JPH11218980A - Pulling unit and image forming device provided therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operability without causing cost rising in terms of dimensional accuracy and the lowering of positioning accuracy by supporting mounted parts mounted on a pulling member by an elastic supporting member so that they can move up and down. SOLUTION: A positioning pin Pa is provided to be perpendicularly erected on a unit bottom board 20, and a positioning hole Ha is provided at the bottom part of a fixing device 10 corresponding to the pin Pa. The pin Pa and the hole Ha are set so that the diameter of the hole Ha may be a little larger than the diameter of the pin Pa so as to be freely attached/detached in a perpendicular direction. A coil spring 27 is made to intervene on the base end side of the pin Pa. The upper end of the spring 27 press-contacts with a clearance part 28 formed at the bottom part of the fixing device 10, and the fixing device 10 is supported in such a state so as to move up and down on the bottom board 20. Gaps G1 and G2 are set to be specified dimension in a state where the spring 27 press-contacts therewith by the gravity of the fixing device 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawer unit that can be pulled out of an apparatus main body and an image forming apparatus provided with the same.

[0002]

2. Description of the Related Art FIG. 7 is a schematic configuration diagram of a color copying machine using an electrophotographic system. The illustrated color copier 1
It mainly comprises an image reading unit 2, an image processing unit 3, and an image output unit 4. The image reading unit 2 optically reads an image of a document set on a document table such as a platen glass. The image processing unit 3 includes the image reading unit 2
Performs various image processing on the image data read in step (1). The image output unit 4 outputs a copy image corresponding to the original image to a material to be transferred (paper) based on the image data processed by the image processing unit 3, and a laser writing unit 5 as a functional unit therefor. , Photosensitive drum 6, rotary developing device 7, transfer drum 8, cleaner 9, fixing device 10
Etc. are provided.

In the copying operation of the color copying machine 1 having the above-described configuration, first, an image of a document set on a document table is read by an image reading section 2 and the read image data is read by an image processing section 3. Image processing. Next, the laser writing unit 5 is driven in accordance with an image signal provided from the image processing unit 3, so that the photosensitive drum 6 is irradiated with a laser beam. Prior to this, the surface of the photosensitive drum 6 is uniformly charged by the charging corotron 6a, and is irradiated with a laser beam in this state to form an electrostatic latent image on the surface of the photosensitive drum 6. The electrostatic latent image is developed into a first color toner image by the rotary developing device 7.

On the other hand, sheets to be transferred are accommodated in multi-stage paper feed trays 11, 12, and 13 according to size, and sheets of a specified size are sent out toward the transfer drum 8 from among them. The sheet thus sent out is attracted to the surface of the transfer drum 8 by the charging corotron 14, and is sent to a position facing the photosensitive drum 6 in this state.

On the other hand, a transfer corotron 15 is provided in the vicinity of a portion where the photosensitive drum 6 and the transfer drum 8 are opposed to each other.
The first color toner image is transferred to the sheet. At this time, the toner remaining on the photosensitive drum 6 without being transferred to the sheet is removed by the cleaner 9.

Then, in the same procedure as the transfer of the first color toner image, the toner images of the second to fourth colors are sequentially transferred onto the paper in a superimposed manner, whereby one color image is formed on the paper. You. When the transfer of the toner images for the four colors is completed in this manner, the sheet that has been attracted to the transfer drum 8 is separated from the drum surface by the separation corotron 16. Thereafter, the sheet on which the image has been fixed is sent to the fixing device 10, where the image is fixed by the action of pressure and heating, and then discharged to the tray 17.

[0007] A series of copying operations is completed as described above. During such operations, paper jam (jam) occurs due to various factors. If a paper jam occurs, it is impossible to continue the copy operation.Therefore, normally, when the occurrence of a paper jam is detected by a sensor or the like, the copy operation is automatically stopped and a message to that effect is displayed on an operation panel or the like. I have to. In such a situation, it is necessary for the user to remove the paper jammed in the apparatus (hereinafter, jammed paper). In particular, paper jam occurs around the transfer drum 8 in the image output unit 4 where the functional components are densely packed. Then, it becomes extremely difficult to remove the jammed paper.

Therefore, conventionally, as shown in FIG. 8, functional components such as the transfer drum 8 and the fixing device 10 are unitized as a transfer unit 18, and the transfer unit 18 is attached to the main body 1a of the color copying machine 1. What is constituted so that it can be pulled out is provided. With this configuration, when a paper jam occurs, the transfer unit 18 is pulled out by holding the lever 19 provided at the unit end and pulling out the transfer unit 18 with the front cover 1b of the main body 1a opened. Since the peripheral part is exposed to the outside,
Jam paper jammed there can be easily removed.

The fixing device 10 incorporated in the transfer unit 18 is removably mounted on the bottom plate of the transfer unit 18 mainly for the purpose of improving the removability of jammed paper and the maintenance of replacement of parts. .

FIGS. 9A and 9B show a specific example of mounting of the fixing device 10, in which FIG. 9A shows the fixing device 10 viewed from the side, and FIG. 9B shows the fixing device 10 viewed from the end surface. FIG.
In FIG. 9, two positioning pins Pa, Pa are provided on the unit bottom plate 20 in a vertically upright state, and two positioning holes Ha, Ha are formed on the bottom of the fixing device 10 corresponding to the positioning pins Pa, Pa. Is provided. The fixing unit 10 has a positioning hole H provided at the bottom thereof.
a, Ha are mounted from above the unit bottom plate 20 so as to be fitted to the positioning pins Pa, Pa. In this mounting state, the positioning pin Pa and the positioning hole Ha are respectively provided.
The lateral (horizontal) movement of the fixing device 10 on the unit bottom plate 20 is restricted by the fitting.

The fixing unit 10 includes a transfer unit 18.
4 positioning pins Pb and P
b are provided. These positioning pins P
are provided in a state (horizontal state) perpendicular to the positioning pins Pa, Pa described above. On the other hand, the main body 1a of the color copying machine 1
As shown in (a), each positioning pin Pb, Pb,
Are provided corresponding to the positioning holes Hb, Hb,. When the transfer unit 18 is pushed into the main body portion 1a of the color copying machine 1, the corresponding positioning pins Pb and the positioning holes Hb are fitted to each other, so that the main body portion 1a of the color copying machine 1 is fitted. Fixing device 10
Are positioned. The fixing device 10
As a positioning mechanism, a positioning pin Pa and a positioning hole Hb are provided in the fixing device 10 and a positioning hole Ha is provided.
May be provided on the unit bottom plate 20 and the positioning pins Pb on the main body portion 1a of the color copying machine 1 in some cases.

In such a mounting structure of the fixing device 10,
A positioning hole Hb provided in the main body portion 1a of the color copying machine 1 and a positioning pin Pb on the fixing device 10 side fitted in the positioning hole Hb.
As shown in FIG. 10B, the relative positions of the positioning holes Hb and the center axes Ch and Cp of the positioning pins Pb are coaxial with each other (in the same height). Ideally).

[0013]

However, since some intermediate parts are interposed between the main body portion 1a of the color copying machine 1 and the fixing unit 10, variations in individual part dimensions, assembly dimensions, and the like may occur. Accordingly, the center axes Ch and Cp of the positioning holes Hb and the positioning pins Pb also vary in the vertical direction (vertical direction). In such a case, if the center axis Cp of the positioning pin Pb is shifted upward with respect to the center axis Ch of the positioning hole Hb as shown in FIG.

That is, the unit bottom plate 2 of the transfer unit 18
9, since the bottom of the fixing device 10 is in contact with the unit bottom plate 20 as shown in FIG. 9, even if the positioning pin Pb is fitted into the positioning hole Hb, the transfer unit Is locked and cannot be pushed any further. Therefore, the positioning pin Pb
If the diameter of the positioning hole Hb with respect to the positioning pin Pb is set to be sufficiently large, for example, so that the fixing hole can be fitted into the positioning hole Hb even if the central axis Cp of the fixing device 10 is slightly shifted upward, the fixing device 10 with respect to the main body portion 1a is formed due to the fitting play. , The positioning accuracy is significantly reduced. In addition, there is a limit in manufacturing to reduce variations in individual component dimensions and assembly dimensions, and even if those dimensions are strictly controlled, the cost increases enormously.

From this background, in the mechanical component design stage, as shown in FIG. 11B, the center axis Cp of the positioning pin Pb is more than the center axis Ch of the positioning hole Hb.
Is intentionally set so as to be located below the predetermined dimension β so that the vertical relationship between the center axes Ch and Cp does not become the state shown in FIG. We are careful about.

However, when mechanical parts are designed under the conditions shown in FIG. 11B, when the transfer unit 18 is pushed into the main body portion 1a of the color copying machine 1, the fixing unit 10 is always positioned while being lifted. . Therefore, there is a new problem that the load on the user is increased at the moment when the fixing pin 10 is lifted by the positioning pin Pb abutting on the positioning hole Hb while the transfer unit 18 is being pushed in, and the operability is deteriorated.

In particular, in the case of a color copying machine which handles thick paper or the like and requires high-speed processing, a high heating temperature and a high pressing force are required when an image is fixed on a sheet. 10 is also large and heavy. Then, the user load when pushing the transfer unit 18 is further increased.

[0018]

In a drawer unit according to the present invention, a drawer member slidably mounted in a horizontal direction with respect to an apparatus body, and a drawer member mounted on the drawer member. A first engagement portion that is vertically disengageable from the provided engaged portion;
A mounting component having a second engaging portion that is horizontally disengageable from an engaged portion provided in the device main body, and an elastic supporting member that vertically and vertically supports the mounting component mounted on the drawer member. Is adopted.

In the drawer unit having the above structure,
When the mounting component is mounted on the drawer member, the movement of the mounting component in the horizontal direction is regulated by engaging the first engaging portion of the mounting component with the engaged portion on the drawer member side. Further, when the mounting component mounted on the drawer member is supported by the elastic support member, and the drawer member is pushed into the apparatus main body in this state, even if the engaged portion on the device main body side and the second engagement between the mounting component and the mounting component are engaged. Even if the relative position with respect to the part is shifted in the vertical direction, the mounted component moves up and down in accordance with the shift direction, so that the second engaging portion of the mounted component smoothly moves with respect to the engaged portion of the apparatus main body. Can be engaged.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to, for example, the above-described color copying machine (see FIGS. 7 and 8) will be described in detail with reference to the drawings. Note that the drawer unit according to the present invention can be similarly applied to a unit structure (transfer unit or the like) other than a unit structure that is removably incorporated in an image forming apparatus such as a color copying machine.

FIG. 1 is a partially exploded perspective view of a color copying machine to which the present invention is applied. In FIG. 1, the transfer drum 8 is attached to a transfer unit 18 corresponding to a drawer unit.
In addition, a fixing device (not shown) is mounted. A lever 19 for pulling out the transfer unit 18 is provided at the end of the unit. Furthermore, on both sides of the transfer unit 18, telescopic rails 21 are attached along the unit depth direction (the axial direction of the transfer drum 8). The telescopic rail 21 is composed of a pair of rail members slidably engaged with each other, and one of them (an outer rail member) is slidably engaged with the main body side rail 22.

On the other hand, the main body frame 23 of the color copying machine is provided with an opening 24 for taking the transfer unit 18 in and out. A side beam 25 is bridged in the depth direction of the main body frame 23, and the main body side rail 22 is attached to the side beam 25 by screws 26. In the mounted state, the side beam 25
The transfer unit 18 can be pulled out from the opening 24 of the main body frame 23 by the expansion and contraction rail 21 sliding with respect to the main body side rail 22 screwed to the main body 22 and by the sliding operation (expansion and contraction) of the expansion and contraction rail 21 itself. it can.

FIG. 2 is a perspective view showing a mounting state of the fixing unit in the transfer unit. Here, a state where the fixing unit is lifted vertically is shown. In FIG. 2, the unit bottom plate 20 constitutes a drawer member together with other frame components, and the fixing device 10 is mounted thereon. As described in the prior art, two positioning pins Pa and Pa are provided on the unit bottom plate 20, and the fixing device 1 is mounted on these positioning pins Pa and Pa.
The horizontal movement of the fixing device 10 on the unit bottom plate 20 is restricted by fitting a positioning hole (not shown) at the bottom of the unit 0.

FIG. 3 is an enlarged view of a main part showing a mounting state of the fixing device on the unit bottom plate. As shown, a positioning pin Pa is provided on the unit bottom plate 20 in an upright state, and the fixing device 1 corresponding to the positioning pin Pa is provided.
A positioning hole Ha is provided at the bottom of the zero. The diameter of the positioning hole Ha is set slightly larger than the diameter of the positioning pin Pa so that the positioning pin Pa and the positioning hole Ha can be freely disengaged in the vertical direction.

A coil spring 27 is interposed at the base end (lower end) of the positioning pin Pa. The upper end of the coil spring 27 is in pressure contact with a relief portion 28 formed at the bottom of the fixing device 10. In this state, the fixing device 10 is supported on the unit bottom plate 20 so as to be able to move up and down. Further, under the support state, a gap G1 is secured between the fixing device 10 and the unit bottom plate 20, and a gap G2 is also secured between the tip of the positioning pin Pa and the back end of the positioning hole Ha. ing. These gaps G1 and G2 are set to have predetermined dimensions (described later) in a state where the coil spring 27 is pressed against the fixing device 10 by its own weight.

Thus, the fixing device 10 is placed on the unit bottom plate 20.
When the transfer unit 18 is pushed into the main body frame 23 of the color copying machine with the printer mounted, the relative position of the positioning pin Pb on the fixing device 10 side and the positioning hole Hb on the apparatus main body side as shown in FIG. If the relationship is coaxial (same height) in the vertical direction, the fixing device 10 will not be lifted when the positioning pin Pb is fitted into the positioning hole Hb, so that the user does not feel any load fluctuation.
The transfer unit 18 can be pushed.

On the other hand, positioning holes Hb and positioning pins Pb
As shown in FIG. 11 (a), the positional relationship of the positioning pin P with respect to the center axis Ch of the positioning hole Hb is as shown in FIG.
If the center axis Cp of b is displaced upward, a force for pushing down the fixing device 10 when they abut against each other acts, and as shown in FIG. 11B, with respect to the center axis Ch of the positioning hole Hb. When the center axis Cp of the positioning pin Pb is shifted downward, a force for lifting the fixing device 10 when they abut against each other acts.

On the other hand, in the present embodiment, the fixing device 10 is supported on the unit bottom plate 20 by the coil spring 27 so as to be able to move up and down. The coil spring 27 is compressed by assisting (gravitational force), and the coil spring 27 is expanded by the elastic force of the coil spring 27 assisting the lifting force.

As a result, the fixing device 10 is mounted on the center axis C
As shown in FIG. 4, it smoothly moves downward (indicated by a one-dot chain line) or upward (indicated by a two-dot chain line) as shown in FIG. 4 in accordance with the displacement of p and Ch, without imposing an excessive load on the user. By fixing the positioning pin Pb into the positioning hole Hp, the fixing device 10 can be positioned with high accuracy in the apparatus main body.

Here, in designing the mechanical parts, since the fixing device 10 is supported so as to be vertically movable, FIG.
When the fixing device 10 is mounted on the unit bottom plate 20 as shown in FIG.
The central axis Ch of the positioning hole Hb on the apparatus main body side can be set so as to be coaxial (same height) in the vertical direction. As a result, in the conventional case, it is necessary to lift the fixing device 10 by an amount corresponding to a vertical position shift due to variations in individual component dimensions and assembly dimensions. Since the distribution can be performed, the amount of movement (lifting dimension) of the fixing device 10 can be reduced by half.

In addition, due to variations in individual component dimensions and assembly dimensions (allowable dimensional errors in manufacturing), both central axes C
The relative positions of p and Ch are shifted up and down by predetermined distances α and β, respectively, as shown in FIGS. In such a case, the gaps G1 and G2 between the fixing unit 10 and the unit bottom plate 20 (see FIG. 3) should be at least β
By setting the size equal to or larger than the dimension, the locked state when the transfer unit 18 is pushed in can be reliably avoided.

In the above embodiment, the fixing device 10 is supported on the unit bottom plate 20 by the coil spring 27 so as to be able to move up and down. Alternatively, for example, as shown in FIG. A configuration may be adopted in which the bent and formed leaf spring 29 is screwed to the unit bottom plate 20 and the free end of the leaf spring 29 is vertically movably supported in contact with the bottom surface of the fixing device 10.

In the configuration employing the leaf spring 29, the mounting dimension of the spring in the height direction can be reduced as compared with the case where the coil spring 27 is used. Will be effective.

In addition to the spring, an elastic pad 30 having rubber elasticity is interposed between the fixing device 10 and the unit bottom plate 20 as shown in FIG. May be supported so as to be vertically movable. Further, the elastic support member including the coil spring 27, the leaf spring 29, and the elastic pad 30 does not necessarily need to be interposed between the bottom of the fixing device 10 and the unit bottom plate 20 opposed thereto. It is also possible to adopt a configuration in which a wing (not shown) is provided on the surface, and the wing is supported by an elastic support member.

In addition, in the present embodiment, the configuration in which the fixing device 10 is positioned by fitting the positioning pins Pa and Pb with the positioning holes Ha and Hb has been described.
The mechanism for positioning the fixing device 10 may be other than a mechanism using a pin and a hole.

[0036]

As described above, according to the present invention, the structure in which the mounting component mounted on the drawer member is vertically movably supported by the elastic support member is employed, so that the mounting portion and the mounting portion of the apparatus main body are mounted. Even if the relative positional relationship between the component and the second engaging portion is displaced in any of the up and down directions, the mounted component smoothly moves up and down according to the displaced direction, so that an excessive load is imposed on the user. Instead, the second engaging portion can be engaged with the engaged portion. As a result, without increasing the cost in terms of dimensional accuracy and lowering the positioning accuracy,
It is possible to provide a drawer unit having excellent operability.

[Brief description of the drawings]

FIG. 1 is a partial exploded perspective view of a color copying machine to which the present invention is applied.

FIG. 2 is a perspective view illustrating a mounting state of a fixing device in the transfer unit.

FIG. 3 is an enlarged view of a main part showing a mounting state of a fixing device on a unit bottom plate.

FIG. 4 is a diagram illustrating the behavior of the fixing device when the unit is pushed in.

FIG. 5 is a diagram illustrating another embodiment of the present invention.

FIG. 6 is a diagram illustrating still another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram of a color copying machine using an electrophotographic method.

FIG. 8 is a perspective view of a color copying machine having a pull-out type transfer unit.

FIG. 9 is a diagram illustrating a mounting state of a conventional fixing device.

FIG. 10 is a diagram illustrating a method of positioning the fixing device with respect to the apparatus main body.

FIG. 11 is a diagram showing a positional relationship between a positioning pin and a positioning hole.

[Explanation of symbols]

10: fixing device, 18: transfer unit, 20: unit bottom plate, 23: body frame, 27: coil spring, 29: leaf spring, 30: elastic pad, Pa, Pb: positioning pin,
Ha, Hb: Positioning holes

Claims (4)

[Claims] 1. A drawer member slidably mounted in a horizontal direction with respect to an apparatus main body; and a drawer member mounted on the drawer member, which is vertically engaged with and disengaged from an engaged portion provided on the drawer member. A mounting component having a first engagement portion that is freely movable, a second engagement portion that is horizontally disengageable with an engaged portion provided on the apparatus main body, and the mounting component that is mounted on the drawer member. A drawer unit, comprising: an elastic support member that supports the mounted component so as to be vertically movable. 2. The drawer unit according to claim 1, wherein said elastic support member is constituted by a leaf spring. 3. An image forming apparatus comprising the drawer unit according to claim 1. 4. The image forming apparatus according to claim 3, wherein the mounting component is a fixing device that fixes an image transferred to a transfer material.