Image forming apparatus

An image forming apparatus includes a recording head having a nozzle surface including plural nozzles configured to eject liquid droplets, a suction cap configured to seal the nozzle surface of the recording head, a cap holder configured to displaceably hold the suction cap via an elastic member and retractably disposed corresponding to the recording head, and a wiping member configured to wipe the nozzle surface of the recording head in a direction from an upper side to a lower side. The cap holder is provided with a guide part configured to come into contact with an upper end surface of the recording head to frictionally move on the upper end surface of the recording head, and the guide part is disposed on an upper side of the recording head.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The disclosures herein generally relate to an image forming apparatus, and specifically to an image forming apparatus having a recording head for ejecting ink droplets.

2. Description of the Related Art

An inkjet recording apparatus is generally known as an example of a liquid-jet recording image forming apparatus having, for example, a recording head for ejecting ink droplets, such as a printer, a facsimile machine, or a plotter, or a multifunctional peripheral having a combination of these functions.

Such a liquid-jet recording image forming apparatus includes a maintenance-restoration mechanism composed of a cap for capping a nozzle surface of the recording head, a wiper member (may also called “wiper blade”, “wiping blade”, or “blade”) serving as wiping material for wiping the nozzle surface of the recording head to be cleaned, and the like. The maintenance-restoration mechanism is configured to maintain ejecting stability of nozzles of the recording head, prevent ink inside the nozzles from drying, and prevent dirt or dust from entering into the nozzles. For example, the maintenance-restoration mechanism may perform a restoration operation to form a nozzle meniscus by discharging thickened ink from the nozzles into the cap, and then wiping the nozzle surface with the wiper member.

As an example of a related-art maintenance-restoration mechanism, Japanese Patent No. 4186557 (Patent Document 1) discloses a maintenance-restoration mechanism that includes a cap for capping a nozzle surface of a recording head disposed in a vertical direction, an air release opening formed in an upper end part of the cap, and a suction cap having a suction port disposed at a lower part of the cap.

RELATED ART DOCUMENT

Patent Document

In general, a cap holder includes a head guide part disposed such that the head guide part comes into contact with an outer peripheral part of the recording head. The head guide is provided for regulating a cap position corresponding to the recording head.

When the nozzle surface is capped by vertically disposing the nozzle surface of the recording head, and moving the cap in a horizontal direction, a suction operation is conducted in the order of capping, suctioning the head, air releasing from the cap, and de-capping, and then a wiping operation is performed with a wiper member along a nozzle disposed direction from an upper part of the nozzle surface to a lower part of the nozzle surface in order to prevent liquid from dripping.

However, even if a suction unit suctions a waste liquid discharged in the cap, the waste liquid remains in the cap. Hence, when the cap is decapped in that condition, the waste liquid drips from the lower part of the cap and is attached to the head guide part of the cap holder, thereby sticking the dripped waste liquid to the head guide part of the cap holder.

Further, since the waste liquid also remains on the nozzle surface due to the surface tension and viscosity of the waste liquid, in the vertically disposed head, a remaining waste liquid is transferred to a lower side of the head due to gravity, and the remaining waste liquid is also attached to the head guide part of the cap holder and sticks to the head guide part of the cap holder in an end part where the blade-shaped wiper member is detached from the nozzle surface while wiping the nozzle surface in a vertical direction (wiping from the upper part to the lower part of the nozzle surface).

Thus, when the waste liquid is attached to and sticks to the head holder at a lower side of the cap holder, the cap position is shifted from a target position due to the stuck waste liquid. Hence, an airtight sealing condition of the nozzle surface is incomplete, thereby causing dryness of the nozzles, or an increase in viscosity of the liquid, and lowering the suction performance for restoring the nozzles.

SUMMARY OF THE INVENTION

It is a general object of at least one embodiment of the present invention to provide an image forming apparatus having a recording head with a nozzle surface disposed in a vertical direction and capable of preventing a remaining waste liquid from adhering to a cap holder, which substantially eliminate one or more problems caused by the limitations and disadvantages of the related art.

According to an embodiment, there is provided an image forming apparatus that includes a recording head having a nozzle surface including a plurality of nozzles configured to eject liquid droplets;

a suction cap configured to seal the nozzle surface of the recording head; a cap holder configured to displaceably hold the suction cap via an elastic member and be retractably disposed corresponding to the recording head; and a wiping member configured to wipe the nozzle surface of the recording head in a direction from an upper side to a lower side. In the image forming apparatus, the cap holder is provided with a guide part configured to come into contact with an upper end surface of the recording head to frictionally move on the upper end surface of the recording head, and the guide part is disposed on an upper side of the recording head.

Additional objects and advantages of the embodiments will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A detailed description is given of an ink-jet recording device serving as an image forming apparatus to which preferred embodiments are applied with reference to the accompanying drawings.

In the following, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, an image forming apparatus according to an embodiment is described with reference toFIGS. 1 and 2. Note thatFIG. 1is a side diagram of a mechanical part of the image forming apparatus andFIG. 2is a diagram illustrating the mechanical part viewed in an arrow A direction ofFIG. 1;

The image forming apparatus according to the embodiment is a serial-type image forming apparatus. The image forming apparatus includes an image forming part2, a transferring mechanical part5, a sheet-feeding tray4(serving as a sheet-feeding part and including a sheet-feeding cassette) disposed at a lower side of the image forming apparatus where sheets10are stacked. Each of the sheets10is acquired from the sheet-feeding tray4, the image forming part2records a desired image on the sheet10by ejecting liquid droplets in a horizontal direction while the acquired sheet10is intermittently transferred in a vertical direction (perpendicular direction) by the transferring mechanical part5. Having recorded the desired image on the sheet10, the sheet10is further transferred in an upper direction via a sheet-discharging part6so that the sheet10is discharged onto a sheet-receiving tray7provided on an upper side of a main body of the image forming apparatus (herein after also called “an apparatus main body”).

Further, in duplex printing, after an image is printed on one surface of the sheet10, the sheet10is moved from the sheet-discharging part6into an inverting part8so that the sheet10is transferred in an inverse direction (i.e., a downward direction) by the transferring mechanical part5. The inverted sheet10having now the other surface (i.e., a rear surface) as a printable surface is then transferred in the transferring mechanical part5again, so that an image is printed on the other surface (i.e., the rear surface). Having printed a desired image on the rear surface of the sheet10, the sheet is then discharged onto the sheet-receiving tray7.

Note that the image forming part2is configured to slidably hold a carriage23having a recording head24with a main-guide member21and a sub-guide member22that bridge between a left side plate101L and a right side plate101R, so that the image forming part2moves and scans in a main-scanning direction via a timing belt looped over a driving pulley and a driven pulley driven by a main-scanning motor serving as a not-illustrated carriage moving mechanism.

The carriage23includes two recording heads24aand24b(may be integrally called “a recording head24”) having liquid-jet heads for ejecting ink droplets of respective colors of yellow (Y), cyan (C), magenta (M), and black (K). The recording heads24aand24binclude nozzle arrays composed of plural nozzles disposed in a sub-scanning direction orthogonal to the main-scanning direction, and the ink droplet ejecting directions of the nozzles are directed in a horizontal direction. That is, the image forming apparatus according to the embodiment employs a horizontal ejection type having a recording head24in which a nozzle surface having the nozzles ejecting liquid droplets is disposed in a vertical direction and the nozzles are configured to eject liquid droplets in a horizontal direction.

Each of the recording heads24aand24bhas two nozzle arrays having nozzles for discharging liquid-droplets of different colors disposed in array. The recording head24aincludes a first nozzle array configured to eject yellow (Y) liquid-droplets and a second nozzle array configured to eject magenta (M) liquid-droplets. The recording head24bincludes a first nozzle array configured to eject black (K) liquid-droplets and a second nozzle array configured to eject cyan (C) liquid-droplets.

The carriage23includes a head tank29for supplying ink of different colors corresponding to the nozzle arrays of the recording heads24aand24b. Ink is supplied to the ink tank29from ink cartridges (main-tanks) of different colors detachably attached to the apparatus main body.

Each of the sheets10stacked on the sheet-feeding tray4is separated from the others by a semicircular sheet-feeding roll (or semicircular roll)43and a separation pad44, and is fed along the transfer guide member45and then into the apparatus main body. The sheet10fed in the apparatus main body is then transferred between a transfer belt51of the transferring mechanical part5and a presser roll48, where the sheet10is attracted and transferred by the transfer belt51.

The transferring mechanical part5includes the endless transfer belt51looped over a transfer roller serving as a driving roller and a driven roller53, a charging roller54configured to electrostatically charge the transfer belt51, and a platen member55configured to maintain planarity of the transfer belt51at a part (position) facing the image forming part2. Note that the transfer belt51peripherally travels in a belt transferring direction (i.e., the sub-scanning direction, or a sheet-transferring direction) driven by the transfer roller52that is rotationally driven by a sub-scanning motor of a not-illustrated sub-scanning drive mechanism via a timing belt and a timing pulley.

The sheet-discharging part66includes a sheet-discharge guide member61, a combination of a discharging sheet transfer roller62and a spur63, and a combination of a sheet-discharging roller64and a spur65. In this configuration, the sheet10on which the image is formed is discharged from a nip between the sheet-discharging roller64and the spur65onto the sheet-receiving tray7with a surface of the sheet10being face-down.

Further, in order to invert a part of the sheet10discharged onto the sheet-receiving tray7to be transferred into a nip between the transfer belt51and a presser roll48, the inverting part8includes a switching claw81configured to switch a sheet-discharging path into a sheet-inverting path, an inverting guide member82, a combination of an inverting roller83and a spur84serving as an inverting roll, a transferring-assistant roller85facing the driven roller53, a reverse transferring part51bof the transfer belt51, and a bypass guide member86configured to guide the sheet10separated from the reverse transferring part51bof the transfer belt51into a nip between the transfer belt51and the presser48by moving the charging roller54.

Further, a maintenance-restoration mechanism9for maintaining and restoring conditions of nozzles120of the recording head24is disposed in a non-printing area on one side of the scanning direction of the carriage23.

A frame90of the maintenance-restoration mechanism9includes a suction cap91for capping each of nozzle surfaces124(seeFIG. 1) of the recording head24and a moistening cap92, and further includes a wiper member (wiper blade)94configured to wipe the nozzle surface124.

The suction cap91is held by a cap holder93; however, a detailed description of a configuration of the suction cap91and the cap holder93is illustrated later. The suction cap91is connected with a suction-discharge path97having a suction pump96serving as a suction unit, and the suction-discharge path97is in communication with a waste liquid tank98.

The wiper member94is held by a wiper holder194. The wiper holder194has projections formed one on each side in the main-scanning direction, and the projections are fit in guide grooves of a wiping guide195disposed in the sub-scanning direction. Hence, the wiper member94is configured to move in a vertical direction (i.e., the nozzle array direction of the recording head) so as to wipe the nozzle surface124of the recording head24in a direction from the top to the bottom of the nozzle surface124(in a direction indicated by an arrow inFIG. 8).

Further, a non-printing liquid droplet receiver95is disposed for receiving liquid droplets of the ink having increased viscosity, which is not usable for printing and thus discharged from the nozzles as a preliminary discharge (non-printing liquid discharge).

Note that the frame90of the maintenance-restoration mechanism9includes a not-illustrated capping mechanism stepping motor. When the capping mechanism stepping motor rotates in a normal direction, a capping operation is performed by the cap holder93and the suction cap91, while a de-capping operation is performed by the moistening cap92via not-illustrated gears and cams. Further, the suction pump96is driven by rotating the capping mechanism stepping motor in a reverse direction.

Further, a wiper driving stepping motor is disposed for driving a pinion engaged with a rack disposed on the wiper holder194, such that the wiper member94is moved in a vertical direction by driving the wiper driving stepping motor in a normal direction and in a reverse direction.

In the image forming apparatus having the above configuration, each of the sheets10is separately fed from the sheet-feeding tray4, the fed sheet10is electrostatically attracted by the charged transfer belt51, and the sheet10attracted by the transfer belt51is transferred in a vertical direction while the transfer belt51circulates in peripheral directions. Then, the recording head24is driven based on image signals while the carriage23is moved so that the recording head24discharges ink droplets on the temporarily stopped sheet10to thereby record one line of an image. Then, the sheet10is transferred a predetermined distant to record a subsequent line. When the recording is completed after repeatedly recording one line at a time of the image, the recorded sheet10is discharged onto the sheet-receiving tray7.

Then, the carriage23is moved to a home position that faces a position of the maintenance-restoration mechanism9to carry out a maintenance-restoration operation of the nozzles120of the recording head24. The maintenance-restoration operation may include nozzle suctioning to suction the ink inside the nozzles120after the corresponding nozzle surface124is capped with the suction cap91, and a non-printing liquid discharge to eject or discharge ink that is not used for forming an image. As a result of conducting such maintenance-restoration operations, an image may be formed by stably ejecting liquid droplets of the ink onto the sheet10.

In duplex printing, a first surface of the sheet10is printed in the above-described fashion, and a second surface (i.e., the rear surface) of the sheet10is printed in the following fashion. That is, when a rear end of the sheet10passes through an inverting part (i.e., the switching claw81), the sheet-discharging roller64is driven in reverse so that the sheet10is switched back to be guided on the inverting guide member82side. The sheet10is then transferred into a nip between the inverting roller83and the spur84, and is further transferred into a nip between the reverse transferring part51bof the transfer belt51and the transferring-assistant roller85.

Accordingly, the sheet10is attracted by the transfer belt51, and the attracted sheet10is transferred by the peripheral traveling of the transfer belt51. The sheet10is then separated from the transfer belt51on the transfer roller52side to be guided by the bypass guide member86(via a bypass). The sheet10is then transferred into a nip between a normal transferring part51aand the presser roll48to be attracted by the transfer belt51. Thereafter, the sheet10is transferred again into the image forming region where an image is printed on the second surface of the sheet10by the recording head24, and the sheet10having the image printed on the second surface is discharged onto the sheet-receiving tray7.

Next, details of a cap part of a maintenance-restoration mechanism according to a first embodiment are described with reference toFIGS. 3 and 4. Note thatFIG. 3is a schematic diagram illustrating the cap part andFIG. 4is a front diagram illustrating the recording head.

The recording head24includes a nozzle cover241configured to cover a peripheral part of the nozzle surface124and an outer peripheral surface of the recording head24including an upper end surface and a lower end surface of the recording head24.

The suction cap91includes an air release port connected to an air-release valve191and configured to allow air inside the suction cap91to be open to the atmosphere with the suction cap91being in a capping state, and a suction port connected to the suction-discharge path97and configured to discharge a waste liquid inside the suction cap91. Note that an air release port and a suction port are disposed on the upper side and the lower side of the suction cap91, respectively. Note also that the air release port may either be directed in a vertical direction or in a horizontal direction.

The suction cap91is movably (displaceable) held by the cap holder93retractably disposed in a direction indicated by an arrow via a spring192serving as a elastic member.

The cap holder93includes a head guide part193configured to be brought into contact with the upper end surface of the recording head24(i.e., the upper end surface of the nozzle cover241) so as to come into contact with the upper end surface of the recording head24to frictionally move on the upper end surface of the recording head24while the suction cap91is in the capping state. The suction cap91is located corresponding to the nozzle surface124by allowing the head guide part193to come into contact with the upper end surface of the recording head24to frictionally move on the upper end surface of the recording head24.

Note that the cap holder93is not provided with a head guide part configured to come into contact with the lower end surface of the recording head24to frictionally move on the lower end surface of the recording head24.

With this configuration, a cleaning operation is performed when a predetermined maintenance-restoration operation is required, such as when the nozzles120of the recording head24are clogged, or when a negative pressure inside the head tank29is not maintained to break the meniscuses of the nozzles120. The cleaning operation includes a suction operation to suction the ink from the nozzles120of the recording head24, a wiping operation to wipe the nozzle surface124, and a non-printing liquid discharge operation to discharge or eject liquid droplets that are not used for forming an image.

Note that the suction operation is performed in the order of capping, ink suctioning, air releasing, internal cap suctioning, and decapping. The suction operation is described with reference toFIGS. 5A and 5B.

Initially, as illustrated inFIG. 5A, the head guide part193of the cap holder93comes in contact with an upper end of the recording head24, and a capping position is restricted by causing the head guide part193to run on the upper end of the record head24along a shape of an inclined surface193aof the head guide part193.

Thereafter, a nip part of the suction cap91comes in contact with the nozzle surface124, and an airtight space is formed by further pushing the nip part of the suction cap91against the nozzle surface124.

In this state, after a predetermined amount of ink is suctioned from the nozzles120by driving the suction pump96, the air-release valve191of the suction cap91is then opened, and ink inside the suction cap91is suctioned (i.e., the internal cap suctioning) by utilizing the suction pump96again.

Subsequently, as illustrated inFIG. 58, the cap holder93is moved in a decapping direction such that the suction cap91is separated from the nozzle surface124(decapping).

Then, the carriage23is moved to a wiping position, and a not-illustrated wiping stepping motor is rotationally driven in a normal direction so as to perform a vertical wiping operation to wipe the nozzle surface124with the wiper member94by moving the wiper member94in a direction from the top to the bottom of the nozzle surface124.

Subsequently, the non-printing liquid droplet discharge operation is performed by moving the carriage23to a position where the recording head24faces a non-printing liquid droplet receiver95. Then, the wiper member94is moved back to a standby position by rotationally driving the wiping stepping motor in a reverse direction while moving the carriage23to a non-printing liquid droplet discharge position.

In this state, the ink may be discharged into the suction cap91in some usage environment. Hence, the amount of ink (i.e., waste liquid) remaining inside the suction cap may be increased even if the ink inside the suction cap is suctioned. In such a case, the ink amount in a decapping condition is large, which may cause ink dripping when the suction cap91is decapped (i.e., the decapping condition).

In this case, since the cap holder93according to the embodiment is not provided with the head guide part on its lower side, ink will not adhere to the head guide part. Accordingly, accuracy in the cap position when the nozzle surface124is capped with the suction cap91(i.e., capping condition) is maintained, and suctioning performance may be prevented from lowering.

Further, since the ink interfering with the lower end surface of the recording head24in the vertical wiping operation is not brought into contact with the head guide part of the cap holder93, the ink will not adhere to the head guide part. Accordingly, accuracy in the cap position when the nozzle surface124is capped with the suction cap91may be maintained, and suctioning performance may be prevented from lowering.

Details of the above condition is described with reference to a comparative example illustrated inFIG. 9AtoFIG. 11C.

In this comparative example, the cap holder93is provided with a head guide part393configured to come into contact with the lower end surface of the recording head24to frictionally moved on the lower end surface of the recording head24.

With this configuration, when a waste liquid400remains inside suction cap91after having performed the internal cap suctioning as illustrated inFIG. 9A, the remaining waste liquid400is dripping on the head guide part393when the suction cap91is decapped, and the dripping waste liquid adheres to the head guide part393as illustrated inFIG. 9B.

Further, in the vertical wiping operation performed with the wiping member94as illustrated inFIG. 10A, the waste liquid400may interfere with the lower end surface of the recording head24when the wiper member94is separated from the recording head24at a wiping end part as illustrated inFIG. 100.

In this condition, the cap holder93is moved in the capping direction to cap the nozzle surface124of the recording head24with the suction cap91as illustrated inFIG. 11A, the waste liquid400remaining on the lower end surface of the recording head24comes in contact with a lower side of the head guide part393of the cap holder93as illustrated inFIG. 11B. Accordingly, the waste liquid400may be transferred onto the lower side of the head guide part393of the cap holder93when the suction cap91is decapped, and the transferred waste liquid400may adhere to the lower side of the head guide part393as illustrated inFIG. 11C.

Thus, when the waste liquid400is attached to and adheres to the lower side of the head guide part393of the cap holder93, the airtight sealing condition may become incomplete by shifting a cap position from a target position. Hence, the nozzles120may be dried, or viscosity of the liquid ink may be increased, which may lower the suction performance conducted for restoring the nozzles120.

Compared to the above comparative example, since the maintenance-restoration mechanism according to the first embodiment includes no lower side head guide part393of the cap holder93, the above malfunction due to dryness of the nozzles or increase in viscosity does not occur.

Next, a maintenance-restoration mechanism according to a second embodiment is described with reference toFIGS. 6A and 6B.FIGS. 6A and 6Bare schematic diagrams illustrating a cap part of the maintenance-restoration mechanism according to the second embodiment.

In the maintenance-restoration mechanism according to the second embodiment, a nozzle cover241of the recording head24does not have a part to cover an outer circumference of the lower end surface of the recording head24. That is, the nozzle cover241does not have a bending part bent along the lower side of the recording head24, such that a lower end of the nozzle cover241has an edge shape.

With such a configuration, a waste liquid does not interfere with the lower end surface of the recording head24when the vertical wiping operation is performed. In addition, since the cap holder93does not have a lower side of the head guide part, the waste liquid will not be transferred to the lower side of the head guide part.

Accordingly, accuracy in the cap position when the nozzle surface124is capped with the suction cap91may be maintained, which may be able to not only prevent the suction performance from lowering but also prevent the waste liquid from adhering to the lower end surface of the recording head24, which may prevent the internal parts of the image forming apparatus from becoming contaminated.

In this case, it is preferable that the lower end of the nozzle cover241be downwardly projected from the lower end surface of the recording head24(see a projected amount indicated with “L” inFIG. 7Ain this example) because the nozzle cover241having the above configuration may securely prevent the waste liquid from interfering with the lower end surface of the recording head24, as illustrated inFIGS. 7A and 7B.

Next, a maintenance-restoration mechanism according to a third embodiment is described with reference toFIG. 8.FIG. 8is a schematic diagram the maintenance-restoration mechanism according to a third embodiment.

In the maintenance-restoration mechanism according to the third embodiment, an ink receiver201serving as a liquid receiving member configured to receive a liquid dripping from the recording head24or the suction cap91(i.e., the waste liquid) is disposed on a bottom surface inside the image forming apparatus. The ink receiver201is disposed such that a position of the ink receiver201is aligned with a position of the recording head24when the suction cap91is decapped.

That is, there may be a large amount of the waste liquid (ink) remaining inside the suction cap91in some usage environment, and ink dripping may be observed when the suction cap91is decapped. In such a condition, since the head guide part is not disposed on the lower side of the cap holder93as mentioned earlier, a dripping waste liquid may adhere to the nozzle surface124or fall onto the bottom inner part of the image forming apparatus.

Accordingly, the liquid dripping from the recording head25or the suction cap91(i.e., the waste liquid) is received by the ink receiver201, thereby preventing the waste liquid from contaminating the inside of the image forming apparatus.

Note that the ink receiver201is disposed on the maintenance-restoration mechanism9side. For example, the ink receiver201may be fixed on a frame101L (seeFIG. 2) with screws or the like.

Further, the maintenance-restoration mechanism according to the third embodiment further includes an ink receiver surface202serving as a liquid receiver surface configured to receive liquid droplets scattered in a rearward direction when the wiper member94is detached from the recording head24at the end of wiping operation. The ink receiver surface202is disposed below the recording head24in parallel with the nozzle surface124when the nozzle surface124is directed to its front side.

That is, in performing the vertical wiping operation, the waste liquid wiped with the wiper member94may be blown off in a direction below and behind the recording head24immediately after having the lower end of the nozzle cover241wiped with the wiper member94.

Thus, the waste liquid may be prevented from adhering to the carriage23, and the waste liquid may be prevented from being transferred from the carriage23to the sheet10by allowing the ink receiver surface202to receive the waste liquid being blown off (scattered).

In this case, the number of components may be reduced by integrally forming the ink receiver201and the ink receiver surface202.

Note that in the present application, a material of the “sheet” is not limited to paper, but may include an overhead projector (OHP) film, cloth, glass, and a substrate, to which ink droplets or other liquids are attachable. Examples of the materials for the sheets may be called a “recording medium subject to being recorded on”, a “recording medium”, “recording paper”, and a “recording sheet”. Further, the terms “image forming”, “recording”, “printing”, and “copying” may be used as synonyms.

In addition, the term an “image forming apparatus” indicates an apparatus that forms an image onto media such as paper, string, fiber, fabric, leather, metal, plastic, glass, wood, and ceramics by discharging liquid onto such media. Moreover, the term “forming an image” or “image formation” not only indicates providing an image having some kind of meaning onto the media such as characters and symbols, but also indicates an image without having any meaning such as patterns (i.e., by simply discharging ink droplets onto the media).

Further, the term “ink” is not specifically limited to those generally called “ink”, but may used as a generically called “liquid” capable of forming an image, such as a recording liquid, a fixing liquid, and a liquid. The term “ink” further includes DNA specimens, resist, a patterning material, resin, and the like.

Moreover, the “image” is not limited a two-dimensional image, but may include an image applied to a three-dimensionally formed object, and to a three-dimensional image formed of a molded object.

Further, in the illustration of the maintenance-restoration mechanism according to the above embodiments, the sheet is transferred in a direction along the vertical direction (perpendicular direction), and the liquid droplets are ejected in the horizontal direction. However, the maintenance-restoration mechanism may be configured such that the sheet is transferred in a direction inclined to the vertical direction (perpendicular direction), and the liquid droplets is ejected in a direction inclined to the horizontal direction.

In the image forming apparatus according to the above embodiments having the recording head with the nozzle surface being disposed in the vertical direction, the remaining waste liquid may be prevented from adhering to the cap holder.

This patent application is based on Japanese Priority Patent Application No. 2012-006229 filed on Jan. 16, 2012, the entire contents of which are hereby incorporated herein by reference.