pump duty of the liquid delivery pump 433 is 20% as shown in FIG. 4A, there is a separation between the graph of the liquid delivery amount of the ink I when the liquid delivery pump 433 is new and the graphs of the liquid delivery amounts of the ink I when it is 40% deteriorated and when replacement is necessary, as compared with FIGS. 4B to 4D. This means that the state of the deterioration degree of the liquid delivery pump 433 has a great influence on the liquid delivery amount of the ink I.

[0083] Referring also to FIGS. 4B to 4D, as the pump duty increases, the graphs come closer to each other. This means that the influence of the state of the deterioration degree of the liquid delivery pump 433 on the liquid delivery amount of the ink I is decreasing.

[0084] For example, in FIGS. 4A to 4D, let the differences between the liquid delivery amounts of the ink I at a filter deterioration degree of 10 when the liquid delivery pump 433 is new and the liquid delivery amounts of the ink I at a filter deterioration degree of 10 when replacement is necessary be Df1 to Df4, respectively. In this case, Df1 > Df2 > Df3 > Df4, and when the pump duty of the liquid delivery pump 433 is 100%, the influence of the state of the deterioration degree of the liquid delivery pump 433 is the smallest.

[0085] Thus, when diagnosing the filter deterioration degree, a relatively large pump duty at which the influence of the state of the deterioration degree of the liquid delivery pump 433 is small is desirable, and the maximum value of the pump duty, 100%, is most desirable.

[0086] The pressure loss when the ink I passes through the filter 432 increases as the flow rate of the ink I increases. That is, increasing the pump duty makes the influence of the deterioration of the filter 432 on the liquid delivery amount measurement greater. Therefore, increasing the pump duty increases the influence of the deterioration of the filter 432 on the liquid delivery amount measurement, so that the deterioration of the filter 432 can be diagnosed more accurately.

[0087] From the above, when diagnosing the filter degradation degree, in the present embodiment, the change amount of the liquid feed amount of the ink I with respect to the filter degradation degree is large, and the influence given by the degradation degree state of the liquid feed pump 433 is small, so the pump duty of 100% is used.

[0088] Next, with reference to FIGS. 5A to 5D, the reason for reducing the pump duty at the time of pump diagnosis with respect to the reference pump duty will be described.

[0089] FIGS. 5A to 5D are graphs showing the relationship between the pump degradation degree and the liquid feed amount of the ink I. FIG. 5A is a graph when the pump duty of the liquid feed pump 433 is 20%. FIG. 5B is a graph when the pump duty of the liquid feed pump 433 is 40%. FIG. 5C is a graph when the pump duty of the liquid feed pump 433 is 70%. FIG. 5D is a graph when the pump duty of the liquid feed pump 433 is 100%.

[0090] In FIGS. 5A to 5D, with the liquid feed amount of the ink I when the filter 432 and the liquid feed pump 433 are new being 100, the liquid feed amount of the ink I with respect to the pump degradation degree is graphed. Also, in FIGS. 5A to 5D, the state when the liquid feed pump 433 is new is set as the pump degradation degree 0 (0%), and the state where the liquid feed pump 433 needs to be replaced (for example, the state where the reference liquid feed amount cannot be obtained) is set as the pump degradation degree 10 (10%). Further, in FIGS. 5A to 5D, when the filter 432 is new, when it is 30% degraded, and when replacement is necessary are shown by a solid line, a broken line, and a one-dot chain line, respectively.

[0091] In the case where the pump duty of the liquid feed pump 433 shown in FIG. 5A is 20%, the change amount (slope) of the liquid feed amount of the ink I with respect to the pump degradation degree is larger than that in FIGS. 5B to 5D, regardless of whether the filter 432 is new, 30% degraded, or needs to be replaced.

[0092] Referring also to FIGS. 5B to 5D, as the pump duty increases, the change amount of the liquid feeding amount of Ink I with respect to the pump degradation degree becomes smaller regardless of whether the liquid feeding pump 433 is new, 30% degraded, or in need of replacement.

[0093] For example, in FIGS. 5A to 5D, regarding the change amount of the liquid feeding amount of Ink I with respect to the pump degradation degree when the liquid feeding pump 433 is new, let the change amounts from a filter degradation degree of 0 to a filter degradation degree of 10 be Cp1 to Cp4, respectively. In this case, Cp1 > Cp2 > Cp3 > Cp4, and when the pump duty of the liquid feeding pump 433 is 20%, the change amount of the liquid feeding amount of Ink I with respect to the pump degradation degree is the largest.

[0094] Thus, when diagnosing the pump degradation degree, a relatively small pump duty at which the change amount of the liquid feeding amount of Ink I with respect to the pump degradation degree becomes large is desirable, and a pump duty of 20% is most desirable.

[0095] Also, referring to FIG. 5A, when the pump duty of the liquid feeding pump 433 is 20%, the graphs of the liquid feeding amounts of Ink I when the filter 432 is new, 30% degraded, and in need of replacement are closer compared to FIGS. 5B to 5D. This means that the influence of the degradation degree state of the filter 432 on the liquid feeding amount of Ink I is small.

[0096] Referring also to FIGS. 5B to 5D, as the pump duty increases, the graphs move apart from each other. This means that the influence of the degradation degree state of the filter 432 on the liquid feeding amount of Ink I is increasing.

[0097] For example, in FIGS. 5A to 5D, let the differences between the ink I liquid delivery amounts at a pump degradation degree of 10 when the filter 432 is new and the ink I liquid delivery amounts at a pump degradation degree of 10 when replacement is necessary be Dp1 to Dp4, respectively. In this case, Dp1 < Dp2 < Dp3 < Dp4, and when the pump duty of the liquid delivery pump 433 is 20%, the influence exerted by the degradation degree state of the filter 432 is the smallest.

[0098] Thus, when diagnosing the pump degradation degree, a relatively small pump duty at which the influence exerted by the degradation degree state of the filter 432 is reduced is desirable. Here, as an example, since the liquid delivery pump 433 with a minimum adjustable pump duty of 20% is used, 20% is most desirable as the pump duty when diagnosing the pump degradation degree. If the liquid delivery operation of the ink I can be guaranteed, a liquid delivery pump with a different minimum value may be used, and in that case, the minimum value of the pump duty of the liquid delivery pump is most desirable as the pump duty when diagnosing the pump degradation degree.

[0099] The pressure loss when the ink I passes through the filter 432 becomes smaller as the flow rate of the ink I becomes slower. That is, reducing the pump duty reduces the influence on the measurement of the liquid delivery amount due to the degradation of the filter 432. Therefore, when the pump duty is reduced, for the measurement of the liquid delivery amount, the influence due to the degradation of the filter 432 is reduced, and the influence of the degradation of the liquid delivery pump 433 becomes prominent, so that the degradation of the liquid delivery pump 433 can be diagnosed more accurately.

[0100] From the above, when diagnosing the pump degradation degree, in this embodiment, the pump duty of 20% is used, at which the change amount of the liquid delivery amount of the ink I with respect to the pump degradation degree is large and the influence exerted by the degradation degree state of the filter 432 is reduced.

[0101] Based on the above findings, by using a pump duty appropriate for diagnosing the filter degradation degree or a pump duty appropriate for diagnosing the pump degradation degree, it is possible to accurately diagnose the degradation degree of at least one of the filter 432 and the liquid feed pump 433.

[0102] In the present embodiment, the measurement of the liquid feed amount of the ink I fed by the liquid feed pump 433 is performed using the liquid level sensor 445 provided in the second ink storage unit 440, as will be described with reference to FIG. 6 below.

[0103] That is, in the present embodiment, without changing the configuration of the inkjet printer 100 or adding a new configuration, the liquid feed amount of the ink I fed by the liquid feed pump 433 can be measured. Therefore, in the present embodiment, by simply changing the pump duty of the liquid feed pump 433, it is possible to accurately diagnose the degradation degree of the filter 432 and the liquid feed pump 433 without changing the configuration of the apparatus or adding a configuration.

[0104] [Diagnosis method of degradation degree] With reference to FIGS. 1, 2, and 6, a method for diagnosing the degradation degree of the filter 432 or the liquid feed pump 433 will be described. FIG. 6 is a flowchart for explaining a method for diagnosing the degradation degree of the filter 432 or the liquid feed pump 433 in the ink supply unit 40.

[0105] (Step S11) The diagnosis unit controls the ink supply unit 40 to adjust the liquid level of the ink I in the second sub-tank 441 to a predetermined height, for example, the lower limit of the second sub-tank 441.

[0106] Specifically, when the liquid level of the ink I in the second sub-tank 441 is higher than the lower limit, the diagnosis unit discharges the ink I from the nozzles of the inkjet head until the liquid level sensor 445 detects that the liquid level of the ink I has reached the lower limit. At this time, the same control as the operation for eliminating the above-described nozzle clogging is performed to discharge the ink I from the nozzles of the inkjet head.

[0107] On the other hand, when the liquid level of Ink I in the second sub-tank 441 is lower than the lower limit, the diagnosis unit uses the sub-pumping unit 430 to pump Ink I from the first sub-tank 421 to the second sub-tank 441 until the liquid level sensor 445 detects that the liquid level of Ink I reaches the lower limit. At this time, since the liquid level can be adjusted to the lower limit more accurately by pumping slowly, it is desirable that the pump duty of the pumping pump 433 be 20%, which is the minimum value that can be set.

[0108] (Step S12) The diagnosis unit sets the pump duty of the pumping pump 433. In the present embodiment, as described above, when diagnosing the filter deterioration degree, the diagnosis unit sets the pump duty to 100%, and when diagnosing the pump deterioration degree, the diagnosis unit sets the pump duty to 20%.

[0109] (Steps S13 - S17) The diagnosis unit opens the liquid supply valve 434, turns on the liquid supply pump 433, drives the liquid supply pump 433 for a predetermined time (for example, 5 seconds) at the set pump duty, then turns off the liquid supply pump 433, and closes the liquid supply valve 434.

[0110] As the predetermined time, when the filter 432 and the liquid supply pump 433 are new, the number of seconds it takes for the liquid level to rise to the target height is set in advance. The higher the predetermined height, the higher the accuracy of the deterioration degree diagnosis. However, to avoid upper limit errors, a margin is set up to the upper limit. For example, if the upper limit detection is 30 mm, the target height is set to 20 mm. If the liquid supply speed is 4 mm / s when the filter 432 and the liquid supply pump 433 are new, the predetermined time is set to 5 seconds.

[0111] Also, when diagnosing the filter deterioration degree, the pump duty is set to 100%, and when diagnosing the pump deterioration degree, the pump duty is set to 20%. Therefore, depending on the pump duty, the time it takes for the liquid level to rise to the target height is set as the predetermined time.

[0112] (Step S18) The diagnostic unit measures the liquid level height of the ink I in the second sub-tank 441 with the liquid level sensor 445, and obtains the liquid level rise width from a predetermined height (the lower limit of the second sub-tank 441). When the filter 432 and the liquid feed pump 433 deteriorate due to use, the liquid feed rate decreases. For example, when the liquid feed rate drops to 3 mm / s, if the liquid feed pump 433 is driven for 5 seconds, the liquid level rise width will be 15 mm. The diagnostic unit can obtain the liquid feed amount of the ink I by the liquid feed pump 433 from the liquid level rise width.

[0113] (Step S19) The diagnostic unit obtains the degree of deterioration of the filter 432 and the liquid feed pump 433 based on the set pump duty and the obtained liquid feed amount. For example, the diagnostic unit can accurately diagnose the degree of deterioration of the filter 432 and the liquid feed pump 433 by referring to the graphs shown in FIGS. 4A to 5D based on the set pump duty and the obtained liquid feed amount.

[0114] As described above, in the present embodiment, the ink supply unit 40 includes a diagnostic unit. The diagnostic unit drives the liquid feed pump 433 with a second set value (pump duty 20%, 100%) different from the first set value (pump duty 40%) regarding the driving force for normal use, and obtains a numerical value regarding the liquid feed amount fed to the second ink storage unit 440. Then, the diagnostic unit diagnoses the degree of deterioration of at least one of the liquid feed pump 433 and the filter 432 based on the obtained numerical value.

[0115] According to the present embodiment configured in this way, since an appropriate pump duty for diagnosing the degree of filter deterioration and the degree of pump deterioration is used, the degree of deterioration of at least one of the filter 432 and the liquid feed pump 433 can be accurately diagnosed.

[0116] Also, in the present embodiment, since there is no need to change the device configuration or add a new configuration to the device, the degree of deterioration of at least one of the filter 432 and the liquid feed pump 433 can be accurately diagnosed with a simple configuration.

[0117] In the present embodiment, the liquid feeding amount is obtained based on the liquid level height of the ink I in the second sub-tank 441. However, for example, a flow meter may be provided in the sub liquid feeding unit 430, and the liquid feeding amount may be obtained based on the measurement results (flow velocity or flow rate) of the flow meter. In this case, it is desirable to set the predetermined time for driving the liquid feeding pump 433 to a time when sufficient measurement accuracy of the flow meter can be obtained.

[0118] <Modification Example 1> FIG. 7 is a flowchart for explaining a method of more accurately diagnosing the degradation degrees of the filter 432 and the liquid feeding pump 433 by combining filter diagnosis and pump diagnosis in the ink supply unit 40. FIGS. 8A to 8C are diagrams for explaining a method of calculating the filter degradation degree and the pump degradation degree by combining filter diagnosis and pump diagnosis. FIG. 8A is a diagram for explaining a method of calculating the pump degradation degree from the pump diagnosis value. FIG. 8B is a diagram for explaining a method of calculating the filter degradation degree from the filter diagnosis value based on the pump degradation degree calculated in FIG. 8A. FIG. 8C is a diagram for explaining a method of calculating the pump degradation degree from the pump diagnosis value based on the filter degradation degree calculated in FIG. 8B.

[0119] In the above embodiment, the degradation degrees of the filter 432 and the liquid feeding pump 433 are diagnosed using an appropriate pump duty for diagnosing the filter degradation degree and the pump degradation degree. Based on the diagnosis of the filter degradation degree and the pump degradation degree described in the above embodiment, the degradation degrees of both the filter 432 and the liquid feeding pump 433 can be more accurately diagnosed by the method described below.

[0120] (Step S21) The diagnosis unit assumes that the filter degradation degree is 0% and obtains the pump degradation degree from the pump diagnosis value. Here, the pump diagnosis value is the liquid level rise width at the time of pump diagnosis in the flowchart shown in FIG. 6. The pump diagnosis value is obtained by the method described in FIG. 6. The diagnosis unit previously obtains and holds data showing the relationship between the pump diagnosis value and the pump degradation degree for each filter degradation degree shown in the graph of FIG. 8A. The pump degradation degree is represented with 0 (0%) for a new product and 10 (100%) for a state where replacement is necessary.

[0121] Here, assuming the filter degradation degree is 0%, and as an example, since the pump diagnosis value is 12 mm, from the graph of 0% filter degradation degree shown in FIG. 8A, the pump degradation degree can be obtained as 50%.

[0122] (Step S22) The diagnosis unit obtains the filter degradation degree from the filter diagnosis value based on the obtained pump degradation degree. Here, the filter diagnosis value is the liquid level rise width at the time of filter diagnosis in the flowchart shown in FIG. 6. The filter diagnosis value is acquired by the method described in FIG. 6. Note that the diagnosis unit acquires and holds in advance data showing the relationship between the filter diagnosis value and the filter degradation degree for each pump degradation degree shown in the graph of FIG. 8B. The filter degradation degree is represented with 0 (0%) for a new product and 10 (100%) for the state where replacement is necessary.

[0123] Here, the pump degradation degree is 50%, and as an example, since the filter diagnosis value is 14 mm, in FIG. 8B, from the graph of 50% pump degradation degree, the filter degradation degree can be diagnosed as 39%. In FIG. 8B, the graph of 50% pump degradation degree is not shown, but for example, a graph of 50% pump degradation degree can be created from the data of the graph shown in FIG. 8B. Also, even without creating a graph of 50% pump degradation degree, the filter degradation degree corresponding to the filter diagnosis value when the pump degradation degree is 50% can be obtained from the data.

[0124] (Step S23) The diagnosis unit obtains the pump degradation degree from the pump diagnosis value based on the obtained filter degradation degree.

[0125] Here, since the filter degradation degree is 39% and the pump diagnosis value is 12 mm as described above, in FIG. 8C, from the graph with a filter degradation degree of 39%, it can be diagnosed that the pump degradation degree is 43%. In FIG. 8C, the graph with a filter degradation degree of 39% is not shown, but for example, a graph with a filter degradation degree of 39% can be created from the data of the graph shown in FIG. 8C. Also, even without creating a graph with a filter degradation degree of 39%, the pump degradation degree corresponding to the pump diagnosis value when the filter degradation degree is 39% can be obtained from the data. Note that the graph itself shown in FIG. 8C is the same as the graph shown in FIG. 8A.

[0126] (Step S24) The diagnosis unit determines whether repetition of the flow is necessary. For example, the user may set the number of repetitions in advance, or the diagnosis unit may determine whether the filter degradation degree and the pump degradation degree have converged and determine whether to repeat. If repetition is necessary (YES), return to step S22, and if repetition is not necessary (NO), end the series of flows.

[0127] In this modification example, based on the relationship between the degradation degree of the filter and the degradation degree of the pump, the degradation degree of the filter and the degradation degree of the pump are diagnosed again, so the degradation degrees of both the filter 432 and the liquid feed pump 433 can be diagnosed more accurately. Furthermore, by repeating the flow, the degradation degrees of both the filter 432 and the liquid feed pump 433 can be diagnosed more accurately.

[0128] <Modification Example 2> FIGS. 9A to 9C are diagrams for explaining an example of a method for recommending replacement of the filter 432 of the ink supply unit 40. FIG. 9A is a graph showing the transition of the filter degradation degree and an approximation formula for predicting the failure time at the point in time when 200 days have passed since the start of use. FIG. 9B is a graph showing the transition of the filter degradation degree and an approximation formula for predicting the failure time at the point in time when 600 days have passed since the start of use. FIG. 9C is a graph showing the transition of the filter degradation degree and an approximation formula for predicting the failure time at the point in time when 909 days have passed since the start of use.

[0129] In the above-described embodiment and Modification 1, the diagnostic unit obtains the filter degradation degree, and using the obtained filter degradation degree, it is possible to recommend replacement of the filter 432. Here, as an example, replacement of the filter 432 is recommended, but replacement of the liquid feed pump 433 can be recommended in the same manner, and the explanation thereof is omitted here for the liquid feed pump 433.

[0130] The diagnostic unit can measure and record the filter degradation degree obtained in the above-described embodiment and Modification 1, for example, daily, grasp the trend thereof, predict the failure time of the filter 432, and recommend replacement of the filter 432 to the user.

[0131] The diagnostic unit obtains the filter degradation degree by implementing a diagnostic mode or the like, for example, before shutdown after job completion in the inkjet printer 100. The diagnostic mode may be implemented every operating day of the inkjet printer 100, or the implementation frequency may be reduced when using Ink I in which degradation is less likely to occur.

[0132] The sub-liquid feed unit 430 having the filter 432 and the liquid feed pump 433 is provided for each color, and some apparatuses have a plurality of sub-liquid feed units 430 within the same color. If the diagnostic mode can be independently implemented in all the sub-liquid feed units 430, the diagnostic unit implements the diagnostic mode for all the sub-liquid feed units 430 simultaneously and in parallel. If there is a sub-liquid feed unit 430 in which the diagnostic mode cannot be implemented simultaneously and in parallel, the diagnostic mode may be implemented sequentially, or the implementation date may be changed to implement the diagnostic mode.

[0133] The filter degradation degree obtained by implementing the diagnostic mode is recorded, for example, in the storage unit 94, or recorded in the storage device of the external device 200 via the input / output interface 80. The diagnostic unit predicts the failure time of the filter 432 from the transition of the recorded filter degradation degree and recommends replacement as described below.

[0134] Specifically, the diagnostic unit obtains an approximation formula for predicting the failure time, for example, by the least squares method, based on the transition of the filter degradation degree with respect to the number of days elapsed after the start of use of the new filter 432. Using the obtained approximation formula, the number of days when the filter degradation degree reaches 100% is obtained, and the remaining number of days that the filter 432 can be used is obtained from the said number of days.

[0135] For example, as shown in FIG. 9A, at the point when 200 days have elapsed since the start of use of the new filter 432, the diagnostic unit obtains an approximation formula (refer to the broken line in the figure) for predicting the failure time by the least squares method based on the transition of the filter degradation degree with respect to the number of days elapsed. Using the obtained approximation formula, the number of days 884 days when the filter degradation degree reaches 100% is obtained, and the remaining number of days 684 days that the filter 432 can be used is obtained from the said number of days. In FIGS. 9A to 9C, the degradation degree is represented with 0 (0%) for a new product and 10 (100%) for the state where replacement is necessary.

[0136] Similarly, as shown in FIG. 9B, at the point when 600 days have elapsed since the start of use of the new filter 432, the diagnostic unit obtains an approximation formula (refer to the broken line in the figure) for predicting the failure time by the least squares method based on the transition of the filter degradation degree with respect to the number of days elapsed. Using the obtained approximation formula, the number of days 980 days when the filter degradation degree reaches 100% is obtained, and the remaining number of days 380 days that the filter 432 can be used is obtained from the said number of days.

[0137] Similarly, as shown in FIG. 9C, at the point when 909 days have elapsed since the start of use of the new filter 432, the diagnostic unit obtains an approximation formula (refer to the broken line in the figure) for predicting the failure time by the least squares method based on the transition of the filter degradation degree with respect to the number of days elapsed. Using the obtained approximation formula, the number of days 959 days when the filter degradation degree reaches 100% is obtained, and the remaining number of days 50 days that the filter 432 can be used is obtained from the said number of days.

[0138] When the remaining number of days reaches a predetermined number of days, for example, 50 days, the diagnostic unit notifies the user of a message recommending replacement of the filter 432 using, for example, the operation display unit 70. The smaller this predetermined number of days, the longer the filter 432 can be used. However, considering the need to ensure a buffer for replacement time and that there is a certain degree of error in the predicted remaining number of days, it is necessary to set the predetermined number of days. Here, as an example, the predetermined number of days is set to 50 days.

[0139] As described above, based on the transition of the filter degradation degree with respect to the number of days elapsed since the start of use of the new filter 432, the diagnostic unit can predict the failure time of the filter 432, predict the replacement time, and notify the user of a message recommending replacement of the filter 432.

[0140] The same applies to the liquid delivery pump 433. That is, based on the transition of the pump degradation degree with respect to the number of days elapsed since the start of use of the new liquid delivery pump 433, the diagnostic unit can predict the failure time of the liquid delivery pump 433, predict the replacement time, and notify the user of a message recommending replacement of the liquid delivery pump 433.

[0141] <Modification Example 3> Figures 10A to 10C are diagrams for explaining another example of a method for recommending replacement of the filter 432 of the ink supply unit 40. Figure 10A is a graph showing the transition of the filter degradation degree at the point in time when 200 days have elapsed since the start of use and the determination value of the filter degradation degree for recommending replacement. Figure 10B is a graph showing the transition of the filter degradation degree at the point in time when 600 days have elapsed since the start of use and the determination value of the filter degradation degree for recommending replacement. Figure 10C is a graph showing the transition of the filter degradation degree at the point in time when 858 days have elapsed since the start of use and the determination value of the filter degradation degree for recommending replacement.

[0142] The diagnostic unit may recommend replacing the filter 432 not only in the above-described Modification 2 but also by the method described below. Here too, as an example, replacement of the filter 432 is recommended, but replacement of the liquid feed pump 433 can be recommended in the same way, and the description of the liquid feed pump 433 is omitted here.

[0143] The diagnostic unit measures and records the degree of filter deterioration obtained in the above-described embodiment and Modification 1 daily, for example, by the above-described diagnostic mode, and can recommend to the user to replace the filter 432 based on the measured degree of filter deterioration and the determination value of the degree of filter deterioration.

[0144] For example, as shown in FIG. 10A, the diagnostic unit determines whether to recommend replacement based on the measured degree of filter deterioration and the determination value at the point in time when 200 days have passed since the start of use of the new filter 432.

[0145] The larger the determination value, the longer the filter 432 can be used. However, the measured degree of filter deterioration includes a certain degree of error, and if the determination value is too large, it is possible that, although the measured degree of filter deterioration is below the determination value, replacement is actually necessary. Therefore, it is necessary to set the determination value in consideration of such a situation. Here, as an example, the determination value is set to 9 (90%).

[0146] At the point in time when 200 days have passed since the start of use shown in FIG. 10A, the degree of filter deterioration is 2.06 and has not reached the determination value of 9, so the diagnostic unit does not recommend replacing the filter 432. In FIGS. 10A to 10C, the degree of deterioration is represented with 0 (0%) for a new product and 10 (100%) for the state where replacement is necessary.

[0147] Similarly, as shown in FIG. 10B, at the time when 600 days have passed since the start of use of the new filter 432, the diagnostic unit determines whether to recommend replacement based on the measured filter degradation degree and the determination value. At the time when 600 days have passed since the start of use, the filter degradation degree is 6.63 and has not reached the determination value of 9, so the diagnostic unit does not recommend replacing the filter 432.

[0148] Similarly, as shown in FIG. 10C, at the time when 858 days have passed since the start of use of the new filter 432, the diagnostic unit determines whether to recommend replacement based on the measured filter degradation degree and the determination value. At the time when 858 days have passed since the start of use, the filter degradation degree is 9.07 and has exceeded the determination value of 9. Therefore, the diagnostic unit notifies the user, for example, using the operation display unit 70, that replacement of the filter 432 is recommended.

[0149] As described above, the diagnostic unit can notify the user of a filter replacement recommendation message for the filter 432 based on the measured filter degradation degree and its determination value.

[0150] The same applies to the liquid feed pump 433. That is, the diagnostic unit can notify the user of a liquid feed pump replacement recommendation message for the liquid feed pump 433 based on the measured pump degradation degree and its determination value.

[0151] <Modification Example 4> In the above Modification Examples 2 and 3, the diagnostic unit predicts the failure time of the filter 432 and the liquid feed pump 433 using the obtained filter degradation degree and pump degradation degree. However, these may be used to calibrate the pump duty of the liquid feed pump 433.

[0152] During the normal liquid feeding operation of feeding Ink I from the first ink storage unit 420 to the second ink storage unit 440, a predetermined pump duty (for example, pump duty 40%) is set so as to obtain a sufficient liquid feeding amount. Also, during the ink circulation operation performed when air bubbles enter the inkjet head in the head module 50, a predetermined pump duty (for example, pump duty 40%) is set so as to obtain sufficient pressure in the second sub-tank 441.

[0153] However, as the filter 432 and the liquid feeding pump 433 deteriorate due to use and the deterioration progresses to a certain extent, the liquid feeding operation of Ink I cannot be properly performed, and sufficient pressure cannot be obtained in the second sub-tank 441, so that the ink circulation operation cannot be properly performed. Therefore, the liquid feeding operation and the ink circulation operation take longer than usual, and in some cases, an error occurs and the inkjet printer 100 stops.

[0154] Therefore, in this modified example, in order to prevent the occurrence of the above-described problems, the diagnosis unit determines whether the ink liquid feeding force during the liquid feeding operation or the ink circulation operation has decreased based on the obtained filter deterioration degree and pump deterioration degree. Then, when the ink liquid feeding force during the liquid feeding operation or the ink circulation operation has decreased, the diagnosis unit calibrates the pump duty during the liquid feeding operation or the ink circulation operation to an appropriate value based on the obtained filter deterioration degree and pump deterioration degree.

[0155] The determination of whether the ink liquid feeding force has decreased and the calibration of the pump duty to an appropriate value are performed, for example, by the following method.

[0156] (Calibration Method 1) (1-1) Based on the experimental values, a determination table for determining whether the ink pumping force has decreased is created in advance. For example, the determination table is stored in the storage unit 94 so that the diagnosis unit can refer to it. Then, the diagnosis unit refers to the determination table and determines whether the ink pumping force has decreased based on the obtained filter degradation degree and pump degradation degree, and determines whether it is necessary to change the pump duty. For example, when the diagnosis unit refers to the determination table and determines that the ink pumping force has decreased by 10%, it determines that it is necessary to change the pump duty.

[0157] (1-2) The diagnosis unit increases the pump duty by a predetermined percentage (for example, 10%) from the currently set pump duty, and obtains the liquid level rise width using the flow described in FIG. 6. When the diagnosis unit can determine from the obtained liquid level rise width that a sufficient liquid delivery volume can be obtained, it sets the pump duty at that time as the appropriate pump duty during the liquid delivery operation or the ink circulation operation.

[0158] (Calibration method 2) (2-1) The diagnosis unit holds in advance a calculation formula for calculating the appropriate pump duty during the liquid delivery operation or the ink circulation operation from the filter degradation degree and the pump degradation degree. When obtaining the coefficients of the calculation formula, for example, they may be obtained by machine learning the relationship between the experimental results and the degradation degree, or may be obtained using an approximate formula based on the experimental results.

[0159] (2-2) The diagnosis unit calculates the pump duty from the calculation formula based on the obtained filter degradation degree and pump degradation degree, and sets the calculated pump duty as the appropriate pump duty during the liquid delivery operation or the ink circulation operation.

[0160] By calibrating the pump duty during the liquid delivery operation and the ink circulation operation to the appropriate pump duty by the above method, even if the filter 432 and the liquid delivery pump 433 deteriorate, the liquid delivery operation and the ink circulation operation can be properly performed.

[0161] The above embodiments and modification examples are merely examples of the implementation of the present invention, and the technical scope of the present invention should not be construed as being limited thereby. That is, the present invention can be implemented in various forms without departing from its gist or main features.

[0162] For example, the ink supply unit 40, which is a liquid feeding device according to the present invention, feeds ink, but the liquid feeding device according to the present invention is also applicable when feeding liquids other than ink.

Explanation of Reference Numerals

[0163] 10 Conveying unit 20 Supply unit 30 Discharge unit 40 Ink supply unit 50 Head module 70 Operation display unit 80 Input / output interface 90 Control unit 100 Inkjet printer 200 External device 400 Main ink reservoir 401 Main tank 410 Main liquid feeding unit 411 Main supply path 412 Supply pump 413 Supply valve 420 First ink reservoir 421 First sub-tank 422 Liquid level sensor 430 Sub liquid feeding unit 431 Sub supply path 432 Filter 433 Liquid feeding pump 434 Liquid feeding valve 440 Second ink reservoir 441 Second sub-tank 442 Air flow path 443 Back pressure valve 444 Back pressure pump 445 Liquid level sensor 450 Pressure adjustment unit 451 First air release path 452 First air release valve 453 Pressure adjustment path 454 Pneumatic pump 455 Pressure adjustment valve 456 Second air release path 457 Second air release valve 461 Head supply path 470 Circulation section 471 Circulation path 472 Circulation valve

Claims

1. A liquid delivery device comprising: a flow path section having a pump for delivering a liquid from a first storage section to a second storage section, and a filter for collecting foreign matter from the liquid to be delivered; a diagnostic section that drives the pump with at least one second set value different from a first set value regarding a driving force for normal use, acquires a numerical value regarding a liquid delivery amount to be delivered to the second storage section, and diagnoses a degree of deterioration of at least one of the pump and the filter based on the numerical value; a liquid delivery device.

2. When diagnosing the degree of deterioration of the filter, the second set value is larger than the first set value. The liquid delivery device according to claim 1.

3. When diagnosing the degree of deterioration of the pump, the second set value is smaller than the first set value. The liquid delivery device according to claim 1.

4. The diagnostic section rediagnoses the degrees of deterioration of the filter and the pump based on a relationship between the degree of deterioration of the filter and the degree of deterioration of the pump. The liquid delivery device according to claim 1.

5. The diagnostic section predicts a replacement timing of the filter based on a transition of the degree of deterioration of the filter, and notifies a user of a replacement recommendation message. The liquid delivery device according to claim 1.

6. The diagnostic section predicts a replacement timing of the pump based on a transition of the degree of deterioration of the pump, and notifies a user of a replacement recommendation message. The liquid delivery device according to claim 1.

7. The diagnostic section calibrates the first set value so that a liquid delivery amount delivered to the second storage section becomes a predetermined liquid delivery amount based on the degree of deterioration of the filter and the degree of deterioration of the pump. The liquid delivery device according to claim 1.

8. The numerical value regarding the liquid delivery amount is a liquid level height in the second storage section. The liquid delivery device according to claim 1.

9. a first storage section and a second storage section for storing ink; the liquid delivery device according to any one of claims 1 to 8 for delivering the ink; an image forming section for forming an image using the ink supplied from the second storage section; characterized by comprising an image forming device.

10. A diagnostic method for a liquid delivery device, the liquid delivery device comprising a flow path section having a pump for delivering a liquid from a first storage section to a second storage section, and a filter for collecting foreign matter from the liquid to be delivered, the method comprising: Drive the pump with at least one second set value different from the first set value regarding the driving force usually used, obtain a numerical value regarding the liquid feed amount fed to the second storage section, and diagnose the degree of deterioration of at least one of the pump and the filter based on the numerical value. Diagnosis method of a liquid feed device.

Images