Patent Description:
An apparatus including a plurality of liquid discharge heads that discharge different types of liquid is known as a liquid discharge apparatus for discharging liquid to a medium. Examples of such different types of liquid include liquid ink of different colors.

An apparatus including an angle adjuster that adjusts an angle of each liquid discharge head relative to a drum-shaped member that conveys a medium is known. The angle adjuster is disposed above the drum-shaped member, and includes a plurality of liquid discharge heads disposed along a conveyance direction of the medium (e.g., <CIT>).

Like the apparatus disclosed in <CIT>, if liquid discharge head arrays are radially disposed along an outer circumference of a drum-shaped member, a position of the center of gravity of the liquid discharge head array is important for adjustment of a liquid discharge head with good accuracy such that that the liquid discharge head is oriented at a predetermined angle. The liquid discharge head array is a long member in a direction parallel to a rotation axis direction of the drum-shaped member. Thus, for angle adjustment of the liquid discharge head array with respect to the drum-shaped member, angles in the longitudinal direction in general need to be adjusted to the same angle.

However, a member for controlling an operation of the liquid discharge head is fixed to a position opposite a fixation position of the liquid discharge head in the longitudinal direction of the long member of the liquid discharge head array. In such a case, a position of the center of gravity of the liquid discharge head array is provided outside a size of a rotation shaft of the drum-shaped member, that is, the outside of supports that are disposed in the front and back of the liquid discharge head in a slide direction. If a position of the center of gravity is displaced toward one side of the long member, the support does not function as a fulcrum when an angle is adjusted. Consequently, the adjustment accuracy is degraded.

<CIT> discloses a head device, a head position adjustment mechanism, and an image forming apparatus.

The present disclosure is directed to not only a liquid discharge head angle adjuster that can enhance accuracy of angle adjustment of a liquid discharge head, but also a liquid discharge module and a liquid discharge apparatus.

According to the invention, there is provided an improved liquid discharge head angle adjuster for individually adjusting inclination angles of a plurality of liquid discharge heads, as defined in the claims.

Further described is an improved liquid discharge module that includes the liquid discharge head angle adjuster described above, and the plurality of liquid discharge heads to discharge liquid to a medium.

Still further described is an improved liquid discharge apparatus that includes the liquid discharge head angle adjuster described above, a drum to convey a medium, and the plurality of liquid discharge heads. The plurality of liquid discharge heads is disposed on an outer circumferential surface of the drum, and discharges liquid to the medium.

According to the present disclosure, accuracy of liquid discharge head angle adjustment can be enhanced.

The aforementioned and other aspects, features, and advantages of the present disclosure are 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, within the scope of the appended claims.

Embodiments of the present disclosure are described with reference to the drawings. First, a description is given of a configuration of an inkjet printer <NUM> as one example to which a liquid discharge apparatus according to an embodiment of the present disclosure is applied.

<FIG> is a diagram illustrating a general arrangement of the inkjet printer <NUM>. The inkjet printer <NUM> is, for example, an image forming apparatus employing an on-demand line scanning system, and includes an image forming device <NUM>, a sheet feeding device <NUM>, a registration adjuster <NUM>, a drying device <NUM>, a recording medium reverse device <NUM>, and a sheet ejection device <NUM>. Next, a description is given of one example of a series of image formation output operations (printing operations) performed by the inkjet printer <NUM> including such configurations. The image forming device <NUM> corresponds to the liquid discharge apparatus according to the embodiment of the present disclosure.

First, sheets W1 as recording media stacked on a sheet stacker <NUM> disposed in the sheet feeding device <NUM> are picked up one by one by an air separator <NUM>, and the picked-up sheet W1 is conveyed to a direction toward the image forming device <NUM>. When the sheet W1 conveyed from the sheet feeding device <NUM> reaches the registration adjuster <NUM>, a skew of the sheet W1 with respect to a conveyance direction is corrected by a registration roller pair <NUM> disposed inside the registration adjuster <NUM>.

The sheet W1 (the registration of which has been) corrected by the registration roller pair <NUM> is fed to the image forming device <NUM>. Then, the sheet W1 is fed to a surface of a tubular drum <NUM> by a conveyance roller pair <NUM>. The drum <NUM> includes a plurality of recoding medium grippers <NUM>. A leading end of the fed sheet W1 is nipped by one of the grippers <NUM>, and the sheet W1 is conveyed to a position opposite a plurality of head arrays <NUM> (<NUM> through 100P) by rotation of the drum <NUM>.

The plurality of head arrays <NUM> discharges liquid ink by an inkjet method. In the image forming device <NUM>, the plurality of head arrays <NUM> is disposed along a surface of the tubular drum <NUM> in a rotation direction of the drum <NUM> in a state in which the plurality of head arrays <NUM> is filled with predetermined-color ink. Each of the head arrays <NUM> is disposed in a predetermined radial position according to a curvature of an outer circumferential surface of the drum <NUM>. An angle of each of the head arrays <NUM> is adjusted such that a liquid discharge direction is perpendicular to the surface of the drum <NUM>. That is, in a radial direction from a rotation axis of the drum <NUM>, each of the head arrays <NUM> is disposed at a different angle.

In other words, the plurality of head arrays <NUM> as a liquid discharge module has angles with respect to the drum <NUM>, and each of the angles is adjusted toward the rotation center of the drum <NUM> such that the head arrays <NUM> discharge ink (liquid) to an outer circumferential surface of the sheet W1 retained on the surface of the drum <NUM>.

In addition, a dummy discharge receptacle <NUM> is disposed on the outer circumferential surface of the drum <NUM>. The dummy discharge receptacle <NUM> receives ink that is dummy-discharged when the head arrays <NUM> are not discharging ink to the sheet W1. Upon image formation, the sheet W1 is conveyed to the drying device <NUM>.

The drying device <NUM> includes a dryer <NUM>. The sheet W1 passes below the dryer <NUM>, so that moisture of the sheet W1 evaporates. The drying device <NUM> also includes the recording medium reverse device <NUM> including a recording medium reverse device <NUM>. If duplex printing is performed, the sheet W1 is reversed by the recording medium reverse device <NUM>, and then is conveyed again toward a direction of the image forming device <NUM> by a reverse conveyance device <NUM>. Before the sheet W1 reaches the drum <NUM>, a skew of the sheet W1 is corrected by a registration roller <NUM> disposed inside the image forming device <NUM>. The sheet W1 which has been dried by the drying device <NUM> is conveyed to the sheet ejection device <NUM>, and is stacked in a state in which an end of the sheet W1 is aligned.

The image forming device <NUM> includes an image forming controller <NUM> that partially controls a liquid discharge operation performed by the image forming device <NUM>. However, the image forming controller <NUM> may comprehensively control operations of the inkjet printer <NUM>. Alternatively, the sheet feeding device <NUM>, the registration adjuster <NUM>, and the drying device <NUM> may separately include controllers. In such a case, cooperation of the image forming controller <NUM> with the controllers can comprehensively control operations of the inkjet printer <NUM>.

As illustrated in <FIG>, a conveyance direction of the sheet W1 is a direction X. A rotation direction of the drum <NUM> which conveys the sheet W1 when an image forming process is executed is a counter clockwise (CCW) direction on an X-Z plane.

Next, a liquid discharge head angle adjuster <NUM> according to an embodiment of the present disclosure is described. <FIG> is an enlarged view of the plurality of head arrays <NUM>. As illustrated in <FIG>, the head arrays <NUM> include a plurality of array members <NUM> and a plurality of flanges <NUM> as array supports. The array members <NUM> fix discharge heads <NUM>, and the flanges <NUM> support the array members <NUM>. As illustrated in <FIG>, in the head arrays <NUM>, each of the plurality of discharge heads <NUM> is supported at a different angle. An inclination angle of each discharge head <NUM> is adjusted to a radial direction that passes a rotation axis of the drum <NUM>. That is, an inclination angle of each array member <NUM> is maintained such that a direction perpendicular to a tangent of a position in which liquid ink discharged from the corresponding discharge head <NUM> lands on the drum <NUM> is a discharge direction.

In the head arrays <NUM>, the discharge heads <NUM> are supported in positions opposite an outer circumferential surface (a surface on which the sheet W1 is held and conveyed) of the drum <NUM> in a state in which the discharge heads <NUM> are sequentially disposed in a direction along the outer circumferential surface. Thus, the flanges <NUM> and the array members <NUM> are also sequentially disposed in the direction along the outer circumferential surface.

The discharge heads <NUM> are configured to discharge respective liquid ink of black (K), cyan (C), magenta (M), and yellow (Y) for color printing. In addition, certain discharge heads <NUM> discharge special color ink (S) and coating liquid (P) that coats a sheet W1 to which liquid is to adhere. In the following description, only the discharge heads <NUM> for liquid ink (K, C, M, Y) of four colors are described.

The head arrays <NUM> include the flanges <NUM> and the array members <NUM>. The flanges <NUM> and the array members <NUM> serve as a liquid discharge head angle adjuster <NUM> that adjusts a liquid discharge direction for each of the discharge heads <NUM>. The liquid discharge head angle adjuster <NUM> is configured such that the array member <NUM> is supported by the flanges <NUM> at a predetermined angle. The angle adjustment is made such that a discharge direction of the discharge head <NUM> is set on a virtual axis line perpendicular to and toward an outer circumferential surface from the rotation center of the drum <NUM>. In other words, a vertical axis line of the array member <NUM> (in a virtual radial direction passing through the rotation center of the drum <NUM>) is adjusted to an angle to pass through the rotation center of the drum <NUM>.

The flange <NUM> as the array support includes a V roller <NUM> as a first support, a pressing flat roller <NUM> as a pressing member, and an adjustment roller <NUM> that are disposed on one surface of the flange <NUM> out of the front surface and the back surface of the flange <NUM> in the rotation direction of the drum <NUM> (the conveyance direction of the sheet W1). The V roller <NUM>, the adjustment roller <NUM>, and the pressing flat roller <NUM> are disposed on the same surface of the flange <NUM>. On the other surface of the flange <NUM>, a support flat roller <NUM> as a second support is disposed.

The V roller <NUM> supports a V rail <NUM> that is described below. Each of the V roller <NUM> and the V rail <NUM> has a V-shaped longitudinal section in a rotation axis direction of the drum <NUM>. Thus, the V roller <NUM> has two inclined surfaces that face each other, and an intersection point of the inclined surfaces is a tip. Moreover, the V rail <NUM> has two inclined surfaces that face each other, and an intersection point of the inclined surfaces is a bottom portion. The tip of the V roller <NUM> contacts the bottom portion of the V rail <NUM>, and such a contact functions as a fulcrum for rotation when an angle of the array member <NUM> is adjusted. The angle adjustment is described below.

The pressing flat roller <NUM> as the pressing member has a configuration by which an urging force for pressing the tip of the V roller <NUM> against the bottom portion of the V rail <NUM> is applied to the V roller <NUM>. The urging force by the pressing flat roller <NUM> can prevent a phenomenon in which the fulcrum provided by the V rail <NUM> and the V roller <NUM> is lifted due to a difference in positions of the centers of gravity.

The adjustment roller <NUM> functions as an angle adjustment device that pushes an adjustment flat rail <NUM> disposed in the array member <NUM> to adjust an inclination angle of the array members <NUM>.

The support flat roller <NUM> restricts a rotation of the array member <NUM>, and supports the array member <NUM> to be held at a predetermined inclination angle. The phrase "rotation of the array member <NUM>" used herein represents a rotation of the array member <NUM> by its own weight about the V roller <NUM> as a first fulcrum.

The flanges <NUM> are fixed to a wall surface (e.g., a side plate) of a casing in which a structure including the head arrays <NUM> are stored. As illustrated in <FIG>, fixation positions of the flanges <NUM> are predetermined positions spaced a certain distance apart in a rotation direction (a main scanning direction) of the drum <NUM>. The array member <NUM> is laid across the flanges <NUM> fixed to the predetermined positions, so that the array member <NUM> remains at a predetermined inclination angle with respect to a predetermined radial direction of the drum <NUM>.

The array member <NUM> as an angle adjusted device is a long member. A longitudinal direction of the array member <NUM> is a rotation axis direction of the drum <NUM>. The array member <NUM> has a surface opposite the drum <NUM>, and the discharge head <NUM> is fixed to such a surface of the array member <NUM>. The array member <NUM> includes the V rail <NUM> as a first supported portion and the adjustment flat rail <NUM> on one surface out of the front surface and the rear surface in the rotation direction of the drum <NUM> (the conveyance direction of the sheet W1). The array member <NUM> includes a supported flat rail <NUM> as a second supported portion on the other surface.

The V rail <NUM> of the array member <NUM> is laid across the V roller <NUM> of the flange <NUM>. Moreover, the supported flat rail <NUM> disposed on the surface at a side opposite the V rail <NUM> is laid across the support flat roller <NUM>. The adjustment flat rail <NUM> on the same surface as the V rail <NUM> is disposed in a position that is to be pushed by the adjustment roller <NUM>.

The adjustment roller <NUM> has a structure by which an amount of projection of the adjustment roller <NUM> from a side surface of the flange <NUM> is variable. If a projection amount of the adjustment roller <NUM> becomes greater, the adjustment flat rail <NUM> is pushed more by the adjustment roller <NUM>. Herein, the position in which the tip of the V rail <NUM> is in contact with the V roller <NUM> becomes a rotation fulcrum, so that a lower end side of the array member <NUM> to which the discharge head <NUM> is fixed rotates in the same direction as the rotation direction of the drum <NUM>. Accordingly, a position of the discharge head <NUM> moves in the rotation direction of the drum <NUM>, and a liquid ink discharge direction can be adjusted to an angle toward the rotation axis of the drum <NUM>.

As illustrated in <FIG>, the head arrays <NUM> disposed upstream in the conveyance direction and the head arrays <NUM> disposed downstream in the conveyance direction are inclined in opposite directions relative to a boundary that is in a position of a vertical diameter of the drum <NUM>. For example, the head arrays <NUM> disposed upstream in the conveyance direction are "inclined rightward", and the head arrays <NUM> disposed downstream in the conveyance direction are "inclined leftward".

The flanges <NUM> inclined rightward are configured such that the V rail <NUM> and the adjustment flat rail <NUM> on a lower side of the inclination are respectively caught by the V roller <NUM> and the adjustment roller <NUM> of the flange <NUM> disposed upstream in the conveyance direction. Moreover, the supported flat rail <NUM> on the opposite surface is configured to be caught by the support flat roller <NUM> of the flange <NUM> disposed downstream in the conveyance direction. On the other hand, the flanges <NUM> inclined leftward are symmetric with respect to the flanges <NUM> inclined rightward.

As for an angle adjustment method for the discharge head <NUM>, an example of an axial-center adjustment method for the array member <NUM> is described. <FIG> is a front view partially illustrating the head arrays <NUM>. Similarly, <FIG> is a schematic view partially illustrating the head arrays <NUM>.

As illustrated in the example in <FIG>, if attention is focused on one of the discharge heads <NUM> in the head arrays <NUM>, the V rail <NUM> and the adjustment flat rail <NUM> are disposed on one side surface of the array member <NUM> in the conveyance direction, and only the supported flat rail <NUM> is disposed on the other side surface of the array member <NUM>. A discharge array to be described in the following description is inclined rightward.

When the discharge array is inserted between the flanges <NUM> and installed in a liquid discharge module, that is, when the discharge array slides in a direction Y and a position of the discharge array is determined, a weight of the discharge array causes a vertical axis line to shift relative to the rotation center of the drum <NUM> as illustrated in <FIG>. In a case where an operation continues in such a state, a distance (a discharge gap) between the discharge head <NUM> and the sheet W1 to be conveyed by the drum <NUM> differs for each discharge head <NUM>. In this case, an attachment position (a landing position) of liquid discharged from the discharge head <NUM> to the sheet W1 is shifted from an expected position. As a result, quality of an image to be Formed with the liquid ink is affected.

Accordingly, as illustrated in <FIG>, a projection amount of the adjustment roller <NUM> is adjusted, so that an end portion of the array member <NUM> on the side of the drum <NUM> is moved. Herein, the tip of the V rail <NUM> of the array member <NUM> is in contact with the V roller <NUM>, and such a tip in contact with the V roller <NUM> functions as a rotation fulcrum. Such a rotation enables an inclination angle to be adjusted such that a vertical axis line of the array member <NUM> is oriented toward the rotation center (a drum center <NUM>) of the drum <NUM>.

More particularly, a clearance between a side surface of a vibration restriction pin <NUM> disposed on a lower surface of the array member <NUM> and a jig <NUM> disposed on a surface of the drum <NUM> is adjusted to a predetermined value. The predetermined value is, for example, <NUM> or less.

Moreover, as illustrated in <FIG>, if a vertical axis line of the array member <NUM> is adjusted so as to be oriented toward the drum center <NUM> of the drum <NUM>, a virtual line connecting a plurality of vibration restriction pins <NUM> disposed in the front and the rear (a Y-axis direction) of the array member <NUM> and a rotation axial line of the drum <NUM> become parallel.

Herein, the head array <NUM> is configured such that a clearance between each of the plurality of vibration restriction pins <NUM> and the jig <NUM> becomes the predetermined value as described above.

Next, a configuration of the array member <NUM> is further described in detail. Each of <FIG> is a side view of the array member <NUM>. The left side and the right side of each of <FIG> are respectively the front side and the rear side of the head array <NUM>. In each of <FIG>, general arrangement of the flange <NUM> is omitted, and only a configuration functioning as a support that supports the array member <NUM> is illustrated.

As illustrated in <FIG>, the array member <NUM> is a long member in a width direction of the drum <NUM> (the width direction of the drum <NUM> is a direction that is perpendicular to the conveyance direction and also referred to as a main scanning direction). The discharge head <NUM> is disposed on the lower surface in one end portion (in the front direction) of the array member <NUM>. Moreover, a component such as a power circuit and a control board <NUM> that controls operations of the discharge head <NUM> is disposed on an upper surface in the other end portion (the rear side) that is a side opposite the position of the discharge head <NUM>.

The array member <NUM> is supported in a predetermined position by the support flat roller <NUM> and the V roller <NUM> of the flanges <NUM> disposed in the width direction of the drum <NUM>. In the width direction of the drum <NUM>, a plurality of V rollers <NUM> and a plurality of support flat rollers <NUM> are disposed. The flange <NUM> is disposed in a position within a range of width direction size of the drum <NUM>.

As illustrated in <FIG>, if the array member <NUM> is inserted between the flanges <NUM> so that the array member <NUM> is supported by the flanges <NUM> and functions, a front portion and a middle portion of the V rail <NUM> are supported by the V rollers <NUM>.

Moreover, as illustrated in <FIG>, if the array member <NUM> is pulled out toward the front side of the drum <NUM>, the middle portion and a rear portion of the V rail <NUM> are supported by the V rollers <NUM>.

A clearance of <NUM> or less is arranged between the support flat roller <NUM> and the supported flat rail <NUM>.

For example, if the state illustrated in <FIG> is shifted to the state illustrated in <FIG>, the center of gravity G of the array member <NUM> is displaced from a position between the V rollers <NUM> which support the V rail <NUM> at two locations in a longitudinal direction of the array member <NUM>, and moves to a farther rear side than the V roller <NUM> on the rear side. Accordingly, as illustrated in <FIG>, a rotational moment is generated such that the end portion on the front side of the array member <NUM> is lifted and the end portion on the rear side is lowered.

In other words, a rotational moment in a clockwise direction (CW direction) is generated in the array member <NUM> as seen from the right side of the array member <NUM> illustrated in <FIG>, and the array member <NUM> is inclined in the width direction of the drum <NUM>. As a result, when the adjustment roller <NUM> pushes the side surface of the array member <NUM> to adjust an angle, the tip of the V roller <NUM> does not function as a fulcrum. That is, angle adjustment accuracy of the head array <NUM> is degraded.

As described with reference to <FIG>, the rotational moment due to displacement of the center of gravity degrades the function as the first supports formed by the V rollers <NUM> separately disposed in two locations in a longitudinal direction of the array member <NUM>. To prevent a such a case, the head array <NUM> according to the present embodiment, as illustrated in <FIG>, includes a structure by which the pressing flat roller <NUM> urges the adjustment flat rail <NUM> downward. Hereinafter, the urging structure of the pressing flat roller <NUM> is described.

Each of <FIG> is a diagram illustrating the urging structure of the flange <NUM>. <FIG> is a right-side view illustrating one portion of the head array <NUM> from the same direction as <FIG>. Since the urging structure is disposed on a left surface of the flange <NUM> as illustrated in <FIG>, a description of the urging structure is mainly given with reference to <FIG>.

As illustrated in <FIG>, the pressing flat roller <NUM> is disposed on a swing arm <NUM>. The pressing flat roller <NUM> is rotatable with respect to the swing arm <NUM>. The swing arm <NUM> rotates about a rotation center <NUM> as a spindle fixed to the flange <NUM>. The swing arm <NUM> is urged by an elastic member <NUM> in a CCW direction in <FIG> with respect to the flange <NUM> disposed on the front side of the array member <NUM>.

The elastic member <NUM> is, for example, a tension spring. One end portion of the elastic member <NUM> is fixed to an end portion of the swing arm <NUM>, and the other end portion of the elastic member <NUM> is fixed to a fixation portion <NUM> disposed on one portion of the flange <NUM>.

An urging force of the elastic member <NUM> as an urging member can be set according to size of an inclination angle of the array member <NUM> with respect to a radial direction of the drum <NUM>. For example, if a plurality of array members <NUM> has different inclination angle, an elastic member <NUM> that provides an urging force necessary for an array member <NUM> having a larger inclination angle can be used.

As described above, if the center of gravity is positioned in the rear of the array member <NUM>, a rotational moment by which the front (the front side) of the array member <NUM> tends to rotate in a CW direction in <FIG> is generated. Since the urging by the elastic member <NUM> is applied in an opposite direction with respect to the rotational moment, the pressing flat roller <NUM> attached to the swing arm <NUM> is pressed against the adjustment flat rail <NUM>.

As a result, the adjustment flat rail <NUM> is pushed downward, and the V rail <NUM> is pushed against the V roller <NUM> of the flange <NUM>.

With such action, the contact of the V roller <NUM> with the V rail <NUM> becomes reliable, and thus a contact position of the V rail <NUM> with respect to the V roller <NUM> can function as a rotation fulcrum of the array member <NUM>. As a result, when a lower portion of the array member <NUM> is pushed sideward by using the adjustment roller <NUM>, the accuracy of the rotation of the array member <NUM> can be enhanced, and the accuracy of the rotation angle adjustment of the array member <NUM> can be enhanced. Hence, an axial center of the array member <NUM> can be adjusted with good accuracy.

A position of the center of gravity of the array member <NUM> changes depending on a configuration such as the control board <NUM>, a power circuit, and wiring to be arranged. Thus, an urging force can be adjusted according to movement of the position of the center of gravity. For example, the elastic member <NUM> may be changed to change an urging force to an appropriate value, or a position of the fixation portion <NUM> may be changed to adjust an urging force.

The greater the inclination angle of the array member <NUM>, the greater the lift-up amount of the V rail <NUM> with respect to the V roller <NUM>. Accordingly, an urging force (a pressing force) by the elastic member <NUM> needs to be increased. If an urging force is set to an urging force necessary for an array member <NUM> having a larger inclination angle, a functional effect of the pressing member can be obtained in all the array members <NUM> regardless of inclination angles.

A structure of the adjustment roller <NUM> is described in detail with reference to <FIG> is a diagram illustrating a cross section of the right surface side of the adjustment roller <NUM>. <FIG> is a cross-sectional view of the adjustment roller <NUM>.

As illustrated in <FIG>, the adjustment roller <NUM> is disposed to be slidable in a front direction and a depth direction in an adjustment roller groove <NUM> formed inside the flange <NUM>. The adjustment roller <NUM> is configured such that an amount of projection toward the adjustment flat rail <NUM> of the array member <NUM> from a side of the flange <NUM> changes according to an amount of movement toward a depth direction from the front side.

As illustrated in <FIG>, the adjustment roller <NUM> includes a moving roller <NUM> that is rotatably disposed with respect to a roller moving wedge <NUM> inside the adjustment roller groove <NUM>. The roller moving wedge <NUM> has a wall against which a wedge pressing screw <NUM> is pressed. In addition, a wedge return screw <NUM> is screwed into the roller moving wedge <NUM>.

As illustrated in <FIG>, if the wedge pressing screw <NUM> is screwed, the roller moving wedge <NUM> is pushed, and the adjustment roller groove <NUM> moves in the depth direction. The roller moving wedge <NUM> has a shape that is tapered from the front side toward the depth direction, and an inclined surface of the roller moving wedge <NUM> is in contact with a spindle (a rotation shaft) of the moving roller <NUM>. Thus, if the roller moving wedge <NUM> is moved in the depth direction, the inclined surface of the roller moving wedge <NUM> pushes the spindle of the moving roller <NUM> toward the adjustment flat rail <NUM>.

That is, a projection amount of the moving roller <NUM> changes according to a screwing amount of the wedge pressing screw <NUM>. In a case where a projection amount of the moving roller <NUM> is reduced to move the moving roller <NUM> away from the adjustment flat rail <NUM>, a screwing amount of the wedge return screw <NUM> can be adjusted.

Therefore, since the adjustment roller <NUM> can adjust a pushing amount for the adjustment flat rail <NUM> with good accuracy, a rotation angle of the array member <NUM> can be adjusted with good accuracy.

As illustrated in <FIG>, a moving roller 1131a as a device that adjusts a projection amount of the adjustment roller <NUM> may be disposed on an eccentric shaft <NUM> disposed in a vertical direction of the flange <NUM>. In such a case, adjustment of a rotation angle of the eccentric shaft <NUM> can adjust a projection amount of the moving roller <NUM>.

Next, the V roller <NUM> as an angle adjuster disposed in the head array <NUM> according to the present embodiment is further described.

As described above, the array member <NUM> of the head array <NUM> is inserted between the flanges <NUM> which are arranged in a state in which the flanges <NUM> are inclined at predetermined angles relative to a horizontal plane. Thus, as illustrated in <FIG>, the array member <NUM> is inclined at an angle corresponding to the insertion location, and a load of the array member <NUM> is supported while the inclination state is being retained by the V roller <NUM> and the support flat roller <NUM>. Herein, the adjustment roller <NUM> is separated from the adjustment flat rail <NUM> disposed in the array member <NUM>.

Immediately after insertion of the array member <NUM>, a load of the supported flat rail <NUM>, which is supported by the support flat roller <NUM>, with respect to the support flat roller <NUM> is applied as illustrated in <FIG> in which a surface direction component force Fh as a component force of an array load F by a weight of the array member <NUM> is applied.

Moreover, as illustrated in <FIG>, an inclined surface direction component force Fv is applied to the V roller <NUM> by the array load F.

Then, as illustrated in <FIG>, a resultant force Fz of the surface direction component force Fh and the inclined surface component force Fv causes an inclined surface component force Fzv that is applied to the inclined surface of the V roller <NUM> to be directed toward the outside of the V roller <NUM> as indicated by a broken-line arrow. The inclined surface component force Fzv, as illustrated in <FIG>, is a force that acts such that the V rail <NUM> slides outward from the V roller <NUM>.

Thus, an angle of the inclined surface of the V roller <NUM> needs to be defined to prevent removal of the V rail <NUM> from the V roller <NUM> due to the inclined surface component force Fzv.

An angle of one of the inclined surfaces of the V roller <NUM> needs to be defined. Accordingly, an inclination angle with respect to a horizontal plane of the array member <NUM> is set "θ", and a half value of the inclined surface of the V roller <NUM> is set to "α". In this case, an angle "β" that is used for calculation of the inclined surface direction component force Fv of the V roller <NUM> is calculated by Expression <NUM>.

Using Expression <NUM>, a V roller inclined surface limit angle "λ" as an angle to be a threshold value at which the V rail <NUM> is not removed from the V roller <NUM> is calculated by Expression <NUM>.

According to Expression <NUM>, a lower limit of a threshold angle is "<NUM> degrees".

If an angle of a tip portion of the V roller <NUM> is set between <NUM> degrees to <NUM> degrees, an upper limit of the inclination angle of the V roller <NUM> is estimated to be <NUM> degrees. In this case, if Expression <NUM> is used to calculate an upper limit of a threshold angle, Expression <NUM> is provided.

According to Expression <NUM>, an upper limit of the threshold angle is "<NUM> degrees". Thus, the upper limit is roughly <NUM> degrees.

Therefore, a preferable value of the V roller inclined surface limit angle "λ" as an angle in a range within which the V rail <NUM> is not removed from the V roller <NUM> falls within a range of <NUM> degrees to <NUM> degrees.

In the head array <NUM> according to the present embodiment, even if the array member <NUM> is inclined at <NUM> degrees or more, the V rail <NUM> is not removed from the V roller <NUM> as long as an inclination angle of the inclined surface of the V roller <NUM> as the first support is <NUM> degrees or greater relative to a horizontal plane.

An angle of the V roller <NUM> is suitably greater than an angle formed by the two inclined surfaces of the V rail <NUM>. A tip of the V rail <NUM> provided in a groove of the V roller <NUM> serves as a rotation fulcrum to suitably swing the array member <NUM>.

The V roller <NUM> disposed in the head array <NUM> according to the present embodiment is further described with reference to <FIG>. As described above, a value of the V roller inclined surface angle "λ" can be set to a range of <NUM> degree to <NUM> degrees. Such a value of "λ" is, as described above, adjusted and set according to a movement amount of the adjustment roller <NUM>.

The adjustment roller <NUM> is moved in a direction indicated by an arrow A illustrated in <FIG> to adjust the axial center of the array member <NUM>. Accordingly, a force in a direction indicated by an arrow B with respect to the V roller <NUM> is applied to the V rail <NUM>. As a result, a force in a direction indicated by an arrow C is applied to the V roller <NUM> as a rotator. The arrow C represents a direction moving away from a rotation shaft. That is, if an axial center of the array member <NUM> is adjusted using the adjustment roller <NUM>, rotation of the array member <NUM> applies a force to the V rail <NUM> supported by the V roller <NUM> in a direction away from the flange <NUM>.

After the axial center adjustment using the adjustment roller <NUM> is finished, the array member <NUM> is supported by the V roller <NUM> and the adjustment roller <NUM>, and a load of the array member <NUM> is barely applied to the support flat roller <NUM>. Thus, the support flat roller <NUM> and the supported flat rail <NUM> are simply in contact with each other or are separated with several millimeters.

In such a state, if a force in a rotation axis direction of the V roller <NUM> is being applied to the V roller <NUM>, rotation of the V roller <NUM> is hindered. That is, the V roller <NUM> enters "a non-smooth rotation" state. Since the force is applied in a direction in which the V rail <NUM> is pressed against the V roller <NUM> to adjust an angle of the array member <NUM>, the V roller <NUM> desirably makes smooth rotation.

Thus, the V roller <NUM> according to the present embodiment as illustrated in <FIG> includes a locking brim <NUM> as a movement restrictor on an end portion of the rotation shaft. The locking brim <NUM> restricts movement of the V roller <NUM> toward the rotation axis direction. In addition, a slide member <NUM> is disposed between the locking brim <NUM> and a side surface of the V roller <NUM> to avoid hindrance of smooth rotation of the V roller <NUM> due to friction with the locking brim <NUM>. The slide member <NUM> is disposed such that a friction coefficient becomes smaller than a metal-to-metal friction coefficient.

For the slide member <NUM>, a thrust bearing or a slide bearing can be used. The use of the slide member <NUM> can prevent an increase in friction resistance due to an external force (a force toward the rotation axis direction) to the V roller <NUM> by adjustment of an angle of the array member <NUM>.

As described above, in the discharge array according to the present embodiment, since adjustment of the axial center of the array member <NUM> applies a force to the V roller <NUM> as the first support in a direction moving away from the rotation shaft, the locking brim <NUM> and the slide member <NUM> are disposed to the V roller <NUM>. Such a configuration can eliminate or reduce an increase in friction resistance and enables the array member <NUM> to be pulled out more easily while preventing the V roller <NUM> from moving away.

The description has been given based on the premise that contact of the V rail <NUM> with the V roller <NUM> represents a case in which a tip portion of the V rail <NUM> contacts a valley portion surrounded by two inclined surfaces of the V roller <NUM> as a point. However, contact of the V rail <NUM> with the V roller <NUM> is not limited thereto.

For example, as illustrated in <FIG>, in a longitudinal section of the V roller <NUM>, a valley portion surrounded by two inclined surfaces of the V roller <NUM> may be flat. In such a case, a tip portion of the V rail <NUM> can have a rounded curved shape that is rounded from a sharp tip shape.

In such a case, the V rail <NUM> contacts not only the inclined surface of the V roller <NUM> as a point, but also the flat area of the valley portion as a point, that is, the V rail <NUM> contacts the V roller <NUM> at two locations. As a result, even if a force that presses the V rail <NUM> against the V roller <NUM> is generated, a load to the V roller <NUM> can be reduced.

Moreover, since the V rail <NUM> is supported by the flat area of the V roller <NUM>, a position of the V rail <NUM> in a height direction can be determined.

Therefore, in the head array <NUM> according to the present embodiment, a tip portion of the V rail <NUM> that contacts a groove of the V roller <NUM> has a round shape, so that a contact area can be increased. As a result, a load to the bottom of the V roller <NUM> can be reduced.

In addition, the V rail <NUM> is supported by a flat area of the V roller <NUM>, so that the V rail <NUM> can be positioned in a height direction (a direction indicated by an arrow D in <FIG>) and an operator can determine the correct position of the V rail <NUM> in the height direction. The V rail <NUM> is also supported by an inclined surface of the V roller <NUM>, so that a force can be dispersed. As a result, a load to the V roller <NUM> can be reduced.

The present disclosure has been described above with reference to specific embodiments but is not limited thereto. Various modifications and enhancements are possible without departing from scope of the appended claims.

Claim 1:
A liquid discharge head angle adjuster (<NUM>) for individually adjusting inclination angles of a plurality of liquid discharge heads (<NUM>), the liquid discharge head angle adjuster comprising:
a plurality of array members (<NUM>) configured to hold the liquid discharge heads; and
a plurality of array supports (<NUM>) configured to support the array members (<NUM>), with each array member located between two array supports;
at least one of the plurality of array members (<NUM>) including a V rail (<NUM>);
at least one of the plurality array supports including
a first support (<NUM>) disposed on one side in a direction in which one of the liquid discharge heads is rotated when an inclination angle of the one of the liquid discharge heads is adjusted, and configured to support the V rail (<NUM>), with contact between the first support (<NUM>) and the V rail (<NUM>) functioning as a rotation fulcrum of the at least one of the plurality of array members; and
a second support (<NUM>) disposed on a side opposite the first support and configured to support another of the array members; and characterized in that
the at least one of the plurality of array supports further includes a pressing member (<NUM>) configured to press the V rail (<NUM>) against the first support (<NUM>) at the rotation fulcrum.