JP2002023506A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device by which the cost for replacing an image formation unit can be reduced by decreasing the constituent components of the image formation unit. SOLUTION: This device is equipped with an image formation unit 100 which is constituted freely attachably to and detachably from a printer body 200 containing a photoreceptor 1, an electrostatically charging roller 2, a development unit 3, a cleaning unit 4, etc., and a separating mechanism which separates transfer paper 8 from the photoreceptor 1 is constituted by using a separation claw 203 and a support member 202 which supports the separation claw 203 and is fitted to an opening/closing cover structure 201 on the device body side through a conveyance guide plate 201a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
The present invention relates to an image forming apparatus that accommodates a rotating body used for image formation and at least one of a member and an apparatus used for image formation, and has an image forming unit that is detachable from an apparatus main body.

[0002]

2. Description of the Related Art Conventionally, consumable parts such as an image carrier, a charging device, a developing device, a cleaning device, a toner storage unit, and a waste toner storage unit are unitized as an image forming apparatus such as a copying machine, a facsimile, and a printer. An image forming unit (also referred to as a process cartridge) is known. For example, Japanese Patent Application Laid-Open No. 9-281810
Japanese Patent Application Publication No. JP-A-2005-115139 discloses an image forming apparatus in which an image forming unit containing a photosensitive drum as an image carrier, a developing device, a charging device, a cleaning device, and the like is detachably mounted. Such an image forming apparatus is excellent in that maintenance can be simplified because all consumable parts in the image forming unit can be integrally replaced only by replacing the image forming unit.

[0003]

By the way, in the image forming apparatus described in the above publication, a photosensitive member is used as a separating mechanism for separating a sheet (transfer material) conveyed in contact with the photosensitive drum from the photosensitive drum. A separation claw provided so as to contact the drum with a predetermined pressure is used. Since the separation claw is adhesively fixed to a photosensitive body housing which is a support housing of the photosensitive drum in the image forming unit, it is integrally replaced with the image forming unit when the image forming unit is replaced.

[0004] However, the above image forming unit includes:
Replacement is performed when toner runs out or waste toner is full.For example, when used under printing conditions that consume a large amount of toner, the separation claw is replaced before it reaches the end of its service life. There is a problem that waste is caused.

The above problem is limited to the case where the image carrier such as the photosensitive drum and the separation mechanism for separating the transfer material from the image carrier are housed in the same image forming unit. For example, when a rotating body used for image formation such as a fixing roller for fixing a transfer image on a transfer material and a separation mechanism for separating the transfer material from the rotating body are housed in the same image forming unit. It is thought that this occurs similarly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the number of components of an image forming unit and to reduce the cost of replacing the image forming unit. An object of the present invention is to provide an image forming apparatus.

[0007]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The invention according to claim 1 is used for image formation.Rotating body
And at least one of members or devices used for image formation.
And an image forming unit that is detachable from the apparatus main body.
In an image forming apparatus having a knit, the image forming apparatus is in contact with the rotating body.
Separation mechanism to separate transfer material conveyed by touch from rotating body
Is provided in the apparatus main body.

In this image forming apparatus, since the separating mechanism is provided on the apparatus main body side, the number of components of the image forming unit is reduced as compared with the case where the separating mechanism is provided in the image forming unit. The cost of replacing forming units is reduced.

According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the separation mechanism is configured by using a sheet-shaped member provided so that a front end portion contacts the rotating body,
The shape of the sheet-shaped member is set so that the transfer material is guided in such a direction that the transfer image bearing surface of the transfer material is not in contact with the member arranged in the vicinity of the separation mechanism. It is a feature.

In this image forming apparatus, the transfer material is guided by the sheet-like member in such a direction that the transfer image carrying surface of the transfer material is not in contact with the member. Contact with the support surface is avoided, and occurrence of image rubbing due to the contact is prevented.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the separating mechanism is constituted by using two sheet-like members provided so that a leading end thereof contacts the rotating body. At the same time, the two sheet-shaped members are separated from each other so that the two sheet members are in contact with the edges of the both sides of the transfer material in the direction orthogonal to the transfer material transport direction on the rotating body side. Are arranged at a predetermined angle with respect to a plane parallel to.

In this image forming apparatus, the two sheet-shaped members come into contact with the edges of the both ends of the transfer material in the direction orthogonal to the transfer material transport direction on the side of the rotating body, so that the sheet-shaped members and the transfer material Are in line contact with the transfer material edge. Therefore, the two sheet-like members are arranged in parallel to the plane parallel to the transfer material after separation, and the sheet-like members are compared with the case where the two sheet-like members and the transfer material come into surface contact with each other. And the contact area between the sheet and the transfer material can be reduced. Therefore, the chance that the transfer image on the transfer material is rubbed by the sheet-like member is reduced, and the occurrence of image rubbing is suppressed.

According to a fourth aspect of the present invention, in the image forming apparatus of the first, second or third aspect, the sheet-shaped member is a member having elasticity at least in contact with the rotating body. It is.

In this image forming apparatus, since at least the contact portion of the sheet member with the rotating member has elasticity, damage to the surface of the rotating member due to the contact with the sheet member is prevented.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a laser printer as an image forming apparatus utilizing an electrophotographic process will be described below. First, an outline of the entire apparatus will be described with reference to FIG. The printer 200 includes a drum-shaped photoconductor 1 as an image carrier, which is a rotating body used in an image forming apparatus, a charging roller 2 as a charging unit,
The image forming unit 100 includes a developing unit 3 as a developing unit, a cleaning unit 4 as a photosensitive member cleaning unit, and the like, which is detachably mountable to a main body of the printer 200 (see FIG. 2).

On the side of the image forming unit 100,
A latent image writing unit 6 for writing an electrostatic latent image on the photoconductor 1 is provided. For example, the latent image writing unit 6 emits an optical signal corresponding to image information read by a scanner or the like from a semiconductor laser, scans the laser light with a polygon mirror that is driven to rotate, and scans the laser light. A device that writes an optical signal 6a corresponding to color-separated image information on a photoreceptor through a lens for converging and correcting a surface tilt of a polygon mirror, a mirror for deflecting a laser beam, or the like provided in an optical path is used. be able to.

Further, below the image forming unit 100, a paper feed roller 9 for separating and feeding the transfer paper 8 as a transfer material stored in the paper feed cassette 7 one by one, and the paper feed roller 9 After the transfer paper 8 fed by the printer 9 is temporarily stopped in front of the photoreceptor 1, the leading end of the image formed on the photoreceptor 1 and the leading end of the transfer paper 8 are transferred to the photoreceptor 1. A registration roller 11 is provided for re-feeding the transfer paper 8 in synchronization with the rotation of the photoconductor 1 at a timing when the nip reaches the nip portion with the transfer roller 10 as a means.

Further, above the image forming unit 100, a fixing roller 14 and a press roller 15 having a built-in heater 13 rotatably disposed so as to be pressed against each other with a transfer path 12 for the transfer paper 8 therebetween. Is provided. The transfer paper 8 that has passed through the nip between the fixing roller 14 and the press roller 15 is placed downstream of the fixing device 16 in the transfer paper transport direction.
A discharge roller 18 for discharging to a stacker 17 as a discharge tray formed on the upper part of the main body case 200a is provided.

The main body case 200 of the printer 200
In a, an electrical unit 20 is provided as control means for controlling image forming means and print information related to the image forming process of the printer 200. The electrical unit 20 includes a control board (not shown) and various adjustment switches and control units mounted on the control board, and is arranged from the side of the latent image writing unit 6 to below. It is housed in a metal electrical case 21.

In the printer 200 having such a configuration, first, the photosensitive member 1 is uniformly charged by the charge from the charging roller 2 during rotation. Next, the latent image writing unit 6 is driven based on image information read from the outside, whereby the image information is formed as an electrostatic latent image on the charged area (image forming area) of the photoconductor 1. You. The electrostatic latent image formed on the photoconductor 1 is
Is developed by the developer (toner) supplied to the photoreceptor 1 by the developing roller 3a to become a visible image (toner image).

On the other hand, while the toner image is being formed on the photosensitive member 1, the transfer paper 8 is pulled out from the paper supply cassette 7 by the paper supply roller 9, and the leading end of the transfer paper 8 is In a state where the transfer paper 8 is in contact with the nip portion 11, the transfer paper 8 is temporarily waited. Then, at the timing when the leading end of the transfer paper 8 coincides with the leading end of the toner image, the registration roller 11 starts to rotate in synchronization with the rotation of the photoconductor 1, so that the transfer paper 8 is in contact with the photoconductor 1. The photosensitive member 1 is conveyed to a transfer position formed by a nip with a transfer roller 10 which rotates while being pressed against the photosensitive member 1. As a result, the transfer image on which the toner image on the photoreceptor 1 has been transferred at the transfer position is fixed by the transfer image in the process of being conveyed by the fixing roller 14 and the press roller 15 of the fixing device 16, and the paper is discharged. The paper is discharged onto the stacker 17 by the rollers 18. In the meantime, during the transfer process of the toner image onto the transfer paper 8,
The residual toner remaining on the photoreceptor 1 without being transferred onto the
The cleaning blade 4 of the cleaning unit 4
The cleaning container 4 is removed from the photosensitive member 1 by a
Collected in b.

The charge on the transfer sheet 8 is removed by a charge removing brush 22 as a charge removing means disposed downstream of the transfer roller 10 in the transfer sheet transfer direction. Also,
The printer 200 according to the present embodiment includes a separation claw 20 that separates the transfer paper 8 conveyed in contact with the photoconductor 1 from the photoconductor.
The transfer paper 8, which has been neutralized by the neutralization brush 22, is physically separated from the photoconductor 1. The separation mechanism using the separation claw 203 will be described later in detail.

On the other hand, the main body case 200 of the printer 200
a is a transport path 1 for the transfer paper 8 of the main body case 200a.
An opening / closing cover structure 201 forming two side surfaces, and a manual feed unit 23 for manually feeding the transfer paper,
Each is supported by the same support shaft 202. The manual feed unit 23 has an open position shown in FIG. 1 and a manual feed unit storage portion 2 which is a concave portion of the opening / closing cover structure 201.
It is configured to be able to take a closed position (see FIG. 2) stored in the storage unit 01c. The transfer paper fed by using the manual feed unit 23 is conveyed to the registration roller 11 by rotation of a manual feed roller 24 provided on the printer main body 200 side.

The opening / closing cover structure 201 includes:
As shown in FIG. 3, a holder 201b for holding the transfer roller 10 is fixed, whereby the transfer roller 10 is supported by the opening / closing cover structure 201. The opening / closing cover structure 201 includes
Is also attached.

Further, a transfer guide plate 201 a for forming a transfer paper transfer surface of the transfer path 12 and guiding the transfer paper 8 to the fixing device 16 is formed on the opening / closing cover structure 201.
However, the photosensitive member 1 is guided so that the transfer paper 8 is guided by the end face.
Are arranged along the longitudinal direction (see FIG. 7). In the present embodiment, the transport guide rib 201a
Is formed as an integral part with the opening / closing cover structure 201,
Although the number of components of the printer is reduced, it may be formed of a separate member and attached to the opening / closing cover structure 201. For example, if the transport guide plate 201a is formed using a conductive member having a medium resistance, toner dust of an unfixed image is suppressed, and a higher quality image can be obtained.

In FIG. 1, the opening / closing cover structure 20
2 is opened in the clockwise direction in FIG. 2 around the support shaft 202, as shown in FIG. 2, the transport guide plate 201 a, the transfer roller 10, and the neutralization brush 22 move the transfer path 12 of the transfer paper 8. Evacuate greatly from each. Therefore, operations such as attachment and detachment of the image forming unit 100 to and from the printer main body, replacement of the fixing device 16, and jam clearance of the transfer paper 8 jammed in the transport path 12 can be easily performed.

Next, a separating mechanism for separating the transfer paper 8 from the photoreceptor 1, which is a feature of the present embodiment, will be described with reference to FIGS. FIG. 3 is a sectional view showing a schematic configuration of the separation mechanism, and FIG. 4 is a perspective view of the separation mechanism.
The separating mechanism includes the separating claw 203 made of a sheet-like member.
And a support member 202 that supports the separation claw 203. The tip of the separation claw 203 is formed at an acute angle as shown. The separation claw 201 is supported by the supporting member 20 so that its tip can contact the surface of the photoconductor 1.
3 is supported. The separation claw 203 and the support member 202 are connected to the photosensitive member 1 of the transport guide plate 201a.
Transport guide plates 201a at both ends in the longitudinal direction of
(See FIG. 7). In the present embodiment, the support member 202 is a double-sided tape,
01a.

The material of the separation claw 203 is as follows.
It is preferable that at least the contact portion with the photoconductor has elasticity so that the surface of the photoconductor 1 is not damaged by the contact with the photoconductor 1. In the present embodiment, a sheet member made of a PET (polyethylene terephthalate) film having a thickness of 0.125 mm is used as the separation claw 203. Further, as the support member 202, a 1 mm thick S
US material is used.

As described above, in the printer 200 according to the present embodiment, the separation mechanism that separates the transfer paper 8 conveyed in contact with the photoconductor 1 is connected to the main body of the printer 200 via the conveyance guide plate 201a. The opening / closing cover structure 20
1 is provided in the image forming unit 10 as compared with the case where the separating mechanism is provided in the image forming unit 100.
0 can be reduced, and the cost for replacing the image forming unit 100 can be reduced.

The separation claw 203 guides the transfer paper 8 in such a direction that the transfer image carrying surface of the transfer paper 8 is not in contact with the housing 4c of the cleaning unit 4 arranged near the separation claw 203. The shape is set. Specifically, as shown in FIG. 4, the separation claw 203 is bent in a direction away from the housing 4c of the cleaning unit 4. Separation claw 2 set in such a shape
The operation and effect of the printer 200 according to the present embodiment having No. 03 will be described below in comparison with a comparative example.

FIG. 5 shows a printer 200 according to this embodiment.
FIG. 6 is an explanatory diagram for explaining the traveling direction of the transfer paper 8 of FIG.
FIG. 7 is an explanatory diagram illustrating a traveling direction of a transfer sheet 8 of a printer 200 according to a comparative example. In the comparative example shown in FIG. 6, the separation claw 203 has no bent portion, and the front end portion is in contact with the photosensitive member 1 while keeping the linear shape. In the configuration of the comparative example in FIG. 6, the transfer paper 8 that has passed the transfer position is conveyed while being electrostatically attracted to the photoconductor 1, and is physically separated by the separation claw 203. Then, the transfer paper 8 after separation advances in the arrow direction in the figure. For this reason, the toner image carrying surface of the transfer paper 8 may come into contact with the housing 4c of the cleaning unit 4 and the toner image may be rubbed.

On the other hand, in the configuration of this embodiment shown in FIG. 5, the transfer paper 8 after being physically separated by the separation claw 203 is
The transport guide plate 2 is bent by the bent portion of the separation claw 203.
It is guided to the 01a side and proceeds in the direction of the arrow in the figure. Therefore, the toner image carrying surface of the transfer paper 203 is separated by the separating claw 203 from the housing 4 of the cleaning unit 4.
This makes it possible to guide the transfer material in a direction in which the transfer material does not come into contact with the transfer member c, so that contact between the housing 4c and the toner image bearing surface of the transfer paper 8 can be avoided. Thus, the unfixed toner image is not rubbed, and the occurrence of a rubbed image due to the contact can be prevented.

Also, in the present embodiment, the two separation claws 203 are brought into contact with the edges on the photosensitive member 1 side at both end surfaces of the transfer paper in a direction orthogonal to the transfer paper conveyance direction. The separation claws 203 are arranged at a predetermined angle with respect to a plane parallel to the transfer paper 8 after separation.
Specifically, as shown in FIGS. 7 and 8, the two separating claws 203 are brought into contact with the edge 8 a of the transfer paper 8.
A support member 202 supporting each separation claw 203 is provided at an angle α with respect to a plane parallel to the transfer paper 8 after separation.
In the illustrated example, α is set to 18 degrees. In such a configuration, the separation claw 203 and the transfer paper 8 are
Line contact at the edge 8a. Therefore, for example, FIG.
Like a separation claw 203 'shown by a middle virtual line (two-dot broken line),
The separation claw 2 is disposed in parallel with a surface parallel to the transfer paper 8 after separation.
The contact area between the separation claw 203 and the transfer paper 8 can be reduced as compared with a case where the transfer paper 8 is in surface contact with the transfer paper 03 '. Therefore, the toner image on the transfer paper 8 is
Can reduce the chance of rubbing, and can suppress occurrence of image rubbing. Note that the value of the angle α may be appropriately set within a range in which the transfer paper 8 can be satisfactorily separated while suppressing the occurrence of image rubbing.

[0033]

According to the first to fourth aspects of the present invention, there is an effect that the number of components of the image forming unit can be reduced and the cost for replacing the image forming unit can be reduced.

In particular, according to the second aspect of the present invention, it is possible to avoid contact between a member or a device disposed near the separation mechanism and the transfer image carrying surface of the transfer material, and to prevent image rubbing caused by the contact. There is an effect that can be.

In particular, according to the third aspect of the present invention, the chance that the transferred image on the transfer material is rubbed by the sheet-like member can be reduced.
There is an effect that occurrence of image rubbing can be suppressed. In particular, when the present invention is applied to the image forming apparatus of the second aspect, it is possible to more reliably prevent the occurrence of image rubbing.

In particular, according to the invention of claim 4, there is an effect that damage to the surface of the rotating body due to contact with the sheet-like member can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating an entire printer according to an embodiment.

FIG. 2 is a schematic configuration diagram illustrating a state where an opening / closing cover of the printer is opened.

FIG. 3 is a sectional view showing a schematic configuration of a separation mechanism.

FIG. 4 is a perspective view of the separation mechanism.

FIG. 5 is an explanatory diagram for explaining a traveling direction of transfer paper of the printer according to the embodiment.

FIG. 6 is an explanatory diagram for explaining a traveling direction of transfer paper of a printer according to a comparative example.

FIG. 7 is a side view of the separation mechanism and the conveyance guide plate as viewed from a transfer material conveyance direction.

FIG. 8 is an explanatory diagram for explaining an arrangement of separation claws constituting a separation mechanism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photoconductor 2 charging roller 3 developing unit 4 cleaning unit 8 transfer paper 10 transfer roller 12 transfer paper transport path 14 fixing roller 15 press roller 16 fixing device 22 static elimination brush 100 process cartridge 200 printer 200a printer main body case 201 open / close cover 201a transport Guide plate 202 Support member 203 Separating claw (sheet-like member)

Claims (4)

[Claims] 1. An image forming apparatus, comprising: a rotating body used for image forming; and at least one of a member and an apparatus used for image forming, and having an image forming unit detachable from an apparatus main body. An image forming apparatus, wherein a separation mechanism for separating a transfer material conveyed in contact with a body from a rotating body is provided in the apparatus main body. 2. The image forming apparatus according to claim 1, wherein the separating mechanism is configured by using a sheet-shaped member provided so that a leading end thereof contacts the rotating body, and the transfer member is formed by the sheet-shaped member. An image forming apparatus, wherein the shape of the sheet-shaped member is set such that the transfer material is guided in such a direction that the transfer image bearing surface is not in contact with a member disposed near the separation mechanism. 3. The image forming apparatus according to claim 1, wherein the separating mechanism is constituted by using two sheet-like members provided so that a leading end thereof contacts the rotating body. The two sheet-shaped members are placed on a surface parallel to the separated transfer material such that the sheet members of the two contact each other with the edges of the transfer member in the direction orthogonal to the transfer material transport direction. An image forming apparatus, wherein the image forming apparatus is disposed at a predetermined angle with respect to the image forming apparatus. 4. The image forming apparatus according to claim 1, wherein the sheet-shaped member is an elastic member at least in a contact portion with the rotating body.