JPH06186793A - Process cartridge and image forming device capable of attaching/detaching it - Google Patents

Abstract

PURPOSE:To evade a shutter in a minimum housing space by changing the shape of a protective cover depending on whether it locates at the protective or retreating position. CONSTITUTION:The shape of the sheet-like shutter 9 as the protective cover of a photosensitive drum 1 is changed depending on whether it locates at the protective or retreating positions. The shutter 9 is a sheet having string-like parts on the right and left both ends and when the shutter 9 is closed, that is, the protective cover is located at the protective position for protecting the surface of the photosensitive drum 1, the image region of the drum 1 is completely covered and protected. A rotary body 91 is rotated centering the center of the rotation 93 and when the shutter 9 is pulled against the spring force of a roller 92, the drum 1 is exposed (the shape of the wavy line of the shutter 9). In this way, the sheet-like shutter 9 receives tensile force by the force of a spring pressing the roller 92, is in a close contact state with a process cartridge 30 and hardly requires housing volume at the time of opening the shutter, as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process cartridge used in a copying machine, a laser beam printer, a facsimile and the like, and an image forming apparatus to which the process cartridge can be attached and detached.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic process, in order to improve maintainability, an image carrier, a charger, a developing unit, a cleaner, etc. acting on the image carrier are detachably attached to the main body of the apparatus. Many process cartridge type devices are used.

Among these process cartridges, one having a movable protective cover for protecting the surface of the image bearing member is very excellent in improving the life of the image bearing member.

FIG. 7 shows an example of a protective cover (shutter).
Show types. a and b are examples in which the shutter is opened and closed about one point as a rotation center, a is an example in which the shutter is retracted to the developing device side, and b is an example in which the shutter is retracted to the cleaner side.

In c and d, the shutter 9 is rotated by the rotation of another rotating body 91, and c is retracted to the developing device side,
d is an example of saving to the cleaner side.

[0006]

However, the above-mentioned conventional example has the following drawbacks.

That is, at the retracted position of the shutter, as shown in FIG. 8, the shutter may interfere with the paper conveyance path. In order to avoid such an inconvenience, there may be a restriction on the shape and main body configuration of the process cartridge. In addition, depending on the opening timing of the shutter, the movement path of the shutter may hinder the paper conveyance, which imposes restrictions on the main body configuration.

As described above, the restriction of the shutter of the process cartridge may hinder the downsizing of the main body.

[0009]

The present invention for solving the above problems provides a process cartridge having an image carrier and a movable protective cover for protecting the surface of the image carrier. The protective cover is characterized in that its shape changes depending on whether it is located at a protective position for protecting the surface of the image carrier or at a retracted position retracted from the protective position.

Further, according to the present invention for solving the above-mentioned problems, a mounting for mounting a process cartridge having an image carrier and a movable protective cover for protecting the surface of the image carrier. In the image forming apparatus, the opening / closing means has a protection position for protecting the surface of the image carrier, and an opening / closing means for moving the protection cover to a retracted position retracted from the protection position. It is characterized in that the protection position and the retracted position are changed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram for explaining a process cartridge which is a first embodiment of the present invention. The process cartridge is roughly divided into a developing section A and a cleaner section B. The developing section A has at least a sleeve 3 having a magnet 2 therein, a blade 4 in contact with the sleeve 3, and a toner 5 in a hopper around the photosensitive drum 1.
In addition, the cleaner section includes a blade 6 and a primary charging roller 7.
have.

The process cartridge L is shown in FIG.
A latent image is formed on the drum 1 by the laser light L emitted from the laser scanner 11 mounted on the BP. In the developing device B, the toner 5 attracted to the magnet 2 is supplied to the latent image by the rotating sleeve cylinder 3, and the latent image on the photosensitive drum 1 is visualized. Thereafter, the paper P is sandwiched between the transfer roller 8 on the main body of the electrophotographic apparatus and the photoconductor drum 1 to transfer the image on the photoconductor drum onto the paper P. After the transfer is completed, the toner remaining on the photosensitive drum 1 is removed by the cleaner blade 6, and the potential is made uniform by the primary charging roller 7.

The paper P is a paper feed roller 12 and a transport roller 1.
3 is conveyed on the conveyance guide 91 and sandwiched between the photoconductor drum 1 and the transfer roller 8, and then is conveyed on the conveyance guide 92 and is sent to the fixing device 15 by the downstream side conveyance device 14. In the fixing device, the toner on the paper is melted and fixed on the paper by heat and pressure.

The process cartridge is taken out of the apparatus when a paper jam occurs in the apparatus or when the process cartridge of another color is used. At this time, if the photoconductor drum comes into contact with another object, scratches may occur to deteriorate the quality of the print image thereafter, or an abnormality may occur in the photoconductor due to a chemical reaction to affect the image quality. Therefore, conventionally, many process cartridges are provided with a shutter for protecting the photosensitive drum 1.
The shutter is used so as to cover the photosensitive drum when the process cartridge is taken out of the apparatus, and expose the photosensitive drum when the process cartridge is set at a predetermined position in the apparatus.

Reference numeral 9 in FIG. 1 is a sheet-like shutter made of vinyl chloride having infinite refraction points, and the shape of the sheet when unfolded is a sheet having thin string-like portions on the left and right ends as shown in FIG. . One end of this sheet is a roller 92
Have been sown. The roller 92 is urged in the direction of the arrow in the figure by a spring (not shown), and a force to wind up the sheet-like shutter acts. The other end of the sheet-like shutter is connected to a wire-shaped rotating body 01 for both left and right, and this rotating body 91 rotates around a rotation center 93.

A method of mounting the cartridge 30 will be described here.

As shown in FIG. 6, the cartridge 30 can be attached and detached with the image forming apparatus main body 40 opened.
When the cartridge 30 is mounted in the direction of the arrow in FIG. 6 and the apparatus body 40 is closed around the rotation fulcrum 16, the projection 17 provided at the rotation center 93 of the protective cover (shutter) 9 is provided on the apparatus body. The opening / closing member 18 abuts, and the projection 17 rotates as the upper frame of the apparatus main body is closed, whereby the protective cover 9 is gradually opened. Cartridge 30
FIG. 5 shows a state in which is completely attached to the apparatus main body. At this time, the rotation shaft of the photosensitive drum is positioned by the positioning member 19 provided in the apparatus body 40. The broken line shape in FIG. 1 is a state in which the drum 91 is exposed by pulling the sheet-like shutter 9 against the spring force of the roller 92 by rotating the rotating body 91. The relative positional relationship between the sheet-like shutter 9 and the photosensitive drum is shown in FIG. When the shutter is closed, that is, when the protective cover is in the protective position for protecting the surface of the image carrier, the photosensitive drum 1 is at the position B with respect to the sheet-like shutter 9, and the image area is completely covered. ,
Protected. In FIG. 2, the sheet-like shutter 9
At this time, the left and right string-like portions of the upper part of the are wound around the rollers 92. When the rotator 91 rotates and the shutter 9 opens, the shutter 9 moves downward in FIG. That is, in the relative relationship with the photoconductor drum 1, the photoconductor drum 1 is located at the portion A indicated by the broken line, and the image area is exposed. That is, the protective cover is located at the retracted position retracted from the protected position. As shown in FIG. 1, the sheet-like shutter 9 is in a state of being in close contact with the process cartridge due to the tension of the spring (not shown) that biases the roller 92 in the arrow direction, that is, the protective position and the retracted position. Since the shape has changed due to and, even when the shutter is open, it requires almost no storage volume.

Therefore, it is possible to provide a paper passage path without being restricted by the shutter storage position.
It is also useful for downsizing the entire device.

(Other Embodiments) A second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

The shutter 9 shown in FIG. 3 is a member composed of short plate-shaped members a, b, c, d, and e. In FIG. 3, both the exposed state and the covered state of the photosensitive drum 1 are shown. ing.

The shutter is composed of a wire body-shaped frame 91 that rotates about a rotation center 93 on the process cartridge as a fulcrum and a combination body 9 of short plate-shaped members. The shutter member 9 is shown in FIG. 4 when no external force is applied. It has a shape close to a semi-circle. The members a, b, c, d, and e forming the shutter member 9 are partially connected as shown in the enlarged view of FIG. The member 9 is made of a nylon material and has a semicircular shape in the free state as shown in FIG. 4, but it can be extended to a state close to a straight line. In addition, the force to recover the shape is working by utilizing the elasticity of the resin material. Therefore, as shown in FIG. 3, the shutter member 9 is in a state of being almost linear when the drum is covered, but when the drum is exposed, the members a, b, c, which form the shutter member 9,
It becomes possible for d and e to bend at the joint points of the respective members and to be in close contact with the process cartridge, and to be stored in a minimum occupied space.

At this time, the bending force at the joining point between a and b is ab, the bending force at the joining point between b and c is bc, and similarly, cd and de are the same, and ab>bc>cd> de. It is set so that

[0023]

The shutter member, which is a member for protecting the drum, which is necessary for improving the reliability of the process cartridge, obstructs the conveyance of the recording material during the printing operation and obstructs the miniaturization of the apparatus as much as possible. It becomes possible to avoid the shutter with a minimum storage space by holding down the presser foot.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram illustrating the shape of a shutter member according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram illustrating a configuration of a shutter member according to a second embodiment of the present invention.

FIG. 5 is a sectional view of the image forming apparatus of the present invention.

FIG. 6 is a sectional view of the upper frame of the image forming apparatus of the present invention when expanded.

FIG. 7 is a diagram showing opening and closing of a shutter of a conventional process cartridge.

FIG. 8 is a list view showing a relationship between a retracted position of a shutter of a conventional process cartridge and a paper path.

[Explanation of symbols]

 1 Photoreceptor Drum 2 Magnet 3 Sleeve Cylinder 4 Blade 5 Toner Container and Toner 6 Cleaner Blade 7 Primary Charging Roller 9 Shutter Member 30 Process Cartridge 91 Shutter Opening / Closing Rotating Member 92 Shutter Rewinding ID 93 Shutter Opening / Closing Rotating Member Center of rotation

Claims (4)

[Claims] 1. A process cartridge having an image carrier and a movable protective cover for protecting the surface of the image carrier, wherein the protective cover is a protective position for protecting the surface of the image carrier. A process cartridge characterized in that the shape thereof changes depending on whether it is located at a position where it is located at or at a retracted position retracted from the protection position. 2. The process cartridge according to claim 1, wherein the protective cover is a sheet-shaped member. 3. The process cartridge according to claim 1, wherein the protective cover has a bending portion. 4. A mounting portion for mounting a process cartridge having an image carrier and a movable protective cover for protecting the surface of the image carrier, and a protection position for protecting the surface of the image carrier. And an opening / closing means for moving the protective cover to the retracted position retracted from the protected position, wherein the opening / closing means changes the shape of the protective cover between the protected position and the retracted position. An image forming apparatus characterized by.