JP6686908B2 - Droplet ejection head unit, position adjusting method of droplet ejection head, and image forming apparatus - Google Patents

Description

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

  2. Description of the Related Art Conventionally, there is known an inkjet recording apparatus that discharges ink droplets from a plurality of nozzles provided in a droplet discharge head to form an image on a recording medium.

  In recent years, as the accuracy of an image formed by an inkjet recording apparatus has increased, a plurality of nozzles provided in a droplet discharge head have been arranged at high density. Therefore, if the position of the droplet discharge head shifts with respect to the holding unit that holds the droplet discharge head, there is a problem that the formed image has streaks or unevenness and the image deteriorates. Therefore, it is required to position the droplet discharge head with respect to the holding portion with high accuracy.

Therefore, for example, a method is disclosed in which a rotatable eccentric top member that contacts the head and an eccentric cam that keeps contact between the head and the eccentric top member are provided, and the position of the head is adjusted by rotating the eccentric cam. (For example, see Patent Document 1).
Further, a method is disclosed in which the taper portion of the adjustment screw is in contact with the position adjustment portion of the droplet discharge head, and the position of the droplet discharge head is adjusted by moving the position of the adjustment screw (see, for example, Patent Documents 1 and 2). ).

Japanese Patent No. 2758060 JP 2001-341293 A

  However, in recent droplet discharge heads, positioning of the droplet discharge heads may require position adjustment on the order of several μm.

  On the other hand, in the method of Patent Document 1, the amount of eccentricity can be adjusted in the range of half a rotation (180 degrees) by rotating the eccentric top, but for example, when the adjustment range is ± 100 μm, the adjustment resolution is , About 1 μm / degree. In this case, when adjusting on the order of several μm, the eccentric top must be adjusted at an angle of several degrees, and it is difficult to obtain high resolution from the viewpoint of operability.

  Further, in the method using the adjusting screw of Patent Documents 1 and 2, the taper portion of the adjusting screw and the abutting portion of the position adjusting portion are largely moved by the rotation of the adjusting screw. Therefore, in order to enable the position adjustment on the order of several μm, it is necessary to process the range that can be the contact portion between the taper portion of the adjustment screw and the position adjustment portion with high accuracy, which requires cost. In addition, even if there is a slight deviation in the arrangement of the adjustment screws, an error occurs, so it is technically very difficult to perform position adjustment on the order of several μm.

  The present invention has been made in view of such a problem, and has a high droplet landing position accuracy with respect to a recording medium, and a position adjustment of the liquid drop ejection head unit in which the positional accuracy can be easily adjusted. A method and an image forming apparatus are provided.

（式中、ｄ_１は、前記回転軸部材の中心から前記回転調整部と前記ハウジングの当接部までの距離を表す。θ_１は、前記回転軸部材の中心を通り前記液滴吐出ヘッドの移動方向に平行な軸から前記回転調整部と前記ハウジングの当接部までの角度を表す。ｄ_２は、前記回転軸部材の中心から前記位置調整部における位置移動の基準となる基準部位までの距離を表す。θ_２は、前記回転軸部材の中心を通り前記液滴吐出ヘッドの移動方向に平行な軸から前記基準部位までの角度を表す。）
また、上記課題の解決のために、請求項２に記載の発明は、
液滴吐出ヘッドユニットであって、
液滴を吐出する液滴吐出ヘッドと、
前記液滴吐出ヘッドを着脱自在に保持する保持部と、
回転軸部材により回転可能なハウジングと、
前記ハウジングと当接して当該ハウジングの回転を調整する回転調整部と、
前記ハウジングに設けられ、前記液滴吐出ヘッドに当接して前記液滴吐出ヘッドの前記保持部に対する保持位置を調整する位置調整部と、
を備え、
前記位置調整部の先端部、又は、前記位置調整部が当接する前記液滴吐出ヘッドの当接部、のどちらか一方が球面状であり、
下記式（１）を満たすことを特徴とする。

（式中、ｄ _１ は、前記回転軸部材の中心から前記回転調整部と前記ハウジングの当接部までの距離を表す。θ _１ は、前記回転軸部材の中心を通り前記液滴吐出ヘッドの移動方向に平行な軸から前記回転調整部と前記ハウジングの当接部までの角度を表す。ｄ _２ は、前記回転軸部材の中心から前記位置調整部における位置移動の基準となる基準部位までの距離を表す。θ _２ は、前記回転軸部材の中心を通り前記液滴吐出ヘッドの移動方向に平行な軸から前記基準部位までの角度を表す。） In order to solve the above problems, the invention described in claim 1 is
A droplet discharge head unit,
A droplet discharge head for discharging droplets,
A holding portion that detachably holds the droplet discharge head;
A housing that is rotatable about a rotation axis that is perpendicular to the direction in which droplets are discharged from the droplet discharge head, by a rotation shaft member;
A rotation adjusting portion that abuts on the housing and adjusts the rotation of the housing;
A position adjusting unit which is provided in the housing and which adjusts a holding position of the droplet discharge head with respect to the holding unit by contacting the droplet discharge head;
Equipped with
It is characterized by satisfying the following formula (1).

(In the formula, d ₁ represents the distance from the center of the rotary shaft member to the contact portion of the rotation adjusting unit and the housing. Θ ₁ passes through the center of the rotary shaft member and The angle from the axis parallel to the moving direction to the contact portion of the rotation adjusting portion and the housing, d ₂ is from the center of the rotating shaft member to a reference portion that serves as a reference for position movement in the position adjusting portion. Represents a distance. Θ ₂ represents an angle from the axis passing through the center of the rotary shaft member and parallel to the moving direction of the droplet discharge head to the reference portion.)
In order to solve the above problems, the invention according to claim 2 is
A droplet discharge head unit,
A droplet discharge head for discharging droplets,
A holding portion that detachably holds the droplet discharge head;
A housing rotatable by a rotary shaft member,
A rotation adjusting portion that abuts on the housing and adjusts the rotation of the housing;
A position adjusting unit which is provided in the housing and which adjusts a holding position of the droplet discharge head with respect to the holding unit by contacting the droplet discharge head;
Equipped with
Either the tip of the position adjusting section or the contact section of the droplet discharge head with which the position adjusting section contacts is spherical.
It is characterized by satisfying the following formula (1).

(In the formula, d ₁ represents the distance from the center of the rotary shaft member to the contact portion of the rotation adjusting unit and the housing. Θ ₁ passes through the center of the rotary shaft member and The angle from the axis parallel to the movement direction to the contact portion of the rotation adjusting portion and the housing, d ₂ is from the center of the rotating shaft member to a reference portion that serves as a reference for position movement in the position adjusting portion. Represents a distance. Θ ₂ represents an angle from the axis passing through the center of the rotary shaft member and parallel to the moving direction of the droplet discharge head to the reference portion.)

According to a third aspect of the invention, in the droplet discharge head unit according to the first or second aspect ,
The distance from the center of the rotating shaft member to the contact portion between the position adjusting portion and the droplet discharge head is greater than the distance from the center of the rotating shaft member to the contact portion between the rotation adjusting portion and the housing. It is also characterized by being short.

According to a fourth aspect of the present invention, in the droplet discharge head unit according to the first or third aspect ,
It is characterized in that either the tip of the position adjusting section or the contact section of the droplet discharge head with which the position adjusting section abuts has a spherical shape.

According to a fifth aspect of the invention, in the droplet discharge head unit according to any one of the first to fourth aspects,
The droplet discharge head is
A first contact portion provided on one surface parallel to the droplet discharge direction of the droplet discharge head;
A second contact portion provided on another surface parallel to the droplet discharge direction of the droplet discharge head different from the one surface,
The holding portion is
The droplet discharge head includes a fixing portion that is fixed in a state in which the first contact portion is in contact with the droplet discharge head so as to be rotatable about an axis along the droplet discharge direction of the droplet discharge head.
The second contact portion is in contact with the position adjusting portion.

According to a sixth aspect of the invention, in the droplet discharge head unit according to any one of the first to fourth aspects,
The droplet discharge head is
A first contact portion provided on one surface parallel to the droplet discharge direction of the droplet discharge head;
A second contact portion provided on another surface parallel to the droplet discharge direction of the droplet discharge head different from the one surface;
Equipped with
The housing, the rotation adjusting portion, and the position adjusting portion are separately provided corresponding to the first contact portion and the second contact portion, respectively.
The first contact portion and the second contact portion are in contact with the corresponding position adjusting portions.

The invention according to claim 7, in the liquid droplet ejecting head unit according to any one of claims 1-4,
The droplet discharge head is
A first contact portion provided on a first surface parallel to the droplet discharge direction of the droplet discharge head;
A second contact portion provided on a second surface which is different from the first surface and is parallel to the droplet discharge direction of the droplet discharge head;
A third contact portion provided on a third surface parallel to the droplet discharge direction of the droplet discharge head;
Equipped with
The housing, the rotation adjusting portion, and the position adjusting portion are separately provided corresponding to the first contact portion, the second contact portion, and the third contact portion, respectively.
It is characterized in that the first contact portion, the second contact portion, and the third contact portion contact the corresponding position adjustment portions.

The invention according to claim 8 is a droplet discharge head unit according to any one of claims 1 to 7 , characterized in that a plurality of the droplet discharge heads are arranged one-dimensionally or two-dimensionally. is there.
According to a ninth aspect of the present invention, the housing, the rotation adjusting unit, and the position adjusting unit are provided corresponding to each of the plurality of arranged droplet discharge heads, and the droplets are adjacent to each other in a predetermined direction. 9. The droplet discharge head unit according to claim 8, wherein the housing and the position adjusting unit corresponding to one of the adjacent droplet discharge heads are arranged between the discharge heads .

The invention described in claim 10 is a method for adjusting the position of a droplet discharge head in the droplet discharge head unit according to any one of claims 1 to 9 ,
The position adjusting unit is moved by the rotation of the housing, and the holding position of the droplet discharge head with respect to the holding unit is adjusted.

An eleventh aspect of the present invention is an image forming apparatus including the droplet discharge head unit according to any one of the first to ninth aspects .

  According to the present invention, the landing position accuracy of a droplet on a recording medium is high, and the position accuracy can be easily adjusted.

It is a perspective view showing a schematic configuration of an image forming apparatus. It is a perspective view of a droplet discharge head unit. It is a bottom view of a droplet discharge head unit. FIG. 3 is a plan view showing a droplet discharge head and a position adjusting mechanism. It is a right side view showing a droplet discharge head and a position adjustment mechanism. It is a schematic diagram for demonstrating the positional relationship of a position adjustment part and an adjustment screw. It is a schematic diagram which shows the example in which a position adjustment part is a needle shape. It is a schematic diagram which shows the example in which a position adjustment part is a rectangular parallelepiped shape. It is a schematic diagram for demonstrating the position adjustment mechanism in an adjustment part. It is a graph which shows the screw operation amount of an adjustment screw, and the relationship of a position adjustment displacement amount. It is a schematic diagram which shows the modification 1 which performs position adjustment at two places of a droplet discharge head. It is a schematic diagram which shows the modification 2 which adjusts a position at three places of a droplet discharge head. It is a schematic diagram which shows the modification 3 of a structure of a droplet discharge head and an adjustment part. FIG. 13 is a schematic diagram showing a modified example 4 of the configurations of the droplet discharge head and the adjustment unit.

Hereinafter, preferred embodiments of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated example. Further, in the following description, components having the same function and configuration are designated by the same reference numerals, and the description thereof will be 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, but the present invention can be applied to an appropriate drawing method, for example, scanning. A drawing method using a method or a drum method may be adopted.
Further, in the following description, the conveyance direction of the recording medium K will be described as the front-rear direction, the direction orthogonal to the conveyance direction on the conveyance surface of the recording medium K will be the left-right direction, and the direction perpendicular to the front-rear direction and the left-right direction will be 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 its upper surface, and when the transport roller 102 is driven, the platen 101 transports the recording medium K in the transport direction (front-back direction).
The line heads 200, 201, 202, and 203 are provided in parallel in the width direction (horizontal direction) orthogonal to the transport direction from the upstream side to the downstream side in the transport direction (front-back direction) of the recording medium K. At least one droplet discharge head unit 1 to be described later is provided inside the line heads 200, 201, 202, and 203, for example, cyan (C), magenta (M), yellow (Y), Black (K) ink is ejected toward the recording medium K.

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

  The droplet discharge head unit 1 is configured by holding the droplet discharge head 2 so that the bottom surface thereof is exposed from the opening of the holder 3 by the holder 3. Further, the holding unit 3 holds the plurality of droplet discharge heads 2 in a zigzag shape as a whole, and specifically, for example, three droplets in the left-right direction and two droplets in the front-rear direction. It holds the ejection head 2.

[Droplet ejection head]
The droplet discharge head 2 includes a droplet discharge section 21 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, and an ink in the ink chamber 22. And an ink discharge part 222 for discharging the ink in the ink chamber 22.
The droplet discharge unit 21 has a pressure chamber (not shown) corresponding to each nozzle N therein, ink is supplied from the ink chamber 22 to the pressure chamber, and a piezoelectric element provided above the pressure chamber. When the ink in the pressure chamber is pressurized by the displacement of the element (not shown), the ink droplets are ejected from the nozzle N.

Further, the droplet discharge head 2 faces the position fixing portion 23 as a fixing portion provided on one side surface parallel to the droplet discharge direction (vertical direction) and the side surface provided with the position fixing portion 23. The positioning part 25 provided on the side surface is provided (see FIG. 4 and the like).
For convenience of explanation, FIG. 4 shows only the droplet discharge head 2 provided on the front side in the right direction of the droplet discharge head unit 1 shown in FIG. 2 and a position adjusting mechanism thereof. There is.

  The position fixing portion 23 has a V-shaped groove 24 and is configured so that the V-shaped groove 24 can abut against the position reference pin 4 fixed to the holding portion 3. Then, the position fixing portion 23 is pressed in the direction of abutting against the position reference pin 4 by the elastic member 31 as a biasing means provided in the holding portion 3 and fixed by the contact portion (first contact portion T1). The droplet discharge head 2 is fixed so as to be rotatable around the axis of the position reference pin 4.

  The positioning portion 25 is abutted against the position adjusting portion 51 of the adjusting portion 5 which will be described later, and the elastic member 32 as a biasing means provided on the holding portion 3 causes the positioning portion 25 to abut against the position adjusting portion 51. 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.

[Position adjustment mechanism]
The adjusting unit 5 that adjusts the position of the droplet discharge head 2 includes a position adjusting unit 51 that contacts the positioning unit 25, a housing 53 that is rotatably provided on the holding unit 3 by a rotating shaft member 52, and a rotation of the housing 53. An adjusting screw 54 as a rotation adjusting unit for adjusting the rotation amount, an adjusting screw holding unit 55 fixed to the holding unit 3 and rotatably holding the housing 53 and the adjusting screw 54 are provided.

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

  The housing 53 is configured to be rotatable around a rotary shaft member 52 provided at the bottom of the housing 53. Further, a rear surface near the upper portion of the housing 53 has a contact surface with the adjusting screw 54, and when the adjusting screw 54 moves in the forward direction while contacting the contact surface, the housing 53 moves to the rotating shaft. The member 52 rotates in the forward direction about the center. On the other hand, when the adjusting screw 54 moves rearward while being in contact with the contact surface, the housing 53 rotates rearward around the rotation shaft member 52.

Further, the contact portion between the position adjusting portion 51 and the positioning portion 25 (second contact portion T2) and the contact portion between the adjusting screw 54 and the housing 53 are located above the rotary shaft member 52 of the housing 53, respectively. Since they are located, when the housing 53 rotates in the front direction (or the rear direction), the respective contact portions also move in the front direction (or the rear direction).
Further, the distance from the center of the rotating shaft member 52 to the contact portion between the position adjusting portion 51 and the positioning portion 25 is shorter than the distance from the center of the rotating shaft member 52 to the contact portion between the housing 53 and the adjusting screw 54. Therefore, the moving distance of the position adjusting section 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 rotatably fixed to the position reference pin 4 by the position fixing portion 23. Therefore, by moving the position adjusting unit 51 in the front-back direction, the position can be moved around the axis of the position reference pin 4, and the rotation angle with respect to the front-back direction and the left-right direction perpendicular to the droplet ejection direction can be adjusted. You can

  The adjusting screw 54 is held by the adjusting screw holding portion 55 in a state in which the adjusting screw 54 is rotatable, and can rotate to move in the front-rear direction. The rotation of the housing 53 can be controlled by moving the position of the adjusting screw 54.

[Positional relationship between the position adjustment unit and the adjustment screw]
The positional relationship between the position adjusting unit 51 and the adjusting screw 54 in the adjusting unit 5 will be described using schematic diagrams of the position adjusting unit 51, the rotating shaft member 52, the housing 53, and the adjusting screw 54, and the relational expressions shown below (FIG. 6).
In FIG. 6, for convenience of description, when the center of the rotary shaft member 52 is the origin O, the contact portion between the adjusting screw 54 and the housing 53 is A1, and the spherical center of the tip end portion of the position adjusting portion 51 is the same. Relational expressions in the front-rear direction and the vertical direction will be described as the reference part B1. Here, the reference portion B1 is a portion that serves as a reference for position movement in the position adjusting unit 51.
Further, in FIGS. 6 to 9, the front 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 forward direction passing through the origin O to A1 is θ ₁ , and between the origin O and the reference part B1. Where d _{2 is} the distance between the origin O and the reference part B1 in the front-back direction is x ₂ , and the angle from the axis parallel to the forward direction passing through the origin O to the reference part B1 is θ ₂ , the relational expression is Can be expressed as

Further, the absolute value of the change amount of x ₁ (dx ₁ / dθ) and the absolute value of the change amount of x ₂ (dx ₂ / dθ) due to the rotation of the housing 53 can be expressed by the following formulas by differentiation.

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

Here, by defining d ₁ , θ ₁ , d ₂ and θ ₂ so as to satisfy the above equation (1), the amount of movement of the position adjusting unit 51 (the amount of change in x ₂ ) is the amount of movement of the adjusting screw 54. It can be made smaller than (change amount of x ₁ ).
When one of the droplet discharge heads 2 is rotatably fixed to the position reference pin 4 by the position fixing portion 23 and the other is moved by the position adjusting portion 51 as in the present embodiment, the droplet discharge head 2 is moved. Moves in the rotation direction 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 in x ₂ (dx ₂ / dθ) are very small, and the amount of movement in the left-right direction is extremely smaller than the amount of movement in the front-back direction. The amount of movement of the droplet discharge head 2 can be approximated to the amount of movement of the position adjusting unit 51 in the front-rear direction.

In the above description, as an example of the shape of the position adjusting unit 51, the example in which the tip of the position adjusting unit 51 is spherical is described, but the shape of the position adjusting unit 51 is not limited to the above example. It is selectable. For example, the position adjusting unit 51 may have a needle shape with a sharp tip (see FIG. 7) or a rectangular parallelepiped shape (see FIG. 8).
Here, when the position adjusting portion 51 is formed into a needle shape, the contact portion between the sharpened tip of the needle shape and the positioning portion 25 is set as the reference portion B1, and as in the present embodiment, d ₁ , θ. The relational expression of ₁ , d ₂ and θ ₂ can be represented by the above expression (1).
Further, when the position adjusting portion 51 is formed in a rectangular parallelepiped shape, the contact portions between the corners of the rectangular parallelepiped shape and the positioning portion 25 are used as the reference portion B1, and as in the present embodiment, d ₁ , θ ₁ , d. The relational expression of ₂ and θ ₂ can be expressed by the above expression (1).
The reference portion B1 can be arbitrarily determined as long as it serves as a reference for position movement in the position adjusting unit 51. For example, the center of gravity of the position adjusting unit 51 may be the reference portion B1. By the way, when the tip of the position adjusting part 51 is spherical as in the present embodiment, the position of the abutting part of the position adjusting part 51 and the positioning part 25 moves on the spherical surface, so The contact portion cannot be the reference portion B1. On the other hand, when the needle shape or the rectangular parallelepiped shape is selected for the position adjusting section 51, the contact section between the position adjusting section 51 and the positioning section 25 does not move, so that the contact section can be the reference site B1. Is.

[Relational expression of position adjustment mechanism]
In the position adjusting mechanism in the adjusting unit 5, the amount of forward movement ds of the position adjusting unit 51 when the adjusting screw 54 is moved forward by dx position, the position adjusting unit 51, the rotary shaft member 52, the housing 53, A description will be given using a schematic diagram of the adjusting screw 54 and a relational expression shown below (see FIG. 9).
In FIG. 9, for convenience of description, when the center of the rotary shaft member 52 is the origin O, the contact portion between the adjusting screw 54 and the housing 53 is moved by A1, and the adjusting screw 54 is moved forward by dx. The position after the movement of A1 is A2, the rotation angle of the housing 53 when the adjusting screw 54 is moved forward dx is γ, the spherical center of the tip of the position adjusting portion 51 is the reference portion B1, and the housing 53 is an angle. A relational expression in the front-rear direction and the up-down direction will be described, where the position after the movement of the reference portion B1 when rotated by γ is B2.

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 α ₁ is α ₁ , and the angle parallel to the upward direction passing through O. The angle from the axis to A2 is β ₁ , the longitudinal distance between O and the reference portion B1 is l ₂ , the vertical distance between O and the reference portion B1 is r ₂ , and the reference portion 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.

Further, when the relational expression of 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 is If the housing 53 is rotated by using the adjusting screw 54 that is 0.5 μm / 1 rotation (advancing by 0.5 μm when rotated 360 °), the screw operation amount (degree) that is the rotation angle of the adjusting screw 54 and the position The relational expression with the position adjustment displacement amount (μm) in the front-rear direction of the adjusting portion 51 can be expressed as shown in FIG. In the equation (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) have a substantially proportional relationship. In addition, in FIG. 10A, 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.

  Further, FIG. 10B is a comparative example with respect to the present embodiment, and in the case of using the adjusting screw 54 having the same screw pitch of 0.5 μm / 1 rotation as in the present embodiment, the displacement amount of the tip end portion of the adjusting screw 54 is shown. As the position adjustment displacement amount, a relational expression between the screw operation amount (degree) and the position adjustment displacement amount (μm) is shown. Since the adjustment screw 54 of the comparative example moves in position in proportion to the angle (screw movement amount) by which the screw is rotated, the relational expression between the screw movement amount (degree) and the position adjustment displacement amount (μm) is a linear expression. expressed.

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

Further, although l ₁ , r ₁ , l ₂ , r ₂ , and the screw pitch have been described by showing an example of numerical values, it is naturally possible to appropriately change them. Further, by setting the value to be an appropriate value according to the application, it is possible to further increase the reduction ratio and to enhance the linearity of the relational expression of the screw operation amount and the position adjustment displacement amount.
Specifically, by increasing l ₁ or decreasing r ₂ , ds / dx can be decreased and the reduction ratio can be increased. Further, by increasing r ₁ or decreasing l ₂ , it is possible to improve the linearity of the relational expression between the screw operation amount and the position adjustment displacement amount.

[Modification 1]
Hereinafter, modified examples of the present embodiment will be described. Note that the description of the same configuration as that of the present embodiment is omitted.
Modification 1 is a modification in which position adjustment is performed at two different positions of the droplet discharge head 2, and an example will be described with reference to FIG. 11. For convenience of explanation, FIG. 11 is a schematic view showing only the positional relationship between the droplet discharge head 2 and the adjusting unit 5, and omits the details.

  The droplet discharge head 2 is provided with positioning portions 25 on one side surface parallel to the droplet discharge direction (vertical direction) of the droplet discharge head 2 and on the side surface facing the side surface. Specifically, for example, the droplet discharge head 2 is provided with one positioning portion 25 on each of the left side surface and the right side surface.

Further, the adjusting section 5 is separately provided corresponding to each positioning section 25, and the position adjusting section 51 of the adjusting section 5 is in contact with the positioning section 25.
Further, each of the positioning parts 25 is pressed in the direction of abutting against the position adjusting part 51 by an elastic member (not shown) as a biasing means provided in the holding part 3, as in the present embodiment. And are fixed by the respective contact portions (first contact portion T1 and second contact portion T2).

Further, by moving the position adjusting unit 51 in the front-rear direction, it is possible to adjust the position of the droplet discharge head 2 with respect to the holding unit 3 in a plane perpendicular to the droplet discharge direction (front-rear left-right direction).
Specifically, when the two position adjusting parts 51 are simultaneously moved in the same direction in the front-rear direction, it is possible to move the droplet discharge head 2 in the front-rear direction. When only one side position adjusting section 51 is moved in the front-back direction, the other one side position adjusting section 51 is rotatably fixed, so that the one-side position adjusting section 51 moves in the front-back direction. By the movement, the droplet discharge head 2 can be rotationally moved with respect to the front, rear, left, and right surfaces.

[Modification 2]
Modification 2 is a modification in which position adjustment is performed at three different positions of the droplet discharge head 2, and an example will be described with reference to FIG. For convenience of description, FIG. 12 is a schematic view showing only the positional relationship between the droplet discharge head 2 and the adjusting unit 5, and omits the details.

The droplet discharge head 2 is provided with, for example, adjustment units 5 on the left side surface and the rear side surface of the droplet discharge head 2, and the position adjustment units 51 of the respective adjustment units 5 are provided. , Is in direct contact with the main body of the droplet discharge head 2.
Further, the liquid droplet ejection head 2 is projected from the front side and the right side of the liquid droplet ejection head 2 to the respective position adjusting parts 51 by an elastic member (not shown) as a biasing means provided in the holding part 3. It is pressed in the contacting direction and is fixed by the respective contact portions (first contact portion T1, second contact portion T2 and third contact portion T3).

  Then, the position adjustment unit 51 provided on the rear side moves in the front-rear direction and the position adjustment unit 51 provided on the left side moves in the left-right direction, so that the holding unit 3 is perpendicular to the droplet ejection direction. It is possible to perform position adjustment on a flat surface (front-back, left-right direction).

[Modification 3]
Modification 3 is a modification of the configuration of the adjusting unit 5, and an example will be described with reference to FIG. 13. Note that, for convenience of description, FIG. 13 schematically illustrates the droplet discharge head 2, the holding unit 3 that schematically shows only the front and rear portions of the droplet discharge head 2, and the adjustment unit 5. It is shown in the figure and details are omitted.

The droplet discharge head 2 includes a holding plate 26 that projects between the droplet discharge unit 21 and the ink chamber 22 in the left-right direction, and the upper surface of the holding plate 26 includes the adjustment unit 5 similar to this embodiment.
A positioning unit 25 is provided on the front side of the holding unit 3 with the droplet discharge head 2 interposed therebetween, and an elastic member (not shown) provided on the rear side of the holding unit 3 moves the droplet discharge head 2 to the front side. The position adjusting portion 51 is fixed in a state of being pressed in the direction and abutting against the positioning portion 25.
By moving the position adjusting unit 51 in the front-rear direction, the droplet discharge head 2 can be moved with respect to the holding unit 3.

[Modification 4]
Modification 4 is a modification of the configuration of the adjusting unit 5, and an example will be described with reference to FIG. For convenience of explanation, FIG. 14 schematically shows the droplet discharge head 2, the holding portion 3 that simply shows only the front and rear portions of the droplet discharge head 2, and the adjustment portion 5. It is shown in the figure and details are omitted.

The droplet discharge head 2 includes a holding plate 26 protruding between the droplet discharge unit 21 and the ink chamber 22 in the left-right direction, as in the third modification.
The adjusting unit 5 of the present embodiment is provided on the rear side of the holding unit 3 with the droplet discharge head 2 interposed therebetween, and the position adjusting unit 51 of the adjusting unit 5 contacts the rear surface of the holding plate 26. It is provided so that it touches. Further, the liquid droplet ejection head 2 is pressed backward by an elastic member (not shown) provided on the front side of the holding unit 3, and the position adjusting unit 51 is fixed in a state of being abutted against the holding plate 26. ing.
By moving the position adjusting unit 51 in the front-rear direction, the droplet discharge head 2 can be moved with respect to the holding unit 3.
Although the position adjusting unit 51 is configured to abut against the holding plate 26, the abutting location can be changed as appropriate as long as it is a part of the droplet discharge head 2.

[Technical effects of the present invention]
As described above, in the droplet discharge head unit 1 of the present invention, the position of the droplet discharge head 2 is adjusted by moving the position adjusting portion 51 that comes into contact with the droplet discharge head 2, and the liquid is discharged to the recording medium. It is possible to improve the landing accuracy of drops.

  Further, the position adjusting mechanism according to the present invention has a simple structure and is capable of obtaining a high reduction rate, and can be provided by appropriately changing the design according to the shape and arrangement conditions of the droplet discharge head 2. Therefore, it is very useful as a means for adjusting the position of the droplet discharge head 2 and the like.

  Specifically, the adjusting unit 5 can reduce the moving amount of the position adjusting unit 51 with respect to the moving amount of the adjusting screw 54 by configuring the adjusting unit 5 to satisfy the above-described formula (1).

Further, the distance from the center of the rotary shaft member 52 of the housing 53 to the contact portion between the position adjusting portion 51 and the droplet discharge head 2 is the distance between the center of the rotary shaft member 52 of the housing 53 and the adjusting screw 54 and the housing 53. It is shorter than the distance to the contact part.
With such a configuration, the amount of movement of the position adjusting portion 51 can be further reduced with respect to the amount of movement of the adjusting screw 54, and a high reduction rate can be obtained.

  Further, the tip of the position adjusting portion 51 of the present invention has a spherical shape, and the tip is in contact with the positioning portion 25. With such a configuration, the contact portion between the position adjusting portion 51 and the positioning portion 25 can move stably on the spherical surface, so that stable position adjustment can be performed.

  Further, in the present embodiment, since the position fixing portion 23 is rotatably fixed to the position reference pin 4, the rotation angle can be adjusted with respect to the direction perpendicular to the droplet discharge direction. With such a configuration, the position adjustment of the droplet discharge head 2 can be performed by the position movement of the position adjustment unit 51 at one location, and the position adjustment operation can be performed more easily.

  Moreover, in the first modification, it is possible to perform the position adjustment at two different positions of the droplet discharge head 2. With such a configuration, since the absolute position of the droplet discharge head 2 can be adjusted with respect to the surface perpendicular to the droplet discharge direction, the position can be adjusted with higher accuracy.

  In the second modification, it is possible to perform position adjustment at three different positions on the droplet discharge head 2. With such a configuration, the absolute position can be adjusted with respect to the plane perpendicular to the droplet discharge direction while the droplet discharge head 2 is more stably fixed at three places, and thus the higher position can be obtained. The position can be adjusted accurately.

  Further, as in the third modification, the adjustment unit 5 is provided on the holding plate 26 of the droplet discharge head 2, and as in the fourth modification, the adjustment unit 5 is positioned with respect to the holding plate 26 of the droplet discharge head 2. The position can be adjusted by bringing the adjusting portion 51 into contact with each other. Even with such a configuration, the position of the droplet discharge head 2 can be adjusted with high accuracy.

[Other]
It should be considered that the embodiments disclosed herein of the present invention are illustrative in all points and not restrictive. The scope of the present invention is not limited to the above detailed description, but is defined by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope. .

For example, an example in which one to three adjusting units 5 are provided for the droplet discharge head 2 in the droplet discharge head unit 1 equipped with the position adjusting mechanism of the present embodiment, the modified example 1 and the modified example 2 is shown. However, if the configuration is such that one or more droplet discharge heads 2 are provided, the number of adjusting units 5 provided can be changed as appropriate.
Further, the arrangement location of the adjusting unit 5 is not limited to the embodiments of the present embodiment, the modified example 1 and the modified example 2, and can of course be appropriately changed.

  Further, as a position adjusting method performed by bringing the position adjusting unit 51 of the adjusting unit 5 into contact with each other, a method of contacting with the positioning unit 25 of the droplet discharge head 2, a method of contacting with the main body of the droplet discharge head 2, An example of a method of contacting the positioning part 25 provided on the holding part 3 and a method of contacting the holding plate 26 has been shown, but if the adjusting part 5 of the present invention is used, the position adjusting part 51 may be used. Of course, the location and method of contacting the can be changed appropriately.

Further, in the present embodiment, the V-shaped groove 24 of the position fixing portion 23 is rotatably fixed to the position reference pin 4, but it is possible to adjust the rotation angle of the droplet discharge head 2. The configuration can be changed as appropriate.
Further, although the position reference pin 4 is fixed to the holding unit 3, it can be changed as appropriate as long as the position fixing unit 23 can be fixed. It may be configured so that it can be moved left and right.

  Further, although the tip end portion of the position adjusting portion 51 is spherical, the tip end portion may be flat if the contact surface of the positioning portion 25 with which the tip end portion abuts is spherical. Here, it is technically possible to make both the tip end portion of the position adjusting portion 51 and the contact surface of the positioning portion 25 spherical or flat, but it is not stable when moving the position, so either It is desirable that one of them has a spherical shape.

  Further, although the example in which the adjusting screw 54 is used as the rotation adjusting unit that adjusts the rotation of the housing 53 has been described, the configuration can be appropriately changed as long as the housing 53 can be rotated. For example, the housing can be changed by displacement of the piezoelectric element. The configuration may be such that 53 is rotated.

  Further, the droplet discharge head 2 is configured to discharge droplets of ink or the like by using a piezoelectric element, but it is sufficient if it has a mechanism capable of discharging droplets, for example, thermal (electrothermal conversion element). May be used.

Further, an example in which different elastic members 31 and 32 are used as the means for urging the position fixing portion 23 to the position reference pin 4 and the means for urging the positioning portion 25 to the position adjusting portion 51 has been shown. Any means can be naturally changed as long as it can urge the droplet discharge head 2 to the position reference pin 4 and the position adjusting part 51. For example, the main body of the droplet discharge head 2 may be directly urged by one elastic member, and the elastic member 31 and the elastic member 32 provided between two adjacent droplet discharge heads 2 may be The same single elastic member may be used.
Further, as a method of fixing the droplet discharge head 2 to the holding portion 3, a fixing screw or the like may be further provided so as to be fixed to the holding portion 3.

  Furthermore, the scope of the present invention is not limited to the above, and various improvements and design changes may be made without departing from the spirit of the present invention.

  INDUSTRIAL APPLICABILITY The present invention can be used in a droplet discharge head unit including a droplet discharge head, a position adjusting method of the droplet discharge head, and an image forming apparatus such as an inkjet recording device including the droplet discharge head unit.

1 Droplet Ejection Head Unit 2 Droplet Ejection Head 23 Position Fixing Section 3 Holding Section 51 Position Adjusting Section 52 Rotating Shaft Member 53 Housing 54 Adjusting Screw (Rotation Adjusting Section)
100 image forming apparatus B1 reference part T1 first contact part T2 second contact part T3 third contact part

Claims (11)

A droplet discharge head for discharging droplets,
A holding portion that detachably holds the droplet discharge head;
A housing that is rotatable about a rotation axis that is perpendicular to the direction in which droplets are discharged from the droplet discharge head, by a rotation shaft member;
A rotation adjusting portion that abuts on the housing and adjusts the rotation of the housing;
A position adjusting unit which is provided in the housing and which adjusts a holding position of the droplet discharge head with respect to the holding unit by contacting the droplet discharge head;
Equipped with
A droplet discharge head unit characterized by satisfying the following expression (1).

(In the formula, d ₁ represents the distance from the center of the rotary shaft member to the contact portion of the rotation adjusting portion and the housing. Θ ₁ passes through the center of the rotary shaft member and The angle from the axis parallel to the moving direction to the contact portion of the rotation adjusting portion and the housing, d ₂ is from the center of the rotating shaft member to a reference portion that serves as a reference for position movement in the position adjusting portion. Represents a distance. Θ ₂ represents an angle from the axis passing through the center of the rotary shaft member and parallel to the moving direction of the droplet discharge head to the reference portion.) A droplet discharge head for discharging droplets,
A holding portion that detachably holds the droplet discharge head;
A housing rotatable by a rotary shaft member,
A rotation adjusting portion that abuts on the housing and adjusts the rotation of the housing;
A position adjusting unit which is provided in the housing and which adjusts a holding position of the droplet discharge head with respect to the holding unit by contacting the droplet discharge head;
Equipped with
Either the tip of the position adjusting section or the contact section of the droplet discharge head with which the position adjusting section contacts is spherical.
A droplet discharge head unit characterized by satisfying the following expression (1).

(In the formula, d ₁ Represents the distance from the center of the rotating shaft member to the contact portion of the rotation adjusting portion and the housing. θ ₁ Represents the angle from the axis passing through the center of the rotary shaft member and parallel to the moving direction of the droplet discharge head to the contact portion of the rotation adjusting portion and the housing. d _Two Represents the distance from the center of the rotating shaft member to a reference portion that serves as a reference for position movement in the position adjusting unit. θ _Two Represents the angle from the axis passing through the center of the rotary shaft member and parallel to the moving direction of the droplet discharge head to the reference portion. ) The distance from the center of the rotating shaft member to the contact portion between the position adjusting portion and the droplet discharge head is greater than the distance from the center of the rotating shaft member to the contact portion between the rotation adjusting portion and the housing. 3. The droplet discharge head unit according to claim 1, wherein the droplet discharge head unit is also short. Tip of the position adjusting section, or the liquid of claim 1 or 3 wherein the position adjusting section abutting portions of the liquid droplet ejecting head abuts, either of which being a spherical shape Drop discharge head unit. The droplet discharge head is
A first contact portion provided on one surface parallel to the droplet discharge direction of the droplet discharge head;
A second contact portion provided on another surface parallel to the droplet discharge direction of the droplet discharge head different from the one surface,
The holding portion is
The droplet discharge head includes a fixing portion that is fixed in a state in which the first contact portion is in contact with the droplet discharge head so as to be rotatable around an axis along the droplet discharge direction of the droplet discharge head.
The second contact portion, the liquid droplet ejection head unit according to any one of claims 1 to 4, characterized in that contact with the position adjusting section. The droplet discharge head is
A first contact portion provided on one surface parallel to the droplet discharge direction of the droplet discharge head;
A second contact portion provided on another surface parallel to the droplet discharge direction of the droplet discharge head different from the one surface;
Equipped with
The housing, the rotation adjusting portion, and the position adjusting portion are separately provided corresponding to the first contact portion and the second contact portion, respectively.
It said first contact portion and the second contact portion, the liquid droplet ejection head unit according to any one of claims 1 to 4, characterized in that contact with the position adjusting section corresponding to each. The droplet discharge head is
A first contact portion provided on a first surface parallel to the droplet discharge direction of the droplet discharge head;
A second contact portion provided on a second surface which is different from the first surface and is parallel to the droplet discharge direction of the droplet discharge head;
A third contact portion provided on a third surface parallel to the droplet discharge direction of the droplet discharge head;
Equipped with
The housing, the rotation adjusting portion, and the position adjusting portion are separately provided corresponding to the first contact portion, the second contact portion, and the third contact portion, respectively.
Said first contact portion, the second contact portion, and the third contact portion, to any one of claims 1-4, characterized in that contact with the position adjusting section corresponding to each The droplet discharge head unit described. Droplet discharge head unit according to any one of claims 1 to 7, characterized in that the droplet discharge heads, which are arrayed one-dimensionally or two-dimensionally. The housing, the rotation adjusting unit, and the position adjusting unit are provided corresponding to each of the plurality of arranged droplet discharge heads, and the adjacent droplet discharge heads are adjacent to each other in a predetermined direction. 9. The droplet discharge head unit according to claim 8, wherein the housing and the position adjusting unit corresponding to one of the droplet discharge heads are arranged. A position adjusting method of the droplet discharge head of the droplet ejection head unit according to any one of claims 1 to 9
A position adjusting method of a droplet discharge head, wherein the position adjusting unit is moved by rotation of the housing to adjust a holding position of the droplet discharging head with respect to the holding unit. An image forming apparatus comprising: a droplet ejection head unit according to any one of claims 1 to 9.

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