HEAD-MAINTENANCE DEVICE AND LIQUID DISCHARGE APPARATUS

A head-maintenance device includes a suction cap to cap a nozzle surface of a head to discharge liquid, a suction unit to suck the inside of the suction cap, an air-release channel communicating with the inside of the suction cap, a lid to close an opening of the suction cap, and processing circuitry. The processing circuitry performs an air-release channel suction operation to close the air-release channel and suck the inside of the suction cap by the suction unit, with the opening of the suction cap closed by the lid, and open the air-release channel with the inside of the suction cap in a negative pressure.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2022-164443, filed on Oct. 13, 2022, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.

BACKGROUND

Technical Field

Embodiments of the present disclosure relate to a head-maintenance device and a liquid discharge apparatus.

Related Art

An apparatus that includes a head for discharging liquid typically includes a maintenance device as a maintenance and recovery mechanism including a suction cap to cap a nozzle surface, i.e., a discharge surface of the head to maintain and recover the condition of the head.

An apparatus is known that includes a maintenance device in which a suction channel to collect liquid sucked from nozzles of a head into a suction cap and an air-release channel are connected to each other. The air-release channel introduces air into the suction cap sealed between the head and the suction cap to return the space inside the suction cap to an atmospheric pressure.

SUMMARY

In an embodiment of the present disclosure, a head-maintenance device includes a suction cap to cap a nozzle surface of a head to discharge liquid, a suction unit to suck the inside of the suction cap, an air-release channel communicating with the inside of the suction cap, a lid to close an opening of the suction cap, and processing circuitry. The processing circuitry performs an air-release channel suction operation to close the air-release channel and suck the inside of the suction cap by the suction unit, with the opening of the suction cap closed by the lid, and open the air-release channel with the inside of the suction cap in a negative pressure.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described below with reference to the accompanying drawings.

FIG.1is a diagram illustrating a head-maintenance device3according to a first embodiment of the present disclosure.

The head-maintenance device3includes a maintenance unit300and a maintenance controller830. The maintenance controller830controls a maintenance operation performed by the maintenance unit300.

The maintenance unit300includes a suction cap311to cap a nozzle surface112of a head101that discharges liquid. An absorber332is disposed in the suction cap311. A drain channel333is connected to a suction hole311aof the suction cap311. A suction pump334serving as a suction unit that sucks the inside of the suction cap311is disposed in the drain channel333.

The head-maintenance device3includes an air-release channel335communicating with the inside of the suction cap311. An on-off valve336is disposed on the air-release channel335. The air-release channel335can be opened and closed by opening and closing the on-off valve336.

The head-maintenance device3further includes a lid337to close an opening of the suction cap311. The lid337is made of a rigid material having a flat surface and is formed of, for example, a resin or a sheet metal. The lid337is disposed at the same height as the nozzle surface112of the head101.

In the present embodiment, the head101and the suction cap311are relatively movable in X directions indicated by a double-headed arrow inFIG.1. Similarly, the lid337and the suction cap311are also relatively movable in the X directions. The head101and the lid337may be integrally movable or individually movable. The head101, the lid337, and the suction cap311are relatively movable in Z directions indicated by a double-headed arrow inFIG.1.

In the present embodiment, the suction cap311can reciprocate in the X directions by the maintenance-unit moving mechanism320, and can be lifted and lowered, i.e., movable up and down, in the Z directions by a cap reciprocating mechanism325. The head101and the lid337may reciprocate in the X directions and may move up and down in the Z directions. Alternatively, the suction cap311may reciprocate in the X directions and the head101and the lid337may move up and down in the Z directions.

The maintenance controller830drives and controls the maintenance-unit moving mechanism320, the cap reciprocating mechanism325, the suction pump334, and the on-off valve336to control the maintenance operation including an air-release channel suction operation according to embodiments of the present disclosure.

FIGS.2,3,4, and5are diagrams each illustrating the head101and the maintenance operation controlled by the maintenance controller830, according to the present embodiment.

When the maintenance operation is started, as illustrated inFIG.1, the maintenance controller830closes the on-off valve336to close the air-release channel335. As illustrated inFIG.1, the maintenance controller830drives and controls the cap reciprocating mechanism325such that the suction cap311moves up to a position at which the suction cap311faces the head101to cap the nozzle surface112.

Subsequently, the maintenance controller830drives the suction pump334to generate a negative pressure inside the suction cap311. As illustrated inFIG.2, the maintenance controller830causes liquid, which turns to be waste liquid400, to be sucked from the head101and drained into the suction cap311. This operation is referred to as a nozzle suction operation.

In so doing, a negative pressure is also generated in a portion of the drain channel333from the suction cap311to the suction pump334. Accordingly, the waste liquid400enters into the drain channel333. A negative pressure is also generated in a portion of the air-release channel335from the suction cap311to the on-off valve336. Accordingly, the waste liquid400also enters into the air-release channel335.

The maintenance controller830continues the nozzle suction operation until a predetermined time elapses from the start of driving the suction pump334. Subsequently, as illustrated inFIG.3, the maintenance controller830causes the on-off valve336to open such that the air-release channel335is opened.

Such a configuration as described above allows air to be introduced through the air-release channel335into the suction cap311set to have the negative pressure. Accordingly, the waste liquid400in the suction cap311is sucked by the suction of the suction pump334to be drained to, for example, a waste-liquid container through the drain channel333.

The waste liquid400that has entered the air-release channel335is also drained into the suction cap311and is drained to, for example, the waste-liquid container through the drain channel333. However, the waste liquid400that has entered the air-release channel335is not entirely drained only by introducing air into the suction cap311through the air-release channel335, and a part of the waste liquid400may remain in the air-release channel335as illustrated inFIG.3.

Subsequently, the maintenance controller830stops driving the suction pump334, drives and controls the cap reciprocating mechanism325to move down the suction cap311, and retracts the suction cap311from the nozzle surface112of the head101to decap the nozzle surface112.

Then, the maintenance controller830closes the air-release channel335to suck the inside of the suction cap311by the suction pump334when the opening of the suction cap311is closed by the lid337, and controls the air-release channel suction operation to open the air-release channel335when the inside of the suction cap311is set to the negative pressure.

In the above-described air-release channel suction operation, first, the maintenance controller830drives and controls the maintenance-unit moving mechanism320to cause the suction cap311to relatively move to a position facing the lid337as illustrated inFIG.4.

As illustrated inFIG.4, the maintenance controller830drives and controls the cap reciprocating mechanism325to move up the suction cap311and causes the suction cap311to contact the lid337such that the opening of the suction cap311is closed by the lid337. Subsequently, the maintenance controller830closes the on-off valve336.

As the maintenance controller830drives the suction pump334for a predetermined period of time under the above conditions, the inside of the suction cap311and the inside of the portion of the air-release channel335from the suction cap311to the on-off valve336is set to the negative pressure.

After the predetermined period of time elapses from the start of driving the suction pump334, the maintenance controller830opens the on-off valve336as illustrated inFIG.5. As a result, air flows into the air-release channel335at once, and the waste liquid400that has remained in the air-release channel335flows into the suction cap311and is drained through the drain channel333.

As the suction cap311is capped by the lid337when the suction pump334is driven, the inside of the suction cap311and the inside of the air-release channel335can be set to a high negative pressure. When the on-off valve336is opened under the above conditions, the air flows into the air-release channel335at once, and the waste liquid400that has remained in the air-release channel335is pushed away toward the suction cap311. Accordingly, the residual waste liquid400is eliminated from the air-release channel335, and occurrence of clogging of the air-release channel335due to fixation of the waste liquid400over time can be prevented. As a result, deterioration of the maintenance performance of the head-maintenance device3over time can be prevented.

The above-described air-release channel suction operation can be repeated multiple times. Accordingly, the waste liquid400that has entered the air-release channel335can be reliably drained. At this time, the number of repetitions of the air-release channel suction operation can be changed depending on, for example, environmental conditions, or the type of liquid to be discharged. Such a configuration as described above allows the maintenance operation of the head-maintenance device3to be performed in a more efficient manner.

FIGS.6and7are diagrams each illustrating a maintenance device according to a control sample of the present disclosure.

The maintenance device according to the control sample does not include the lid337of the first embodiment.

In the maintenance device of the control sample, when the waste liquid400in the suction cap311is drained, the waste liquid400that has entered the air-release channel335may remain in the air-release channel335without being drained, as described inFIG.3of the first embodiment.

When the waste liquid400remains in the air-release channel335, the waste liquid400may be solidified over time and may block a part or all of the air-release channel335. In such a case, when air inside the suction cap311is released to the outside, the air may not flow into the suction cap311, or it may take time for the air to flow into the suction cap311. Accordingly, the waste liquid400in the suction cap311may not be drained.

In the present control sample, even if the suction force of the suction pump334is increased to suck the waste liquid400in the air-release channel335, as illustrated inFIG.7, the liquid, i.e., the waste liquid400, is sucked only from the head101. Accordingly, the residual waste liquid400in the air-release channel335is not drained into the suction cap311.

Alternatively, in the above-described first embodiment, the waste liquid40is sucked from the air-release channel335when the opening of the suction cap311is closed by the lid337, not when the nozzle surface of the head101is capped. Such a configuration as described above allows the suction force of the suction pump334to be increased to suck and drain the waste liquid400in the air-release channel335. Thus, the residual amount of the waste liquid400in the air-release channel335can be reduced.

In other words, the maintenance controller830can control such that the output of the suction pump334when the air-release channel suction operation is performed is higher than the output of the suction pump334when the nozzle suction operation is performed. Accordingly, the residual waste liquid400in the air-release channel335can be more reliably drained.

The air-release channel suction operation does not need to be performed every time the nozzle suction operation is performed. The timing at which the air-release channel suction operation is performed can be changed depending on the environmental condition or the type of liquid to be discharged. At the same time, the timing at which the air-release channel suction operation is performed can be changed depending on a print job for which the liquid is discharged from the head101.

FIG.8is a diagram illustrating the head-maintenance device3according to a second embodiment of the present disclosure.

In the second embodiment, an absorber338is disposed on a surface of the lid337with which the suction cap311contacts. A porous body such as a sponge or a nonwoven fabric is employed for the absorber338.

The head-maintenance device3according to the second embodiment has such a configuration as described above. Accordingly, in the maintenance operation, when the suction cap311is pressed against the lid337to close the opening of the suction cap311, the waste liquid400that adheres to a nip331aas a contact portion of the suction cap311can be absorbed by the absorber338.

In other words, in the present embodiment, the lid337also functions as a stamper when performing a stamper operation for removing the waste liquid adhered to the nip331bof the suction cap311from the nip331b.

As a result, the maintenance time can be shortened as compared with a case in which a stamper is separately disposed to perform the stamper operation.

FIG.9is a diagram illustrating the head-maintenance device3according to a third embodiment of the present disclosure.

In the third embodiment, entry sensors339aand339bare disposed as liquid sensors to detect the waste liquid400in the air-release channel335. The entry sensor339ais disposed at a position close to the suction cap311on the air-release channel335, and the entry sensor339bis disposed at a position closer to the on-off valve336than the entry sensor339aon the air-release channel335.

In the third embodiment, the air-release channel335is connected to the inside of the suction cap311through a peripheral wall311cof the suction cap311. Accordingly, the entry sensor339acan be disposed at a position such that the entry sensor339acan detect the waste liquid400in the vicinity of an inlet portion of the air-release channel335close to the suction cap311.

When a reflective or transmissive optical sensor is employed as the entry sensors339aand339b, the air-release channel335is formed of, for example, a transparent tube. The entry sensors339aand339bare not limited to optical sensors, and for example, electrostatic sensors may be employed for the entry sensors339aand339b. For example, the number of the entry sensors339aand339band the positions at which the entry sensors339aand339bare disposed are not limited to the above example.

Detection outputs of the entry sensors339aand339bare input to the maintenance controller830.

When the maintenance operation is performed, the maintenance controller830determines whether at least one of the entry sensors339aand339bdetects the waste liquid400. At this time, when at least one of the entry sensors339aand339bdetects the waste liquid400, the maintenance controller830controls such that the above-described air-release channel suction operation is performed a predetermined number of times. On the other hand, when the entry sensors339aand339bdo not detect the waste liquid400, the maintenance controller830controls such that the air-release channel suction operation as a part of the maintenance operation is not performed.

As a result, an unnecessary air-release channel suction operation does not need to be performed. Accordingly, the time to perform the maintenance operation can be shortened.

When the entry sensor339adetects the waste liquid400, i.e., the waste liquid400is present in the air-release channel335and the entry sensor339bdoes not detect the waste liquid400, i.e., the waste liquid400is not present in the air-release channel335, the air-release channel suction operation is performed N times, N is an integer of one or more, which is a predetermined number of times. When both of the entry sensors339aand339bdetect the waste liquid400and the waste liquid400is present in the air-release channel335, the air-release channel suction operation is performed N+n times, N and n are integers of one or more, which is a predetermined number of times. In other words, the number of times of the air-release channel suction operation can be changed in accordance with the length of an area in which the waste liquid400enters in the air-release channel335.

As a result, the air-release channel suction operation can be performed more efficiently, and the waste liquid400that has entered the air-release channel335can be reliably drained.

FIGS.10A,10B,10C, and10Dare diagrams each illustrating the head-maintenance device3according to a fourth embodiment of the present disclosure.

In the fourth embodiment, multiple heads101a,101b,101c, and101d, four heads in the present embodiment, are arranged, and one suction cap311shared by the heads101a,101b,101c, and101dis disposed. The heads101a,101b,101c, and101dmay also be referred to simply as the head101when a similar description applies to all the heads101a,101b,101c, and101d. A lid337aand a lid337bare disposed on both sides outside an area in which the heads101a,101b,101c, and101dare arranged.

In such a configuration as described above, when the maintenance operation of the head101cis performed as illustrated inFIG.10A, the suction cap311is moved to the lid337bdisposed at a relatively short distance from the head101cto perform the air-release channel suction operation as illustrated inFIG.10B. The maintenance operation of the head101dis performed in a similar manner to the maintenance operation of the head101cdescribed above.

Alternatively, when the maintenance operation of the head101bis performed as illustrated inFIG.10C, the suction cap311is moved to the lid337adisposed at a relatively short distance from the head101bto perform the air-release channel suction operation as illustrated inFIG.10D. The maintenance operation of the head101ais performed in a similar manner to the maintenance operation of the head101bdescribed above.

As a result, when the multiple heads101a,101b,101c, and101dare arranged, a movement distance of the suction cap311relative to the heads101a,1011b,101c, and101dfor performing the air-release channel suction operation is shorter than a case in which the single lid337is disposed at one position. For this reason, the time to perform the maintenance operation of the entire multiple heads101a,101b,101c, and101dcan be shortened.

The number of heads, the number of suction caps, and the number of lids are not limited to the examples described in the above embodiments. For example, in the configuration described in, for example, the above-described first embodiment, the lids may be disposed on both outer sides of the head.

FIG.11is a schematic diagram of a printer1as an apparatus for discharging liquid according to a fifth embodiment of the present disclosure.

FIG.12is a plan view of a discharge unit provided for the printer ofFIG.11.

The printer1includes a loading device10to load sheet materials S into the printer1, a pretreatment device20as a coater, a printing device30, a first drier40, a second drier50, a reversing mechanism60, and a sheet stacker70.

In the printer1, the pretreatment device20applies pretreatment liquid as application liquid to a sheet material S fed and supplied from the loading device10as needed, and the printing device30applies given liquid to the sheet material S to perform printing as desired.

After the liquid that has adhered to the sheet material S is dried by the first drier40and the second drier50, the printer1ejects the sheet material S to the sheet stacker70via the reversing mechanism60as is, or ejects the sheet material S after printing has been performed on both sides of the sheet material S.

The loading device10includes a lower loading tray11A and an upper loading tray11B to accommodate multiple sheet materials S and a feeding device12A and a feeding device12B to separate and feed the sheet materials S one by one from the lower loading tray11A and the upper loading tray11B, respectively, and supplies the sheet materials S to the pretreatment device20.

The pretreatment device20includes, for example, a coater21as a treatment-liquid applying device to coat an image formation surface of a sheet material S with a treatment liquid having an effect of aggregating ink particles to prevent bleed-through.

The printing device30includes a drum31and a liquid discharger32. The drum31is a bearer or a rotator that bears a sheet material S on a circumferential surface of the drum31and rotates. The liquid discharger32discharges liquid toward the sheet material S borne on the drum31.

The printing device30includes transfer cylinders34and35. The transfer cylinder34receives a sheet material S from the pretreatment device20and forwards the sheet material S to the drum31. The transfer cylinder35receives the sheet material S conveyed by the drum31and forwards the sheet material S to the drier40.

The transfer cylinder34includes a sheet gripper to grip the leading end of the sheet material S conveyed from the pretreatment device20to the printing device30. The sheet material S that is gripped by the sheet gripper is conveyed as the transfer cylinder34rotates. The sheet material S conveyed by the transfer cylinder34is forwarded to the drum31at a position facing the drum31.

Similarly, the drum31includes a sheet gripper on the surface of the drum31, and the leading end of the sheet material S is gripped by the sheet gripper. The drum31includes multiple suction holes dispersedly formed on the surface of the drum31, and a suction unit. The suction unit generates suction airflows directed inward of the drum31from the suction holes of the drum31.

The sheet gripper of the drum31grips the leading end of the sheet material S forwarded from the transfer cylinder34to the drum31, and the sheet material S is attracted to and borne on the drum31by the suction airflows generated by the suction unit. As the drum31rotates, the sheet material S is conveyed.

The liquid discharger32includes discharge units33A,33B,33C,33D, and33E as liquid application units. The discharge units33A,33B,33C,33D, and33E may also be referred to simply as the discharge unit33when a similar description applies to all the discharge units33A,33B,33C,33D, and33E. For example, the discharge unit33A discharges liquid of cyan (C), the discharge unit33B discharges liquid of magenta (M), the discharge unit33C discharges liquid of yellow (Y), and the discharge unit33D discharges liquid of black (K). The discharge unit33E is used to discharge a special liquid, for example, a liquid of spot color such as white, gold, or silver.

The discharge unit33includes, for example, a head array100(seeFIG.12) which is a liquid discharger.

The head array100includes a full-line head in which the multiple heads101each having multiple nozzle rows, in which multiple nozzles111are arranged on the nozzle surface112, are arranged in a staggered manner on a base103. Each of the discharge units33A,33B,33C,33D, and33E also includes a sub-tank as a liquid container that stores liquid to be supplied to corresponding ones of the heads101of the head array100.

The discharge operation of each of the discharge units33A,33B,33C, and33D of the liquid discharger32is controlled by drive signals corresponding to print data. When a sheet material S borne on the drum31passes through an area facing the liquid discharger32, the liquid of multiple colors is discharged from the discharge units33A,33B,33C,33D, and33E, and an image corresponding to the print data is printed.

The drier40includes a heater42such as an infrared (IR) heater and irradiates infrared light to a sheet material S, to which the liquid has been applied and conveyed by a conveyor41including, for example, a conveyance belt, to heat and dry the sheet material S.

The reversing mechanism60includes a reversing device61and a duplex conveyor62. The reversing device61reverses a sheet material S by a switchback method when duplex printing is performed on the sheet material S that has passed through the drier40and has liquid applied to one surface of the sheet material S and dried. The duplex conveyor62reversely conveys the reversed sheet material S upstream from the transfer cylinder34of the printing device30.

The sheet stacker70includes an output tray71on which multiple sheet materials S are stacked. The sheet materials S that are conveyed from the reversing mechanism60are sequentially stacked one on another and held on the output tray71.

In the present embodiment, an example in which the sheet material S is a cut sheet material is described. However, embodiments of the present disclosure can be applied to, for example, an apparatus that employs a large-sized sheet material such as wallpaper, a continuous medium such as continuous paper and a web-shaped sheet material.

FIG.13is a plan view of the maintenance units300A.300B,300C,300D, and300E and the head arrays100according to the present embodiment. The maintenance units300A,300B.300C,300D, and300E may also be referred to simply as the maintenance unit300when a similar description applies to all the maintenance units300A,300B,300C,300D, and300E.

FIG.14is a front view of the maintenance unit300and the head array100according to the present embodiment.

FIG.15is a perspective view of the maintenance unit300and the head array100according to the present embodiment.

InFIG.13, the drum31is unfolded. InFIG.14, only one row of the heads101is illustrated at capping positions at which the heads101are capped by moisture-retention caps312.

InFIG.13, the maintenance units300A,300B,300C,300D, and300E corresponding to the discharge units33A,33B.33C.33D, and33E, respectively, are disposed to be movable in directions indicated by a double-headed arrow X, which is a direction in which the heads101are arranged.

In the maintenance unit300, the suction caps311that cap the respective nozzle surfaces112of the heads101, the moisture-retention caps312, and a blade-shaped wiper314to wipe the nozzle surfaces112are arranged on a base301.

The maintenance unit300includes the lids337aand337b, each held on each of both sides outside the row of the heads101on the base103of the discharge unit33. The lids337aand337bcan also be used as the stampers as described in the second embodiment.

As described in the first embodiment, the drain channel333in which the suction pump334as the suction unit is disposed and the air-release channel335in which the on-off valve336is disposed are connected to the suction cap311. The suction cap311is disposed to be vertically movable with respect to the base301and moves toward and retracts from the nozzle surface112of the head101. Each of the moisture-retention caps312is held on the base301via an elastic member317.

Such a configuration as described above allows each of the suction caps311and the corresponding one of the moisture-retention caps312to individually move toward and retract from the nozzle surface112.

As illustrated inFIG.14, the heights at which the suction caps311and the moisture-retention caps312contact the respective nozzle surfaces112are different from each other. In other words, the moisture-retention cap312does not contact the nozzle surface112when the nozzle surface112is capped by the suction cap311.

The suction caps311, the moisture-retention caps312, and the wiper314are disposed at positions relative to the rows of the heads101disposed in a staggered manner.

In the present embodiment, the number of the moisture-retention caps312is the same as the number of the heads101, and all the heads101can be capped with the respective moisture-retention caps312. When the nozzle surface112is capped by the moisture-retention cap312, the suction cap311does not cap the nozzle surface112.

FIG.16Ais a perspective view of the maintenance-unit moving mechanism320of the maintenance unit300, according to the present embodiment.FIG.16Bis a side view of the maintenance-unit moving mechanism320of the maintenance unit300, according to the present embodiment.

In the maintenance unit300, rollers302are rotatably attached to both ends of the base301in the longitudinal direction, i.e., in a direction in which the maintenance unit300moves. The maintenance unit300is movably held by guides303, disposed in a direction in which the heads are arranged, via the rollers302.

The maintenance-unit moving mechanism320includes a timing belt324wound around a motor pulley322of a stepping motor321and a pulley323.

A coupler304disposed at one end of the base301is coupled to the timing belt324.

Accordingly, driving the stepping motor321allows the maintenance unit300to be moved in directions indicated by a double-headed arrow X inFIG.16A.

FIG.17AandFIG.17Bare diagrams each illustrating a lifting mechanism to move up and down the suction cap, i.e., the cap reciprocating mechanism325, according to the present embodiment.

The cap reciprocating mechanism325includes a cam follower343with which the suction cap311is in contact. The cam follower343moves along the peripheral surface of a cam341to rotate about a shaft342by a cap reciprocating motor344. Accordingly, the suction cap311moves up and down to move toward and retract from the head101.

FIG.18is a block diagram of a maintenance controller830and components related to the maintenance controller830, illustrating how maintenance control of the printer1is performed, according to a fifth embodiment of the present disclosure.

The maintenance controller830drives and controls the motor321of the maintenance-unit moving mechanism320to control the movement of the maintenance unit300. The maintenance controller830drives and controls the cap reciprocating motor344of the cap reciprocating mechanism325to control the suction cap311such that the suction cap311moves toward and retracts from the head101. The maintenance controller830controls driving and stopping of the suction pump334to control suction in the suction cap311, and controls opening and closing of the on-off valve336to control opening and closing of the air-release channel335.

The detection outputs of the entry sensors339aand339bare input to the maintenance controller830.

The maintenance controller830controls a maintenance operation similar to the maintenance operation described in the first embodiment, such that the suction operation of the air-release channel335is performed a predetermined number of times, which is once or multiple times, when at least one of the entry sensors339aand339bdetects the waste liquid400in the air-release channel335.

FIG.19is a plan view of mechanical components of the printer1as an apparatus for discharging liquid, according to a sixth embodiment of the present disclosure.

FIG.20is a diagram illustrating a lateral side of a relevant part of the mechanical components of the printer1, according to the sixth embodiment.

The printer1is a serial-type printer. A guide1001is bridged between a left-side plate1010A and a right-side plate1010B to hold a carriage1003, such that the carriage1003is reciprocally movable in main-scanning directions indicated by a double-headed arrow inFIG.19. The carriage1003reciprocates in the main-scanning directions, i.e., the X directions, by a main-scanning motor1005via a timing belt1008stretched between a driving pulley1006and a driven pulley1007.

Four liquid discharge units1004are mounted on the carriage1003. Each of the liquid discharge units1004integrally includes the heads101to discharge liquid and a sub-tank1035.

Each of the heads101includes two nozzle rows in which the multiple nozzles111are arranged, and each of the nozzle rows is assigned to discharge, for example, black (K), cyan (C), magenta (M), yellow (Y), white (W), or transparent (V) liquid.

The sub-tank1035includes a tank to store liquid of multiple colors to be supplied to corresponding one of the heads101.

A cartridge holder1051, on which main tanks1050containing liquid of multiple colors are replaceably mounted, is disposed in the body of the printer1. The cartridge holder1051includes liquid-feed pumps1052. The liquid-feed pumps1052supply ink of multiple colors from the main tanks1050to the sub-tanks1035, respectively, via supply tubes1056for liquid of multiple colors, which are also referred to as a liquid supply channel.

To convey a sheet material S, the printer1also includes a conveyance belt1012as a sheet conveyor. The conveyance belt1012attracts the sheet material S to convey the sheet material S at a position facing the head101. The conveyance belt1012is an endless belt stretched between a conveyance roller1013and a tension roller1014. The conveyance belt1012attracts the sheet material S by electrostatic force or air aspiration.

The conveyance belt1012rotates in a sub-scanning direction as the conveyance roller1013is rotationally driven by a sub-scanning motor1016via a timing belt1017and a timing pulley1018.

At one end of a moving range of the carriage1003in the main-scanning direction, the maintenance unit300that performs maintenance of the heads101is disposed lateral to the conveyance belt1012.

The maintenance unit300includes, for example, the suction caps311, which also serve as the moisture-retention caps to cap the respective nozzle surfaces112of the heads101, the three moisture-retention caps312, and the blade-shaped wiper314to wipe the nozzle surfaces112.

As described in the first embodiment, the drain channel333in which the suction pump334as the suction unit is disposed and the air-release channel335in which the on-off valve336is disposed are connected to the suction cap311. In the present embodiment, the suction cap311and the moisture-retention caps312are driven by the cap reciprocating motor344, which is common to the suction cap311and the moisture-retention caps312, to move toward the heads101to the capping positions and to move away from the heads101to decapping positions at which the heads101are decapped at the same timing.

The lids337aand337bof the maintenance unit300are disposed on both sides of the carriage1003in the direction in which the heads101are arranged.

In the printer1, a sheet material S is fed onto the conveyance belt1012to be attracted onto the conveyance belt1012and is conveyed in the sub-scanning direction by the rotation movement of the conveyance belt1012.

The heads101are driven in accordance with the image signal while the carriage1003is moved in the main-scanning direction. By so doing, the liquid is discharged onto the sheet material S which is stopped to record one line of an image on the sheet material S. Then, the sheet material S is fed by a predetermined distance to record another line of the image.

The printer1ends the recording operation when the printer1receives a signal indicating an end of recording or a signal indicating that a rear end of the sheet material S reaches a recording area. Then, the printer1ejects the sheet material S outside the printer1.

A control unit800of the printer1according to the present embodiment is described below with reference to a block diagram ofFIG.21.

The control unit800includes a central processing unit (CPU)801, a read only memory (ROM)802, and a main control unit800A including a random access memory (RAM)803. The CPU801controls the entire printer1. The ROM802stores fixed data, such as various programs including programs executed by the CPU801. The RAM803temporarily stores image data and other data.

The control unit800includes a non-volatile random-access memory (NVRAM)804and an image processing unit805. The NVRAM804holds data even while the power supply of the printer1is cut off. The image processing unit805processes various signals on image data, performs sorting or other image processing, and processes input and output signals to control the entire printer1.

The control unit800includes a head-driver control unit808and a head driver809as a driver integrated circuit (IC). The head-driver control unit808includes a data transmitter to drive and control the heads101. The head driver809drives the heads101disposed on the carriage1003.

The control unit800includes a scan-driver control unit810. The scan-driver control unit810drives, for example, the main-scanning motor1005for moving and scanning the carriage1003and the sub-scanning motor1016for driving the conveyance roller1013.

The control unit800includes a maintenance-driver control unit831to drive and control the suction pump334, the on-off valve336, and the cap reciprocating motor344of the maintenance unit300. In the present embodiment, the carriage1003is moved in the main-scanning directions to cause the lids337aand337bto move to respective positions facing the respective suction caps311. In other words, the maintenance controller830described in the above embodiments includes the scan-driver control unit810and the maintenance-driver control unit831.

The control unit800includes an input and output (I/O) unit813. In addition to the detection outputs of the entry sensors339aand339b, the I/O unit813acquires the data from a temperature sensor and other various sensors provided for the printer1, extracts the data to be used for controlling the printer1, and uses the extracted data for various controls.

The control unit800is connected to an operation panel814to input and display the data to be used by the printer1.

The control unit800includes an interface (I/F)806to send and receive data and signals to and from a host, such as an information processing apparatus, e.g., a personal computer or an image reader. The control unit800receives such data and signals from the host with the I/F806via a cable or network.

In the present embodiment, when the maintenance operation is performed on the heads101, the scan-driver control unit810moves the carriage1003to move the target heads101to positions facing the respective suction caps311.

The maintenance-driver control unit831controls a maintenance operation similar to the maintenance operation described in the first embodiment, and controls to perform the air-release channel suction operation a predetermined number of times when at least one of the entry sensors339aand339bdetects the waste liquid400in the air-release channel335. When the air-release channel suction operation is performed, the scan-driver control unit810controls such that the carriage1003is moved to move the lids337aand337bto positions facing the respective suction caps311.

In embodiments of the present disclosure, the liquid to be discharged is not limited to a particular liquid as long as the liquid has a viscosity or surface tension to be discharged from a liquid discharge head. However, preferably, the viscosity of the liquid is not greater than 30 mPa·s under ordinary temperature and ordinary pressure or by heating or cooling. Specific examples of such liquids include, but are not limited to, solutions, suspensions, and emulsions containing solvents such as water, organic solvents, colorants such as dyes, pigments, functionality imparting materials such as polymerizable compounds, resins, surfactants, biocompatible materials such as deoxyribonucleic acid (DNA), amino acid, protein, calcium, and/or edible materials such as natural colorants. Such liquids can be used as inkjet inks, surface treatment liquids, liquids for forming compositional elements of electric or luminous elements or electronic circuit resist patterns, and three-dimensional object forming material liquids.

Examples of an energy source for generating energy to discharge liquid include a piezoelectric actuator, for example, a laminated piezoelectric element or a thin-film piezoelectric element, a thermal actuator that employs a thermoelectric conversion element, such as a thermal resistor, and an electrostatic actuator including a diaphragm and opposed electrodes.

Examples of the liquid discharge apparatus include an apparatus capable of discharging liquid to a material onto which liquid can adhere and an apparatus to discharge liquid toward gas or into liquid.

The liquid discharge apparatus can include at least one of devices for feeding, conveying, and ejecting a material onto which liquid can adhere. The liquid discharge apparatus can further include at least one of a pretreatment apparatus and a post-treatment apparatus.

The liquid discharge apparatus may be, for example, an image forming apparatus to form an image on a sheet by discharging ink, or a three-dimensional apparatus to discharge a molding liquid to a powder layer in which powder material is formed in layers to form a three-dimensional object.

The liquid discharge apparatus is not limited to an apparatus to discharge liquid to visualize meaningful images, such as letters or figures. For example, the liquid discharge apparatus may be an apparatus to form meaningless images, such as meaningless patterns, or fabricate three-dimensional images.

The above-described term “material onto which liquid can adhere” denotes, for example, a material or a medium onto which liquid is adhered at least temporarily, a material or a medium onto which liquid is adhered and fixed, or a material or a medium onto which liquid is adhered and into which the liquid permeates. Examples of the “material onto which liquid can adhere” include recording media or medium such as a paper sheet, a recording paper, and a recording sheet of paper, film, and cloth, electronic components such as an electronic substrate and a piezoelectric element, and media or medium such as a powder layer, an organ model, and a testing cell. The “material onto which liquid can adhere” includes any material on which liquid adheres unless particularly limited.

The above-mentioned “material onto which liquid can adhere” may be any material as long as liquid can temporarily adhere such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, or ceramics.

The term “liquid discharge apparatus” may be an apparatus to relatively move a head and a medium onto which liquid can adhere. However, the liquid discharge apparatus is not limited to such an apparatus. Examples of the liquid discharge apparatus include a serial-type apparatus which moves the liquid discharge head, and a line-type apparatus which does not move the liquid discharge head.

Examples of the liquid discharge apparatus further include a treatment liquid coating apparatus to discharge a treatment liquid to a sheet to coat the treatment liquid on a sheet surface to modify the sheet surface and an injection granulation apparatus in which a composition liquid including raw materials dispersed in a solution is discharged through nozzles to granulate fine particles of the raw materials.

First Aspect

A head-maintenance device includes a suction cap to cap a nozzle surface of a head to discharge liquid, a suction unit to suck the inside of the suction cap, an air-release channel communicating with the inside of the suction cap, a lid to close an opening of the suction cap, and a maintenance controller. The maintenance controller performs an air-release channel suction operation to close the air-release channel and suck the inside of the suction cap by the suction unit, with the opening of the suction cap closed by the lid, and open the air-release channel with the inside of the suction cap in a negative pressure.

Second Aspect

In the head-maintenance device according to the first aspect, the maintenance controller repeats the air-release channel suction operation multiple times w % ben the maintenance controller performs the air-release channel suction operation.

Third Aspect

The head-maintenance device according to the first or second aspect, further includes an absorber disposed on a surface of the lid with which the suction cap contacts.

Fourth Aspect

The head-maintenance device according to any one of the first to third aspects, further includes a liquid sensor to detect the liquid in the air-release channel. The maintenance controller does not perform the air-release channel suction operation when the liquid sensor does not detect the liquid in the air-release channel.

Fifth Aspect

In the head-maintenance device according to any one of the first to fourth aspects, the maintenance controller repeats the air-release channel suction operation multiple times, and the number of repetitions of the air-release channel suction operation varies depending on environmental conditions.

Sixth Aspect

In the head-maintenance device according to any one of the first to fifth aspects, the maintenance controller repeats the air-release channel suction operation multiple times, and the number of repetitions of the air-release channel suction operation varies depending on the type of the liquid.

Seventh Aspect

In the head-maintenance device according to any one of the first to sixth aspects, the maintenance controller repeats the air-release channel suction operation at different timings depending on at least one of the environmental conditions or the type of the liquid.

Eighth Aspect

In the head-maintenance device according to any one of the first to seventh aspects, the maintenance controller repeats the air-release channel suction operation at different timings depending on a job in which the liquid is discharged from the head.

Ninth Aspect

In the head-maintenance device according to any one of the first to eighth aspects, the suction unit sucks the inside of the suction cap, with the nozzle surface capped with the suction cap, at an output of the suction unit higher than the output of the suction unit when the suction unit sucks the inside of the suction cap in the air-release channel suction operation.

Tenth Aspect

The head-maintenance device according to any one of the first to ninth aspects further includes multiple lids including the lid.

Eleventh Aspect

A liquid discharge apparatus includes a head to discharge liquid and the head-maintenance device according to any one of the first to tenth aspects.