JP2002196648A - Electrophotographic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic image forming device where an accurate operation can be carried out without relying on a user's judgement when a process cartridge is attached, detached and aligned to a device main body. SOLUTION: The image forming device is provided with an operating lever 101 that can be moved between a first position m1 where the process cartridge B is made attachable to or detachable from the device main body and a second position m2 where the process cartridge B can be attached to and aligned to the device main body. When this operating lever 101 is not at the first position m1 nor second position m2, this lever 101 is energized toward the middle point between the first position m1 and the second position m2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a photocopier, an electrophotographic printer (for example, a laser printer), a facsimile machine, and a word processor for forming an image on a recording medium using an electrophotographic image forming method. Related to the device.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus, a configuration using a process cartridge is often employed.

A process cartridge integrates a photosensitive drum, a developing unit, a cleaning unit, and a charging roller in addition to a toner, and replaces consumables and parts whose performance deteriorates due to durability with the cartridge. This realizes maintenance-free operation of the apparatus.

Since the use of the process cartridge pursues the convenience of the user as described above, it must be easy to attach and detach the process cartridge to and from the image forming apparatus main body. On the other hand, the process cartridge contains the main components that determine image quality, such as the photosensitive drum,
It is necessary to position the image forming apparatus with high accuracy.

Therefore, in the method of attaching and detaching the process cartridge to and from the image forming apparatus main body, many attempts have been made in the shape and positioning structure of the insertion guide in order to achieve both easy attachment and detachment and high-precision positioning.

As a method of attaching and detaching the process cartridge to and from the image forming apparatus main body, a cartridge insertion port is provided in the front of the main body, and the cartridge is linearly moved into the main body along a guide rail laid in the main body through the opening. There is a configuration in which the cartridge is swung within the main body and fixed at a predetermined positioning position by operating a manual lever provided on the main body after the cartridge is inserted in the main body.

According to this method, the position of the opening of the main body is at the front of the main body, there is no need for the user to lift the cartridge to the upper surface of the apparatus, and one end of the cartridge rides on the guide rail at the time of attachment / detachment. The operability is improved because the load for supporting the cartridge is small. Further, since positioning is performed in the main body mechanism, there is an advantage that there is no defective positioning.

[0008]

It should be noted that the above-mentioned method of attaching and detaching and positioning the process cartridge is performed by manually operating a lever member and the like. That is, the user operates the lever member or the like between the cartridge attaching / detaching position and the cartridge positioning position. At this time, reaching the state where the lever member or the like is in the attaching / detaching position or the positioning position depends on the judgment of the user. And does not always fit in either position.

For example, in the process of positioning the cartridge after the operation, the latch is activated at the position where the positioning is completed.
If the operation is not performed to the completion position, the latch is not engaged and the positioning is incomplete, and the cartridge vibrates during image formation, resulting in an image defect.

When the operation is incomplete in the cartridge detachable state and the state is not latched, the swing guide for moving the cartridge from the mounting position to the detaching position and the detaching guide for detaching the cartridge are used. Transfer may be incomplete and the cartridge may not be removable.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to perform a reliable operation without depending on a user's judgment when attaching / detaching / positioning a process cartridge to / from an apparatus main body. An object of the present invention is to provide an electrophotographic image forming apparatus capable of performing the above-mentioned operations.

[0012]

A typical configuration according to the present invention for achieving the above object is an electrophotographic image forming apparatus in which a process cartridge can be detachably mounted. Operating means which can be shifted to a first position for mounting the process cartridge on the apparatus main body and a second position for positioning the process cartridge. When the operating means is not at the first position or the second position, The means is configured to be biased between the first position and the second position.

In the above configuration, when the operating means is not at the position where the process cartridge is attached or detached or the position where the process cartridge is mounted, the operating means is urged toward an intermediate position between the two positions. It can be easily confirmed that no operation has been performed. Further, an interlock in the case where the operation is incomplete can be easily configured.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an electrophotographic image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(Overall Configuration of Apparatus) First, the overall configuration of an electrophotographic image forming apparatus according to this embodiment will be described with reference to FIG. FIG. 6 shows an electrophotographic image forming apparatus main body A.
FIG. 3 is an explanatory cross-sectional view showing a state where a process cartridge B is mounted on the printer.

The process cartridge B in the main body A of the image forming apparatus has a drum-shaped electrophotographic photosensitive member, that is, a photosensitive drum 3. The photoconductor drum 3 is charged by the charging roller 4, and then a laser beam is irradiated from the optical unit 1 to form a latent image on the photoconductor drum 3 according to image information. This latent image is developed by the developing means 5 of the process cartridge B, and becomes a visible image, that is, a toner image.

On the other hand, the recording medium P set in the sheet cassette 2 is conveyed to the transfer position by the pickup roller 6, the separation roller pair 7, the conveyance roller pair 8, and the registration roller pair 9 in synchronization with the formation of the toner image. A transfer roller 10 as a transfer unit is disposed at the transfer position, and transfers a toner image on the photosensitive drum 3 to a recording medium by applying a voltage.

The recording medium P to which the toner image has been transferred is conveyed to the fixing means 12 by the conveyance guide 11. The fixing unit 12 fixes the transferred toner image on the recording medium P by applying heat and pressure to the recording medium P passing therethrough. The recording medium is conveyed by a discharge roller pair 13 and discharged to a discharge tray 14.

On the other hand, the process cartridge B contains a toner, and a developing container holding a developing means such as a developing roller 5b and a developing blade is integrally connected to a toner container 5a having a toner feeding member to form a developing frame. Further, the developing frame is integrally formed with a cleaning frame including a photosensitive drum 3, a cleaning means such as a cleaning blade, and a charging roller 4, thereby forming a cartridge.

(Cartridge Attaching / Removing Positioning Configuration) Next, a configuration for attaching / detaching the process cartridge B to / from the image forming apparatus main body A of the present embodiment will be described with reference to FIGS. FIG. 1 is an explanatory view showing a state in which a cover is opened for attaching / detaching a cartridge, FIG. 2 is a sectional explanatory view showing a state in which a cartridge is inserted, and FIG. FIG. 4 is a cross-sectional explanatory view of a state where the plunger is urged for mounting and positioning, and FIG. 5 is a cross-sectional explanatory view of a state where the cartridge is locked at a cartridge attaching / detaching position.

As shown in FIG. 1, the cartridge mounting procedure is as follows. The front cover 401 is opened, and the cartridge B is linearly inserted along the guide rail 510 laid inside through the opening 402 on the front surface of the apparatus main body. . Cartridge B
When the cartridge B is inserted to the abutting position, as shown in FIG. 2 and FIG.
At the same time, the projection shaft 901 of the cartridge is supported on the cam surface of the cam 102 fixed by the holding mechanism described later. At this time, the operation lever 10 as an operation means
Reference numeral 1 denotes a first position where the process cartridge can be inserted into and pulled out of the apparatus main body.

Here, a holding release button (not shown) is pressed,
The state holding of the cam 102 is released, and the lever 101 as an operating means around the shaft 100 is moved about 6 clockwise in FIG.
When the cartridge B is rotated by 0 °, the cartridge B rotates 16 ° counterclockwise in the apparatus main body A with the contact point between the foot 903 of the cartridge and the main body side receiving block 104 as a fulcrum, and the drum shaft
902 is seated on the drum bearing 103 and positioned at a position where an image can be formed.

As shown in FIG. 3 and FIG.
Pressurized plunger spring in frame 112 on the same rotation axis of 101
A pressure plunger 110 urged by 111 is provided. When the lever 101 is further rotated clockwise by 30 ° to the second position, the pressure plunger 110 is moved to the frame of the cartridge B. Contact the top, plunger spring
By the action of 111, the cartridge B is pressed toward the axis of the drum. As a result, the cartridge receives a pressurizing action from the plunger 110 in addition to its own weight,
The toner is reliably urged by the drum bearing portion 103, and the image forming state is established.

The procedure for removing the cartridge is as follows.
From the image forming state, the lever 101 is rotated counterclockwise by about 90 ° to return to the cartridge detachable state, and then the cartridge B is linearly pulled out from the opening 402 of the main body along the guide rail 510. .

(Removable state holding and releasing mechanism) Next, the holding mechanism and releasing mechanism in the cartridge removable state will be described. The state holding mechanism, as shown in FIG.
Has a lock plate 620 that is rotatable around one and the lock plate 620
Is urged by the torsion coil spring 622 in the direction of the arrow in FIG.

On the other hand, the elevating arm 631 connecting the cam 102 and the drive shaft 100 has a claw 631a at an end, which is engaged with an upper edge of a square hole provided in the lock plate 620. Thus, the rotation of the drive shaft 100 in the clockwise direction in the figure is stopped. In this state, since the drive shaft 100 does not rotate, the cam 102 is held at the position shown in FIG.

At this position (first position), the process cartridge can be inserted into and pulled out of the apparatus main body, and can be removed. When the lock plate 620 is rotated in the counterclockwise direction against the bias of the torsion coil spring 622 in the above state, the pawl 631a of the elevating arm 631 is released, and the shaft 63
100 rotations are possible.

In this embodiment, a taper cone (not shown) is provided on a shaft 641 shown in FIG. 5 to release the locking of the pawl 631a, and the lock plate 620 is tapered by moving it in the axial direction. It is configured to be pushed in the normal direction of. Thus, when the lock plate 620 is rotated to release the locking of the claw 631a of the elevating arm 631, the lock is released and the shaft 100 becomes rotatable, and the lever 101 becomes rotatable.

The linear movement of the shaft 641 is configured to be linked with the operation of a button (not shown) incorporated in the operation lever 101.

(Neutral position of lever) By the way, in order to keep the cartridge B detachable,
It is necessary to rotate 101 in a counterclockwise direction until the claw 631a of the lifting arm 631 is locked to the edge of the lock plate 620 (first position). At this time, if the locking of the claw 631a is incomplete, The height of the guide portion 905 of the cartridge and the guide rail 510 (see FIG. 2) of the apparatus main body do not match, and the cartridge B
The cartridge may not be able to be removed, or the cartridge may swing down during jam clearance at the bottom of the cartridge.

On the other hand, in positioning the cartridge, the lever 101 must be rotated clockwise to the position where the plunger 110 presses the cartridge B (second position), and pressurization is obtained due to insufficient operation angle. If there is no cartridge B, the seating of the cartridge B on the drum bearing portion 103 will be incomplete, and the cartridge B will vibrate during sheet conveyance, causing an adverse effect such as image distortion.

Therefore, in the present embodiment, the positions of the levers 101 corresponding to the cartridge detachable state (first position) and the positioning completed state (second position) are respectively set to m.
As shown in FIG. 5, when the lever 101 is not detachable using two tension springs 610 and 611 or the positioning is not completed, the lever 101 is moved to the first position m1 as shown in FIG. And the second position m2.

As a result, when the cartridge B does not exist, the neutral position of the lever becomes the intermediate point between the first position m1 and the second position m2, and when the cartridge B exists, as shown in FIG. Then, the lever 101 is rotated by 60 °, the drum shaft 902 is seated on the drum bearing 103, and the position of the cam surface of the cam 102 and the support shaft of the cartridge come into contact m0.

In this embodiment, as shown in FIG. 3, markings 115 and 116 are provided on the front panel corresponding to the first position m1 and the second position m2 of the lever 101, respectively. To clearly recognize the completion and incompleteness of the operation.

Further, as shown in FIG.
The shape of the pressure receiving portion 906 of the cartridge B pressed by 0 is concave. Then, the tip of the plunger 110 is formed into a spherical surface, and the spherical portion engages with the concave portion to complete the operation. During this engagement, the plunger 110 rides over the concave crest 906a, so that the lever 101 is locked at the second position m2, and a click feeling is obtained in the operation. In addition, the user can be strongly conscious of the completion of the operation.

Further, as shown in FIG. 1, the protruding block 405 is located inside the front cover 401 and at a position facing the lever 101.
When the lever 101 is at the neutral position m0, the lever
The structure is such that the front cover 401 does not close due to interference between the 101 and the protruding block 405. Whether or not the front cover 401 is closed is detected by a limit switch (not shown), and this is one of the image forming preparation completion conditions. As a result, the lever 101 is moved to the neutral position, that is, the second position also in the first position.
If it is not at the position, the front cover 401 cannot be closed, so that an interlock that does not set the image formation preparation completion state can be taken.

Whether or not the lever 101 is at the neutral position m0 is determined by directly checking the phase of the lever 101 or the rotation shaft 100.
It may be detected by a limit switch or the like. In this case, the positioning incomplete signal can be used as a signal independent of a signal for detecting opening / closing of the front cover 401.

[0038]

The present invention is constructed as described above.
When the operating means is not at the position where the process cartridge is attached / detached or mounted, the user is urged toward an intermediate position between the two positions, so that the user can easily confirm that the operating means is not being operated accurately. obtain. Further, an interlock in the case where the operation is incomplete can be easily configured.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a state in which a cover is opened for attaching and detaching a cartridge.

FIG. 2 is an explanatory sectional view of a state where a cartridge is inserted.

FIG. 3 is an explanatory cross-sectional view illustrating a state in which an inserted cartridge is pivoted to swing to a positioning position.

FIG. 4 is an explanatory cross-sectional view of a state in which a plunger is urged for mounting and positioning.

FIG. 5 is an explanatory sectional view of a state where the cartridge is locked at a cartridge attaching / detaching position.

FIG. 6 is an explanatory sectional view of a state where a process cartridge B is mounted on an electrophotographic image forming apparatus main body A;

[Description of Signs] A: Main body B: Cartridge P: Recording medium m1: First position m2: Second position 1 ... Optical means 2 ... Paper feed cassette 3 ... Photoconductor drum 4 ... Charging roller 5 ... Developing means 5a ... Toner container 6… Pickup roller 7… Separation roller pair 8… Transport roller pair 9… Registration roller pair 10… Transfer roller 11… Transport guide 12… Fixing means 13… Discharge roller pair 14… Discharge tray 100… Shaft 101… Lever 102… Cam 103: Drum bearing part 104: Main body side receiving block 110: Plunger 111: Plunger spring 112: Frame 115, 116 ... Marking 401: Front cover 402: Opening part 405: Projecting block 510: Guide rails 610, 611: Tension spring 620… Lock plate 621… Shaft 622… Torsion coil spring 631… Elevating arm 631a… Claw 641… Shaft 901… Protruding shaft 902… Drum shaft 903… Feet 905… Guide 906… Pressure receiving part 906a… Yamabe

Claims (5)

[Claims] 1. An electrophotographic image forming apparatus in which a process cartridge is detachable, wherein a first position at which the process cartridge is detachable from the apparatus main body, and a second position at which the process cartridge is mounted on the apparatus main body and positioned. When the operating means is not at the first position or the second position, the operating means is biased toward between the first position and the second position. An electrophotographic image forming apparatus, comprising: 2. The electrophotographic image forming apparatus according to claim 1, wherein when the operation means is at the first position and the second position, the operation means is locked at the position. 3. The electrophotographic image forming apparatus according to claim 2, wherein the lock at the first position is performed by locking a claw portion of the operation means to a predetermined portion of the apparatus main body. 4. The electrophotography according to claim 2, wherein the lock at the second position is performed by engagement of a convex portion of the plunger interlocked with the operating means with a concave portion provided in the process cartridge. Image forming device. 5. An electrophotographic image forming apparatus according to claim 1, wherein when the operation unit is not at the second position, the image formation is not enabled.