JPWO2016186014A1 - Droplet discharge head, droplet discharge head unit, image forming apparatus, and method of mounting droplet discharge head - Google Patents

Abstract

An object of the present invention is to provide a droplet discharge head or the like that has high landing position accuracy of droplets on a recording medium and that can be easily adjusted in position. The droplet discharge head 2 of the present invention is detachably attached to the holding unit 3 of the image forming apparatus, and makes contact with a position reference pin 4 provided on the holding unit 3 to adjust the position of the droplet discharge head 2. In the droplet discharge section 21 facing the recording surface of the recording medium K, the first direction D1 perpendicular to the relative movement direction of the recording medium K and the droplet discharge head 2 and the first direction D1 When a plurality of nozzles n arranged two-dimensionally in the intersecting second direction D2 and the position reference pin 4 are brought into contact with each other, the droplet discharge head 2 is discharged from the center of the reference nozzle Sn. The position is fixed so that the perpendicular line dropped on the first rotation shaft 41 for adjusting the position in the rotation direction rotating around the direction perpendicular to the portion 21 and the first direction D1 are in a predetermined condition. And a unit 23.

Description

  The present invention relates to a droplet discharge head, a droplet discharge head unit, an image forming apparatus, and a method for mounting a droplet discharge head.

  2. Description of the Related Art Conventionally, an ink jet recording apparatus that forms an image on a recording medium by discharging ink droplets from a plurality of nozzles provided in a droplet discharge head is known.

  In recent years, with the increase in accuracy of images formed by an ink jet recording apparatus, a plurality of nozzles provided in a droplet discharge head are arranged at high density. Therefore, when the holding position of the droplet discharge head is shifted with respect to the holding portion that holds the droplet discharge head, there is a problem that streaks or unevenness occurs in the formed image and the image deteriorates. Therefore, it is required to position the droplet discharge head with high accuracy with respect to the holding unit.

  Therefore, as a method of positioning the droplet discharge head with high accuracy, for example, the V-groove portion of the droplet discharge head is brought into contact with a position reference pin (tip reference pin) fixed to a holding portion (carriage), and the position reference A method for adjusting the position of a droplet discharge head by rotating the droplet discharge head around a pin is disclosed (see Patent Document 1).

Japanese Patent No. 4892846

  By the way, when mounting the droplet discharge head on an image forming apparatus such as an ink jet recording apparatus, among the many nozzles provided in the droplet discharge head, the nozzle arranged at the end in the print width direction is used as a reference nozzle. First, the position of the reference nozzle is adjusted. Next, in order to adjust the print width, for example, the position of the droplet discharge head is adjusted by rotating the droplet discharge head around a position reference pin or the like fixed to the apparatus side.

  However, in the droplet discharge head as in Patent Document 1, the position of the reference nozzle is slightly shifted when the droplet discharge head is rotated after alignment with the reference nozzle. For this reason, when printing is performed with the reference nozzle slightly shifted, there is a problem that the formed image is streaked or uneven and the image deteriorates. In particular, such a problem has become more prominent in a liquid droplet ejection head in which a large number of recent nozzles are positioned with high accuracy.

  The present invention has been made in view of such a problem, and has a liquid droplet ejection head, a liquid droplet ejection head unit, an image forming apparatus, and a liquid droplet landing head that has high landing position accuracy with respect to a recording medium and can be easily adjusted. A method for mounting a droplet discharge head is provided.

In order to solve the above problems, the invention described in claim 1
A droplet discharge head that is detachably attached to a holding unit of an image forming apparatus and performs position adjustment by contacting a position reference unit provided in the holding unit,
On a nozzle forming surface facing the recording surface of the recording medium, a first direction orthogonal to the relative movement direction of the recording medium and the droplet discharge head and a second direction intersecting the first direction A plurality of nozzles arranged two-dimensionally;
When contacting the position reference portion, the position of the droplet discharge head is adjusted from the center of the reference nozzle of the plurality of nozzles in a rotation direction that rotates about a direction perpendicular to the nozzle formation surface. A position fixing portion arranged so that a perpendicular line to the first rotation shaft for the first direction and the first direction are a predetermined condition;
It is characterized by providing.

According to a second aspect of the present invention, in the liquid droplet ejection head according to the first aspect,
The reference nozzle is a nozzle located at an end of the nozzle forming surface on the position fixing portion side.

According to a third aspect of the present invention, in the liquid droplet ejection head according to the second aspect,
The reference nozzle is a nozzle located at an end portion in a third direction orthogonal to the first direction of the nozzle forming surface.

According to a fourth aspect of the present invention, in the liquid droplet ejection head according to any one of the first to third aspects,
The second direction is a direction in which the relative moving direction is inclined in the first direction,
Two nozzles that form dots adjacent in the first direction are arranged so as not to be adjacent in the second direction, and are orthogonal to the first direction of the two-dimensionally arranged nozzles It arrange | positions so that it may not isolate | separate into the one end part and other end part in a 3rd direction.

The invention described in claim 5
A liquid droplet ejection head according to any one of claims 1 to 4,
A droplet discharge head unit comprising: the holding unit that detachably holds the droplet discharge head.

According to a sixth aspect of the present invention, in the liquid droplet ejection head unit according to the fifth aspect,
The position fixing portion has a V-groove portion,
The holding portion includes the position reference portion that contacts the V-groove portion.

The invention according to claim 7 is the liquid droplet ejection head unit according to claim 5 or 6,
A housing having a shaft member having a second rotating shaft;
A rotation adjusting unit that contacts the housing and adjusts the rotation of the housing;
A position adjusting unit that is provided in the housing and adjusts a holding position of the droplet discharge head with respect to the holding unit in contact with the droplet discharge head;
With
The following formula (1) is satisfied.

(Where d ₁ represents the distance from the center of the shaft member to the contact portion of the rotation adjusting portion and the housing. Θ ₁ passes through the center of the shaft member and the moving direction of the droplet discharge head) .d ₂ representing the angle of to the contact portion of the housing and the rotary adjuster from an axis parallel to represent the distance from the center of the shaft member to the reference site as a reference of position movement in the position adjusting section .Shita ₂ represents the angle from the axis parallel to the moving direction of said axis around the street the droplet discharge head member to the reference site.)

The invention according to claim 8 is the droplet discharge head unit according to claim 7,
Either the tip of the position adjusting unit or the contact portion of the droplet discharge head with which the position adjusting unit abuts has a spherical shape.

  A ninth aspect of the present invention is an image forming apparatus comprising the droplet discharge head unit according to any one of the fifth to eighth aspects.

The invention according to claim 10 is:
A method for mounting a droplet discharge head, wherein the droplet discharge head according to any one of claims 1 to 4 is mounted on the holding unit.
Position adjustment in the rotational direction with respect to an axis perpendicular to the nozzle forming surface is performed by rotating the position reference portion as an axis while contacting the position fixing portion and the position reference portion. It is characterized by.

  According to the present invention, the droplet landing position accuracy with respect to the recording medium is high, and the position adjustment can be easily performed.

1 is a perspective view illustrating a schematic configuration of an image forming apparatus. Perspective view of droplet discharge head unit Bottom view of droplet discharge head unit Top view of droplet discharge head unit Bottom view of droplet discharge head Explanatory drawing of nozzle arrangement of comparative example Explanatory drawing which shows arrangement | positioning of the nozzle in a nozzle formation area Explanatory drawing which shows the other example of arrangement | positioning of the nozzle in a nozzle formation area. Explanatory drawing explaining the positional relationship between the position reference pin and the reference nozzle Explanatory drawing explaining arrangement | positioning of a reference nozzle when the perpendicular from the center of a reference nozzle to a 1st rotating shaft becomes a main scanning direction and predetermined conditions. Right side view of droplet discharge head unit Schematic diagram for explaining the positional relationship between the position adjustment unit and the adjustment screw Schematic diagram for explaining the position adjustment mechanism in the adjustment unit Graph showing the relationship between the amount of movement of the adjustment screw and the amount of position adjustment displacement

Hereinafter, preferred embodiments of the present invention (hereinafter also referred to as “present embodiments”) will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. Moreover, in the following description, about what has the same function and structure, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
In the following description, an embodiment of a one-pass drawing method in which drawing is performed only by transporting a recording medium using a line head will be described as an example. However, the embodiment can be applied to an appropriate drawing method. A drawing method using a method or a drum method may be adopted.
In the following description, the conveyance direction (sub-scanning direction Y) of the recording medium K is the front-rear direction, and the print width direction (main scanning direction X) orthogonal to the conveyance direction on the conveyance surface of the recording medium K is the left-right direction. The direction perpendicular to the direction and the left-right direction will be described as the up-down direction.

[Outline of image forming apparatus]
The image forming apparatus 100 includes a platen 101, a conveyance roller 102, line heads 200, 201, 202, 203, and the like (FIG. 1).
The platen 101 supports the recording medium K on the upper surface, and transports the recording medium K in the transport direction (front-rear direction) when the transport roller 102 is driven.
The line heads 200, 201, 202, and 203 are provided in parallel in the width direction (left-right direction) orthogonal to the transport direction from the upstream side to the downstream side in the transport direction (front-rear direction) of the recording medium K. In the line heads 200, 201, 202, and 203, at least one droplet discharge head unit 1 described later is provided. For example, cyan (C), magenta (M), yellow (Y), Black (K) ink is ejected toward the recording medium K.

[Droplet discharge head unit]
The droplet discharge head unit 1 includes a droplet discharge head 2, a holding unit 3 that detachably holds the droplet discharge head 2, and a position reference unit that fixes the droplet discharge head 2 to the holding unit 3 so as to be rotatable. As a position reference pin 4 and an adjustment unit 5 for adjusting the position of the droplet discharge head 2 (see FIGS. 2 to 4 and the like).

  The droplet discharge head unit 1 is configured to be detachably held by the holding unit 3 such that the bottom surface of the droplet discharge head 2 is exposed from the opening of the holding unit 3. The holding unit 3 holds a plurality of droplet discharge heads 2 so as to form a staggered pattern as a whole. Specifically, for example, three droplets in the left-right direction and two droplets in the front-rear direction are used. The discharge head 2 is held.

[Droplet ejection head]
The droplet discharge head 2 includes a droplet discharge portion 21 as a nozzle formation surface in which a plurality of nozzles n that discharge droplets are arranged on the bottom surface, an ink chamber 22 that supplies ink to each of the plurality of nozzles n, An ink supply unit 221 that supplies ink to the ink chamber 22 and an ink discharge unit 222 that discharges ink from the ink chamber 22 are configured.
The droplet discharge section 21 has a pressure chamber (not shown) corresponding to each nozzle n inside, and is supplied with ink from the ink chamber 22 to the pressure chamber. When the element (not shown) is displaced and the ink in the pressure chamber is pressurized, ink droplets are ejected from the nozzle n.

The droplet discharge head 2 is opposed to a position fixing portion 23 as a fixing portion provided on one side surface parallel to the droplet discharge direction (vertical direction), and a side surface on which the position fixing portion 23 is provided. The positioning part 25 provided in the side surface is provided (refer FIG. 4 etc.).
FIG. 4 is an enlarged view of the right front portion of the droplet discharge head unit 1 shown in FIG. 2 for convenience of explanation.

The position fixing portion 23 has a V-groove portion 24 and is configured to be able to abut the V-groove portion 24 against a position reference pin 4 as a position reference portion fixed to the holding portion 3. . Further, the position fixing portion 23 is pressed by the elastic member 31 as the urging means provided in the holding portion 3 in the direction of abutting against the position reference pin 4 and fixed by the contact portion (first contact portion T1). The droplet discharge head 2 is fixed so as to be rotatable along the axis of the position reference pin 4. Then, the droplet discharge head 2 is adjusted in position in the rotation direction about the first rotation shaft 41 that is an axis passing through the center of the position reference pin 4 as a rotation axis.
The form of the position reference pin 4 can be selected as appropriate as long as the position fixing portion 23 can stably come into contact. For example, as shown in FIG. 4, the distance from the first rotation shaft 41 to the outer periphery may be a constant perfect circle in the cross section in the front-rear and left-right directions, and the distance from the first rotation shaft 41 to the circumference It is good also as the form (illustration omitted) of the plate cam which is not constant. When the plate cam is used, the rotation axis of the plate cam is the first rotation axis.

  The positioning unit 25 is abutted against a position adjusting unit 51 of the adjusting unit 5 described later, and in a direction of abutting against the position adjusting unit 51 by an elastic member 32 as an urging means provided in the holding unit 3. It is pressed and fixed by the contact portion (second contact portion T2). The positioning unit 25 can be moved in the front-rear direction with respect to the holding unit 3 by moving the position adjusting unit 51 in the front-rear direction.

[Nozzle arrangement]
Next, based on FIGS. 5-8, a preferable form is demonstrated about the example of arrangement | positioning of the nozzle n formed in the droplet discharge part 21. FIG.

As shown in FIG. 5, each nozzle n is parallel to a first direction D1 parallel to the main scanning direction X and a second direction D2 slightly inclined from the sub-scanning direction Y to the main scanning direction X. The four nozzle formation areas N1 to N4 having a parallelogram shape are arranged in a matrix along the first direction D1 and the second direction D2.
The four nozzle formation areas N1 to N4 are all parallelograms that are long along the main scanning direction X, and have the same direction and size. These nozzle formation areas N1 to N4 are arranged in a predetermined order along the sub-scanning direction Y. This order will be described later.

  The droplet discharge head 2 can form dots with a dot pitch dpx in the main scanning direction X and a dot pitch dpy in the sub-scanning direction Y (not shown for control setting values). All the nozzles n formed in the droplet discharge unit 21 are individually applied to all the dots D formed at the dot pitch dpx along the main scanning direction X within the dot formation possible range of the droplet discharge head 2. It corresponds.

Here, the dispersed arrangement of each nozzle n will be described with reference to FIG. FIG. 6 is a comparative example in which the order in which the nozzle formation areas N1 to N4 are arranged differs from that in FIG. 5 in order to explain the dispersion arrangement of the nozzles n of the present invention shown in FIG.
Note that in FIG. 6, numbers in circles indicate the arrangement of the nozzles n when the droplet discharge unit 21 is viewed from below. The numbers in the circles indicate what number of dots D are ejected from the upstream end (the left end in FIG. 6) in the main scanning direction X among the dots D in which the nozzle n is arranged along the main scanning direction X. It shows.
In FIG. 6 and FIGS. 7 and 8 to be described later, in order to facilitate understanding, the inclination angle of the second direction D2 with respect to the sub-scanning direction Y is increased.

  By the way, when two nozzles n and n that form adjacent dots D and D in the main scanning direction X are arranged close to each other, when resonance occurs due to ink discharge, the discharge speed of the other adjacent nozzle n is set to be the same. This causes the image quality to deteriorate. For this reason, it is desirable that the two nozzles n, n forming the adjacent dots D, D are dispersedly arranged so as not to have the same nozzle formation area.

  Here, if the two nozzles n, n forming the adjacent dots D, D are arranged so as not to be simply the same nozzle formation area, as in the comparative example of FIG. For the nozzle formation areas N1 to N4 arranged in order in Y, the nozzles n corresponding to the dot arrangement order are arranged in order. That is, the nozzle n corresponding to the 4k + 1th dot is arranged in the nozzle formation area N1, and the nozzle n corresponding to the 4k + 2nd dot is arranged in the nozzle formation area N2, corresponding to the 4k + 3rd dot. The nozzles n are arranged in the nozzle formation area N3, and the nozzles n corresponding to the 4k + 4th dot are arranged in the nozzle formation area N4 (where k = 0, 1, 2, 3,...).

That is, within each nozzle formation area N1 to N4, a prescribed number (for example, eight) of nozzles n are arranged along the second direction D2 so that the arrangement order of the dots is four, and the prescribed number of nozzles. A predetermined number (for example, 32) of n nozzle rows is formed at regular intervals along the first direction D1.
In each of the nozzle formation areas N1 to N4, the nozzle pitches of the nozzles n and n adjacent along the second direction D2 are npx in the main scanning direction X and npy in the sub-scanning direction Y.
The nozzle pitch npx in the main scanning direction X is four times the dot pitch dpx in the main scanning direction X because the dot arrangement order skips four.
The nozzle pitch npy in the sub-scanning direction Y is arbitrary, but is set to an integer multiple of the dot pitch dpy in the sub-scanning direction Y from the relationship between the conveyance speed of the recording medium K and the synchronization of the ink ejection timing of each nozzle n. It is desirable.
The second direction D2 is θ = tan ⁻¹ (npx / npy), where θ is an inclination angle with respect to the sub-scanning direction Y.
Further, by assigning the nozzles n corresponding to the arrangement order of the dots D by the above method, the end positions in the main scanning direction X of the nozzle forming areas N1 to N4 are sequentially arranged from the nozzle forming area N1 in the main scanning direction X. In this arrangement, the dot pitch dpx is offset on the downstream side.

  When the nozzles n are distributed in order to the four nozzle formation areas N1 to N4 in accordance with the arrangement order of the dots D in the main scanning direction X, the two nozzles n and n adjacent to the dots belong to different nozzle formation areas. It becomes. Thereby, it is possible to avoid the adjacent arrangement of the nozzles, reduce the influence on the other nozzles n due to the resonance from the nozzles n, and avoid the deterioration of the image quality.

However, in the nozzle arrangement of FIG. 6, the order in which the nozzles n are allocated according to the dot arrangement order matches the arrangement order in the sub-scanning direction Y of the nozzle formation areas N1 to N4. In some cases, two adjacent nozzles n and n are arranged farthest in the sub-scanning direction Y within the overall area including the four nozzle formation areas N1 to N4.
For example, the nozzle n of the 32nd dot and the 33rd nozzle n, the nozzle n of the 64th dot and the 65th nozzle n correspond to this.
As described above, when the two nozzles n and n having dots adjacent to each other in the main scanning direction X are arranged apart from each other in the sub-scanning direction Y, the droplet discharge head 2 is attached to the line heads 200, 201, 202, and 203. When the droplet discharge head 2 is tilted due to an attachment error or the like, the amount of misalignment of the dots D and D in the main scanning direction X increases, resulting in a deterioration in image quality.

Therefore, in the droplet discharge head 2 according to the embodiment of the present invention, the arrangement order of the sub-scanning directions Y of the nozzle formation areas N1 to N4 formed in the droplet discharge unit 21 is changed, and adjacent to each other in the main scanning direction X. The two nozzles n and n forming the dots D and D are separated into an upstream end in the sub-scanning direction Y and a downstream end in the sub-scanning direction Y within a range including all the nozzle formation areas N1 to N4. Arranged not to be.
FIG. 7 is a plan view of the droplet discharge unit 21 showing the arrangement of the nozzles n in which the arrangement order in the sub-scanning direction Y of each of the nozzle formation areas N1 to N4 is changed. In FIG. 7, the numbers written inside the nozzle formation areas N <b> 1 to N <b> 4 indicate the arrangement of the nozzles n and the number of dots D that the nozzles n eject from the upstream side in the main scanning direction X.

In the droplet discharge section 21 of the droplet discharge head 2, nozzle formation areas are arranged in the order of N1, N4, N2, and N3 from the upstream side in the sub-scanning direction Y.
In this order, the nozzle n corresponding to the 32k + 31st dot is arranged at the most downstream end in the sub-scanning direction Y in the region including all the nozzle formation areas N1 to N4, and the sub-scanning direction Y The nozzles n corresponding to the 32k + 1-th dot are arranged at the most upstream end (where k = 0, 1, 2, 3,...).
Accordingly, the nozzle n at one end in the sub-scanning direction and the nozzle n at the other end in the entire region including the plurality of nozzle formation areas N1 to N4 are arranged so that the dots D to be formed are not adjacent to the main scanning direction X. .

The arrangement order of the nozzle formation area in the sub-scanning direction Y is not limited to the order of N1, N4, N2, and N3, and the most downstream nozzle formation area and the most upstream nozzle formation area in the sub-scanning direction Y are: Other orders may be used as long as they do not coincide with the order in which the nozzles n corresponding to the dot arrangement order are allocated.
That is, the most downstream nozzle formation area and the most upstream nozzle formation area in the sub-scanning direction Y may be N1-N2, N2-N3, N3-N4, or N4-N1.

  Although all nozzle formation areas have the same orientation, the present invention is not limited to this. For example, as shown in FIG. 8, nozzle formation areas NA3 and NA4 in which the directions of the nozzle formation areas N3 and N4 in FIG. 7 are changed may be used.

Specifically, as shown in FIG. 8, with respect to the nozzle formation areas NA3 and NA4, the outer shapes of the nozzle formation areas N3 and N4 in FIG. 7 and the arrangement of the nozzles n are reversed around the axis along the main scanning direction X. It is good also as the structure made to do. Even when the arrangement of the nozzles n is reversed in this way, the arrangement of the nozzles n in the sub-scanning direction Y does not change, so the correspondence between the order of the dots D in the main scanning direction X and the nozzles n is maintained.
Then, by arranging these nozzle formation areas in the order of N1, N2, NA4, and NA3 from the upstream side in the sub-scanning direction Y, the nozzles n and n adjacent to the dots D and D are arranged as in the example of FIG. While avoiding the adjacent arrangement, the nozzles n and n adjacent to the dots D and D are arranged at the downstream end and the upstream end in the sub-scanning direction Y in the entire nozzle formation areas N1, N2, NA4, and NA3. It can be avoided that the arrangement is far away.

[Position fixing part]
The position fixing part 23 has a V-groove part 24 and is configured to be able to abut the V-groove part 24 against the position reference pin 4. Further, the position fixing unit 23 is pressed by the elastic member 31 provided in the holding unit 3 in a direction in which the position fixing unit 23 abuts against the position reference pin 4 and is fixed by the first contact unit T1, and the droplet discharge head 2 is fixed. It is fixed so as to be rotatable along the axis of the position reference pin 4 (see FIG. 4).
Further, the position fixing unit 23 is configured such that when the position fixing unit 23 is brought into contact with the position reference pin 4, a perpendicular line dropped from the center of the reference nozzle Sn to the first rotation shaft 41 and the main scanning direction X (first direction). D1) and the predetermined conditions are arranged (see FIG. 5). The predetermined condition will be described later. First, in the most preferred form, the perpendicular line dropped from the center of the reference nozzle Sn to the first rotation shaft 41 and the main scanning direction X (first direction D1) are completely parallel. The reference nozzle Sn will be described with reference to FIG.

  In the present invention, the reference nozzle Sn is a nozzle that serves as a reference for alignment. Position adjustment in the rotational direction about the vertical direction of the droplet discharge head 2 is performed by first adjusting the position of the reference nozzle Sn and then discharging the droplet with the position reference pin 4 as an axis in order to adjust the print width. Position adjustment in the rotation direction of the head 2 is performed.

The reference nozzle Sn can be arbitrarily selected from the nozzles n provided in the droplet discharge unit 21, but from the viewpoint of easier alignment, the nozzle n located at the end on the position fixing unit 23 side. It is preferable that Further, from the same viewpoint, it is more preferable that the end portion is on the side of the position fixing portion 23 and the end portion in the sub-scanning direction Y.
Specifically, in FIG. 7 showing the nozzle arrangement of the present invention, the first to fourth nozzles n are preferable, and the first nozzle is more preferable.
In FIG. 5, the first nozzle is set as the reference nozzle Sn, and the position fixing unit 23 is set so that the perpendicular line dropped from the center of the reference nozzle Sn to the first rotation shaft 41 and the first direction D1 are parallel to each other. An example in which is provided.

  When the position of the droplet discharge head 2 is adjusted in the rotation direction, the position of the reference nozzle Sn is also shifted in the main scanning direction X and the sub-scanning direction Y. Here, the shift in the sub-scanning direction Y orthogonal to the main scanning direction X (printing width direction) can be easily adjusted by controlling the droplet discharge timing, but the main scanning direction X (printing width) Deviation in the direction) is difficult to adjust.

The position fixing unit 23 according to the present invention is disposed on the droplet discharge head 2 so that the perpendicular line drawn from the center of the reference nozzle Sn to the first rotation shaft 41 is parallel to the main scanning direction X (first direction D1). Since it is provided, the shift in the main scanning direction X can be suppressed.
Specifically, as shown in FIG. 9, when the droplet discharge head 2 is rotated by an angle dθ with the first rotation shaft 41 as a rotation axis, the reference nozzle Sn ₁ of the present invention is in the main scanning direction X. , Dx ₁ shift occurs. On the other hand, when the reference nozzle Sn ₂ as a comparative example is arranged at a location not parallel to the main scanning direction X (first direction D1) from the position reference pin 4, the reference nozzle Sn ₂ is moved in the main scanning direction X. On the other hand, a deviation of dx ₂ occurs.
Here, since the perpendicular line drawn from the center of the reference nozzle Sn ₁ to the first rotation shaft 41 is parallel to the main scanning direction X, when the droplet discharge head 2 is moved in the rotation direction, it is perpendicular to the main scanning direction X. Therefore, there is almost no shift in the main scanning direction X. Therefore, when the droplet discharge head 2 is rotated by an angle dθ with the first rotation shaft 41 as the rotation axis, the deviation of the reference nozzle Sn ₁ of the present invention and the reference nozzle Sn ₂ of the comparative example in the main scanning direction X is dx ₁ a <dx _2.

Further, as described above, it is most preferable that the perpendicular line drawn from the center of the reference nozzle Sn to the first rotation shaft 41 is completely parallel to the main scanning direction X (first direction D1), but satisfies a predetermined condition. It only has to be.
In the present invention, the predetermined condition is that the reference nozzle Sn is arranged so as to satisfy conditional expressions C1 and C2 to be described later, and the perpendicular line drawn from the center of the reference nozzle Sn to the first rotation shaft 41 is the main scanning direction X. Is parallel or almost parallel.

Hereinafter, the case where the reference nozzles Sn are arranged so as to satisfy the conditional expressions C1 and C2 will be described in detail with reference to FIG. FIG. 10 shows a straight line m orthogonal to the first rotation axis 41 and parallel to a direction perpendicular to the main scanning direction X on the XY plane, and a reference nozzle Sn _{3 and a} reference nozzle Sn at positions slightly shifted from the straight line m in the Y direction. _{3 is} the deviation from the main scanning direction X when the angle between the perpendicular line drawn from the center of ₃ to the first rotation axis 41 and the straight line m is θ, and the reference nozzle Sn ₃ is rotated by the angle dθ with the first rotation axis 41 as the rotation axis. dx ₃ is shown. At this time, the perpendicular line from the center of the reference nozzle Sn ₃ to the first rotation shaft 41 is substantially parallel to the main scanning direction X.
By the way, in the rotation adjustment of the present invention, the rotation adjustment is performed within the range of dθ of ± 1 ° with the first rotation shaft 41 as the rotation axis. If the positional deviation in the main scanning direction X is not more than ½ of the dot pitch dpx (see FIG. 6 etc.) that is the interval between adjacent dots D in the main scanning direction X, white that can be recognized visually. It does not result in image defects such as streaks.
Therefore, when | dθ | ≦ 1 °, the reference nozzle Sn ₃ only needs to be arranged at a position satisfying dx ₃ <(dpx / 2). Further, dx ₃ can be expressed as dx ₃ = | rcos (θ) −rcos (θ + dθ) |. Therefore, if the reference nozzle Sn ₃ is arranged at a position satisfying the following conditional expressions C1 and C2, the reference The effect of the present invention can be obtained even if the perpendicular drawn from the center of the nozzle Sn ₃ to the first rotation shaft 41 is substantially parallel to the main scanning direction X.
| Rcos (θ) −rcos (θ + 1 °) | <0.5 dpx... C1
| Rcos (θ) −rcos (θ−1 °) | <0.5 dpx... C2
As described above, the position fixing unit 23 according to the present invention is configured such that when the position fixing unit 23 is brought into contact with the position reference pin 4, the vertical line dropped from the center of the reference nozzle Sn to the first rotation shaft 41 and the main scanning. It only has to be arranged at a position where the direction X (the first direction D1) is a predetermined condition.
The dot pitch dpx is, for example, about 21.2 μm when using a 1200 npi (nozzle per inch) high-resolution inkjet head, about 42.3 μm when using a 600 npi inkjet head, and using a 300 npi inkjet head. Is about 84.7 μm.

[Position adjustment mechanism]
The adjustment unit 5 that adjusts the position of the droplet discharge head 2 includes a position adjustment unit 51 that contacts the positioning unit 25, a housing 53 that is provided in the holding unit 3 so as to be rotatable by the shaft member 52, and rotation of the housing 53. An adjustment screw 54 as a rotation adjustment portion to be adjusted, and an adjustment screw holding portion 55 that is fixed to the holding portion 3 and rotatably holds the housing 53 and the adjustment screw 54 (see FIG. 11 and the like).

  The position adjustment unit 51 is provided in front of the lower portion of the housing 53 and above the center of the shaft member 52, and is configured to be movable in the front-rear direction by rotation of the housing 53 described later. Further, the position adjustment unit 51 has a spherical tip, and the tip is in contact with the positioning unit 25.

  The housing 53 is configured to be rotatable with the center of the shaft member 52 provided at the lower portion of the housing 53 as the second rotation shaft 521. Further, a rear surface near the upper portion of the housing 53 has a contact surface with the adjustment screw 54. When the adjustment screw 54 moves forward while contacting the contact surface, the housing 53 It rotates in the forward direction about the rotation shaft 521. On the other hand, when the adjustment screw 54 moves backward while contacting the contact surface, the housing 53 rotates backward about the second rotation shaft 521.

Further, the abutting portion (second abutting portion T2) between the position adjusting portion 51 and the positioning portion 25 and the abutting portion between the adjusting screw 54 and the housing 53 are above the second rotating shaft 521 of the housing 53, respectively. Therefore, when the housing 53 rotates forward (or rearward), each contact portion also moves forward (or rearward).
Further, since the distance from the center of the shaft member 52 to the contact portion between the position adjustment unit 51 and the positioning unit 25 is shorter than the distance from the center of the shaft member 52 to the contact portion between the housing 53 and the adjustment screw 54, The moving distance of the position adjusting unit 51 is smaller than the moving distance of the adjusting screw 54, and a high reduction ratio is obtained.

  The droplet discharge head 2 is fixed to the position reference pin 4 by a position fixing unit 23 so as to be rotatable. Therefore, the position adjustment unit 51 can move along the axis of the position reference pin 4 by moving the position in the front-rear direction, and adjust the rotation angle with respect to the front-rear, left-right direction perpendicular to the droplet discharge direction. Can do.

  The adjustment screw 54 is held by the adjustment screw holding portion 55 in a state where the adjustment screw 54 is rotatable, and can be moved in the front-rear direction by rotating. The rotation of the housing 53 can be controlled by moving the position of the adjustment screw 54.

[Positional relationship between position adjustment section and adjustment screw]
The positional relationship between the position adjustment unit 51 and the adjustment screw 54 in the adjustment unit 5 will be described using a schematic diagram of the position adjustment unit 51, the shaft member 52, the housing 53, and the adjustment screw 54 and the following relational expressions (FIG. 12). reference).
In FIG. 12, for convenience of explanation, when the center of the shaft member 52 is the origin O, the contact portion between the adjustment screw 54 and the housing 53 is A1, and the spherical center at the tip of the position adjustment portion 51 is a reference. As the part B1, a relational expression in the front-rear direction and the up-down direction will be described. Here, the reference part B <b> 1 is a part serving as a reference for position movement in the position adjustment unit 51.
In FIG. 12, the forward direction is the X direction.

The distance between the origin O and A1 is d ₁ , the distance between the origin O and A1 in the front-rear direction is x ₁ , the angle from the axis parallel to the front direction passing through the origin O to A1 is θ ₁ , and the distance between the origin O and the reference part B1 Is the distance d ₂ , the distance in the front-rear direction between the origin O and the reference part B 1 is x ₂ , and the angle from the axis parallel to the front direction passing through the origin O to the reference part B 1 is θ ₂ . Can be expressed as:

The absolute value of the absolute value and _{x 2} of the variation of the amount of change _{x 1} by the rotation _(dx 1 / dθ) of the housing 53 _(dx 2 / dθ) can be expressed by the following equation by differentiating.

In the present embodiment, since the absolute value of the movement amount due to the housing rotation of x ₂ is designed to be smaller than the absolute value of the movement amount due to the housing rotation of the x _1, | dx ₂ / dθ | <| dx ₁ / dθ |, and the relational expression of d ₁ , θ ₁ , d _2, and θ ₂ can be expressed by the following expression (1).

Here, by defining d ₁ , θ ₁ , d _2, and θ ₂ so as to satisfy the above formula (1), the amount of movement of the position adjusting unit 51 (the amount of change of x ₂ ) is changed to the amount of movement of the adjusting screw 54. it can be smaller than (the amount of change in x _1).
When one of the droplet discharge heads 2 is rotatably fixed to the position reference pin 4 by the position fixing unit 23 and the other is moved by the position adjustment unit 51 as in the present embodiment, the droplet discharge head 2 Moves in the direction of rotation along the axis of the position reference pin 4. However, the amount of change in _{x 1 (dx 1} / _dθ) and the amount of change _{x 2 (dx 2} / _dθ) are each small, since the movement amount in the lateral direction is very small relative to the amount of movement in the longitudinal direction The movement amount of the droplet discharge head 2 can be approximated to the movement amount of the position adjustment unit 51 in the front-rear direction.

In the above description, as an example of the shape of the position adjustment unit 51, an example in which the tip of the position adjustment unit 51 is spherical has been described. However, the shape is not limited to the above example, and the shape of the position adjustment unit 51 is appropriately determined. Selectable. For example, the position adjusting unit 51 can have a needle shape with a sharp tip or a rectangular parallelepiped shape.
The reference part B1 can be arbitrarily determined as long as it is a part that serves as a reference for position movement in the position adjustment unit 51. For example, the center of gravity of the position adjustment part 51 may be used as the reference part B1. By the way, when the tip of the position adjustment unit 51 is spherical as in the present embodiment, the position of the contact portion between the position adjustment unit 51 and the positioning unit 25 moves on the spherical surface. The contact portion cannot be the reference portion B1. On the other hand, when a needle shape or a rectangular parallelepiped shape is selected for the position adjustment unit 51, the contact portion between the position adjustment unit 51 and the positioning unit 25 does not move, so that the contact portion can be used as the reference portion B1. It is.

[Relationship of position adjustment mechanism]
In the position adjustment mechanism in the adjustment unit 5, the position adjustment unit 51, the shaft member 52, the housing 53, and the amount ds of movement of the position adjustment unit 51 in the forward direction when the adjustment screw 54 is moved forward by dx position. A description will be given using a schematic diagram of the adjustment screw 54 and the following relational expression (see FIG. 13).
Note that FIG. 13 has the same configuration as that of FIG. 12, but for convenience of description, description will be made using a diagram in which symbols and the like are appropriately changed. Specifically, when the center of the shaft member 52 is the origin O, the contact position between the adjustment screw 54 and the housing 53 is A1, and the position after the movement of A1 after the adjustment screw 54 is moved dx forward. , The rotation angle of the housing 53 when the adjustment screw 54 is moved dx forward, γ, the spherical center of the tip of the position adjustment unit 51 is the reference portion B1, and the reference portion B1 when the housing 53 is rotated by the angle γ A relational expression in the front-rear direction and the up-down direction will be described with B2 as the position after the movement.

The vertical distance between O and A1 is l ₁ , the longitudinal distance between O and A1 is r ₁ , the angle from the axis parallel to the upward direction passing through O to A1 is α ₁ , and the upward direction passing through O is parallel to the upward direction The angle from the axis to A2 is β ₁ , the distance in the front-rear direction between O and the reference part B1 is l ₂ , the vertical distance between O and the reference part B1 is r ₂ , and the reference part from the axis parallel to the front direction passing through O When the angle to B1 is α ₂ and the angle from the axis parallel to the forward direction passing through O to B2 is β ₂ , the relational expression can be expressed as follows.

Moreover, when the relational expression between dx and ds is expressed from these values, it can be expressed as the following expression (2).

Here, for example, when l ₁ = 17.5 mm, r ₁ = 0 mm, l ₂ = 4.35 mm, and r ₂ = 2 mm are set as values satisfying the expression (1) and substituted into the expression (2), the screw pitch If the housing 53 is rotated by using the adjustment screw 54 that is 0.5 μm / 1 rotation (rotating 360 μm, it advances 0.5 μm), the screw operation amount (degree) that is the rotation angle of the adjustment screw 54 and the position The relational expression with the position adjustment displacement amount (μm) in the front-rear direction of the adjustment unit 51 can be expressed as shown in FIG. In Expression (2), dx is a value proportional to the screw operation amount (degree), and ds is a value corresponding to the position adjustment displacement amount.
From the inclination of the relational expression, it can be seen that the screw operation amount (degree) and the position adjustment displacement amount (μm) are in a substantially proportional relationship. In FIG. 14A, a value obtained by linearly approximating the relationship between the screw operation amount (degree) and the position adjustment displacement amount (μm) is indicated by a broken line.

  FIG. 14B is a comparative example with respect to the present embodiment. When the adjustment screw 54 having the same screw pitch 0.5 μm / 1 rotation as that of the present embodiment is used, the displacement amount of the tip of the adjustment screw 54 is shown. As the position adjustment displacement amount, a relational expression between the screw operation amount (degrees) and the position adjustment displacement amount (μm) is shown. Since the adjustment screw 54 of the comparative example moves in proportion to the angle (screw operation amount) by which the screw is rotated, the relational expression between the screw operation amount (degree) and the position adjustment displacement amount (μm) is a linear equation. expressed.

  Further, comparing this embodiment with a comparative example, when the same adjustment screw 54 is turned by the same angle, the position adjustment displacement amount is about 1/10 in this embodiment. Therefore, it can be seen that a reduction ratio of about 1/10 was obtained in this embodiment.

In addition, although l ₁ , r ₁ , l ₂ , r ₂ , and the screw pitch have been described with examples of numerical values, it can be changed as appropriate. In addition, by setting the value to an appropriate value according to the application, it is possible to obtain a higher reduction ratio and to improve the linearity of the relational expression between the screw operation amount and the position adjustment displacement amount.
Specifically, by increasing l ₁ or decreasing r ₂ , ds / dx can be reduced and the reduction rate can be increased. Further, by increasing r ₁ or decreasing l ₂ , the linearity of the relational expression between the screw operation amount and the position adjustment displacement amount can be improved.

[Technical effects of the present invention]
As described above, in the liquid droplet ejection head 2 of the present invention, the perpendicular line extending from the center of the reference nozzle Sn to the first rotation shaft 41 and the main scanning direction X (print width direction) are set as predetermined conditions. Therefore, when the position adjustment is performed in the rotation direction, the displacement of the reference nozzle Sn in the main scanning direction X is suppressed, and the landing position accuracy can be improved. In addition, since the droplet discharge head 2 of the present invention can obtain the effects of the present invention only by adjusting the positional relationship between the reference nozzle Sn and the position fixing unit 23, the position adjustment can be easily performed with a simple configuration. Can be done.

  In the embodiment of the droplet discharge head 2 of the present invention, the reference nozzle Sn is preferably a nozzle n located at the end on the position fixing portion 23 side, and is also an end in the sub-scanning direction Y. It is preferable. Thereby, alignment of the holding position with respect to the holding part 3 of the droplet discharge head 2 can be performed more easily.

  In the embodiment of the droplet discharge head 2 of the present invention, the two nozzles n and n that form the dots D adjacent in the first direction D1 (main scanning direction X) intersect with the first direction D1. It is preferable that they are arranged so as not to be adjacent to the two directions D2, and are arranged so as not to be separated into one end and the other end in the third direction D3 (sub scanning direction Y) orthogonal to the first direction D1. . By adopting such a nozzle arrangement, it is possible to reduce the influence of the variation in the distance between adjacent dots D due to the mounting error of the droplet discharge head 2 and maintain high image quality.

  In the embodiment of the droplet discharge head unit 1 of the present invention, the position adjustment unit 51 is moved by the rotation of the housing by the rotation adjustment unit, and the holding position of the droplet discharge head 2 with respect to the holding unit 3 is adjusted. It is preferable to configure so as to satisfy the formula (1). Thereby, the position adjustment of the holding position with respect to the holding part 3 of the droplet discharge head 2 can be performed with high accuracy.

[Others]
It should be thought that embodiment disclosed this time of this invention is an illustration and restrictive at no points. The scope of the present invention is not limited to the above detailed description, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. .

  For example, FIG. 5 shows an example in which the position fixing unit 23 of the present invention is provided in the vicinity of the front side on the left side of the droplet discharge head 2, but when the position fixing unit 23 is brought into contact with the position reference pin 4, The position can be appropriately changed as long as the perpendicular line extending from the center to the first rotation shaft 41 and the main scanning direction X (first direction D1) satisfy the predetermined conditions. For example, it may be provided on the right side of the droplet discharge head 2 in FIG.

  Moreover, although the case where four nozzle formation areas composed of the nozzles n formed in the droplet discharge section 21 are provided in the droplet discharge head 2, the number thereof can be increased or decreased. However, the number of nozzle formation areas is preferably 3 or more, and more preferably 4 or more.

The plurality of nozzles n are divided into a plurality of nozzle formation areas in which the nozzles n are formed in an arrangement arranged along the first direction and the second direction, and two adjacent dots are formed in the main scanning direction. Although a more preferable example is shown in which nozzles n and n are dispersed so as not to be in the same nozzle formation area and arranged not to be adjacent in the sub-scanning direction, the present invention is not limited to this.
The plurality of nozzles n are two-dimensionally arranged in the first direction (main scanning direction) and the second direction, and two nozzles n and n forming adjacent dots in the main scanning direction are not adjacent in the sub-scanning direction. In the region where all the nozzles arranged in a two-dimensional manner are arranged, two nozzles n and n forming adjacent dots are arranged at one end in the third direction (sub-scanning direction). What is necessary is just to arrange | position so that it may not isolate | separate into an other end part. Within a range that satisfies these conditions, for example, in the above-described embodiment, two nozzles n that form adjacent dots in the main scanning direction by replacing a plurality of nozzle rows extending in the first direction (main scanning direction). n may be arranged in the same area, or the whole may be one nozzle formation area.
Moreover, although the case where the number of the nozzles n formed inside the nozzle formation areas N1 to N4 is 8 × 32 is illustrated, it is not limited to the individual number. The number of nozzles n may be increased or decreased according to the dot density required for the droplet discharge head 2.

  When the nozzle formation areas N1 to N4 are arranged in close contact with each other in the sub-scanning direction Y (the nozzle pitch in the sub-scanning direction Y of the two nozzles n and n located at the boundary between one and the other area is the same area) In this example, the two nozzles n and n adjacent to each other in the sub-scanning direction Y have the same arrangement as the nozzle pitch npy. However, the present invention is not limited to this. For example, a gap may be provided between the nozzle formation areas N1 to N4 at an integral multiple of the nozzle pitch npy.

Moreover, in the droplet discharge head unit 1 equipped with the position adjustment mechanism of the present embodiment, an example in which one adjustment unit 5 is provided for the droplet discharge head 2 has been shown. If it is the structure provided with the head 2, the number which provides the adjustment part 5 can be changed suitably.
In addition, the arrangement location of the adjustment unit 5 can be changed as appropriate.

  As a position adjustment method performed by bringing the position adjustment unit 51 of the adjustment unit 5 into contact, the method of contacting the positioning unit 25 of the droplet discharge head 2 and the position and method of contacting the position adjustment unit 51 are naturally appropriate. For example, it may be brought into direct contact with the main body of the droplet discharge head 2.

Further, in this embodiment, the V-groove portion 24 of the position fixing portion 23 is configured to be fixed to the position reference pin 4 so as to be rotatable. However, as long as the rotation angle of the droplet discharge head 2 can be adjusted, The configuration can be changed as appropriate.
Further, although the position reference pin 4 is fixed to the holding portion 3, the position reference pin 4 can be appropriately changed as long as the position fixing portion 23 can be fixed. It is good also as a structure which can be moved to right and left.

  In addition, the tip of the position adjusting unit 51 is spherical, but if the contact surface of the positioning unit 25 with which the tip is in contact is spherical, the tip may be flat. Here, it is technically possible to make both the tip of the position adjusting unit 51 and the contact surface of the positioning unit 25 spherical or flat, but either one is not stable when moving, so either One of the surfaces is preferably spherical.

  Moreover, although the example which uses the adjustment screw 54 as a rotation adjustment part which adjusts rotation of the housing 53 was demonstrated, if the housing 53 can be rotated, a structure can be changed suitably, for example, a housing is changed by the displacement of a piezoelectric element. It is good also as a structure which rotates 53. FIG.

  In addition, the droplet discharge head 2 is configured to discharge droplets such as ink using a piezoelectric element, but may be provided with a mechanism capable of discharging droplets, for example, thermal (electrothermal conversion element) It is good to use.

Moreover, although the example which uses the elastic member 31 and the elastic member 32 which respectively differed as a means to urge the position fixing part 23 to the position reference | standard pin 4 and a means to urge the positioning part 25 to the position adjustment part 51 was shown, Any means capable of urging the droplet discharge head 2 toward the position reference pin 4 and the position adjusting unit 51 can be changed as appropriate. For example, the main body of the droplet discharge head 2 may be directly urged by one elastic member, and an elastic member 31 and an elastic member 32 provided between two adjacent droplet discharge heads 2 may be used. The same elastic member may be used.
Further, as a method of fixing the droplet discharge head 2 to the holding unit 3, a configuration may be adopted in which a fixing screw or the like is further provided so as to be fixed to the holding unit 3.

  The present invention can be used in a droplet discharge head, a droplet discharge head unit, an image forming apparatus, and a method for mounting a droplet discharge head on a holding unit of the image forming apparatus.

DESCRIPTION OF SYMBOLS 1 Droplet discharge head unit 2 Droplet discharge head 21 Droplet discharge part (nozzle formation surface)
23 Position fixing part 24 V groove part 3 Holding part 4 Position reference pin (position reference part)
41 1st rotating shaft 51 Position adjustment part 52 Shaft member 521 2nd rotating shaft 53 Housing 54 Adjustment screw (Rotation adjustment part)
100 Image forming apparatus K Recording medium n Nozzle Sn Reference nozzle D1 First direction D2 Second direction X Main scanning direction Y Sub-scanning direction (third direction)
D dot B1 reference part

Claims (10)

A droplet discharge head that is detachably attached to a holding unit of an image forming apparatus and performs position adjustment by contacting a position reference unit provided in the holding unit,
On a nozzle forming surface facing the recording surface of the recording medium, a first direction orthogonal to the relative movement direction of the recording medium and the droplet discharge head and a second direction intersecting the first direction A plurality of nozzles arranged two-dimensionally;
When contacting the position reference portion, the position of the droplet discharge head is adjusted from the center of the reference nozzle of the plurality of nozzles in a rotation direction that rotates about a direction perpendicular to the nozzle formation surface. A position fixing portion arranged so that a perpendicular line to the first rotation shaft for the first direction and the first direction are a predetermined condition;
A liquid droplet ejection head comprising:   2. The droplet discharge head according to claim 1, wherein the reference nozzle is a nozzle located at an end of the nozzle forming surface on the position fixing portion side.   The droplet discharge head according to claim 2, wherein the reference nozzle is a nozzle located at an end portion in a third direction orthogonal to the first direction of the nozzle forming surface. The second direction is a direction in which the relative moving direction is inclined in the first direction,
Two nozzles that form dots adjacent in the first direction are arranged so as not to be adjacent in the second direction, and are orthogonal to the first direction of the two-dimensionally arranged nozzles The liquid droplet ejection head according to claim 1, wherein the liquid droplet ejection head is arranged so as not to be separated into one end and the other end in the third direction. A liquid droplet ejection head according to any one of claims 1 to 4,
A droplet discharge head unit comprising: the holding unit that detachably holds the droplet discharge head. The position fixing portion has a V-groove portion,
The droplet discharge head unit according to claim 5, wherein the holding portion includes the position reference portion that abuts on the V groove portion. A housing having a shaft member having a second rotating shaft;
A rotation adjusting unit that contacts the housing and adjusts the rotation of the housing;
A position adjusting unit that is provided in the housing and adjusts a holding position of the droplet discharge head with respect to the holding unit in contact with the droplet discharge head;
With
The droplet discharge head unit according to claim 5, wherein the following formula (1) is satisfied.

(Where d ₁ represents the distance from the center of the shaft member to the contact portion of the rotation adjusting portion and the housing. Θ ₁ passes through the center of the shaft member and the moving direction of the droplet discharge head) .d ₂ representing the angle of to the contact portion of the housing and the rotary adjuster from an axis parallel to represent the distance from the center of the shaft member to the reference site as a reference of position movement in the position adjusting section .Shita ₂ represents the angle from the axis parallel to the moving direction of said axis around the street the droplet discharge head member to the reference site.)   8. The droplet discharge according to claim 7, wherein either the tip end portion of the position adjustment unit or the contact portion of the droplet discharge head with which the position adjustment unit abuts is spherical. Head unit.   An image forming apparatus comprising the droplet discharge head unit according to claim 5. A method for mounting a droplet discharge head, wherein the droplet discharge head according to any one of claims 1 to 4 is mounted on the holding unit.
Position adjustment in the rotational direction with respect to an axis perpendicular to the nozzle forming surface is performed by rotating the position reference portion as an axis while contacting the position fixing portion and the position reference portion. A method of mounting a droplet discharge head characterized by the above.

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