JP2991813B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame structure of an image exposure apparatus used in an image forming apparatus such as an electrophotographic copying machine or a laser beam printer.

[0002]

2. Description of the Related Art A process cartridge and a frame of an image exposure apparatus will be described with reference to FIG. A photosensitive drum 1 serving as an image carrier is provided in a housing of a process cartridge 102 which is detachably provided in an apparatus main body 100 of the image forming apparatus.
1. A primary charger 1 for uniformly charging the photosensitive drum 11
2. A developing device 13 for supplying toner to the latent image formed on the photosensitive drum 11 and developing the latent image as a toner image, a cleaning device 14 for cleaning residual toner from the photosensitive drum 11 after transferring the toner image, and the like. Process equipment is stored and arranged.

When the toner in the developing unit 13 is exhausted, when the cleaning unit 14 is full of waste toner, or when the photosensitive drum 11 or the developing unit 13 reaches the end of its life, the process cartridge The replacement of the entire 102 facilitates maintenance.

Above the process cartridge 102, a light source 3 for irradiating a document surface and guiding a document image to a photosensitive drum 11 in the process cartridge, a reflection shade 4,
A frame (hereinafter, referred to as an optical frame 1) for holding the 4 'and the image forming body 5, an upper cover 2 for sealing the upper opening of the optical frame 1, and a connection to the image forming apparatus main body 100. There is an image exposure apparatus 101 composed of a composite member 6, and the process cartridge 102 is provided on the photosensitive drum 1 of the optical frame 1.
The process cartridge positioning member 11a disposed at the same position as the center of the optical frame 1 and a guide rail 1b for inserting the process cartridge 102 set at the left end of the optical frame 1 are inserted and fixed at a predetermined position of the optical frame 1, Thereafter, the opening and closing operation of the image exposure device 101 causes the optical frame 1
Of the engaging member 6 set at a position at the other end remote from the rotation shaft 1a rotatably attached to the main body of the image forming apparatus 100 and the main body 100 side engaging front end 100.
a.

When the engaging member 6 is released, the optical frame 1 is released.
The image exposure apparatus 101 is rotated counterclockwise around the rotation axis 1a by an opening / closing spring (not shown) installed near the rotation axis 1a of the image forming apparatus. From the upper side to be lifted counterclockwise and detached (FIG. 6). Therefore, regardless of the opening / closing operation of the image exposure apparatus 101 due to the attachment / detachment of the process cartridge 102,
Image forming body 5 and photosensitive drum 11 in image exposure apparatus 101
And the set optical path length L1 was always kept constant to satisfy the optical performance.

In the configuration of the image exposure apparatus 101,
Since the process cartridge 102 is vertically moved by rotation with respect to the apparatus main body 100, a gear fixed to the photosensitive drum 11 in the process cartridge 102, that is, an apparatus main body for rotating the photosensitive drum driving member 11b. In many cases, the drive gear on the side, that is, the drive transmission member 21, is disposed below the photosensitive drum drive member 11b. In such a drive arrangement, the drive transmission on the apparatus body 100 side in the direction of arrow A as shown in FIG. When the drive from the member 21 is transmitted to the photosensitive drum driving member 11b, the process cartridge 102 holding the photosensitive drum driving member 11b
Generates a rotational moment in the same direction as the rotation direction of the photosensitive drum 11 (clockwise arrow B) about the same axis as the rotation center of the photosensitive drum 11, but because of the insertion of the process cartridge 102 disposed in the optical frame 1, Guide rail 1
By b, the clockwise rotation of the process cartridge 102 was prevented.

On the other hand, recently, as a drawback of the above-mentioned conventional example 1, since the optical frame 1 rotates while holding the process cartridge 102 itself, the optical frame 1 is pressed by the opening / closing spring (not shown). In order to prevent deformation of the apparatus and to avoid the accompanying increase in size and weight of the apparatus main body, the image exposure apparatus 101 does not hold the process cartridge 102, and only the image exposure apparatus 101 is opened and closed. An image forming apparatus 100 of a type that can be directly attached to and detached from the apparatus main body 100 has been devised.

For example, as shown in FIG. 2, in an image forming apparatus of the type in which the photosensitive drum bearing 11c of the process cartridge 102 is directly positioned in and detached from the U groove 100b inside the apparatus main body 100, when the process cartridge 102 is detached and attached. The set optical path length L1 between the image forming body 5 in the image exposure apparatus 101 and the photosensitive drum 11 in the process cartridge 102 is temporarily released by the opening and closing operation of the image exposure apparatus 101. Therefore, the image exposure apparatus 1
When the process cartridge 102 is closed, the process cartridge 102 abuts a part of the optical frame 1 in the image exposure apparatus 101 on the concave surface 102a where the dimensional accuracy of the process cartridge 102 is ensured so that the set optical path length L1 is kept constant. In the configuration provided with the optical abutting surface 1c, the engaging portion for fixing the image exposure apparatus 101 and the apparatus main body 100 has a mutual engaging tip 6
The gap between a and 100a is not constant due to the variation in the dimensional tolerance of the engaging member or the like, and the optical abutting surface 1c of the optical frame 1 is
a, the engaging tip 6a pulled by the tension spring 18 is engaged with the engaging tip 100 of the apparatus body.
a, the image exposure apparatus 101 may not be fixed to the apparatus main body 100 in some cases. Further, as shown in FIG. 8, there is a margin in the gap between the engagement tip portions 6a and 100a, and there is provided a biasing means for lifting the image exposure apparatus 101 upward from the apparatus main body 100 by the opening / closing spring (not shown) or the like. In some cases, there is a gap Δ between the optical abutting surface 1c of the optical frame 1 and the concave surface 102a of the process cartridge, so that the set optical path length L1 is not secured, and the original image is correctly formed on the surface of the photosensitive drum 11. It is no longer imaged. If this gap Δ is within a range allowed by the depth of focus of the image forming body (hereinafter referred to as a selfoc lens) 5, there is no effect on the image formed on the surface of the photosensitive drum 11. It is inevitable that a focus defect will deteriorate image performance such as image shift. The variation of the set optical path length L1 is a problem even when the ordinary Selfoc lens 5 is used, but becomes a serious problem particularly in the case of the Selfoc lens 5 using a light focusing optical element array having a small depth of focus. .

As a result, it is necessary to always press the image exposure apparatus 101 against the process cartridge 102 by a pressing means such as a spring.

However, as shown in FIG. 9, the process cartridge 102 is directly inserted into the apparatus main body 100, and as a means for fixing the process cartridge 102 to the apparatus main body 100, the optical frame 1 and the upper cover 2 of the image exposure apparatus 101 are provided.
, And pressurizing springs 22 and 22 ′ are disposed between
Is pressed and fixed to the process cartridge 102, the guide frame 1b for preventing the rotation of the process cartridge 102 described in the conventional example 1 is not provided on the optical frame 1, so that the optical frame 1 1 is provided with a rotation restricting surface 1d,
Is pressed to restrict the rotation. The force for restricting the rotation of the process cartridge 102 is a resultant force of the urging means by the weights of the pressure springs 22 and 22 ′ and the optical frame 1. The biasing position of the pressure spring 22 is near the optical axis of the optical frame 1,
02 as a rotating upward surface 102b
A pressure spring 22 'is separately provided at a position corresponding to the upper surface.

In such a configuration, no upward force acts on the photosensitive drum 11 of the process cartridge 102, so that the pressing spring 22 near the optical axis of the optical frame 1 is used.
The spring pressure needs only to be such that the optical abutting surface 1c of the optical frame 1 is pressed against the concave surface 102a of the process cartridge 102 with a light pressure of about the own weight of the optical frame 1, whereas the cleaning of the process cartridge 102 is performed. The spring pressure of the pressure spring 22 ′ located above the rotating upper surface 102 b above the container is the rotational moment of the process cartridge 102, that is, the photosensitive drum driving member 11 b for driving the photosensitive drum 11.
Is a gear, it is affected by the rotational torque, so the spring pressure must be increased in proportion to the magnitude of the rotational load of the process cartridge 102. For this reason, the image exposing device 10 serving as a seating surface for these pressure springs 22 and 22 ′.
The first optical frame 1 and the upper lid 2 may be deformed by the spring pressure.

Further, since the urging force of the spring is used as the means for preventing the rotation of the process cartridge 102, it is not possible to reliably prevent the swing in the rotation direction caused by the rotation moment received by the process cartridge 102. For this reason, the converging point of the light beam from the document surface irradiated onto the photosensitive drum 11 is not stable, or the photosensitive drum 11 has rotation unevenness, which has an adverse effect such as pitch unevenness on the image.

Further, since the optical frame 1 is pressed against the upper lid 2 by a plurality of pressure springs 22 and 22 'having different pressures, the optical frame 1 needs to have rigidity and thus has a large shape. Alternatively, an expensive resin member mixed with glass fiber or the like must be used, and it is possible to provide a user with an inexpensive product by reducing the size of the image exposure apparatus 101, reducing the number of parts, and using an inexpensive material. It has become difficult.

Conventionally, as a means for pressing and fixing the image exposure apparatus 101 to the process cartridge 102, FIG.
A pressure spring 19 is provided between the optical frame 1 of the image exposure apparatus 101 and the push button 7 at a position opposite to the center of rotation of the image exposure apparatus 101 as shown in FIG.
The push button 7 is guided by a guide rail 1f provided on the optical frame 1 so as to be vertically movable. A shaft 20 that contacts the engaging member 6 when it moves downward is provided in contact with the guide rail 1f in a portion of the push button 7 that is engaged with the guide rail 1f. A bearing 6b provided on the engaging member 6 is pivotally attached to a shaft 7a provided on the push button 7. When the image exposure apparatus 101 is closed, the state shown in FIG. 7 is obtained. Further, by pushing the push button 7 until the engagement member 6 is engaged with the shaft 20, the engagement front end portion 6 a is lowered to engage the apparatus main body 100. And Image exposure apparatus 101
Presses the process cartridge 102. When the image exposure device 101 is opened, the engagement member 6 used to open the image exposure device 101 and when the image exposure device 101 is closed, the engagement member 6 is pushed down. Since several kinds of operation members such as the push button 7 for making it easier to enter the combined front end portion 100a are mixed, there is a possibility that a user may be confused in operation when attaching or detaching the process cartridge 102.

The present invention has been made in view of the above-mentioned problems, and has as its object to simplify the structure of the frame even when the process cartridge 102 is pressed and fixed in the apparatus main body by the frame of the image exposure apparatus 101. Exposure device 10 that is small in size and securely fixes process cartridge 102
(1) to provide a frame.

[0016]

According to a first aspect of the present invention, a frame accommodating an optical member having an image forming member for reading a document and forming an image on a photosensitive member, a frame attached to the frame, and a device main body. An image exposure apparatus having an upper lid having one side attached to the apparatus main body so as to open and close the opening on the upper surface and having an engagement tip portion engaged and disengaged with the apparatus main body on the other side; In an image forming apparatus provided with a flexible process cartridge and a pressurizing means for the process cartridge, an upper cover of the image exposure apparatus is rotatably attached to the apparatus body.
And the frame is an upper cover of the image exposure apparatus.
Mounted coaxially with or near the center of rotation
The process cartridge is attached to the apparatus main body so as to be rotatable, and the frame body and the process cartridge are contacted by a pressurizing unit on a vertical line passing through the center of rotation, and an image is formed. In the vicinity of the mounting part of the exposure device ,
An image forming apparatus wherein contact is possible only during driving .

[0017]

[0018]

[0019]

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an image forming apparatus embodying the present invention, and a process cartridge 102 detachably mounted on the apparatus main body 100 through an upper opening 100c of the apparatus main body 100 as in the conventional example. Is provided. In the process cartridge 102, in addition to the photosensitive drum 11 as an image carrier, process devices such as a primary charger 12, a developing device 13, and a cleaning device 14 are integrally incorporated, and the process cartridge 102 is attached to and detached from the apparatus main body 100. This facilitates maintenance of internal devices.

Below the process cartridge 102,
Transfer charger 15, drive transmission member 21, transport belt 16,
A fixing device 17 is provided. Above the process cartridge 102, the optical frame 1 for housing the light source 3, the reflection shades 4, 4 ', the selfoc lens 5, etc., which is an illumination device for reading a document according to the present invention, is provided. The upper opening of the optical frame 1 is closed,
In addition, an upper cover 2 integrally provided with an engagement distal end portion 2b with the apparatus main body 100 is provided as an image exposure apparatus 101.
A document placing glass 8 and a document pressing plate 9 are provided above the image exposure device 101.

FIG. 2 is a view showing the image exposure apparatus of the present invention opened and the mounting and dismounting of the process cartridge 102. In FIG. 2, an optical frame 1 is provided on the left side of the optical frame when the process cartridge 102 is mounted and removed. It is attached to a part of the apparatus main body 100 so as to rotate counterclockwise about the body rotation shaft 1a.

Further, a rotation restricting surface that comes into contact with the cleaning device rotation upward surface 102b is provided below the optical frame 1 located near the optical frame rotation shaft 1a and above the cleaning device of the process cartridge 102. 1d is provided, except when the process cartridge 102 is driven, so that a small gap is provided between the rotation upward surface 102b and the rotation restriction surface 1d of the optical frame 1, and as shown in FIG. Device 101
Is closed with respect to the process cartridge 102, the optical abutting surface 1c of the optical frame 1 always abuts against the concave surface 102a of the process cartridge first.
b is set so as not to enter the main body side engaging tip portion 100a.

Similarly, at the left end of the upper lid 2 above the optical frame 1, an upper lid hinge 2a rotatably fitted to the optical frame rotating shaft 1a is provided, and the optical frame 1 and the upper lid 2 are arranged. It is positioned coaxially and is rotatable. At the right end of the optical frame 1, an engaging claw 1e, which is another engaging portion with the upper cover 2, and a claw receiver 2c of the upper cover 2 are provided.

A pressure spring 22 for pressing and fixing the process cartridge 102 with the optical frame 1 is provided on the optical frame 1 in the vicinity of the SELFOC lens 5 in the longitudinally inner side and the front side of the SELFOC lens 5. It is contracted between the optical frame 1 and the upper lid 2, and the inner wall of the upper lid 2 is used as a spring seat. The right end engaging tip 2b of the upper lid 2 is engaged with the apparatus body side engaging tip 100a by utilizing the elasticity of deforming the upper lid 2, and the image exposure apparatus 101 can be fixed to the apparatus main body 100.

When the image exposure apparatus 101 is closed, the upper cover 2 is fixed to the apparatus main body 100 by the hinge 2a and the engaging tip 2b. The process cartridge 1 receives a force that rotates clockwise about the optical frame rotation axis 1 a and receives the process cartridge 1 on an optical abutting surface 1 c disposed below the optical frame 1.
02 is pressed down and fixed to the concave surface 102a.
On the other hand, in the process cartridge 102, the outer periphery of a drum bearing 11c that supports the photosensitive drum 11 disposed in the front and rear of the photosensitive drum 11 in the axial direction is dropped into a U-shaped groove 100b formed in a part of the apparatus main body. It is placed. The pins 10 provided on the process cartridge 102
2c is loosely fitted into the groove 100d of the apparatus main body 100. In the above configuration, when the image exposure apparatus 101 is closed to fix the process cartridge 102, the optical abutting surface 1c provided below the optical frame 1 of the image exposure apparatus 101
The concave surface 102a.

At this time, as described with reference to FIG. 3, the tip of the engagement tip 2b provided on the right end of the upper cover 2 of the image exposure apparatus 101 has not yet been engaged with the engagement tip 100a on the apparatus main body 100 side. Engagement claw 1e of optical frame 1 and claw receiver 2c of upper lid 2
Is in contact. Then, in order to engage the engaging tip 2b with the engaging tip 100a on the apparatus body 100 side, it is necessary to further push down the upper lid 2 against the spring force of the pressure spring 22. As a result, a sufficient pressing force from the optical frame 1 is obtained in the process cartridge 102, and the optical dimensions between the image exposure apparatus 101 and the process cartridge 102 are reliably maintained.

Next, during the copying operation, as described with reference to FIG. 4 in the first conventional example, the process cartridge 102 tries to rotate in the same rotation direction as the rotation direction of the photosensitive drum 11. Rotation regulating surface 1 of frame 1
d, the cleaning device rotating upward surface 102b of the process cartridge 102 comes into rotational contact with the process cartridge 102, and the process cartridge 1
02 stable process cartridge 1
02 is secured.

[0030]

FIG. 11 shows a second embodiment. In FIG. 11, an upper cover 2 for sealing the upper surface of an optical frame 1 in an image exposure apparatus 101 is mounted near the center of a hinge 2a for attachment to the apparatus main body 100. In addition, an upper lid rotation restricting surface 2d for restricting the rotation of the process cartridge 102 is integrally formed, and the rotation shaft 1a
Since the optical frame 1 is pivotally attached to the upper lid 2, the rotational force of the process cartridge 102 can be received near the hinge 2 a that is rotatably fixed to the apparatus main body of the upper lid 2. Similar effects can be obtained.

Further, the rotation shaft 1 of the optical frame 1 having the above configuration
Since a can move to the optical side, the optical frame 1 can be further reduced in size and weight.

[0032]

As described above, one end of the image exposure apparatus is rotatably supported by the apparatus main body, and the contact surface between the image exposure apparatus and the process cartridge is provided near the rotation center and near the optical axis of the image forming body, respectively. Is provided, and a pressure spring is contracted between the optical frame and the upper lid near the optical axis of the image forming body. By suppressing the swinging vibration of the process cartridge without increasing the number of parts and stabilizing the posture, it is possible to prevent image defects such as pitch unevenness. 2. Since the load applied to the optical frame and the upper lid in the image exposure apparatus is small, the entire apparatus can be reduced in size, the number of parts can be reduced, and inexpensive materials can be used, so that users can be provided with inexpensive products. . 3. Since the engagement between the image exposure apparatus and the apparatus main body can be performed by a single engagement member formed by a part of the upper lid, a user can easily feel the opening and closing operation when attaching or detaching the process cartridge without increasing the manufacturing cost. Can be given.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an image forming apparatus embodying the present invention.

FIG. 2 is a longitudinal sectional view showing a state in which an image exposure device in the image forming apparatus embodying the present invention is opened.

FIG. 3 is a longitudinal sectional view showing a state when the image exposure apparatus embodying the present invention is closed.

FIG. 4 is a longitudinal sectional view showing a driving state of FIG. 1;

FIG. 5 is a longitudinal sectional view of the entire image forming apparatus of Conventional Example 1.

FIG. 6 is a longitudinal sectional view illustrating an open state of the image exposure apparatus of FIG. 5;

FIG. 7 is a longitudinal sectional view showing a defect of the conventional example 2 when opening and closing the image exposure apparatus.

FIG. 8 is a longitudinal sectional view showing a defect of the conventional example 2 when opening and closing the image exposure apparatus.

FIG. 9 is a longitudinal sectional view of Conventional Example 3.

FIG. 10 is a side view of an engagement member of Conventional Example 4.

FIG. 11 is a longitudinal sectional view showing a second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical frame 1c Optical butting surface 1d Rotation restricting surface 2 Top lid 2d Rotation restricting surface 3 Light source 4 Reflector shade 5 Image forming body 22 Pressurizing spring 100 Image forming apparatus main body 100a Engagement tip 100b U groove 100c Opening 101 Image exposure apparatus 102 Process cartridge 102a Recessed surface 102b Rotating upward surface

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G03G 15/00 550 G03G 15/04 G03G 21/16-21/18

Claims (1)

(57) [Claims] 1. A frame housing an optical member having an image forming member for reading a document and forming an image on a photosensitive member, and one side of the device main body attached to the frame and opening and closing an opening on an upper surface of the device main body. An image exposure apparatus having an upper lid provided with an engagement front end on the other side for engaging and disengaging with the apparatus main body, a process cartridge detachable from the apparatus main body through the opening of the apparatus main body, and a pressurizing means for the process cartridge. an image forming apparatus comprising a top cover of the image exposure apparatus to the apparatus main body
The frame is rotatably mounted and the frame is
It is mounted coaxially with the center of rotation of the top lid of the image exposure device.
Or rotatably mounted near the center of rotation.
Ri, process the process cartridge is mounted to permit rotation in the apparatus main body, the frame body and the process cartridge in line in the vertical direction passing through the rotation center, the mounting portion near the image exposure device with contact by pressure means
An image forming apparatus wherein contact is possible only when the cartridge is driven .