JPH11236143A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device requiring minimum space for its mechanism and less operation force for releasing transmission of rotational driving force. SOLUTION: If defective paper conveyance occurs in a conveying roller 18 part, a cover in an armor case is opened. Consequently, a link 32 is moved upward and a spur gear 24 climbs a tilting face 32A so as to move in the axial direction, so that the spur gear 24 is separated from a spur gear 22 and a spur gear 26. In this way, transmission of rotational driving force between a motor and the conveying roller 18 can be released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus for recording an image on a recording medium.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 7, a rotational driving force of a motor 108 is applied to an image forming apparatus through a spur gear 100, 102, 104, 106 in order, as shown in FIG. Is provided.

In this mechanism, the spur gear 104 is connected to the rotating shaft 11
It is attached to the vicinity of the tip of a lever 114 that can rotate with 2 as a fulcrum.

[0004] The lever 114 is configured such that the spur gear 104
The spring 116 is urged in a direction (the direction opposite to the clockwise direction in FIG. 7) that meshes with the gears 02 and 106.

A link 118 is provided at an intermediate portion of the lever 114.
Are linked. The link 118 is connected to an openable and closable cover provided on an outer case of the image forming apparatus.

When the cover is opened in the case where the sheet is transported poorly, the link 118 moves upward, the lever 114 rotates clockwise, and the spur gear 104 turns the spur gear 102,
Move away from 106.

As a result, the motor 100 and the spur gear 106
The transmission path of the rotational driving force between the roller 11 and the roller 11 is separated.
0 can be rotated lightly, and the paper can be easily removed.

[0008]

However, the conventional image forming apparatus has the following problems. (1) The lever 114 needs a certain length, and a space for disposing the lever 114 is required. Accordingly, the rotation shaft 112 of the lever 114 is used to cancel the transmission.
The moving area with the fulcrum as a fulcrum is large and requires space. (2) When the spur gear 104 is separated from the spur gears 102 and 106, one of the spur gears 104, 102 and 106 must rotate to some extent.

Since the spur gear 104 is indirectly connected to a load (for example, the motor 100), an external force large enough to overcome the load is required to release the engagement of the spur gear from the driving force transmission state. Become. (3) When the external force of the above (2) becomes large, it is necessary to close the exterior cover with a force against the failure after solving the problem, and there is a possibility that the operating force is increased, and the exterior cover is deformed or distorted. There is. (4) If the external force of (2) is set to a small value, a problem occurs in which the disengagement of the gear does not operate reliably.

The present invention has been made in view of the above circumstances, and has as its object to provide an image forming apparatus which requires a minimum space for a mechanism and can cancel transmission of a driving force with a small operation force.

[0011]

According to a first aspect of the present invention, there is provided an image forming apparatus for recording an image on a recording medium by an image forming unit, wherein the rotation driving unit for generating a driving force and the rotation shaft are mutually connected. A plurality of gears which are parallel and transmit the rotational driving force of the rotational driving means to the driven member, and at least one of the plurality of gears is moved in the axial direction, and the moved gear is combined with another gear. And moving means for separating.

The operation of the image forming apparatus according to the first aspect will be described. When it is not desired to transmit the rotational driving force from the rotational driving unit to the driven member, at least one of the plurality of gears is moved in the axial direction by the moving unit, and the moved gear is separated from the other gears. Can be done.

Thus, the transmission path of the rotational driving force between the rotational driving means and the driven member is divided.

The separated gears can be meshed again by the moving means.

In the image forming apparatus of the present invention, for example, the transmission path of the rotational driving force can be divided with a movement size slightly larger than the thickness of the gear, so that the space for the mechanism can be minimized.

Further, since the gears are moved in the axial direction to separate the gears, the gears acting as loads are not rotated, and the gears can be separated with a small force. Only a small force is needed.

According to a second aspect of the present invention, there is provided an image forming apparatus for recording an image on a recording medium by an image forming means, comprising: an outer case having an openable and closable cover; a rotary driving means for generating a driving force; A plurality of gears whose rotation axes are parallel to each other and transmit the rotation driving force of the rotation driving means to the driven member; and at least one of the plurality of gears is moved in the axial direction by opening the cover. Moving means for separating the moved gear from other gears.

The operation of the image forming apparatus according to the second aspect will be described. When it is not desired to transmit the rotational driving force from the rotational driving means to the driven member, when the cover is opened, at least one of the plurality of gears is moved in the axial direction by the moving means, and the moved gear and other parts are moved. Can be separated from the gear.

Thus, the transmission path of the rotational driving force between the rotational driving means and the driven member is divided.

When the cover is closed, the separated gears can be meshed again by the moving means.

In the image forming apparatus of the present invention, for example, the transmission path of the rotational driving force can be separated with a movement dimension slightly larger than the thickness dimension of the gear, so that the space for the mechanism can be minimized.

Further, since the gears are moved in the axial direction to separate the gears, the gears serving as loads are not rotated, and the gears can be separated with a small force. Only a small force is needed.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the moving gear and a gear meshing with the moving gear are separated from a mating gear when separated. It is characterized in that the corners on the axial side of the facing teeth are formed in an arc shape.

The operation of the image forming apparatus according to the third aspect will be described. Once the separated gear is returned to the meshing position again, when meshing is performed after the axial corners of the gear contact each other, if the corners are formed in an arc shape, the meshing can be performed smoothly. Will be

According to a fourth aspect of the present invention, in the image forming apparatus according to the first or second aspect, the moving gear and the gear meshing with the moving gear are bevel gears. And

The operation of the image forming apparatus according to claim 4 will be described. Since both the moving gear and the gear meshing with the moving gear are bevel gears, friction can be reduced when the gears are separated and mesh with each other, and the movement in the axial direction is lighter and smoother. .

Further, in the present invention, the gears can be separated from each other with a movement size slightly larger than the height of the teeth, so that space can be saved.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the image forming apparatus according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, inside the outer case 34 of the image forming apparatus 10 of the present embodiment, a laser diode (not shown) that emits a laser beam according to an image to be formed and an optical system including a polygon mirror 3A are shown. System unit 3
And the photosensitive drum 1 are provided.

The photosensitive drum 1 rotates at a constant speed in the direction of the arrow Q. A charging unit 2 for charging the surface of the photosensitive drum 1 at a predetermined charging voltage and a toner image corresponding to the electrostatic latent image , A transfer unit 5 for transferring the toner image to the paper P, and a peeling unit 6 for discharging a peeling voltage to the paper P in order to facilitate the peeling of the paper P from the photosensitive drum 1. Are located.

A sheet P is stacked on the lowermost part of the image forming apparatus 10, and one half of the sheet P is
The sheet P is pulled out one by one, and is transported along a predetermined transport path R by the transport rollers 18 and 20.

The transport path R of the sheet P is set so as to sequentially pass through the nip portion N1 between the photosensitive drum 1 and the transfer unit 5 and the fixing unit 14.

In such an image forming apparatus 10, the laser beam emitted from the laser diode is deflected on the side surface of the rotating polygon mirror 3A and is irradiated on the photosensitive drum 1. At this time, the laser beam deflected by the rotation of the positive mirror 3A scans the outer peripheral surface of the photosensitive drum 1.

On the other hand, since the outer peripheral surface of the photosensitive drum 1 is charged by the charging unit 2, an electrostatic latent image corresponding to an image to be formed is formed on the outer peripheral surface.

The electrostatic latent image reaches the developing unit 4 by the rotation of the photosensitive drum 1, and a toner image is formed by the toner in the developing unit 4. Further, the toner image is transferred to a nip portion N between the photosensitive drum 1 and the transfer unit 5.
1 and is transferred onto the sheet P which has also been conveyed to the nip N1.

The paper P on which the toner image has been transferred is peeled off from the photosensitive drum 1 by the peeling discharge by the peeling unit 6, and is conveyed to the fixing unit 14.

In the fixing unit 14, the toner image is fixed on the sheet P by the heat roller 7 and the pressure roller 8.

The paper P on which the toner image fixing process is completed is
The sheet is peeled from the heat roller 7 and the pressure roller 8 by the sheet peeling finger 9, and is discharged outside the image forming apparatus 10 by the transport roller 20 and the like.

As shown in FIG. 2 and FIG.
8 is coaxially connected to a spur gear 22.

As shown in FIG. 2, a spur gear 24 is arranged beside the spur gear 22, and a spur gear 26 is arranged beside the spur gear 24.

A bush 28 is attached to the axis of the spur gear 24, and a shaft 30 is inserted into the bush 28.

The spur gear 24 is rotatable with respect to the shaft 30 and slidable in the axial direction.

A link 32 is disposed on one side in the axial direction of the spur gear 24 (on the side of the arrow L in FIG. 3).

The link 32 is slidable in the vertical direction, and the upper end of the link 32 is connected to the cover 34A of the outer case 34, as shown in FIG. The cover 34A can be opened upward.

The position of the link 32 in FIGS.
4A shows the position when the cover 4A is closed, and when the cover 34A is opened, the link 32 moves upward from the position shown.

As shown in FIG. 3, the link 32 has a constant thickness T1 except for the vicinity of the lower end, the thickness near the lower end is formed larger than the thickness of the upper part, and the thickness near the lower end is T2 (> T1). Also, the spur gears 22, 24, 26
Are T3 (<T2-T1).

An inclined surface 32A is formed between the thickness T1 portion and the thickness T2 portion of the link 32.

The link 32 is formed with a long hole 36 extending in the vertical direction, and the shaft 30 passes through the long hole 36.

At the end of the shaft 30 in the direction of arrow R,
A retaining ring 38 is mounted, and the spur gear 24 is connected to the shaft 30 between the spur gear 24 and the retaining ring 38 by a link 3.
A coil spring 40 for urging the second side is attached.

When the thickness T2 of the link 32 is opposed to the spur gear 24, the coil spring 40 is compressed. At this time, the position of the retaining ring 38 is set so that the coil spring 40 is not completely adhered. Is set.

The spur gear 26 meshes with a spur gear 44 rotated by a motor 42. Next, the operation of the present embodiment will be described.

For example, when the conveyance failure of the paper P occurs at the conveyance roller 18, the cover 34 of the outer case 34 is used.
A can be opened upward.

Thus, when the link 32 moves upward, the spur gear 24 climbs the inclined surface 32A, the coil spring 40 is compressed and moves to the position shown by the two-dot chain line in FIG. 22 and the spur gear 26.

As a result, the transmission path of the rotational driving force of the motor 42 is cut off, the transport roller 18 can be rotated lightly, and the paper P having a defective transport can be easily removed.

When the cover 34A is closed after removing the paper P, the link 32 is lowered, and the spur gear 24 moves to the link 32 side by the coil spring 40, and the spur gears 22, 2 are moved.
Meshes with 6.

Further, in this embodiment, since the transmission path of the rotational driving force can be divided with a movement size slightly larger than the thickness T3 of the spur gear 24, the spur gear 24 (or the spur gear 22,
If the thickness of 26) is set to be thin, a space for moving components is not required as compared with the conventional image forming apparatus.

Further, since the spur gear 24 is configured to move in the axial direction, the spur gear 26 serving as a load does not need to be rotated, and the spur gear 24 can be separated with a small force. But with little power. [Second Embodiment] A second embodiment of the present invention will be described with reference to FIG. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 4, the teeth 24A of the spur gear 24
The corner of the link 32 side (in the direction of the arrow L) is chamfered in a round shape.

On the other hand, the teeth 22A of the spur gear 22 and the spur gear 2
The sixth tooth 26A is chamfered in a round shape at the corner portion on the side opposite to the link 32 side (in the direction of the arrow R).

As described above, the corners of the teeth are rounded so that the cover 34A is closed and the spur gear 2 is closed.
4 is returned to the meshing position with the spur gears 22 and 26, the meshing becomes smooth, and the coil spring 40
Force can be set small. Third Embodiment A third embodiment of the present invention will be described with reference to FIGS. Note that the same components as those of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIGS. 5 and 6, in this embodiment, a bevel gear 46 is coaxially connected to the transport roller 18.

A bevel gear 48 meshing with the bevel gear 46 is provided on the shaft 30 so as to be rotatable and slidable.

A bevel gear 50 meshing with the bevel gear 46 is coaxially connected to the spur gear 26.

In this embodiment, when the link 32 moves upward, the bevel gear 48 moves in the direction of arrow R, and the bevel gear 48 moves.
Is separated from the bevel gear 46 and the bevel gear 50, the transmission path of the force with the motor 42 is cut off, and the transport roller 18 connected to the bevel gear 46 can be lightly turned. The generated paper P can be easily removed.

In the first embodiment, the thickness T3 of the spur gear 24
Without the above movement, the transmission path of the force with the motor 42 could not be separated, but the transmission path of the rotational driving force was small with a small moving distance enough to separate the tooth of one bevel gear and the tooth of the other bevel gear. Since it can be divided, the space for the transmission mechanism of the rotational driving force can be saved.

In the configuration in which the bevel gear 48 meshes with the bevel gear 46 and the bevel gear 50, meshing when the cover 34A is closed and the bevel gear 48 is returned to the meshing position with the bevel gear 46 and the bevel gear 50 is performed. And the force of the coil spring 40 can be set small.

In the above embodiment, the transport rollers 18
Although the configuration in which the transmission path of the rotational driving force to the rotational drive unit can be divided has been described, the rotational driving force of the rotational driving means (for example, a motor) is driven by a plurality of driven members (for example, the photosensitive drum 1 The present invention can be applied to all the parts transmitted to the second part.

In the above embodiment, the link 32 is moved by opening and closing the cover 34A. However, the present invention is not limited to this, and the link 32 is moved directly by hand or indirectly via another lever or the like. You may do it.

[0069]

As described above, since the image forming apparatus of the present invention has the above-described structure, the space for the mechanism can be minimized, and the transmission path of the rotational driving force can be divided with a small operation force. It has an excellent effect.

The image forming apparatus according to the third aspect of the present invention has the above-described configuration, and has an excellent effect that the meshing is smoothly performed when the gear once separated is returned to the meshing position again. .

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a front view of a driving mechanism of a roller for conveying a sheet.

FIG. 3 is a partial cross-sectional view of a roller driving mechanism shown in FIG. 2;

FIG. 4 is an enlarged view of teeth of a spur gear of the image forming apparatus according to the second embodiment.

FIG. 5 is a front view of a driving mechanism of a sheet conveying roller of an image forming apparatus according to a third embodiment.

FIG. 6 is a side view of the drive mechanism shown in FIG.

FIG. 7 is a front view of a driving mechanism of a sheet conveying roller of a conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 10 image forming apparatus P paper (recording medium) 1 photosensitive drum (image forming means) 2 charging unit (image forming means) 3 optical system unit (image forming means) 4 developing unit (image forming means) 5 transfer unit (image forming means) 6) Peeling unit (image forming means) 14 Fixing unit (image forming means) 18 Conveying roller (driven member) 22 Spur gear 24 Spur gear 26 Spur gear 30 Shaft (moving means) 32 Link (moving means) 34 Outer case 34A Cover 40 Coil spring (moving means) 42 Motor (rotation driving means) 44 Spur gear 46 Bevel gear 48 Bevel gear 50 Bevel gear

Claims (4)

[Claims] 1. An image forming apparatus for recording an image on a recording medium by an image forming means, comprising: a rotation driving means for generating a driving force; A plurality of gears to be transmitted to a driving member; and moving means for moving at least one of the plurality of gears in the axial direction to separate the moved gear from other gears. Image forming apparatus. 2. An image forming apparatus for recording an image on a recording medium by an image forming means, comprising: an outer case having an openable and closable cover; a rotation driving means for generating a driving force; A plurality of gears for transmitting the rotation driving force of the rotation driving means to the driven member; and at least one of the plurality of gears is moved in the axial direction by opening the cover, and the moved gear is replaced with another. An image forming apparatus comprising: a moving unit that separates the gear from the gear. 3. The moving gear and the gear that meshes with the moving gear are formed such that a corner on the axial side of a tooth facing a mating gear when separated is formed in an arc shape. The image forming apparatus according to claim 1 or 2, wherein 4. The image forming apparatus according to claim 1, wherein the moving gear and the gear meshing with the moving gear are bevel gears.