JP2001222069A - Retaining mechanism, and image forming device equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retaining mechanism capable of accurately fixing a pipe type shaft. SOLUTION: A rectangular hole 102 orthogonal to an axial direction is formed on the pipe type shaft 16. Meanwhile, a copper wire 114 is wound round a projection 112 by specified tension on a supporting plate 108 where the shaft 16 is inserted through a hole part 110. The wire 114 advances into the hole 102 and presses the peripheral direction end 116 of the hole 102, that is, the shaft 16 to the lower part of the hole part 110 of the plate 108. Thus, the shaft is prevented from moving up and down and its displacement in a thrust direction is restrained. Furthermore, the wire 114 abuts on the end 116 of the hole 102, thereby, the rotation of the shaft 16 is prevented. Therefore, the shaft 16 is not vibrated and is accurately fixed even when a scanning member performs scanning while it is guided by the shaft 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a locking mechanism for locking a shaft supporting a scanning member to a frame member, and an image forming apparatus provided with the locking mechanism.

[0002]

2. Description of the Related Art For example, in an image forming apparatus, a scanning head having a light emitting unit such as an LED and a lens mechanism for focusing on a predetermined position is configured to be guided by two shafts so that scanning is possible. . Therefore, if the shaft is displaced in the thrust direction or vibrates up and down with the scanning of the scanning head, the scanning state is deteriorated and image formation is deteriorated. Therefore, it is necessary to securely lock the shaft to the frame member. As a method of securely locking the shaft, a groove extending in a direction perpendicular to the axial direction is formed on the surface of the rod-shaped shaft, and a locking member is inserted into the groove to lock the frame member. Is being done.

On the other hand, a shaft having a hollow pipe shape may be used in order to avoid bending due to its own weight.

[0004]

As described above, a method of forming a groove in a shaft and locking it to a frame member with a locking member with high accuracy is general, but a pipe shape is used for weight reduction. It is difficult to form a groove in the shaft.

In order to lock such a shaft to the frame member, a round hole is formed in the surface of the shaft, a projection of the locking member is inserted into the hole, and the locking member and the frame member are abutted. A method for fixing a shaft has been proposed.

However, there is a disadvantage that the unit price is increased because the locking member has a special shape. In addition, since the locking member is merely attached to the shaft and abutted against the frame member, there has been a disadvantage that the vertical movement or rotation of the shaft due to scanning of the scanning member cannot be suppressed.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a locking mechanism capable of accurately fixing a pipe-shaped shaft and an image forming apparatus including the locking mechanism.

[0008]

According to a first aspect of the present invention, there is provided a pipe-shaped shaft having a hole formed in an outer peripheral surface thereof, and a supporting member having a through hole or a concave portion into which the shaft is inserted. A locking member attached to the support member and engaged with a hole of the shaft inserted into the through hole or inserted into the concave portion to urge the shaft toward the side opposite to the hole. It is characterized by.

The operation of the present invention will be described.

After the shaft is inserted into the through hole of the support member or inserted into the concave portion, the locking member attached to the support member is engaged with the hole formed on the outer peripheral surface of the shaft. As a result, the shaft is urged to the opposite side of the hole,
It is pressed against one of the through hole or the concave portion of the support member. Therefore, the shaft is prevented from moving up and down due to the scanning of the scanning member. Further, the engagement (entrance) of the locking member into the hole limits the displacement of the shaft in the thrust direction. Furthermore, since the locking member locks the shaft at both ends in the circumferential direction of the hole, rotation of the shaft is also prevented.

That is, fluctuation (vibration) of the shaft caused by scanning of the scanning member is reliably prevented, and the scanning member can be stably scanned.

According to a second aspect of the present invention, in the first aspect of the present invention, the locking member is provided between a pair of projections provided on a support member and the pair of projections, and is in contact with the hole. And a wire rod that is elastically deformed.

The second aspect of the present invention will be described.

After the shaft is inserted into the through hole of the support member or inserted into the concave portion, the wire attached between the pair of projections provided on the support member is elastically deformed by contact with the hole. As a result, the shaft is urged to the opposite side of the hole by the elastic force of the wire, and the shaft is pressed against one of the through holes of the support member. Therefore, the vertical movement of the shaft due to the scanning of the scanning member can be prevented. Further, the displacement of the shaft in the thrust direction is regulated by engaging (entering) the elastically deformed wire into the hole. Furthermore, since the wire is engaged at the circumferential end of the hole, rotation of the shaft is also prevented.

According to a third aspect of the present invention, in an image forming apparatus for forming an image on a photosensitive material by scanning an exposure head, a shaft for guiding the exposure head includes:
It is locked by the locking mechanism according to claim 1 or 2.

The operation of the invention will be described.

Since the shaft is suppressed from vibrating when the exposure head scans, an accurate image can be formed by the exposure head. In addition, even when the shaft vibrates, since the hollow pipe is used for the shaft, the natural frequency increases (100 Hz or more) as compared with the rod-shaped shaft, and image blur due to the vibration of the shaft is not visually recognized. There is also an advantage.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. (Schematic Description of Image Forming Apparatus) First, an outline of an image forming apparatus using the locking mechanism according to the present invention will be described.

As shown in FIG. 1, in a photosensitive material magazine 58 disposed below a housing 56 of the image forming apparatus 54, a photosensitive material 40 wound around a supply reel 60 is set. The supply reel 60 is rotated by driving means (not shown) to unwind the photosensitive material 40.

The leading end of the photosensitive material 40 is nipped by a pull-out roller 62 provided at the mounting opening of the photosensitive material magazine 58. The pull-out roller 62 pulls out the photosensitive material 40 under a predetermined condition and sends it out to the guide plate 64, or a buffer under the predetermined condition (indicated by a two-dot chain line)
To form

The photosensitive material 40 that has passed through the guide plate 64 is
The image is wound around the exposure drum 14 and an image is exposed by the scanning head 28. In this way, the photosensitive material 40 is wound around the exposure drum 14 and exposed to light, whereby the photosensitive material 4 is exposed.
No wrinkles or the like occur in the width direction of 0, and the flatness of the exposed surface can be ensured.

The image-exposed photosensitive material 40 is sandwiched between a support 65 and a pressure plate 66, and water is applied by a water-absorbing application member 70 (such as a sponge) provided in an application tank 68.

The photosensitive material 40 coated with water is wound around a heat drum 72 having a built-in halogen lamp by tension rollers 74 and 76 at a constant pressure. The wound photosensitive material 40 is superposed from above on an image receiving paper 78 while being heated, and transfers an image.

Next, the photosensitive material 40 onto which the image has been transferred is taken up on a waste reel 80. Thus, the photosensitive material 4
0 is not cut and the supply reel 60 is discarded from the supply reel 60.
The photosensitive material 40 itself functions as a timing belt that applies a constant pressure to the image receiving paper 78.

On the other hand, an image receiving paper 78 wound around a supply reel 84 is set in a receiving material magazine 82 arranged above the housing 56. The image receiving paper 78 is pulled out by a nip roller 86 and cut to a predetermined length.
Is guided by the conveying roller 90 and the guide plate 92, and is wound around the heat drum 72 while being superposed on the photosensitive material 40.

The image receiving paper 78 onto which the image has been transferred from the photosensitive material 40 is peeled off from the heat drum 72 by a peeling claw (not shown), guided by the transport roller 94 and the guide plate 96, and reaches the tray 98. (Explanation of the exposure unit) Next, the exposure unit in which the shaft is locked by the locking mechanism will be described. 1 and 2 show an exposure unit 10 provided with a drive mechanism for a scanning head.

In the exposure section 10, both ends of an exposure drum 14 are supported on a rotatable rotating shaft 12. The exposure drum 14 has a cylindrical shape, and the exposure surface has a constant curvature about the rotation axis 12.

On the upper left side of the exposure drum 14, two shafts 16 and 18 are disposed in parallel with the rotation shaft 12. The shafts 16 and 18 are supported by the support block 2.
0 and 22 are inserted through the through holes 24 and 26 so that a scanning head 28 described later can slide along the shafts 16 and 18. In addition, two support blocks 20 and one support block 22 are provided on the side of the exposure drum 14,
The three planes constitute a plane.

The casing 30 of the scanning head 28 is fixed to the support blocks 20, 22. Inside the bottom plate 32 of the casing 30, three LED chips 36 of RGB which are turned on by a signal from the control unit 34 in which an image signal is stored are provided. Is turned.

Three LED chips 36 are arranged along the main scanning direction of the exposure head 28, and each chip has 31 elements in the sub-scanning direction. LED chip 3
6, a slit plate 38 is provided on the light emitting surface side.
Limits the spread of light.

The imaging lens 4 is provided inside the slit plate 38.
2 are arranged. The imaging lens 42 includes a plurality of lenses and an aperture, and functions to collect light from the LED chip 36 and form an image on the photosensitive material 40 wound around the exposure drum 14. Plays. The focus is automatically adjusted by an auto-focus mechanism (not shown).

On the other hand, a connecting plate 44 is attached to the outer surface of the bottom plate 32. An endless timing belt 46 is fixed to the connecting plate 44. Timing belt 46
Are wound around sprockets 48 and 50 provided near both ends of the shafts 16 and 18, respectively. The rotational force of the stepping motor 52 is transmitted to the sprocket 48 via a speed reducer, and the scanning head 28 reciprocates along the shafts 16 and 18.

The driving of the stepping motor 52 is controlled by the control unit 34, and is synchronized with the step driving of the photosensitive material 40. That is, in a state where the photosensitive material 40 is stepped and stopped, the stepping motor 52 rotates forward, and the scanning head 28 moves along the shafts 16 and 18 in the width direction (main scanning direction) of the photosensitive material 40.

After confirming the predetermined pulse, the photosensitive material 40 is further moved stepwise and stopped.
By reversing the stepping motor 52, reciprocal main scanning is performed. (Description of Locking Mechanism) In the exposure section for performing the scanning exposure as described above, a locking mechanism is used to lock the shaft to the frame member.

Each of the two shafts 16 and 18 is provided with a rectangular hole (square hole) 102 in a rectangular steel plate 100 (see FIG. 3A), and is formed into a circular pipe shape by rounding this. (See FIG. 3B).

As shown in FIG. 4, the shafts 16 and 18 movably support a table 104 on which the scanning head 28 is mounted, and are supported by a frame member 106. That is, as shown in FIG. 5, the shafts 16 and 18 are supported by the support plates 1 disposed at both ends of the frame member 106.
08 and is locked by a steel wire 114 wound around a pair of protrusions 112 provided around the hole 110 of the support plate 108.

The pair of projections 112 are provided at positions facing each other with the hole 110 of the support plate 108 interposed therebetween. Accordingly, when the steel wires 114 are stretched between the pair of protrusions 112 along the support plate 108 with a predetermined tension when the shafts 16 and 18 are inserted, the steel wires 114 are stretched along the shafts 16 and 18.
Are deformed (see FIG. 6). That is, the steel wire 114 enters the square holes 102 of the shafts 16 and 18 and engages with the circumferential ends 116 of the square holes 102 to urge the shafts 16 and 18 downward (in the direction of arrow A) in FIG. . As a result, the shafts 16 and 18 are connected to the frame member 104 (the support plate 10).
8) is locked.

The operation of the image forming apparatus (locking mechanism) configured as described above will be described.

The holes 1 are formed in the pipe-shaped shafts 16 and 18.
The steel wire 114 that has entered the 02 is given a predetermined tension by being wound around the projection 112, and therefore urges the shafts 16 and 18 downward (opposite to the square hole 102, in the direction of arrow A). Therefore, the shafts 16 and 18 are pressed below the hole 102 (in the direction of the arrow A), and the vertical movement of the shafts 16 and 18 is suppressed.

Further, since the steel wire 114 has entered the square hole 102, as shown in FIG.
6 (18) and the supporting plate 108. Therefore,
The shafts 16 and 18 are connected to the support plate 10 via steel wires 114.
8 so that displacement in the thrust direction is reliably prevented.

Further, as shown in FIG. 6, the steel wire 114 wound around the support plate 108 is
02 with the circumferential end portion 116 of FIG.
Direction), the rotation of the shafts 16 and 18 is also reliably prevented.

Therefore, vibrations of the shafts 16 and 18 are effectively suppressed, and an image can be formed with high accuracy by the scanning head 28 placed on the table 104.

Moreover, the rectangular shaft holes 102 are formed in the hollow shafts 16 and 18, and the shaft 16 is formed in the hole portion 110.
18 only needs to be locked by the steel wire 114 attached to the support plate 108 (projection 112) through which
There is also an effect that it can be configured at low cost.

Further, since hollow pipes are used for the shafts 16 and 18, the weight of the shaft is reduced as compared with the case where a rod-shaped (solid) shaft is used, and the amount of bending is reduced. Therefore, an image with higher accuracy can be formed.

The hollow shafts 16 and 18 have a higher natural frequency (100H) than the rod-shaped shaft.
z or more). Therefore, even if the shafts 16 and 18 vibrate at a high frequency, there is an advantage that blurring of an image due to the vibration is not visually recognized.

In the present embodiment, the shafts 16 and 18 are locked by winding the steel wire 114 around the protrusion 112 as a locking member. However, the steel wires 114 enter the square holes 102 of the shafts 16 and 18 with a predetermined urging force. Possible shaft 1
The configuration is not limited to this, as long as the configuration is capable of biasing 6, 18 to the side opposite to the square hole.

In this embodiment, the shafts 16 and 18 are inserted through the holes 110 of the support plate 108.
The present invention can also be applied to a configuration in which it is inserted into a recess.

Further, in this embodiment, the shaft 16,
Although the square hole 102 is formed in 18, the present invention is not limited to this. For example, the shape may be an ellipse.

Further, in this embodiment, the present invention is applied to the image forming apparatus. However, other apparatuses can be applied as long as the scanning member scans along the shaft.

[0050]

As described above, according to the present invention, the shaft for scanning the scanning member can be accurately locked to the supporting member. As a result, the image forming apparatus can form an image with high accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic view of an image forming apparatus provided with a scan head driving mechanism according to an embodiment of the present invention.

FIG. 2 is a front view showing a driving mechanism of the scanning head according to the embodiment of the present invention.

3 (A) and 3 (B) show a manufacturing process of a shaft, (A) shows a steel plate stage, and (B) shows a completed stage.

FIG. 4 is a schematic perspective view illustrating a shaft locking mechanism used in an exposure unit.

FIG. 5 is an enlarged perspective view of a main part of a locking mechanism according to an embodiment of the present invention.

FIG. 6 is a front view of a locking mechanism according to an embodiment of the present invention.

FIG. 7 is a side view of the locking mechanism according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 Image forming apparatus 16, 18 Shaft 28 Scanning head (scanning member) 102 Square hole (hole) 108 Support plate (supporting member) 112 Projection (locking member) 114 Steel material (locking member, wire)

Claims (3)

[Claims] 1. A pipe-shaped shaft having a hole formed in an outer peripheral surface thereof; a support member having a through hole or a concave portion into which the shaft is inserted; and a support member attached to the support member and inserted through the through hole. A locking member that engages with a hole of the shaft inserted into the concave portion and urges the shaft toward the side opposite to the hole. 2. The locking member according to claim 1, wherein the locking member includes a pair of protrusions provided on the support member, and a wire that is attached between the protrusions and elastically deforms by contacting the hole. Item 7. The locking mechanism according to Item 1. 3. An image forming apparatus for forming an image on a photosensitive material by scanning an exposure head, wherein a shaft for guiding the exposure head is provided.
An image forming apparatus, wherein the image forming apparatus is locked by the locking mechanism.