JP4410362B2 - Recording head positioning mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording head positioning mechanism for positioning a recording head of an inkjet printer at a predetermined position, for example.
[0002]
[Prior art]
The ink jet printer has at least one recording head facing a conveyance surface that conveys a recording medium. A large number of ink discharge ports arranged in a direction crossing the conveyance direction of the recording medium are formed at the front end portion where the recording head faces the conveyance surface. In order to form a high-definition image, each ink discharge port is formed in a very small diameter and arranged in high density.
[0003]
For this reason, in particular, in a color printer of a type in which a plurality of recording heads having different ink colors are arranged side by side along the conveyance direction of the recording medium, the ink is discharged through a large number of ink discharge ports provided in the recording heads of the respective colors. In order to superimpose the inks of the respective colors on the recording medium with high accuracy, extremely advanced techniques are required. For this reason, in the conventional color printer, it is necessary to position the recording heads of the respective colors relative to the conveyance surface with high accuracy.
[0004]
[Problems to be solved by the invention]
However, conventional ink jet printers have no effective means for positioning the recording heads of each color with high accuracy. For example, there is a problem that the recording heads are displaced due to vibrations caused by paper jams or vibrations during transportation. there were.
[0005]
The present invention has been made in view of the above points, and an object thereof is to provide a recording head positioning mechanism capable of positioning a recording head with high accuracy.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the recording head positioning mechanism of the present invention is arranged in a second direction orthogonal to the first direction with respect to a conveyance surface that conveys a sheet-like recording medium along the first direction. A recording head having a tip portion provided with a plurality of ink ejection openings along a reference surface disposed opposite one end along the second direction of the recording head, and the recording A first head provided opposite to the other end of the head along the second direction, pressing the other end so as to press the one end against the reference surface, and urging the recording head toward the one end; An urging member and an adjusting unit that presses the one end in a direction away from the reference surface against the urging force of the first urging member and adjusts the position of the recording head along the second direction. And away from the conveying surface of the recording head A holding means for holding the rear end portion, a regulating member which is disposed opposite to one side along the first direction in the vicinity of the tip portion and restricts the tip portion from moving to the one side; and the tip end A second urging member that urges the portion toward the regulating member.
[0007]
According to the above invention, the recording head has its one end along the second direction pressed against the reference plane by the first biasing member, and the position along the second direction is adjusted by the adjusting means. Further, the recording head is held at the rear end by the holding means, and the front end is pressed against the regulating member by the second urging member, so that the movement along the first direction is regulated. That is, by the positioning mechanism of the present invention, the position of the recording head along the second direction can be adjusted with high accuracy, and the position along the first direction can be positioned with high accuracy.
[0008]
According to the above-described invention, the rear end portion of the recording head has a shaft extending in parallel with the second direction, and the holding means has a support member that rotatably supports the shaft. It is characterized by that.
[0009]
Accordingly, the recording head is supported so as to be swingable around the rear end portion thereof, and the front end portion thereof is regulated by the regulating member, so that backlash at the rear end portion can be eliminated, and the first front end portion can be eliminated. The movement in the direction can be regulated with higher accuracy.
[0010]
Further, according to the above-described invention, the second urging member has a leaf spring attached to the recording head that acts on the regulating member.
[0011]
Thus, the structure of the positioning mechanism can be simplified by attaching the leaf spring to the recording head side.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 shows a schematic configuration of an ink jet printer (hereinafter simply referred to as a printer) 1 to which the present invention is applied.
[0014]
The printer 1 has a housing 2, and a substantially cylindrical drum 3 that rotates counterclockwise in the figure at a constant peripheral speed is disposed at a predetermined position in the center of the housing 2. The rotating shaft of the drum 3 extends horizontally from the front side to the rear side of the printer 1 and is rotatably attached to a frame (not shown) fixed to the housing 2.
[0015]
Around the drum 3, a charging charger 4 that charges the outer peripheral surface 3 a (conveying surface) of the drum 3 and charges it to a predetermined potential, and a recording that is electrostatically attracted onto the outer peripheral surface 3 a by the action of the charging charger 4. Nozzle unit 5 that forms a color image by spraying ink on paper as a medium, and a peeling claw (not shown) that peels off the paper on which an image is formed by being adsorbed on outer peripheral surface 3a from drum 3 3 are arranged in order along the rotation direction.
[0016]
The nozzle unit 5 is lifted and lowered by the lifting mechanism 6 in the illustrated position close to the upper side of the drum 3, a maintenance position spaced a predetermined distance above the printing position, and a fixed position spaced further upward from the maintenance position. It is provided to be selectively movable at the position.
[0017]
Further, the nozzle unit 5 is arranged at the illustrated printing position, and has four nozzle heads 5C, 5M, 5Y each having a tip portion facing the outer peripheral surface 3a of the drum 3 with an interval of 1 mm, for example. 5B (recording head). The nozzle heads 5C, 5M, 5Y, and 5B are held by the nozzle unit 5 so as to extend radially from the central axis 3c (see FIG. 2) of the drum 3, and the rotation direction of the drum 3, that is, the sub-scanning direction ( Are spaced apart from each other by a predetermined distance along the first direction. In addition, a large number of ink discharges (not shown) arranged in parallel at equal intervals along the axial direction of the drum 3, that is, the main scanning direction (second direction), are provided at the tip portions of the nozzle heads 5C, 5M, 5Y, and 5B. There is an exit.
[0018]
A maintenance mechanism 10 for cleaning a large number of ink discharge ports provided at the tip of each nozzle head 5C, 5M, 5Y, 5B of the nozzle unit 5 is swingably attached to the rotating shaft of the drum 3. Yes. The maintenance mechanism 10 is disposed between the drum 3 and the nozzle unit 5 with the nozzle unit 5 moved to the above-described maintenance position, and cleans a large number of ink ejection openings of the nozzle heads 5C, 5M, 5Y, and 5B. To do.
[0019]
A paper feed cassette 7 that stores a plurality of sheets in a stacked state is disposed at the bottom of the housing 2, and a discharge tray 8 that discharges sheets on which images are printed is disposed on the top surface of the housing 2. ing. A manual tray 9 for manually feeding paper is attached to the right side wall portion of the housing 2 in the drawing. Further, in the housing 2, each color (C: cyan, M: magenta, Y: yellow, B: black) to be supplied to a number of ink discharge ports of the nozzle heads 5 C, 5 M, 5 Y, and 5 B of the nozzle unit 5. An ink tank 11 containing ink is provided.
[0020]
Thus, the sheets stored in the sheet feeding cassette 7 are picked up one by one from the top end by the pickup roller 7a, or the sheets supplied through the manual feed tray 9 are picked up one by one by the pickup roller 9a. The tip of the aligning roller 12 is once aligned. On the other hand, a predetermined charge is applied to the outer peripheral surface 3 a of the drum 3 rotated at a constant speed through the charging charger 4 in accordance with the feeding timing of the sheet aligned by the aligning roller 12. A predetermined region of the outer peripheral surface 3a is charged to a predetermined potential.
[0021]
Then, the paper aligned by the aligning roller 12 is supplied toward the outer peripheral surface 3 a charged to a predetermined potential, and the paper is electrostatically attracted to the outer peripheral surface 3 a of the drum 3. The sheet electrostatically attracted to the outer peripheral surface 3a of the drum 3 is moved in the sub-scanning direction as the drum 3 rotates, and passes through the printing area between the nozzle unit 5 disposed at the printing position. Ink of each color is ejected through a large number of ink ejection openings of the nozzle heads 5C, 5M, 5Y, and 5B of the nozzle unit 5 to form a color image on the paper.
[0022]
The paper on which the color image has been formed in this manner is peeled off from the outer peripheral surface 3a of the drum 3 by a not-shown peeling claw, is nipped and conveyed by a pair of feed rollers 13, and passes through a plurality of pairs of discharge rollers 14, 15, and 16. And discharged onto the discharge tray 8.
[0023]
Next, a positioning mechanism of the present invention for positioning each nozzle head 5C, 5M, 5Y, 5B with high accuracy in the nozzle unit 5 will be described with reference to FIGS. FIG. 2 is a front view of the positioning mechanism as viewed from the front side of the printer 1, and FIG. 3 is a side view of the nozzle head 5C as viewed along the sheet conveyance direction, for example.
[0024]
As shown in FIG. 2, the nozzle unit 5 has four accommodating portions 21C, 21M, 21Y, and 21B for mounting the nozzle heads 5C, 5M, 5Y, and 5B. Each of the accommodating portions 21C, 21M, 21Y, and 21B extends radially from the central axis 3c of the drum 3 in a state where the nozzle unit 5 is disposed at the illustrated printing position. Nozzle heads 5C, 5M, 5Y, and 5B are inserted and attached to the respective accommodating portions 21C, 21M, 21Y, and 21B from above the nozzle unit 5.
[0025]
Since the positioning mechanisms for positioning the nozzle heads 5C, 5M, 5Y, and 5B in the accommodating portions 21C, 21M, 21Y, and 21B all have the same configuration, in the following description, the positioning is particularly focused on one nozzle head 5C. The mechanism will be described.
[0026]
As shown in FIG. 3, a substantially rectangular frame member 22 is fixed to the lower end of the accommodating portion 21 </ b> C near the drum 3. With the nozzle head 5C mounted in the accommodating portion 21C, the inner side of the frame member 22 facing the longitudinal direction (left and right direction in the figure) of the nozzle head 5C, that is, one end along the main scanning direction (left end part in the figure). The wall functions as a reference surface 22a (see FIG. 4) serving as a reference for adjusting the position along the main scanning direction of the nozzle head 5C.
[0027]
A leaf spring 23 that functions as a first urging member is fixed to the inner wall of the accommodating portion 21C that is opposed to the other end (right end portion in the drawing) of the nozzle head 5C. The spring 23 presses the other end of the nozzle head 5C and biases the nozzle head 5C in a direction in which one end of the nozzle head 5C is pressed against the reference surface 22a.
[0028]
On the other hand, a direction in which one end of the nozzle head 5C pressed against the reference surface 22a by the spring 23 is separated from the reference surface 22a against the urging force of the spring 23 is provided on the side wall of the accommodating portion 21C facing one end of the nozzle head 5C. An adjusting screw 24 (adjusting means) that pushes back is screwed together. The adjustment screw 24 is screwed from the outside of the side wall of the accommodating portion 21C, and the tip thereof abuts on one end of the nozzle head 5C. That is, by adjusting the adjustment screw 24, the position along the main scanning direction in the accommodating portion 21C of the nozzle head 5C can be adjusted.
[0029]
As shown in FIGS. 2 and 3, the upper end holding portion functioning as the holding means of the present invention is provided at both ends along the main scanning direction of the upper end portion (rear end portion) spaced from the drum 3 of the nozzle head 5C. 26 is provided.
[0030]
As shown in more detail in FIG. 5, the upper end holding portion 26 is a pair of support shafts 25 a and 25 b (hereinafter collectively referred to as the support shaft 25) extending along the main scanning direction from the upper end portion of the nozzle head 5 </ b> C. A bearing portion 27 (support member) that rotatably holds the support shaft 25, a fixing member 28 for fixing the bearing portion 27 to the upper end of the accommodating portion 21C, and the bearing portion 27 as a fixing member. There are screws 29 for attaching to 28.
[0031]
On the other hand, the frame member 22 fixed to the lower end of the accommodating portion 21C is provided with a pair of restricting members 31 for restricting the lower end portion of the nozzle head 5C from moving to one side along the sub-scanning direction. Has been. As shown in FIGS. 3 and 4, the pair of regulating members 31 are provided corresponding to both ends along the main scanning direction of the nozzle head 5 </ b> C, and abut on one side near the lower end of the nozzle head 5 </ b> C. The movement of the lower end of the nozzle head 5C is restricted.
[0032]
A pair of leaf springs 32 (second urging members) acting on a pair of regulating members 31 provided corresponding to both ends in the main scanning direction are attached to one side of the nozzle head 5C. When the nozzle head 5C is inserted into the accommodating portion 21C, the pair of leaf springs 32 act on the corresponding restricting members 31 and bias the lower end portions of the nozzle head 5C in a direction to press the restricting members 31.
[0033]
The positioning mechanism configured as described above operates as follows.
[0034]
First, the bearing portion 27 is fitted into the two support shafts 25a and 25b protruding from the upper end portion of the nozzle head 5C. Then, the nozzle head 5C with the bearing portion 27 attached in this way is inserted from the upper end of the accommodating portion 21C, and the nozzle head 5C is attached into the accommodating portion 21C. At this time, the pair of leaf springs 32 attached in the vicinity of the lower end of the nozzle head 5C act so as to sandwich the pair of restricting members 31 protruding from the frame member 22 fixed to the lower end of the accommodating portion 21C. The lower end of the nozzle head 5C is pressed against the regulating member 31. At the same time, the pair of bearing portions 27 attached to the upper end portion of the nozzle head 5C are fitted into a pair of fixing members 28 fixed to the upper end of the accommodating portion 21C.
[0035]
The bearing portion 27 fitted to each fixing member 28 is fixed to the fixing member 28 by screws 29. Thus, by fixing the bearing portion 27 holding the support shaft 25 of the nozzle head 5C in a freely rotatable manner to the fixing member 28 fixed to the upper end of the accommodating portion 21C, the nozzle head 5C is moved upward from the accommodating portion 21C. Can be prevented. In this state, the nozzle head 5C can swing around the support shaft 25 at the upper end.
[0036]
On the other hand, when the nozzle head 5C is inserted into the housing portion 21C, the other end of the nozzle head 5C is attached to the inner wall of the housing portion 21C opposite to the other end along the main scanning direction of the nozzle head 5C. The one end of the nozzle head 5C is pressed against the reference surface 22a of the frame member 22 fixed to the lower end of the accommodating portion 21C. Since the upper end portion of the nozzle head is rotatably supported by the above-described upper end holding portion 26 and the lower end portion thereof is only pressed against the regulating member 31, it can move slightly in the main scanning direction. ing.
[0037]
For this reason, the nozzle head 5C is moved in the main scanning direction by pressing one end of the nozzle head 5C pressed against the reference surface 22a with the adjusting screw 24 against the urging force of the spring 23, and the nozzle head 5C is moved. The position along the main scanning direction is adjusted.
[0038]
As described above, according to the positioning mechanism of the present embodiment, the upper end portion of the nozzle head 5C is rotatably held by the upper end holding portion 26, and the lower end portion of the nozzle head 5C is pressed against the regulating member 31 to perform the sub scanning direction. The position of the nozzle head 5C along the main scanning direction is adjusted by the adjusting screw 24.
[0039]
That is, since the bearing portion 27 that rotatably supports the support shaft 25 protruding from the upper end portion of the nozzle head 5C is fixed to the upper end of the accommodating portion 21C, the nozzle head 5C comes out from the accommodating portion 21C upward. Can be prevented. Further, since the upper end portion of the nozzle head 5C is rotatably held by the upper end holding portion 26 and the lower end portion of the nozzle head 5C is pressed against the restricting member 31, it is possible to prevent backlash at the upper end portion of the nozzle head 5C. The head 5C can be positioned with high accuracy along the sub-scanning direction. Furthermore, since the nozzle head 5C has a configuration in which one end along the main scanning direction is pressed against the reference surface 22a and the one end is pushed away from the reference surface 22a by the adjusting screw 24, the nozzle head 5C is moved in the main scanning direction. The position along can be positioned with high accuracy and ease.
[0040]
According to the positioning mechanism of the present invention, the nozzle head 5C can be positioned with high accuracy with respect to the nozzle unit 5 as described above.
[0041]
Further, the insertion / removal of the nozzle head 5C with respect to the nozzle unit 5 can be accessed from above the nozzle unit 5, and the nozzle head 5C can be easily removed simply by removing the screw 29 of the upper end holding portion 26.
[0042]
Furthermore, at the same time that the nozzle head 5C is inserted from above the nozzle unit 5, the lower end side of the nozzle head 5C can be automatically positioned at a predetermined position in the sub-scanning direction.
[0043]
In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible within the scope of this invention.
[0044]
【The invention's effect】
As described above, since the recording head positioning mechanism of the present invention has the above-described configuration and operation, the recording head can be positioned with high accuracy with respect to the transport surface.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an ink jet printer to which the present invention is applied.
2 is a front view showing a schematic configuration of a nozzle unit incorporated in the ink jet printer of FIG. 1. FIG.
3 is a side view of the nozzle head incorporated in the nozzle unit of FIG. 2 as viewed in the paper transport direction.
FIG. 4 is a partial perspective view partially showing a frame member provided in a housing portion for mounting the nozzle head to the nozzle unit.
FIG. 5 is a cross-sectional view showing components of a holding unit that holds the upper end of the nozzle head rotatably with respect to the upper end of the housing unit.
[Explanation of symbols]
1 ... Inkjet printer,
2 ... Housing,
3 ... Drum,
3a ... outer peripheral surface,
5 ... Nozzle unit,
5C, 5M, 5Y, 5B ... Nozzle head,
21C, 21M, 21Y, 21B ... accommodating portion,
22 ... Frame member,
22a ... reference plane,
23 ... Spring,
24 ... adjusting screw,
25a, 25b ... support shaft,
26 ... upper end holding part,
27 ... Bearing part,
28 ... a fixing member,
29 ... Screw,
31 ... restricting member,
32 ... leaf spring.

Claims (3)

A recording head having a front end portion provided with a plurality of ink discharge ports along a second direction orthogonal to the first direction with respect to a conveyance surface that conveys a sheet-like recording medium along the first direction. A positioning mechanism for positioning,
A reference surface disposed opposite one end of the recording head along the second direction;
The recording head is provided opposite to the other end of the recording head in the second direction, presses the other end so as to press the one end against the reference surface, and biases the recording head toward the one end. 1 biasing member;
Adjusting means for pressing the one end in a direction away from the reference plane against the urging force of the first urging member to adjust the position of the recording head along the second direction;
Holding means for holding a rear end portion of the recording head spaced apart from the conveying surface;
A regulating member disposed opposite to one side along the first direction in the vicinity of the tip, and restricting the tip from moving to the one side;
A second urging member that urges the tip toward the restriction member;
A recording head positioning mechanism characterized by comprising: The rear end of the recording head has an axis extending in parallel with the second direction,
2. The recording head positioning mechanism according to claim 1, wherein the holding unit includes a support member that rotatably supports the shaft. 2. The recording head positioning mechanism according to claim 1, wherein the second urging member includes a leaf spring attached to the recording head that acts on the regulating member.

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