JPH09229081A - Shaft member supporting construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To support a shaft member without rattling by simple construction, without specially working the shaft member such as a guide shaft of a carriage. SOLUTION: The end 8b of a guide shaft 8 is inserted into the shaft hole part 36a of a plate-like frame 32, and a bearing bush 40 is fitted to the shaft end. At this time, the engaging pieces 49a, 49b of the bearing bush 40 are inserted inside the plate-like frame 32 through spread hole parts 36b, 7a. By rotating counterclockwise the bearing bush 40, the pressing piece 47 of the bearing bush 40 is pressed with the slope of a large contact hole part 36c, deformed inward in the radial direction, and the guide shaft 8 is pressure contacted with the shaft hole part 36a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft member supporting structure for supporting a shaft member on a plate-shaped frame, and more specifically, it is possible to restrict the radial movement of the shaft member (so-called rattling is eliminated). (Possible) shaft member support structure.

[0002]

2. Description of the Related Art Conventionally, as a shaft member supporting structure for supporting a shaft member in a plate-shaped frame, there is known a shaft-shaped frame member having a shaft hole portion in which a shaft member is inserted. However, it is extremely difficult to machine so that the inner diameter of the shaft hole and the outer diameter of the shaft member are exactly the same.
Even if it can be processed in this way, it becomes difficult to insert the shaft member. Therefore, it is considered that the shaft hole portion is formed to be slightly larger than the outer diameter of the shaft member so as to restrict the radial movement of the shaft member after the shaft member is inserted.

As the shaft member supporting structure for carrying out such a regulation, for example, a screw hole is provided in the shaft member and the shaft member is fixed to the plate-like frame with a screw, and a groove is provided on the outer periphery of the shaft member. Various structures such as a structure in which a wire spring is engaged with the groove to press the shaft member are considered.

[0004]

However, in these shaft member supporting structures, it is necessary to form screw holes and grooves in the shaft member. Therefore, in the machine having these shaft member supporting structures, the number of steps in the manufacturing process is increased, and the manufacturing cost cannot be sufficiently reduced.

Therefore, the present invention has been made for the purpose of providing a shaft member supporting structure which does not require special processing of the shaft member.

[0006]

Means for Solving the Problems and Effects of the Invention The invention according to claim 1 made to achieve the above object is a shaft member supporting structure for supporting a shaft member on a plate-shaped frame,
A shaft bush formed on the plate-shaped frame, having a shaft hole into which the shaft member can be inserted, a flange having a diameter larger than the shaft hole, and a bearing bush fitted to the shaft member, and the shaft hole. A large contact hole portion continuously formed from a part to the outer circumference, and a pressing piece portion that is connected to the plate frame side edge of the bearing bush and can be inserted into the large contact hole portion, By fitting the shaft member to the bearing bush, inserting the pressing piece into the large contact hole portion, and subsequently rotating the bearing bush, the pressing piece portion is caused by the inner wall of the large contact hole portion. It is characterized in that it is pressed against the shaft member.

Therefore, in the present invention, the shaft member is fitted to the bearing bush, and the pressing piece is inserted into the large contact hole.
Then, by rotating the bearing bush, the pressing piece is pressed against the shaft member by the inner wall of the large contact hole. By this pressure contact, the movement of the shaft member in the radial direction can be restricted. That is, in the present invention, since the shaft member is supported by the pressure contact of the pressing piece portion, it is not necessary to perform special processing such as a screw hole or a groove on the shaft member. Therefore, if the shaft member support structure of the present invention is applied to various machines, the number of steps in the manufacturing process of the machines can be reduced, and the manufacturing cost can be favorably reduced.

According to a second aspect of the present invention, in addition to the structure of the first aspect, at least one of the inner wall of the large contact hole portion and the outer wall of the pressing piece portion gradually extends along the rotational direction of the bearing bush. It is characterized by having an inclined portion with a small diameter. Therefore, in the present invention, the contact between the inclined portion and the outer wall of the pressing piece portion or the inner wall of the large contact hole portion causes the pressing piece portion to gradually move in the axial member direction in accordance with the rotation of the bearing bush. Therefore, by rotating the bearing bush, the pressing piece can be reliably pressed against the shaft member. Therefore, in the present invention, in addition to the effect of the invention described in claim 1,
There is an effect that the shaft member can be more reliably fixed.

The invention described in claim 3 is the first or second invention.
In addition to the configuration described, a part of the shaft hole portion is continuously formed in the outer peripheral direction, and an enlarged hole portion having a larger diameter than the large contact hole portion connected to the large contact hole portion, and the pressing An engagement piece portion that is formed continuously on the tip side of the piece portion and that can be inserted into the opposite side of the plate-shaped frame through the enlarged hole portion is further provided.

Therefore, in the present invention, if the engaging piece is inserted into the opposite side of the plate frame through the enlarged hole and then the bearing bush is rotated as described above, the engaging piece is formed. Engages with the opposite side of the plate frame. Therefore, it is possible to favorably prevent the bearing bush from coming off the plate frame. Therefore, in the present invention, in addition to the effect of the invention described in claim 1 or 2, the effect that the shaft member can be more reliably fixed occurs. Further, since the enlarged hole portion is formed so as to be connected to the large contact hole portion, it is not necessary to form many independent hole portions in the plate-shaped frame, and the strength of the plate-shaped frame is not reduced.

According to a fourth aspect of the present invention, in addition to the structure according to any one of the first to third aspects, the pressing piece portion is elastically deformable in the radial direction of the shaft member. Therefore, in the present invention, when the pressing piece portion is pressed against the shaft member as the bearing bush rotates, the pressing piece portion elastically deforms, and the shaft member can be reliably fixed by this elastic force.
Therefore, in the present invention, in addition to the effects of the invention according to any one of claims 1 to 3, there is an effect that the shaft member can be more reliably fixed.

According to a fifth aspect of the present invention, in addition to the structure according to any one of the first to fourth aspects, the shaft member is capable of contacting the inner wall of the shaft hole portion facing the large contact hole portion, When the bearing bush rotates, the shaft member is held by the pressing piece and the inner wall of the shaft hole.

Therefore, according to the present invention, when the bearing bush is rotated to press the pressing piece against the shaft member, the shaft member can be held between the pressing piece and the inner wall of the shaft hole. The shaft member can be securely fixed by this sandwiching. Therefore, in the present invention, in addition to the effects of the invention according to any one of claims 1 to 4, the effect that the shaft member can be more reliably fixed occurs.

According to a sixth aspect of the present invention, in addition to the structure of the third aspect, the bearing bush, the flange portion, the engaging piece portion, and the pressing piece portion are integrally molded of synthetic resin. Characterize. Therefore, according to the present invention, the bearing bush, the flange portion, the engaging piece portion, and the pressing piece portion can be manufactured very easily, and the manufactured members are extremely firmly integrated. Therefore, in the present invention, in addition to the effect of the invention according to claim 3,
This has the effect of simplifying the manufacturing process of the shaft member support mechanism itself and improving its durability. Therefore, if the shaft member support mechanism of the present invention is applied to various machines, the manufacturing cost of the machine is further reduced, and
The durability of the machine can be further improved.

According to a seventh aspect of the present invention, in the shaft member supporting structure according to any one of the first to sixth aspects, wherein the end portion of the shaft member is supported by the plate frame, the bearing bush is the shaft member. Is provided with a wall surface that prevents movement of the shaft member in the axial direction by abutting on one end thereof.

Therefore, in the present invention, the movement of the shaft member in the axial direction can be prevented by bringing the wall surface of the bearing bush into contact with one end of the shaft member. Therefore, in the present invention, in addition to the effects of the invention according to any one of claims 1 to 6, there is an effect that the axial movement of the shaft member can be surely restricted.

According to an eighth aspect of the present invention, in addition to the structure according to the seventh aspect, the shaft member is a guide shaft that supports a recording head of the printer so as to be movable in the axial direction. That is, the present invention applies the invention according to claim 7 to a guide shaft of a recording head of a printer. The recording head of the printer moves frequently along the guide axis,
Each time, an axial force is applied to the guide shaft. According to the present invention, the movement of the guide shaft (shaft member) in the axial direction can be reliably regulated as described in connection with claim 7,
The effect of the invention according to claim 7 becomes more remarkable.

According to a ninth aspect of the invention, in addition to the configuration of the eighth aspect, the recording head is an ink jet type recording head for ejecting ink onto a recording medium. In the ink jet type recording head, the force applied in the radial direction of the guide shaft is extremely smaller than that in the dot impact type recording head. Therefore, according to the present invention, in addition to the effect of the invention described in claim 8, the movement of the guide shaft (shaft member) in the radial direction can be regulated more reliably, and high-precision and clean dots can be recorded. The effect of being able to do is produced.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. This embodiment is an example in which the present invention is applied to an inkjet printer. As shown in FIGS. 1 and 2, in the inkjet printer 1, the main body unit 2 is fixed to a lower case 3 with screws (not shown). The carriage supporting frame 5 for supporting the carriage 4 has mounting portions 5a at both end portions thereof (FIG. 3).
At, it is fixed to the mounting portion 3a of the lower case 3 with screws. The recording head 6 of the carriage 4 includes four ink jet nozzles for ejecting and recording four color inks of magenta, yellow, cyan, and black, and four ink cartridges 7a to 7d for supplying ink to these ink jet nozzles, respectively. Have. This carriage 4
Is movably supported in the axial direction by a guide shaft 8, and a guide flange 9 formed in the carriage supporting frame 5 in parallel with the guide shaft 8 is slidably engaged with a guided groove 4a (FIG. 2) of the carriage 4. Accordingly, the carriage 4 is restricted from rotating by the guide flange 9. The carriage 4 includes a carriage driving motor 10 attached to the lower surface of the left end of the carriage supporting frame 5 and a wire and a pulley (neither is shown).
It is reciprocatingly driven in the left-right direction via. The front, rear, left, and right directions of the inkjet printer 1 are defined as indicated by arrows in FIG. 1 for convenience of description.

As shown in FIG. 2, a paper feed cassette 11 is detachably attached to the rear portion of the main body unit 2, and the paper in the paper feed cassette 11 is fed by a paper feed roller 12 and conveyed by a conveyance roller 13. Recording is performed by ejecting ink from the inkjet nozzles of the recording head 6 while the sheet is conveyed by the driven roller 14 and passes between the recording head 6 and the guide wall 15. The four support arms 16 that support the driven roller 14 are rotatably supported by the support shaft 17, and the spring 1
8 is urged toward the transport roller 13 side. The paper on which recording is performed by the ink jet nozzle is ejected by the ejection roller 19
And the spur roller 20 discharges to the discharge unit 21.

An electric component unit 22 including a power supply device and a circuit board is arranged below the main unit 2, and a unit cover 23 to which the electric component unit 22 is attached is fixed to the lower case 3 with screws. . In addition, on the lower case 3, a side case 24 that covers both left and right side surfaces of the main body unit 2 and the carriage movement space and a rear side surface of the main body unit 2, and an upper surface side of the main body unit 2 and the carriage movement space. An upper cover 25 for covering is provided.

Next, a guide shaft 8 for supporting the carriage 4
The support structure for supporting both ends of the (shaft member) on the carriage support frame 5 and the carriage support frame 5 will be described. As shown in FIGS. 1 to 3, the carriage supporting frame 5 is an integral part manufactured by forming a steel plate, and the carriage supporting frame 5 is parallel to the guide shaft 8 and is inclined backward about 45 degrees. And a pair of support frames 31 and 32 (corresponding to a plate-shaped frame) that are raised at right angles to both ends of the frame main body 30 arranged at right angles, and are vertically raised to the front end of the frame main body 30. Front wall 3
3 and the above-mentioned guide flange 9 which is bent at a right angle from the upper end of the front wall portion 33 to the rear side and is parallel to the guide shaft 8. The portion near the left end of the guide shaft 8 has the left side support frame 31.
The right end portion of the guide shaft 8 is supported by the right support frame 32.

Next, the support structure of the guide shaft will be described in detail. As shown in FIGS. 4 and 5, in order to support the portion near the left end of the guide shaft 8, the support frame 31 has a holding hole 34.
(FIG. 5) and a cut-and-raised portion 35 cut and raised from a portion near the holding hole 34 are formed. The cut-and-raised portion 35 is formed in a U-shape that is cut and raised orthogonally to the surface of the support frame 31 including the holding hole 34. FIG. 6 shows a state in which the holding hole 34 and the cut-and-raised portion 35A before bending are punched in the support frame 31, and the cut-and-raised portion 35A before bending is placed outside at the position of the folding curve 35B. 4 and 5 by bending at a right angle to
The holding hole 34 and the cut-and-raised portion 35 are formed. Although the upper end of the holding hole 34 is formed in an open shape, it is not shown in FIG.
The upper end portion of the holding hole 34 may be punched so that the upper end portion of the holding hole 34 is not opened as shown by the dotted line.

As shown in FIG. 5, the left end 8a of the guide shaft 8 is
Is inserted into the holding hole 34 from the right direction, the left end 8a of the guide shaft 8 is supported by the holding hole 34, and the end face of the guide shaft 8 is brought into contact with the cut-and-raised portion 35 to regulate the axial position of the guide shaft 8. . As shown in FIG. 7, since the right end 8b of the guide shaft 8 is supported by the support frame 32, the support frame 32 on the right side has an opening 39 including a main opening 36, an auxiliary opening 37, and a pin opening 38. With the right end 8b of the guide shaft 8 inserted into the main opening 36, a bearing bush 40 made of synthetic resin is fitted into the opening 39 from the outside.

As shown in FIGS. 7 and 9, the main opening 36
Is the shaft hole 36a into which the guide shaft 8 fits, and the shaft hole 36
Enlarged hole 3 formed continuously from a part of a in the outer peripheral direction
6b and a large contact hole portion 36c formed to have a smaller diameter than the enlarged hole portion 36b and smoothly connected to the enlarged hole portion 36b. The large contact hole portion 36c is formed so that its diameter gradually becomes smaller as it goes away from the enlarged hole portion 36b. That is, the large contact hole portion 36c has an inclined portion. Also,
The auxiliary opening portion 37 has an enlarged hole portion 37a formed substantially symmetrically with the enlarged hole portion 36b with respect to the center of the shaft hole portion 36a, and an arcuate hole portion formed in an arc shape substantially symmetrical with the great contact hole portion 36c. 37
b.

As shown in FIGS. 7 and 8, the bearing bush 4
0 is a concave fitting hole 4 into which the right end 8b of the guide shaft 8 is fitted.
1 (FIG. 8) is formed, a flange portion 43 formed on the outer periphery of the end of the cap portion 42 on the guide shaft 8 side (hereinafter referred to as the inner surface side), and is connected to the outer peripheral direction of the flange portion 43. Enlarged flange portion 44 having a substantially square shape, and engaging pin portion 4 protrudingly provided on the inner surface side of the enlarged flange portion 44.
5 (FIG. 8), an arc hole 46 (FIG. 7) formed on the outer surface side of the cap portion 42, and a thin wall formed on the peripheral wall of the cap portion 42 at a position corresponding to the outer peripheral side of the arc hole 46, and The pressing piece portion 47 extending in the inner surface direction of the support frame 32, the small protrusion 48 formed along the guide shaft 8 on the outer periphery of the pressing piece portion 47, and the outer periphery of the pressing piece portion 47 protruding and supported. An engagement piece portion 49a that engages with the inner surface side of the frame 32, and an engagement piece portion 49b that is formed substantially symmetrically with the engagement piece portion 49a and the guide shaft 8 and also engages with the inner surface side of the support frame 32. Have and. The pressing piece 4
Since 7 is formed thin and is arranged adjacent to the circular arc hole 46, it is elastically deformable in the radial direction of the fitting hole 41. The bearing bush 40 includes a cap portion 42, a flange portion 43, a pressing piece portion 47, and an engaging piece portion 49.
It is configured by integrally molding a, 49b and the like with a synthetic resin.

When the guide shaft 8 is assembled, before the left end 8a of the guide shaft 8 is supported by the support frame 31, the right end 8b of the guide shaft 8 is inserted into the main opening 36 from the inner surface side and then moved leftward. The left end 8a is inserted into the holding hole 34 and brought into contact with the cut and raised portion 35. Then, the engaging piece 49a,
The flange portion 43 of the bearing bush 40 is brought into contact with the outer surface of the support frame 32 so that 49b faces the enlarged hole portions 36b and 37a, respectively. At this time, the engaging piece 4
9a and 49b are inserted into the opposite side of the support frame 32 through the enlarged holes 36b and 37a. Further, the right end 8b is fitted in the fitting hole 41, and the end face thereof is the bottom surface 41a of the fitting hole 41.
(Fig. 8: Corresponds to the wall surface).

Next, the bearing bush 40 is rotated counterclockwise in FIG. 7 to fit the engagement pin portion 45 into the pin opening portion 38. Then, as shown in FIG. 9B, the engagement pieces 49 a and 49 b engage with the inner surface of the support frame 32. At this time, as shown in FIG. 9A, the small projection 48 is pressed by the outer peripheral surface of the large contact hole portion 36c. In addition,
FIG. 9A is taken along line BB of FIG.
9B is a cross-sectional view taken along line AA in FIG. 9A.

As described above, since the large contact hole portion 36c has a smaller diameter with increasing distance from the enlarged hole portion 36b, the pressing piece portion 47 is gradually pressed toward the right end 8b as the bearing bush 40 rotates. . Therefore, the right end 8b of the guide shaft 8
Is sandwiched between the pressing piece portion 47 and the inner wall of the shaft hole portion 36a, and is supported by the bearing bush 40 in a state where movement in the radial direction is restricted, that is, in a state where there is no rattling. Further, the small protrusion 48 undergoes plastic deformation and collapses (may be scraped) when the pressure contact force becomes excessive.
After the small protrusion 48 is crushed, the outer wall of the pressing piece portion 47 is in direct contact with the inner wall of the large contact hole portion 36c, but the outer wall of the pressing piece portion 47 also gradually becomes smaller along the rotation direction. That is, the pressing piece portion 47 also has an inclined portion. Therefore, the guide shaft 8 can be fixed extremely reliably by the above rotation of the bearing bush 40. Furthermore, the bearing bush 4
In No. 0, the support frame 32 is sandwiched between the flange portion 43 and the engaging piece portions 49a and 49b, and is fixed to the support frame 32. Therefore, the bearing bush 40 is attached to the support frame 3
It doesn't come off easily from 2.

As described above, in the bearing bush 40 and the support frame 32, the guide shaft 8 is supported by pressing the pressing piece portion 47 against the guide shaft 8, so that the guide shaft 8 has screw holes, grooves, etc. No special processing is required. Therefore, the number of steps in the manufacturing process of the inkjet printer 1 is reduced, and the manufacturing cost can be favorably reduced. Moreover, since the large contact hole portion 36c and the pressing piece portion 47 have the inclined portion, the pressure contact force of the pressing piece portion 47 gradually increases according to the rotation of the bearing bush 40, and the guide shaft 8
Can be securely fixed. Further, the pressing piece portion 47 is elastically deformed and pressed against the guide shaft 8 by its elastic force, so that the guide shaft 8 can be more reliably fixed. Furthermore, in the inkjet printer 1, since the force applied in the radial direction of the guide shaft 8 is smaller than that of the dot impact type printer, the guide shaft 8 can be more reliably fixed.

The bearing bush 40 is integrally formed of synthetic resin. Therefore, the bearing bush 40 can be easily manufactured and the durability thereof can be improved. Therefore, the manufacturing process of the inkjet printer 1 can be simplified, the manufacturing cost can be further reduced, and the durability thereof can be further improved. Furthermore,
Since the bottom surface 41a of the fitting hole 41 is in contact with the right end surface of the guide shaft 8, the axial movement of the guide shaft 8 can be reliably regulated. In the inkjet printer 1, the carriage 4 often moves and a large axial force is applied to the guide shaft 8. However, with the above configuration, the force can be effectively countered.

The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the scope of the present invention. For example, in the above embodiment, the pressing piece portion 47 is arranged at the connecting portion between the engaging piece portion 49a and the cap portion 42, but the pressing piece portion is independent of the engaging piece portions 49a and 49b. It may be provided. Further, in the above embodiment, both the large contact hole portion 36c and the pressing piece portion 47 have the inclined portion, but the inclined portion may be provided on only one of them. Also in this case, the pressing piece portion 47 can be reliably pressed against the guide shaft 8. Further, the inclined portion does not have to be provided in particular, and if the outer diameter of the pressing piece portion 47 is appropriately designed, the pressing piece portion 47 can be sufficiently pressed against the guide shaft 8.

Furthermore, in the above embodiment, the bearing bush 40 is integrally formed of synthetic resin. However, each part of the bearing bush 40 may be formed separately and assembled later, and it has elasticity. It may be composed of a material that does not exist. Further, in the above-described embodiment, the case where the present invention is applied to the shaft member support structure that supports the guide shaft 8 has been described as an example, but the present invention is a shaft member support structure that supports shaft members other than the guide shaft 8. Can be similarly applied to.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a configuration of an inkjet printer to which the present invention is applied.

FIG. 2 is a vertical cross-sectional left side view showing the configuration of the inkjet printer.

FIG. 3 is a plan view showing a configuration of a carriage support frame and a guide shaft.

FIG. 4 is a left side view showing a configuration of a guide shaft support structure of a left support frame.

FIG. 5 is a cross-sectional view taken along line VV showing the structure of the guide shaft support structure of the support frame.

FIG. 6 is a plan view showing a configuration of the support frame before bending.

FIG. 7 is an exploded perspective view showing a configuration of a guide shaft support structure of a right support frame.

FIG. 8 is a perspective view showing a configuration of a bearing bush.

FIG. 9 is a cross-sectional view showing a configuration of a guide shaft support structure of a right support frame.

[Explanation of symbols]

1 ... Inkjet printer 2 ... Main unit
4 ... Carriage 5 ... Carriage support frame 6 ... Recording head 8
... Guide shaft 30 ... Frame main body 31, 32 ... Support frame
34 ... Holding hole 35 ... Cut-and-raised part 36 ... Main opening 36a ... Shaft hole 36b, 37a ... Enlarged hole 36c ... Large contact hole 3
7 ... Auxiliary opening 37b ... Arc hole 38 ... Pin opening 40 ... Bearing bush 41 ... Fitting hole 41a ... Bottom 42 ... Cap
43 ... Flange part 44 ... Enlarged flange part 45 ... Engagement pin part 46 ...
Arc hole 47 ... Pressing piece portion 48 ... Small projections 49a, 49b ...
Engaging piece

Claims (9)

[Claims] 1. A shaft member supporting structure for supporting a shaft member in a plate-shaped frame, comprising a shaft hole portion formed in the plate-shaped frame, into which the shaft member can be inserted, and a diameter larger than the shaft hole portion. A bearing bush that has a flange portion and that fits into the shaft member, a large contact hole portion that is formed continuously from a part of the shaft hole portion to the outer periphery, and an edge of the bearing bush on the plate frame side. And a pressing piece portion that is connected to the large contact hole portion, and the shaft member is fitted to the bearing bush, and the pressing piece portion is inserted into the large contact hole portion. A shaft member support structure, wherein the pressing piece is pressed against the shaft member by the inner wall of the large contact hole by rotating the bearing bush. 2. At least one of the inner wall of the large contact hole portion and the outer wall of the pressing piece portion has an inclined portion whose diameter gradually decreases along the rotation direction of the bearing bush. Item 1. The shaft member support structure according to item 1. 3. An enlarged hole portion which is formed continuously from a part of the shaft hole portion in the outer peripheral direction and has a diameter larger than the large contact hole portion connected to the large contact hole portion, and the pressing piece. The engaging piece portion which is continuously formed on the distal end side of the portion and can be inserted into the opposite side of the plate-shaped frame through the enlarged hole portion, further comprising: Shaft member support structure. 4. The shaft member support structure according to claim 1, wherein the pressing piece is elastically deformable in the radial direction of the shaft member. 5. The shaft member is capable of contacting the inner wall of the shaft hole portion facing the large contact hole portion, and when the bearing bush is rotated, the pressing piece portion and the inner wall of the shaft hole portion are used. The said shaft member is clamped, The Claim 1 characterized by the above-mentioned.
The shaft member support structure according to any one of to 4. 6. The shaft member supporting structure according to claim 3, wherein the bearing bush, the flange portion, the engaging piece portion, and the pressing piece portion are integrally molded of synthetic resin. 7. The shaft member supporting structure according to claim 1, wherein an end portion of the shaft member is supported by the plate-shaped frame, wherein the bearing bush is in contact with one end of the shaft member. The shaft member support structure is characterized by including a wall surface for preventing the shaft member from moving in the axial direction. 8. The shaft member support structure according to claim 7, wherein the shaft member is a guide shaft that supports the recording head of the printer so as to be movable in the axial direction. 9. The shaft member support structure according to claim 8, wherein the recording head is an inkjet recording head that ejects ink onto a recording medium.