JP3689633B2 - Process cartridge and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrophotographic image forming apparatus provided with a protective means (hereinafter referred to as a shutter member) for protecting an electrophotographic image carrier (hereinafter referred to as a photoreceptor) constituting a process cartridge.
[0002]
[Prior art]
Examples of the image forming apparatus that forms an image on a recording medium using an electrophotographic image forming process include an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, etc.), an electrophotographic facsimile apparatus, and an electronic Includes photo word processors.
[0003]
Further, as the process cartridge, for example, a charging unit that uniformly charges a photoconductor as an image carrier, a cleaning unit that removes toner remaining on the photoconductor after transfer, and a photoconductor are integrally formed into a cartridge. At least one or all of a type in which the cartridge is removable from the main body of the image forming apparatus, a charging unit, a developing unit that develops a latent image formed on the photosensitive member with a developer such as toner, and the cleaning unit. There is a type in which the photosensitive member is integrally formed into a cartridge so that the photosensitive member can be attached to and detached from the image forming apparatus main body.
[0004]
2. Description of the Related Art Conventionally, various image forming apparatuses having a process cartridge provided with an openable / closable shutter for the purpose of protecting a photoconductor are provided, and the shutter is used for a photoconductor when the process cartridge is attached to and detached from the image forming apparatus main body. Some are intended for protection, others are intended for protecting the photoreceptor when the process cartridge is mounted on the main body of the image forming apparatus, and others are intended to protect the photoreceptor when removing or jamming both. .
As a characteristic configuration of such an image forming apparatus main body, the distance between the transfer unit and the fixing unit is short, and the space for jam processing is narrow.
[0005]
On the other hand, when performing jam processing, it is necessary to secure a space for jam processing by separating the photosensitive member and the transfer unit, and if the jam processing is performed by placing a hand in the secured space, the photosensitive member is damaged. For this reason, there is a known device that protects the photosensitive member by closing the shutter in conjunction with the operation of separating the transfer means.
[0006]
[Problems to be solved by the invention]
However, in the type in which the distance between the transfer unit and the fixing unit is short, the conveyance unit that transfers between both units is also short. Therefore, in the conveyance of the transfer material, the downstream side in the conveyance direction of the transfer material is the pressure contact portion (nip) of the fixing unit. When the image is close to (part), the toner image may be lifted upward, and the unfixed toner image carried on the transfer material may rub against other parts and disturb the image.
[0007]
The invention according to the present application has been made to solve the above-described problems, and an object of the invention is to provide an image forming apparatus that prevents an unfixed toner image from being disturbed by the trailing edge of the transfer material. It is to provide.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a process cartridge having at least an image carrier and detachable from the main body of the image forming apparatus, wherein the image carrier and the image carrier are attached to the main body of the image forming apparatus. A moving member that can move between a first position and a second position in the vicinity of the fixing unit in conjunction with an operation of separating the transfer unit that transfers the toner image on the body to the transfer material, and the moving member includes the first unit When it moves to the position, it moves to the vicinity of the image carrier. When the moving member moves to the second position, it moves to the vicinity of the fixing means, and in the state of moving to the vicinity of the fixing means, toward the fixing means. Upon contact with the transfer material conveyed possess a rotary member rotatable by the contact force, the movable member is a protection means for protecting the image bearing member and said driven rotating member to the mobile member is provided It features that you are It is an process cartridge.
[0011]
According to a second aspect , in the first aspect, a protrusion is provided in the vicinity of the rotated member.
[0012]
According to a third aspect of the present invention, in any one of the above aspects, the rotated member can be replaced.
[0013]
According to a fourth aspect of the present invention, a transfer path for transferring a transfer material onto which a toner image has been transferred by a transfer unit to the fixing unit through a transfer position with respect to the image carrier, and the image carrier and the transfer unit are separated from each other. In an image forming apparatus having a moving member that is movable to a first position and a second position in the vicinity of the fixing unit in conjunction with the movement operation , the elephant carrier is moved when the moving member moves to the first position. When the moving member moves to the second position, it moves to the vicinity of the fixing unit, and is transferred to the fixing unit while being moved to the vicinity of the fixing unit. Upon contact with wood have a rotary member rotatable by the contact force, a protective means for said moving member to protect the image bearing member, and wherein the driven rotating body to the mobile member is provided Image forming equipment It is an.
[0015]
According to a fifth aspect of the present invention, there is provided an image forming apparatus including any one of the first to third process cartridges.
[0017]
A sixth invention is the above-mentioned fourth invention, wherein a projection is provided in the vicinity of the rotated member.
[0018]
A seventh invention is characterized in that, in the fourth or sixth invention, the rotated member is replaceable.
[0019]
An eighth invention is the invention according to any one of the first to third inventions, wherein the distance between the transfer means and the fixing means is shorter than the minimum size of the transfer material.
[0020]
A ninth invention is the invention according to any one of the fourth to seventh inventions, characterized in that the distance between the transfer means and the fixing means is shorter than the minimum size of the transfer material.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. .
First, the overall configuration of the image forming apparatus main body will be described. In FIG. 11, an image forming apparatus main body A has a scanner unit B as an image reading unit that reads image information on the image surface of a book document at the upper part, and an image forming unit C as an image forming unit at the lower part. In addition, the transfer material deck D is assembled to the lower part thereof.
[0022]
The scanner unit B includes a scanning light source 61, a platen glass 62, a document pressure plate 63 that can be opened and closed with respect to the apparatus main body A, a first mirror 64, a second mirror 65, a third mirror 66, a lens 67, and a light receiving element (photoelectric element). Conversion element) 68, an image processing unit, and the like.
[0023]
The scanning system light source 61 and the first mirror 64 constitute a first mirror stage, and the second mirror 65 and the third mirror 66 constitute a second mirror stage, and are scanned in the scanning direction a. The moving state of the first and second mirror bases is indicated by dotted lines.
[0024]
Then, a book document such as a book, cardboard, or curl paper or a sheet-like document is placed on the platen glass 62 with the document surface facing down (the platen glass 62 side), and the document pressure plate 63 presses the document back in a stationary state. When the reading start key of the operation unit (not shown) is pressed, the scanning light source 61 scans the lower part of the platen glass 62 in the direction of arrow a to illuminate the image surface of the document, and the reflected light (image information) 1 Lead to mirror 64.
[0025]
The image information of the document guided to the first mirror 64 is projected onto the light receiving element 68 by the lens 67 through the second mirror 65 and the third mirror 66, and the image information is read by the light receiving element 68 to perform image processing (not shown). The image is processed by the image forming unit, converted into an electric signal, and transmitted to the laser scanner 69 of the image forming unit C.
[0026]
Here, the image forming apparatus main body A functions as a copying machine when the processing signal of the image processing unit is input to the laser scanner 69, and functions as a printer when the output signal of the personal computer is input. Further, if a transmission signal from the facsimile machine of another machine is input or a processing signal of the image processing unit is sent to the facsimile machine of the other machine, it functions as a facsimile machine.
[0027]
On the other hand, a transfer material storage unit and a sheet cassette 21 are mounted below the image forming unit C. The sheet cassette 21 is composed of a lower cassette 21a and an upper cassette 21b as one feeding unit. Yes.
[0028]
Transfer materials as sheets accommodated in the lower and upper cassettes 21a and 21b are fed out by a pickup roller 22 serving as a feeding rotating body, and one sheet at a time by the cooperative action of a feed roller 23 and a retard roller 24. After being separated and fed, it is transported by a pair of transport rollers 25, 26 or 27.
[0029]
Then, the transferred transfer material is brought into contact with the front end of the transfer material after being stopped for a predetermined time in order to absorb the variation in the position of the transfer material by the pair of pre-registration rollers 28, and then rotated and conveyed. 10 is guided to the registration roller pair 11 and is fed to the image forming unit C by the registration roller pair 11 so as to be synchronized with the image forming operation.
[0030]
The image forming unit C includes a photoconductor 1 as an image carrier, an image writing optical system 2, a developing device 3, a transfer roller 6 of a transfer unit 4, and the like. Then, on the surface of the photoreceptor 1 uniformly charged by the primary charger 5, laser light corresponding to the image information emitted from the laser scanner 69 is scanned by the image writing optical system 2 to form a latent image, A toner image is formed on the latent image by the developing device 3, and the toner image is transferred to the first surface of the transfer material by the transfer roller 6 onto the transfer material conveyed in synchronization with the rotation of the photosensitive member 1 by the registration roller pair 11. Is done.
[0031]
On the downstream side in the transport direction of the image forming unit C, a transfer material guide 19 serving as guide means, a fixing device 7 serving as fixing means, and a discharge roller pair 12 are provided. The transfer material on which the toner image is formed is guided by the transfer material guide 19 from the transfer portion E formed by the photosensitive member 1 and the transfer roller 6 and conveyed to the fixing device 7, where the toner image is transferred by being heated and pressurized. It is fixed on the surface of the material.
[0032]
After the fixing, the transfer material is guided in the discharge direction and is stacked on a discharge tray (upper part of the image forming unit C) 13 having a function as an upper surface cover by the discharge roller pair 12. The transfer material is discharged on the paper discharge tray 13 in a face-down manner with the image forming surface on the bottom surface.
[0033]
When recording images on both sides of the transfer material, after passing through the fixing device 7, the transfer material is conveyed by the discharge roller pairs 14 and 12, and immediately after the trailing edge of the transfer material passes through the flapper 15, The discharge roller pair is reversely rotated while holding the sheet, and the transfer material is reversed and temporarily placed on the transfer material double-sided tray 16, and then conveyed by each roller pair 28, 10 to reach the registration roller pair 11, The reversed transfer material is configured such that after the image is formed on the second surface in the same manner as described above, it is discharged and stacked on the discharge tray 13.
[0034]
Here, a resister sensor lever 17 for detecting the transfer material is provided on the upstream side of the registration roller pair 11 in the transport direction. When the transfer material is transported, the resister sensor lever 17 is rotated and the sensor 18 is rotated. Transmits the detection of the transfer material to the CPU of the main body of the image forming apparatus.
[0035]
Next, details of the present embodiment will be described below.
[0036]
First, as shown in FIG. 1, the process cartridge 31 is detachable from the main body of the image forming apparatus, and includes a charging roller 32 of the charging unit 5, a cleaning unit 33 that scrapes residual toner on the photoreceptor 1, A screw 34 for sending the scraped residual toner to the back side in the axial direction of the photosensitive member 1 and a shutter 35 urged in the normally closing direction (first position) to protect the photosensitive member 1 are provided. .
[0037]
The shutter 35 is formed of a resin (engineering plastic) material, and a protective sheet 36 is attached to the inner surface side so that the photoreceptor 1 is not damaged even if the shutter 35 is pressed.
[0038]
The shutter 35 is movable between the first position that covers a part of the photoreceptor 1 exposed from the cartridge body and the second position that is retracted between the fixing device 7 outside the cartridge body. As shown in FIG. 7, the lower end portion of the shutter 35 is positioned in the vicinity of the entrance guide 47 of the fixing device 7 in the second position.
[0039]
Then, when the transfer material that has undergone the transfer process during use of the image forming apparatus passes through the nip portion of the fixing device 7, if the rear end portion of the transfer material on the upstream side in the transport direction from the nip portion jumps, A plurality of spurs 37 are provided in the front-rear direction as rotation buffer members that absorb the hitting of the rear end portion of the material and follow the movement of the transfer material and do not affect the image of the unfixed toner.
[0040]
The spur 37 has a star shape made of a Mylar material having a thickness of about 0.2 mm and is rotatably attached to the shaft 38. The spur 37 is incorporated in the direction of the arrow b with the central hole 37a up to the rotation groove 38a of the shaft 38 (FIG. 2) and is rotatably held so as not to come off (FIG. 3).
[0041]
Further, the shaft 38 is held so that the shaft can be rotated to such an extent that it does not come off the snap fit portions 39 provided at both ends of the shutter 35 in the front-rear direction (FIG. 4).
[0042]
Further, as shown in FIG. 5, five spurs 37 are arranged in the axial direction of the spur shaft 38, and are provided so as to correspond to various sizes of transfer materials. FIG. 5 is a view of FIG. 1 viewed from below.
[0043]
As shown in FIG. 6, when the process cartridge 31 is mounted on the main body of the image forming apparatus, the shutter 35 is moved to a position that protects the lower part of the photoreceptor 1 (first position, hereinafter closed) by an elastic member (not shown). It is energized. At this time, the conveyance unit 40 that holds and integrates the transfer roller 6, the transfer material guide 19, and the like also rotates counterclockwise around a rotation fulcrum 40 a provided on the side opposite to the fixing device 7. The body 1 and the transfer roller 6 are maintained at a position where they are separated (hereinafter referred to as a release position). A space G formed by releasing the conveyance unit 40 becomes a jam processing space.
[0044]
FIG. 6 shows a state in which the shutter 35 of the process cartridge is closed and held in the first position, and a state in which the conveying unit 40 is opened by the opening / closing lever 41 being tilted to the open position. As shown in FIG. 7, the cam portion 41a rotates the pressurizing mechanism portion 42 counterclockwise by rotating it in the direction of the arrow c, and is normally pressed by the spring portion 42a of the pressurizing mechanism portion 42. The conveyance unit 40 is positioned in this state.
[0045]
In addition, a lever (not shown) provided in the transport unit 40 is provided on the process cartridge 31 side in the process in which the transport unit 40 is positioned in a normal state by the rotation of the lever 41 in the arrow c direction. An arm (not shown) having a shape is rotated, and the shutter 35 connected to the arm (not shown) is pushed up to a retracted position (second position, hereinafter referred to as an open state).
[0046]
Further, the developing device 3 constituting a part of the cartridge can be moved independently in the left-right direction, and after the process cartridge 31 is mounted, the developing device is urged toward the photosensitive member 1 to form an image. become.
[0047]
By the way, when the transfer material is stagnated and jammed, the lever 41 is rotated in the direction opposite to the arrow c direction to release the transport unit 40 from the normal position. At this time, it operates in the direction opposite to that described above, the shutter 35 rotates in the closing direction, and the photosensitive member 1 is protected and jamming can be performed (state shown in FIG. 7).
[0048]
The pressure contact portion (nip portion) of the fixing device 7 is composed of a pressure-side roller 43 and a driven-side endless fixing film 44, both of which have a reverse crown shape. When both are in pressure contact, the shape of the pressure side roller is obtained. The endless fixing film 44 is rotatably supported by an arc-shaped heater holder, and a heater 45 as a heat source is provided below the heater holder.
[0049]
Next, the function of the spur will be described with reference to FIGS.
[0050]
When the transfer material passes through the pressure contact portion 46 of the fixing device 7, the transfer material upstream is transported along the transfer material guide 19 by the weight of the transfer material S for a while after passing through the transfer roller 6 ( (Fig. 8) After that, the influence of the pressure contact area will win, and the trailing edge of the transfer material may be lifted (Fig. 9) (the difference varies considerably depending on the type of transfer material, the stiffness of the transfer material, and the environment). is there).
[0051]
As shown in FIG. 10, if there is no rotating body that can be pressed down, such as a spur 37, the unfixed toner image is rubbed on the entrance guide 47 (FIG. 7) of the fixing device 7 and the image is disturbed.
[0052]
Since the spur 37 is configured to smoothly rotate even with a light contact force such as the lifting force of the transfer material, the unfixed toner image is smoothly guided to the fixing pressure contact portion 46 without disturbing the transfer material. And the fixing process can be terminated.
[0053]
In the case of an apparatus like this embodiment in which the distance between the transfer means (transfer roller 6) and the fixing means (nip portion) is as short as about 95 mm (FIG. 6), a jamming process is provided by providing a spur 37 on the shutter 35 that opens and closes. Sometimes the shutter closes and retreats from the jam processing space G, so that it is possible to effectively perform jam processing in a limited space without fear of damaging the spur.
[0054]
Further, since the spur 37 is held by the shutter 35 of the process cartridge 31 that can be attached to and detached from the apparatus main body, the replacement from the snap fit 39 provided on the shutter 35 is facilitated (FIG. 4).
[0055]
In the unlikely event that the tip of the spur 37 is damaged due to bending, bending, etc., it is possible to continue using it by simply reattaching the spur without replacing the entire process cartridge. It is also useful for recycling the shutter part by removing the part.
[0056]
As shown in FIG. 6, during jam processing, when the hand is put in the jam processing space G with the shutter 35 closed, it may give a strange feeling if the tip of the spur 37 hits the hand. In addition, projecting ribs 48 are provided on both sides of the spur 37 in the axial direction.
[0057]
The first position that protects the photoconductor described in the present embodiment and the member that can be moved to the second position are provided in the process cartridge, but the first position that protects the photoconductor provided in the main body of the image forming apparatus. And a member that can move to the second position.
[0059]
【The invention's effect】
As described above, the rotation member is provided on the moving member that protects the photosensitive member in the process cartridge that is detachable from the apparatus main body, and the rotation member is retracted from the jam processing space during the jam processing, thereby transferring the transfer material. In addition to avoiding an adverse effect on the unfixed toner image due to the behavior such as the rising of the downstream side of the direction, a good image can be obtained and a space for jam processing can be efficiently secured.
[0060]
Furthermore, until the transfer material is discharged from the cassette to the outside of the machine, the distance that the transfer material is conveyed is shortened as much as possible, and the distance between the photosensitive member and the fixing means in the image forming unit is shortened. There is an effect that it is possible to provide a device desired by the user that can increase the output of the transfer material on which the image is formed as soon as possible.
[0061]
Furthermore, by providing protrusions on both sides of the rotated member, it is possible to obtain an effect that the user does not feel uncomfortable even in the jam processing in a limited space.
[0062]
In addition, since it is possible to easily remove the rotated member, even if the rotated member is defective, it can be replaced as a single part, so it is efficient even if the entire expensive process cartridge is not replaced. The effect that it can be used is obtained.
[0063]
In addition, there is an effect that it is possible to contribute to recycling of the shutter portion.
[Brief description of the drawings]
1 is a schematic cross-sectional view of a process cartridge showing an embodiment of the present invention. FIG. 2 shows the spur of FIG. 1 and shows a state before being attached to a shaft. FIG. 3 shows the spur of FIG. FIG. 4 is a cross-sectional view taken along line F-F in FIG. 5. FIG. 5 is a view of FIG. 1 viewed from below. FIG. 6 is an image forming apparatus including the process cartridge of FIG. FIG. 7 is a diagram illustrating a state in which the conveyance unit is opened. FIG. 7 is a diagram in which the conveyance unit of the image forming apparatus including the process cartridge illustrated in FIG. 1 is held in a normal state. FIG. 9 is a perspective view showing a state of a rear end portion of a transfer material passing through a nip portion of a fixing device. FIG. 10 is a perspective view showing an operation of a spur according to the embodiment of the invention. Schematic diagram of equipment [Explanation of symbols]
1 Photoconductor
3 Developer 4 Transfer means 5 Primary charger 6 Transfer roller
7 Fixing device
10 Transport roller pair
11 Registration roller pair
12, 14 discharge roller pair
13 Output tray
15 Flapper
16 Duplex tray
17 Regimae sensor lever
18 sensors
21 cassette
22 Pickup roller
23 Feed roller
24 retard roller
25, 26, 27 Pair of transport rollers
28 Pre-registration roller
31 Process cartridge
32 Charging roller
33 Cleaning section
34 Screw
35 Shutter
36 Protection sheet
37 Spur
38 axes
39 snap fit
40 Transport section
41 Lever
43 Pressure roller
44 Fixing film
45 Heater
46 Pressure contact (nip)
47 Entrance guide
48 Projection rib
61 Scanning light source
62 preten glass
63 Original platen
64, 65, 66 mirror
67 Lens
68 Photo detector
69 Laser scanner

Claims (9)

In a process cartridge having at least an image carrier and detachable from the image forming apparatus main body, the image carrier and the toner image on the image carrier are displayed in a state of being attached to the image forming apparatus main body. A moving member that can move to a first position and a second position in the vicinity of the fixing unit in conjunction with an operation of separating the transfer unit that transfers to the transfer material, and the image when the moving member moves to the first position. When the moving member moves to the second position, the moving member moves to the vicinity of the fixing unit, and in the state of moving to the fixing unit, the transfer material is conveyed toward the fixing unit. Upon contact possess a rotary member rotatable by the contact force, the movable member is a protection means for protecting the image bearing member, and said driven rotating member to the mobile member is provided process Cartridges. The process cartridge according to claim 1 , wherein a protrusion is provided in the vicinity of the rotated member. A process cartridge according to claim 1 or 2, characterized in that a replaceable said rotary member. Through the transfer position relative to the image bearing member, a conveying path for conveying the fixing means transfer material the toner image transfer by the transfer means at the transfer position, in conjunction with the operation of separating said transfer means and said image bearing member An image forming apparatus having a moving member movable to a first position and a second position in the vicinity of the fixing unit; and when the moving member moves to the first position, the moving member moves to the vicinity of the elephant carrier; When the moving member moves to the second position, the moving member moves to the vicinity of the fixing unit, and when the moving member contacts the transfer material conveyed toward the fixing unit on the conveying path in a state of moving to the vicinity of the fixing unit, the contact is made. have a rotary member rotatable by a force, a protective means for said moving member to protect the image bearing member, an image forming apparatus, characterized in that said driven rotating member to the mobile member. Image forming apparatus characterized by having a process cartridge according to any one of claims 1 to 3. The image forming apparatus according to claim 4 , wherein a protrusion is provided in the vicinity of the rotated member. The image forming apparatus according to claim 4, wherein the rotated member is replaceable. The process cartridge according to any one of claims 1 to 3, the distance of the transfer means and the fixing means is equal to or shorter than the minimum size of the transfer material. 8. The image forming apparatus according to claim 4, wherein a distance between the transfer unit and the fixing unit is shorter than a minimum size of the transfer material.

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