Patent Description:
A liquid discharge apparatus such as a printer includes a discharge unit in which multiple heads are arrayed and attach to a head mount. The discharge unit is also referred to as a discharge device, a head array, a head module, or the like.

The discharge unit has a configuration in which an inclination angle of the discharge unit is adjustable to adjust gaps between liquid discharge surfaces of heads respectively attached to multiple head mounts and a drum (Patent Literature <NUM>: <CIT>).

A processing accuracy of the head mount to which the head is attached and a position of the center of gravity of the head attached to the head mount may be different in the longitudinal direction of the head mount and the head. Thus, there is a case in which a twist having a different amount of deformation occurs in the longitudinal direction of the head mount.

However, a configuration described in Patent Literature <NUM> has a problem in which it is difficult to adjust a gap variation between the head and a liquid application target due to torsional deformation of a mounting surface (head mount) since only an inclination angle of the mounting surface is adjustable.

<CIT> Al discloses a liquid discharge apparatus according to the preamble of claim <NUM>.

The present embodiment has been made in view of the above-described problem, and an object of the present embodiment is to easily check a state of a liquid applied on the linear member (liquid application state).

The present invention has been made in view of the above problem, and an object of the present invention is to reduce torsion (twist) of the head mount to which the head is attached.

According to the present invention, there is disclosed a discharge unit comprising: a head configured to discharge a liquid; a head mount to which the head is detachably attached; and a holder holding the head mount, wherein the head mount includes multiple rotation mechanisms on respective side plates on respective ends of the head mount arranged in a longitudinal direction of the head mount; and the holder rotatably and independently holds the multiple portions of the head mount by means of the respective rotation mechanisms; wherein the holder rotatably holds both ends of the head mount, which are arranged in the longitudinal direction of the head mount, and the head mount includes eccentric cams and each of the side plates includes an elongated hole, wherein each of the eccentric cams engages with a respective one of the elongated holes so as to rotate each respective end of the head mount, characterized in that: the head mount includes an operation part having a length longer than a length between the side plates, wherein the operation part is attached to the eccentric cam that engages with the elongated hole in one of the side plates, and passes through a hole in the other one of the side plates, so that the operation part is configured to rotate one end of the head mount and is operable from the other end of the head mount.

The liquid discharge apparatus according to the present invention can reduce torsion of the attachment to which the head is attached.

The aforementioned and other aspects, features, and advantages of the present disclosure will be better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:.

However, the disclosure of this patent specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have the same function, operate in a similar manner, and achieve similar results.

Although the embodiments are described with technical limitations with reference to the attached drawings, such description is not intended to limit the scope of the disclosure and all of the components or elements described in the embodiments of this disclosure are not necessarily indispensable.

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, embodiments of the present disclosure are described below. First, a printer <NUM> as a liquid discharge apparatus according to a first embodiment of the present disclosure is described with reference to <FIG>.

<FIG> is a schematic cross-sectional side view of the printer <NUM> according to the first embodiment of the present disclosure.

A printer <NUM> according to the first embodiment includes a loading unit <NUM> to load a sheet P into the printer <NUM>, a pretreatment unit <NUM>, a printing unit <NUM>, a dryer <NUM>, and an ejection unit <NUM>, and a reverse mechanism <NUM>. The sheet P is an application target (print target) to which a liquid is to be applied.

In the printer <NUM>, the pretreatment unit <NUM> applies, as desired, a pretreatment liquid onto the sheet P fed (supplied) from the loading unit <NUM>, the printing unit <NUM> applies liquid to the sheet P to perform desired printing, the dryer <NUM> dries the liquid adhering to the sheet P, and the sheet P is ejected to the ejection unit <NUM>. The pretreatment unit <NUM> serves as a "pretreatment device".

The loading unit <NUM> includes loading trays <NUM> (a lower loading tray 11A and an upper loading tray 11B) to accommodate a plurality of sheets P and feeding units <NUM> (a feeding unit 12A and a feeding unit 12B) to separate and feed the sheets P one by one from the loading trays <NUM> and supply the sheets P to the pretreatment unit <NUM>.

The pretreatment unit <NUM> includes, e.g., a coater <NUM> as a treatment-liquid application unit that coats a printing surface of the sheet P with a treatment liquid having an action and an effect of aggregation of colorant of ink to prevent bleed-through.

The printing unit <NUM> includes a drum <NUM> and a liquid discharge device <NUM>. The drum <NUM> is a bearer (rotating member) that bears the sheet P on a circumferential surface of the drum <NUM> and rotates. The liquid discharge device <NUM> discharges a liquid toward the sheet P borne on the drum <NUM>.

The printing unit <NUM> further includes transfer cylinders <NUM> and <NUM>. The transfer cylinder <NUM> receives the sheet P fed from the pretreatment unit <NUM> and forwards the sheet P to the drum <NUM>. The transfer cylinder <NUM> receives the sheet P conveyed by the drum <NUM> and forwards the sheet P to the dryer <NUM>.

The transfer cylinder <NUM> includes a sheet gripper to grip a leading end of the sheet P conveyed from the pretreatment unit <NUM> to the printing unit <NUM>. The sheet P thus gripped by the transfer cylinder <NUM> is conveyed as the transfer cylinder <NUM> rotates. The transfer cylinder <NUM> forwards the sheet P to the drum <NUM> at a position opposite (facing) the drum <NUM>.

Similarly, the drum <NUM> includes a sheet gripper on a surface of the drum <NUM>, and the leading end of the sheet P is gripped by the sheet gripper of the drum <NUM>. The drum <NUM> includes a plurality of suction holes dispersed on a surface of the drum <NUM>, and a suction unit generates suction airflows directed from desired suction holes of the drum <NUM> to an interior of the drum <NUM>.

The sheet gripper of the drum <NUM> grips the leading end of the sheet P forwarded from the transfer cylinder <NUM> to the drum <NUM>, and the sheet P is attracted to and borne on the drum <NUM> by the suction airflows by the suction device. As the drum <NUM> rotates, the sheet P is conveyed.

The liquid discharge device <NUM> includes discharge units <NUM> (discharge units 33A to 33D) as liquid dischargers to discharge liquids. For example, the discharge unit 33A discharges a liquid of cyan (C), the discharge unit 33B discharges a liquid of magenta (M), the discharge unit 33C discharges a liquid of yellow (Y), and the discharge unit 33D discharges a liquid of black (K), respectively. Further, a discharge unit <NUM> may discharge a special liquid, that is, a liquid of spot color such as white, gold, or silver.

The printer <NUM> controls a discharge operation of each of the discharge units <NUM> of the liquid discharge device <NUM> by a drive signal corresponding to print data. When the sheet P borne on the drum <NUM> passes through a region facing the liquid discharge device <NUM>, the liquids of respective colors are discharged from the discharge units <NUM>, and an image corresponding to the print data is formed on the sheet P.

The drum <NUM> forwards the sheet P onto which a liquid has been applied by the liquid discharge device <NUM> to the transfer cylinder <NUM>. The transfer cylinder <NUM> forwards the sheet P fed from the drum <NUM> to a conveyor <NUM>. The conveyor <NUM> conveys the sheet P to the dryer <NUM> (heater).

The dryer <NUM> dries a liquid adhered (applied) onto the sheet P by the printing unit <NUM>. Thus, a liquid component such as moisture in the liquid evaporates, and the colorant contained in the liquid is fixed on the sheet P. Additionally, curling of the sheet P is restrained.

The reverse mechanism <NUM> reverses, in switchback manner, the sheet P that has passed through the dryer <NUM> in double-sided printing. The reversed sheet P is fed back to an upstream side of the transfer cylinder <NUM> through a conveyance passage <NUM> of the printing unit <NUM>.

The ejection unit <NUM> includes an ejection tray <NUM> and a sheet conveyor <NUM>. A plurality of sheets P is stacked on the ejection unit <NUM>. The plurality of sheets P conveyed through the reverse mechanism <NUM> is sequentially stacked and held on a stack part <NUM>.

The discharge unit <NUM> according to the first embodiment of the present disclosure is described with reference to <FIG>.

<FIG> is a plan view of the discharge unit <NUM> viewed from a nozzle surface side of the discharge unit <NUM>.

<FIG> is a plan view of the discharge unit <NUM> viewed from a side opposite to the nozzle surface side of the discharge unit <NUM>.

<FIG> is a cross-sectional side view of the discharge unit <NUM> along a line A-A of <FIG>.

The discharge unit <NUM> includes a plurality of heads <NUM> to discharge a liquid. The heads <NUM> are arrayed in a staggered manner on a head mount <NUM>. The head mount <NUM> serves as a mounting member to mount the heads <NUM>. One of a row of the heads <NUM> (lower row in <FIG>) arrayed in staggered manner is referred to as a head row 100A, and another row of the heads <NUM> (upper row in <FIG>) is referred to as a head row 100B.

Thus, the multiple heads <NUM> (head row 100A and head row 100B) are attached to the head mount <NUM> in a transverse direction (Y-direction in <FIG>) orthogonal to the longitudinal direction (X-direction in <FIG>) of the head mount <NUM>.

Each of the heads <NUM> includes multiple nozzle arrays. The multiple nozzles <NUM> are arrayed in the multiple nozzle arrays. A liquid is dischargeable from each of the multiple nozzles. A number of nozzle arrays is not limited to two as illustrated in <FIG> and may be any number. As illustrated in <FIG>, the head <NUM> includes a flange <NUM> that faces the base <NUM> (303A and 303B) that configures the head mount <NUM> in a direction perpendicular to a surface of the base <NUM> (in a Z-direction indicated in <FIG>).

The heads <NUM> are inserted into the openings <NUM> of the base <NUM> to be attached to the base <NUM>.

Next, a configuration of the head mount <NUM> is described with reference to <FIG>.

<FIG> is a schematic plan view of the head mount <NUM>.

<FIG> is a cross-sectional front side view of the head mount <NUM> along a line A-A of <FIG>.

<FIG> is a schematic cross-sectional front view of the head mount <NUM> of <FIG>.

<FIG> is a front view of the head mount <NUM> illustrating an arrangement of the head mount <NUM> with respect to the drum <NUM>.

The head mount <NUM> includes two bases <NUM> (303A and 303B). Multiple openings <NUM> are formed in each of two bases <NUM>, and the heads <NUM> are respectively inserted into the multiple openings <NUM>. The bases 303A and 303B are formed of two plate materials (boards). The bases 303A and 303B are fixed to intermediate side plates <NUM> (306a and 306b) and are further fixed to the side plates <NUM> (305a and 305b) outside the intermediate side plates <NUM> (306a and 306b).

As illustrated in <FIG>, a mounting surface <NUM> (331a and 331b) of each of the bases 303A and 303B of the head mount <NUM> is disposed in a direction parallel to a tangential direction of the drum <NUM>.

The head mount <NUM> according to the first embodiment of the present disclosure is described with reference to <FIG>.

<FIG> is a schematic perspective view of the head mount <NUM> and a holder <NUM> according to the first embodiment of the present disclosure.

<FIG> is a schematic perspective view of the head mount <NUM> according to the first embodiment of the present disclosure.

<FIG> is a schematic cross-sectional front view of the head mount <NUM> according to the first embodiment of the present disclosure.

The discharge unit <NUM> includes the holder <NUM> that holds both ends of the head mount <NUM> in a longitudinal direction of the head mount <NUM>. The longitudinal direction of the head mount <NUM> is parallel to a nozzle array direction of the head <NUM> along which the nozzles <NUM> are arrayed in the nozzle array of the head <NUM>. The longitudinal direction of the head mount <NUM> intersects the conveyance direction of the sheet P onto which a liquid is discharged from the head <NUM>.

The holder <NUM> includes two holding parts <NUM> (401a and 401b) that respectively hold side plates <NUM> (305a and 305b) of the head mount <NUM> at both ends in the longitudinal direction of the head mount <NUM>. The two holding parts <NUM> are connected by a connector <NUM> and fixed to an apparatus body of the printing unit <NUM>.

The rotation mechanism <NUM> independently and rotatably holds the side plates <NUM> of the head mount <NUM> with respect to the holding part <NUM>. The side plates <NUM> are disposed at each ends of the head mount in the longitudinal direction of the head mount <NUM>. The head mount <NUM> in the first embodiment is disposed such that the side plate 305a is on a front side of the printer <NUM> and the side plate 305b is on a rear side of the printer <NUM>.

Thus, the discharge unit <NUM> includes a head <NUM> configured to discharge a liquid, the head mount <NUM> to which the head is detachably attachable, and the holder <NUM> configured to hold the head mount <NUM>. The head mount <NUM> includes multiple rotation mechanisms <NUM> on multiple portions (both ends in <FIG>) of the head mount <NUM> in a longitudinal direction of the head mount <NUM>, and the holder <NUM> is configured to rotatably and independently hold the multiple portions of the head mount <NUM> with the rotation mechanisms <NUM>.

The rotation mechanism <NUM> includes detachable rotation shafts <NUM> (317a and 317b). The rotation shaft <NUM> of the rotation mechanism <NUM> is removed to make the head mount <NUM> detachably attachable to the holding part <NUM>.

As illustrated in <FIG> and <FIG> and 2B, the rotation mechanism <NUM> is disposed at a center of the head mount <NUM> in a transverse direction of the head mount <NUM>.

The head mount <NUM> respectively includes elongated holes <NUM> (308a and 308b) in the side plate 305a and 305b to rotate the rotation mechanism <NUM>. The head mount <NUM> further includes eccentric cams <NUM> (309a and 309b) respectively engaging with the elongated holes <NUM>. The eccentric cam <NUM> is attached to an operation part <NUM> (310a and 310b).

Thus, the eccentric cam <NUM> is rotated to rotate the rotation mechanism <NUM> so that the head mount <NUM> is rotated with respect to the holding part <NUM>. After a position of the head mount <NUM> is adjusted with respect to the holding part <NUM>, the head mount <NUM> is fixed to the holding part <NUM> by the fixing member <NUM> (318a and 318b). A fastening member such as a screw can be used as the fixing member <NUM>, for example.

The head mount <NUM> in the first embodiment includes rotation mechanisms 307a and 307b on a front side plate 305a and a rear side plate 305b, respectively. The head mount <NUM> is rotatably held by the holder <NUM> such that the front side plate 305a and the rear side plate 305b are independently and rotatably held by the holding parts 401a and 401b, respectively.

Accordingly, even when the head mount <NUM> is twisted with respected to the holder <NUM> in a front end and a rear end of the head mount <NUM> in the longitudinal direction of the head mount <NUM>, the front side plate 305a and the rear side plate 305b are rotated relative to the holding parts 401a and 401b of the holder <NUM> to reduce the twist. The twist between the front end and the rear end of the head mount <NUM> are a twist between one end and another end of the head mount <NUM> in the longitudinal direction of the head mount <NUM>.

The head mount <NUM> in the first embodiment respectively includes the rotation mechanisms 307a and 307b on the front side plate 305a and the rear side plate 305b. As illustrated in <FIG>, the operation part 310b of the eccentric cam 309b passes through a hole <NUM> in the front side plate 305a and is drawn out to the front side (left side in <FIG>) of the front side plate 305a. The operation part 310b rotates a rear side of the rotation mechanism 307b. The operation part 310b passes through the elongated hole 308b in the rear side plate 305b and the hole <NUM> in the front side plate 305a. In <FIG>, the operation part 310b is a bar that has a length longer than a length between the front side plate 305a and the rear side plate 305b.

Accordingly, the user can access the rear side (another end) of the rotation mechanism 307b from the front side (one end) of the head mount <NUM>. Thus, the discharge unit <NUM> according to the first embodiment can improve a workability of a rotation operation of the head mount <NUM> by the rotation mechanism <NUM>.

Next, an effect of the head mount <NUM> according to the first embodiment is described more specifically below with reference to <FIG>.

First, deformation of the base member (head mounting surface) of the mounting member in the lateral direction will be described with reference to <FIG>.

<FIG> are schematic front views of the head mount <NUM> according to the first embodiment to illustrate the deformation of the bases <NUM>.

The head mount <NUM> is disposed to be inclined around the drum <NUM>. Each head <NUM> in the head rows 100A and 100B attached to the two bases 303A and 303B has an inclination angle for each row. That is, the head <NUM> in the head row 100A and the head <NUM> in the head row 100B have different inclination angles.

As illustrated in <FIG>, an upstream side (right side) of the head rows 100A and 100B is referred to as the head row 100A, and a downstream side (left side) of the head rows 100A and 100B is referred to as the head row 100B in the conveyance direction of the sheet P of the drum <NUM>, for example. The inclination angle θA of the head <NUM> in the head row 100A and the inclination angle θB of the head <NUM> in the head row 100B have a relation of θA > θB. That is, the inclination angle of the head row 100A, disposed lower than the head row 100B, is larger than the inclination angle of the head row 100B in an inclination direction indicated by arrow in <FIG> from a vertical line indicated by a dash-single dot line.

The head <NUM> has a center of gravity, and a load is applied to the lower side of the head <NUM> in a gravity direction. Further, there is a difference in a number of heads <NUM> between the head row 100A and the head row 100B in the first embodiment. That is, the number of heads <NUM> in the head row 100A is different from the number of heads <NUM> in the head row 100B.

Because of the above reasons, the mounting surface <NUM> (base <NUM>) of the head mount <NUM> deforms. Thus, each of the heads <NUM> of the head row 100A and the head row 100B takes a posture indicated by a solid line in an actual attached state with respect to a designed posture indicated by a broken line in <FIG>, for example.

Further, an amount of deformation differs between the mounting surface 331a (base 303A) and the mounting surface 331b (base 303B) of the head mount <NUM>.

Next, a deformation of the base <NUM> (mounting surface <NUM>) of the head mount <NUM> in the longitudinal direction of the head mount <NUM> is described below with reference to <FIG>.

<FIG> is an enlarged partial perspective view of the base <NUM> (mounting surface <NUM>) illustrating the deformation of the base <NUM>.

A processing accuracy of the head mount <NUM> and a position of the center of gravity of the head <NUM> are not identical at both ends (front end and rear end of the head mount <NUM>) in the longitudinal direction of the head mount <NUM>.

Therefore, the amount of deformation may differ between a front end "C" and a rear end "D" of the base 303B of the head mount <NUM> in the longitudinal direction of the base 303B of the head mount <NUM>. Similarly, the amount of deformation may be different between a front end "E" and a rear end "F" of the base 303A of the head mount <NUM> in the longitudinal direction of the base 303A of the head mount <NUM>. Thus, the base <NUM> is twisted in the longitudinal direction of the head mount <NUM>.

Next, influence of the deformation of the base <NUM> (mounting surface <NUM>) of the head mount <NUM> on a landing timing of the liquid onto the sheet P borne on the drum <NUM> is described below with reference to <FIG>.

<FIG> is a schematic front view of the head mount <NUM> according to the first embodiment to illustrate the deformation of the bases <NUM>.

The amount of deformation of the mounting surface 331a of the base 303A is different from the amount of deformation of the mounting surface 331b of the base 303B as illustrated in <FIG>. Thus, a gap Ga between the head <NUM> of the head row 100A and a circumferential surface of the drum <NUM> and a gap Gb between the head <NUM> of the head row 100B and the circumferential surface of the drum <NUM> are different.

Since the gap Ga and the gap Gb are different from each other, the discharge timing of the liquid is different between the head row 100A and the head row 100B. A discharge timing described herein means a discharge timing in a state in which there is no positional deviation between the head row 100A and the head row 100B in the conveyance direction of the sheet P.

An operation of a gap adjustment of the discharge unit <NUM> according to the first embodiment is described below with reference to <FIG>.

<FIG> are schematic cross-sectional front views of the discharge unit <NUM> illustrating the gap adjustment of the discharge unit <NUM>.

As illustrated in <FIG>, it is assumed that the amount of deformation is different between the base 303A and the base 303B of the head mount <NUM>, and it is assumed that the gap Ga of the head row 100A is different from the gap Gb of the head row 100B.

In the above state, the head mount <NUM> is rotated with respect to the holding part <NUM> by the rotation mechanism <NUM> to adjust the gap Ga of the head row 100A to be equal to the gap Gb of the head row 100B (Ga = Gb) as illustrated in <FIG>.

Therefore, the head mount <NUM> is fixed to the holding part <NUM> by the fixing member <NUM> after a position of the head mount <NUM> is adjusted with respect to the holding part <NUM>.

The rotation mechanism <NUM> can adjust and match the discharge timings of the heads <NUM> in the head row 100A and the head row 100B.

As described above, the discharge unit <NUM> according to the first embodiment includes the rotation mechanisms 307a and 307b on the front side plate 305a and the rear side plate 305b of the head mount <NUM>, respectively, as illustrated in <FIG>. The holding part <NUM> independently and rotatably hold the side plates 305a and 305b as illustrated in <FIG>.

The front side plate 305a and the rear side plate 305b are relatively rotatable in opposite directions with respect to the holding parts 401a and 401b to reduce a twist occurred in the longitudinal direction of the head mount <NUM> (between one end and another end of the head mount <NUM>). Thus, the discharge unit <NUM> according to the first embodiment can reduce the twist and adjust the gaps Ga and Gb (see <FIG>) in the longitudinal direction of the head mount <NUM>.

Next, another operational effect of the discharge unit <NUM> according to the first embodiment is described below with reference to <FIG>.

<FIG> is a schematic cross-sectional front view of the discharge unit <NUM> illustrating the operational effect of the discharge unit <NUM>.

In the discharge unit <NUM> according to the first embodiment, the holding part <NUM> rotatably holds the head mount <NUM> by the rotation mechanism <NUM>.

Thus, the discharge unit <NUM> can adjust the base <NUM> of the head mount <NUM> to face a center (rotation axis) of the drum <NUM> even when the holder <NUM> does not face the center of the drum <NUM> as illustrated in <FIG>.

Next, the discharge unit <NUM> according to a second embodiment of the present disclosure is described with reference to <FIG>.

<FIG> is a schematic front view of the discharge unit <NUM> according to the second embodiment useful for understanding the present invention.

The discharge unit <NUM> in the second embodiment includes gap defining members 361A and 361B (abutment members) at an upstream end and a downstream end of the head mount <NUM> in the conveyance direction of the sheet P.

The head mount <NUM> is free to rotate by the rotation mechanism <NUM> (rotation mechanism 307a is illustrated in <FIG>).

Therefore, the head mount <NUM> is held by the holding part <NUM> in a state in which both of the gap defining members 361A and 361B abut against (contact with) a circumferential surface of the drum <NUM>.

Thus, the gap defining members 361A, 361B abut against a circumferential surface of the drum <NUM>, and the gap defining members 361A, and 361B are configured to define a gap between the head <NUM> and the drum <NUM>.

Since the gaps Ga and Gb (see <FIG>) between the head rows 100A and 100B and the drum <NUM> becomes an appropriate posture, the head mount <NUM> is fixed to the holding part <NUM> in this appropriated posture.

The head mount <NUM> includes the gap defining members 361A and 361B arranged in a front side and a rear side of the head mount <NUM> corresponding to the front side and rear side of the rotation mechanisms 307a and 307b. Alternatively, the head mount <NUM> may include the gap defining members 361A and 361B arranged over the longitudinal direction of the head mount <NUM>. That is, the gap defining members 361A and 361B extends in the longitudinal direction of the head mount <NUM>.

Thus, the head mount <NUM> can be fixed to the holder <NUM> in a posture with reduced torsion (twist) even when the head mount <NUM> is twisted.

Next, the discharge unit <NUM> according to a third embodiment of the present disclosure is described with reference to <FIG>.

<FIG> is a schematic front view of the discharge unit <NUM> according to the third embodiment useful for understanding the present invention.

The discharge unit <NUM> according to the third embodiment includes a screw <NUM> on an upper part of an upstream side wall <NUM> of the base 303A of the head mount <NUM> and a spring <NUM> on an upper part of a downstream side wall <NUM> of the base 303B.

The screw <NUM> is attached to the fixing part <NUM> as indicated by arrow in <FIG> so that the screw <NUM> can advance toward and retract from the fixing part <NUM>. A leading end of the screw <NUM> is in contact with an upper end of the upstream side wall <NUM>. The spring <NUM> is disposed between the upper end of the downstream side wall <NUM> and the fixing part <NUM>. The spring <NUM> biases the downstream side wall <NUM> downward.

When the screw <NUM> is loosened, the head mount <NUM> is rotated by a restoring force of the springs <NUM> via the rotation mechanism <NUM> so that the gap between the head row 100A on the base 303A and the circumferential surface of the drum <NUM> increases.

When the screw <NUM> is tightened, the head mount <NUM> rotates in a direction in which the base 303A approaches the drum <NUM> via the rotation mechanism <NUM> so that the gap between the head row 100B on the base 303B and the circumferential surface of the drum <NUM> increases.

The discharge unit <NUM> includes the screw <NUM> and the spring <NUM> respectively corresponding to the front rotation mechanism 307a and the rear rotation mechanism 307b. Thus, the head mount <NUM> can be fixed to the holder <NUM> in a posture with reduced torsion (twist) even when the head mount <NUM> is twisted.

Next, the discharge unit <NUM> according to a fourth embodiment of the present disclosure is described with reference to <FIG>.

<FIG> is a schematic front view of the discharge unit <NUM> according to the fourth embodiment of the present disclosure.

The discharge unit <NUM> in the fourth embodiment includes the rotation mechanism <NUM> at a position other than a center portion of the head mount <NUM> in a transverse direction of the head mount <NUM>. The position other than the center portion of the head mount is a position deviated from the center portion of the head mount <NUM>. The transverse direction is in the conveyance direction of the sheet P.

In <FIG>, the rotation mechanism <NUM> is disposed at a position away from the center of the base 303A by a distance "La" in the transverse direction of the head mount <NUM> and away from the center of the base 303B by a distance "Lb" in the transverse direction of the head mount <NUM>.

Thus, an amount of adjustment of the position of the head mount <NUM> according to a rotation of the rotation mechanism <NUM> is different for each of the head rows 100A and 100B. The discharge unit <NUM> in the fourth embodiment includes the rotation mechanism <NUM> biased toward the base 303B (Lb < La). Thus, the amount of adjustment of the position of the head mount <NUM> due to a rotation of the head mount <NUM> in the base 303A is larger the amount of adjustment of the position of the head mount <NUM> due to a rotation of the head mount <NUM> in the base 303B.

The discharge unit <NUM> in the fourth embodiment includes the rotation mechanism <NUM> at an optimum position according to the amount of deformation of the base <NUM> (mounting surface <NUM>) of the head mount <NUM> and the amount of adjustment of the gaps Ga and Gb for the head rows 100A and 100B so that the discharge unit <NUM> can adjust the position of the head mount <NUM> with a small amount of rotation of the rotation mechanism <NUM>.

Next, the discharge unit <NUM> according to a fifth embodiment of the present disclosure is described with reference to <FIG>.

<FIG> is a schematic front view of the discharge unit <NUM> according to the fifth embodiment of the present disclosure.

The discharge unit <NUM> in the fifth embodiment includes multiple head mounts <NUM> (302A to 302D) to respectively dispose multiple discharge units 33A to 33D around the drum <NUM> (see <FIG>).

As described above, amounts of deformation of the base <NUM> (mounting surfaces <NUM>) of the multiple head mounts <NUM> (302A to 302D) are different. Therefore, the rotation mechanisms 307A to 307D of the multiple head mounts <NUM> (302A to 302D) are disposed at positions at which the amounts of deformation can be reduced in accordance with the amount of deformation of each of the head mounts <NUM> (302A to 302D).

That is, the discharge unit <NUM> in the fifth embodiment includes the multiple head mounts <NUM>, and positions of rotation fulcrums (centers of axis) of at least two head mounts <NUM> among the multiple head mounts <NUM> are different from each other.

Thus, the discharge unit <NUM> having the above configuration can perform appropriate adjustment according to the amount of deformation of the head mount <NUM>.

Thus, the head mount <NUM> includes at least two head mounts <NUM>, and said at least two head mounts <NUM> respectively include at least two rotation fulcrums disposed at different positions in said at least two head mounts <NUM>.

The above-described embodiments describe examples in which the head mount <NUM> includes the multiple head rows 100A and 100B, each including multiple heads <NUM>. However, the present invention may be applied to the head mount including one head <NUM>.

In the present embodiments, a "liquid" discharged from the head is not particularly limited as long as the liquid has a viscosity and surface tension of degrees dischargeable from the head.

Preferably, the viscosity of the liquid is not greater than <NUM> mPa·s under ordinary temperature and ordinary pressure or by heating or cooling.

Examples of the liquid include a solution, a suspension, or an emulsion that contains, for example, a solvent, such as water or an organic solvent, a colorant, such as dye or pigment, a functional material, such as a polymerizable compound, a resin, or a surfactant, a biocompatible material, such as DNA, amino acid, protein, or calcium, or an edible material, such as a natural colorant.

Such a solution, a suspension, or an emulsion can be used for, e.g., inkjet ink, surface treatment solution, a liquid for forming components of electronic element or light-emitting element or a resist pattern of electronic circuit, or a material solution for three-dimensional fabrication.

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

Examples of the "liquid discharge apparatus" include, not only apparatuses capable of discharging liquid to materials to which liquid can adhere, but also apparatuses to discharge a liquid toward gas or into a liquid.

The "liquid discharge apparatus" may include units to feed, convey, and eject the material on which liquid can adhere.

The liquid discharge apparatus may further include a pretreatment apparatus to coat a treatment liquid onto the material, and a post-treatment apparatus to coat a treatment liquid onto the material, onto which the liquid has been discharged.

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 fabrication apparatus to discharge a fabrication liquid to a powder layer in which powder material is formed in layers to form a three-dimensional fabrication 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 arbitrary images, such as arbitrary patterns, or fabricate three-dimensional images.

The above-described term "material on which liquid can adhere" represents a material on which liquid is at least temporarily adhered, a material on which liquid is adhered and fixed, or a material into which liquid is adhered to permeate.

Examples of the "material on which liquid can adhere" include recording media such as a paper sheet, recording paper, and a recording sheet of paper, film, and cloth, electronic components such as an electronic substrate and a piezoelectric element, and media such as a powder layer, an organ model, and a testing cell.

The "material on which liquid can adhere" includes any material on which liquid adheres unless particularly limited.

Examples of the "material on which liquid can adhere" include any materials on which liquid can adhere even temporarily, such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, and ceramic.

The "liquid discharge apparatus" may be an apparatus to relatively move the head and a material on which liquid can adhere.

However, the liquid discharge apparatus is not limited to such an apparatus.

For example, the liquid discharge apparatus may be a serial head apparatus that moves the head or a line head apparatus that does not move the 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 reform the sheet surface, and an injection granulation apparatus in which a composition liquid including raw materials dispersed in a solution is injected through nozzles to granulate fine particles of the raw materials.

Claim 1:
A discharge unit (<NUM>) comprising:
a head (<NUM>) configured to discharge a liquid;
a head mount (<NUM>) to which the head (<NUM>) is detachably attached; and
a holder (<NUM>) holding the head mount (<NUM>),
wherein the head mount (<NUM>) includes multiple rotation mechanisms (307a, 307b) on respective side plates (305a, 305b) on respective ends of the head mount (<NUM>) arranged in a longitudinal direction of the head mount (<NUM>), and
the holder (<NUM>) rotatably and independently holds the side plates (305a, 305b) of the head mount (<NUM>) by means of the respective rotation mechanisms (307a, 307b);
wherein the holder (<NUM>) rotatably holds both ends of the head mount (<NUM>), which are arranged in the longitudinal direction of the head mount (<NUM>), and
the head mount (<NUM>) includes eccentric cams (309a, 309b) and each of the side plates includes an elongated hole (308a, 308b), wherein each of the eccentric cams engages with a respective one of the elongated holes so as to rotate each respective end of the head mount (<NUM>),
characterized in that:
the head mount (<NUM>) includes an operation part (<NUM>10b) having a length longer than a length between the side plates (305a, 305b), wherein the operation part is attached to the eccentric cam (309b) that engages with the elongated hole (308b) in one of the side plates (305b), and passes through a hole (<NUM>) in the other one of the side plates (305a), so that the operation part (<NUM>10b) is configured to rotate one end of the head mount (<NUM>) and is operable from the other end of the head mount (<NUM>).