JP3365700B2 - 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 an image bearing member formed on an image bearing member.
Transfer the toner image to transfer paper conveyed toward the carrier
An image forming apparatus for obtaining a recorded image by performing
At least one of the imaging elements including the body in the unit case
Assemble to form an imaging unit, and
Image formed by detachably mounting the
The present invention relates to a forming apparatus. [0002] 2. Description of the Related Art Copiers, printers, facsimile machines,
In conventional image forming apparatuses such as multifunction peripherals, transfer paper
Transfer paper so that the paper can be transported correctly toward the image carrier.
A guide unit for guiding is provided in the image forming apparatus main body. When
According to this configuration, the rollers are dedicated guides for guiding the transfer paper.
Must be provided in the main body of the image forming apparatus.
As a result, the number of parts of the entire image forming apparatus increases,
But the disadvantage of rising. [0003] Therefore, the unit case of the image forming unit is located under the unit case.
Section can be configured as a guide section for guiding the transfer paper.
Conceivable. By doing so, the component points of the image forming apparatus
Can reduce the number and achieve its cost reduction
You. However, as described above, the unit case
When the transfer paper guide is configured by the lower part,
Remove the printer from the image forming apparatus body and
When placed on the mounting surface, the lower part of the unit case
Transfer paper composed of the lower part because it touches the mounting surface
Will come into contact with the mounting surface. For this reason,
Foreign matter on the mounting surface adheres to the guide,
May damage the guide. Such a work
Use the image unit as it is mounted on the main body of the image forming apparatus
If it does, it adheres to the guide part at the bottom of the unit case
Foreign matter adheres to the transfer paper and stains the transfer paper.
If the guide is damaged, use the transfer paper guide
There is a possibility that the function cannot be performed. [0005] SUMMARY OF THE INVENTION The present invention relates to the above-mentioned new technology.
It has been made on the basis of
Is transferred to the lower part of the unit case of the imaging unit
By providing a paper guide function, the number of parts of the entire image forming apparatus can be reduced.
And the imaging unit is placed on the mounting surface
Transfer paper composed of mushrooms and the lower part of the unit case
Foreign matter adheres to the guide part of the
Therefore, it is described at the beginning that can prevent the injuries
Another object of the present invention is to provide an image forming apparatus of a type. [0006] The present invention achieves the above object.
In order to achieve this, an image forming apparatus of the type described at the beginning
Of the image forming unit attached to the main body of the image forming apparatus.
The lower part of the slot case constitutes the guide for the transfer paper to be transported.
Position the unit case of the imaging unit
On both sides of the paper width range through which the transfer paper passes
From the bottom wall of the unit case to the lower part of the knit case
Is higher than the protruding height of the transfer paper guide.
The guide part is provided on the unit case.
Protruding from the bottom wall and along the transfer paper transport direction.
A plurality of extending guide ribs;
The height of the protrusion of the unit from the bottom wall of the unit case
From the upstream side to the downstream side in the transfer paper transport direction of the drive
It is set so as to become gradually lower, and the upstream side in the transfer paper transport direction.
The unit casing has a free edge that is rounded.
Protruding from the bottom wall of the transfer paper
The middle part between the projections on the downstream side in the paper
The recess is recessed on the bottom wall side of the unit case from the protrusion.
And the two projections and the intermediate portion are
The unit case extends substantially parallel to the ribs.
From outside to the direction perpendicular to the transfer paper transport direction.
When viewed in the direction, the guide rib is located between the protrusion and the intermediate portion.
The guide ribs and projections so as to be covered by the
The projecting height of the unit case from the bottom wall of the unit case is set.
To provide an image forming apparatus characterized in that
You. [0007] [0008] BRIEF DESCRIPTION OF THE DRAWINGS FIG.
explain. FIG. 1 shows an image forming apparatus main body (not shown).
FIG. 2 is a vertical cross-sectional view of the image forming unit 1 attached to FIG.
FIG. 2 is an external perspective view of the image forming unit. This imaging unit
The unit 1 is detachably attached to the main body of the image forming apparatus.
In the example, the image forming unit 1 is imaged in a direction indicated by an arrow A in FIG.
The image is formed by pushing it into the forming device body.
The unit 1 is moved to a predetermined position in the image forming apparatus main body shown in FIG.
And set the image forming unit in the direction opposite to arrow A.
To draw the image forming unit 1 into an image form.
It can be taken out of the apparatus body. Image forming device
Is a copier, printer, facsimile or
It is configured as a joint machine. As shown in FIGS. 1 and 2, an image forming unit
Reference numeral 1 denotes a unit case 2 and a unit case 2 incorporated therein and described later.
Unit with various imaging elements, shown as an example in the figure
The case 2 was attached to the case body 3 and the upper part thereof.
The case cover 4 and an upper wall of a developing device described later are formed.
The developing case cover 5 and a toner conveying path also described later
An upper cover 6 forming a part of the upper wall and the upper wall of the developing device;
And a case cover 4, a developing case cover 5,
And upper cover 6 is snap-fit to case body 3.
It is detachably locked by a socket (so-called patching stop)
ing. Opening 102 formed in developing case cover 5
(FIG. 2) shows an agent cartridge 81 not shown in FIG.
(FIG. 1). FIG. 3 shows the case cover shown in FIGS.
-4, developing case cover 5, and upper cover 6
FIG. 3 is an external perspective view showing a state when the body 3 is detached from the body 3.
4 is a partial sectional plan view in the same state. The unit case 2 has an image bearing
Drum-shaped photoconductor 7 as an example of a body and an example of a charging device
, Each of which is rotatably assembled,
The charging roller 8 extends parallel to the photoconductor 7. Figure
3, the charging roller 8 is separated from the photoreceptor 7.
It is shown in a state. During the image forming operation, the photosensitive member 7 is not shown.
Driven clockwise in Figure 1 by no drive
At this time, a diagram supported by the image forming apparatus main body is shown.
The static elimination light L1 from the static elimination device that is not
Into the unit case 2 through the opening 34 formed in
And irradiates the surface of the photoconductor 7. With this, the photoconductor
7 is a reference voltage whose surface potential is, for example, 0 to -150V.
Averaged to the second place. On the other hand, the charging roller 8
It comes into pressure contact with the surface and rotates
The surface potential of the photoconductor 7 is, for example, -1100.
It is uniformly charged to be around V. At this time, charging
A predetermined voltage is supplied to the controller 8 by a power supply (not shown).
Applied. As described above, the photosensitive member charged to a predetermined polarity
The surface of the body 7 was light-modulated in the exposure unit 9.
The laser beam L2 is irradiated. This laser beam L2 is
Exposure optical system (not shown) supported by the forming apparatus body
And exits through the opening 35 formed in the case cover 4.
To enter the unit case 2. With such exposure,
A predetermined electrostatic latent image is formed on the photoconductor 7. For example,
The photoreceptor portion (image portion) irradiated with the laser light L2 is
The surface potential becomes 0 to -290 V, and the laser light L2 is irradiated.
The surface potential of the photoreceptor part (background part) not irradiated
Maintain around -1100V. Document not shown
And the reflected light image is formed on the photoreceptor 7 to form an electrostatic latent image.
Can also be formed. On the other hand, the unit case 2 has
As shown in FIG. 4, the developing sleeve 11 (see FIG.
3) is rotatably supported, and the sleeve 1
Reference numeral 1 denotes a rotating drive counterclockwise in FIG.
Be moved. Also, the case body in the unit case 2
And a developing case cover 5 for covering a part of the developing case 3
And a developing case 12 of the developing device 10 is constituted by
A developer chamber 90 is defined therein. Such development
The developer chamber 90 of the case 12 contains toner and carrier.
Powdery two-component developer 101 (FIG. 1)
In the developing sleeve 11, the whole is indicated by reference numeral 13.
The plurality of magnets are fixedly arranged. The developing sleeve 11 rotates as described above.
As a result, the developer 101 in the developing case 12
Conveyed while being carried on developing sleeve 11 by the magnetic force of stone 13
And is regulated by the agent regulating member composed of the doctor blade 14.
Thus, the amount of the developer to be conveyed is regulated. Development after regulation
The agent is transferred to a developing area between the developing sleeve 11 and the photoconductor 7.
At this time, for example, -80
Since a developing bias voltage of about 0 V is applied, the current
The toner in the developer conveyed to the image area is
Electrostatically migrates and adheres to the image area, and
A toner image is formed. Electrostatic latent image formed on photoconductor 7
Is visualized as a toner image. On the other hand, the main body of the image forming apparatus is shown in FIG.
As described above, the transfer roller 15 which is an example of the transfer device is a photosensitive member.
7 and rotatably supported. Also image formation
A paper feeder (not shown) is provided on the main unit side.
Transfer paper 100 from the paper feeder shown in FIG.
To the transfer section 22 between the photoconductor 7 and the transfer roller 15
Transported. The transfer paper 100 has a photosensitive end
State in which the tip of the toner image formed on body 7 matches
Through the transfer unit 22 between the photoconductor 7 and the transfer roller 15.
Spend. At this time, the transfer roller 15 moves the transfer paper 100
Counterclockwise in FIG. 1 while contacting the photosensitive member 7 through the
, And the transfer bias is applied to the transfer roller 15.
Since the voltage is applied, the toner image on the photoconductor 7 is transferred.
The image is transferred to copying paper 100. The transfer paper 100 leaving the photoreceptor 7 is shown in FIG.
As shown by the arrow B1, the fixing device (not shown)
The toner image is transferred by the action of heat and pressure.
It is fused and fixed on the paper 100. Transfer paper 100
On the downstream side of the transfer unit 22 in the transport direction, an image forming apparatus
The static elimination needle 16 supported by the installation main body is arranged. this
The static elimination needle 16 is made of a thin metal plate extending parallel to the photoconductor 7.
The portion of the static elimination needle 16 facing the photoreceptor 7 has a sawtooth shape.
And the tip of each tooth is sharply pointed. Or
A voltage is applied to the neutralization needle 16 by a power supply (not shown).
The transfer paper 100 is discharged by this, and the transfer paper 100 is discharged.
100 is easily separated from the photoconductor 7. After the transfer of the toner image, the toner
Residual toner is removed by the cleaning device 17 shown in FIG.
From the surface of the photoconductor 7 by the cleaning blade 18
It will be scraped. Thus, the surface of the photoconductor 7 is cleaned.
Then, the process proceeds to the next image forming operation again. Cleaning device 1
7 is a part of the case body 3 in the unit case 2
Thus, the cleaning case 19 is
The toner scraped off by the cleaning blade 18
Toner conveying member arranged in cleaning case 19
20 is discharged out of the cleaning device 17 by the rotation of
And is reused in the developing device 10 as described later.
You. The toner conveying member 20 is, for example, a toner conveying screw.
Or an appropriate form such as a toner transport coil.
You. The cleaning blade 18 cleans the surface of the photoconductor 7.
It is an example of a cleaning member to be cleaned,
As described in, the case is fixedly held on the case body 3.
You. As described above, the illustrated image forming apparatus includes:
The toner image formed on the image carrier composed of the photoreceptor 7 is
Transferred to the transfer paper 100 conveyed toward the image carrier
The image forming apparatus is configured to obtain a recorded image.
The imaging unit detachably attached to the
At least one of the image forming elements including the image carrier is
In the example shown, the photoreceptor
7, charging roller 8, developing device 10, and cleaning device
17 are assembled to the unit case 2
An image unit 1 is configured. By the way, as described above, the transfer paper
In order to correctly transport 100 toward photoconductor 7,
It is necessary to provide a guide unit for guiding the copying paper 100. This
Therefore, in the image forming apparatus shown in FIG.
Upper and lower guides for guiding the transfer paper 100 conveyed to 22
Parts 23 and 24 are provided. Lower guide part 24
Is guided by a guide member fixed to the image forming apparatus main body.
The guide member is configured to transfer the image from the transfer unit 22.
It also serves to guide the paper 100 in the direction of arrow B1.
You. Here, the upper guide portion 23 also
A guide member fixed to the main body of the image forming apparatus.
Although it is possible to do this,
In addition to the guide member, the upper guide portion 23 is also an independent member.
Must be provided in the image forming apparatus main body.
The number of parts increases and the cost rises.
No. Therefore, in the image forming apparatus of this embodiment,
The unit of the image forming unit 1 attached to the image forming apparatus main body.
The lower part of the case, in the example of the figure, the lower part of the case body 3,
An upper gas that regulates the traveling direction of the transfer paper 100 being conveyed
It constitutes the id part 23. The bottom of the unit case is
Unit of the imaging unit 1 so as to constitute the
The case 2 is positioned with respect to the image forming apparatus main body.
Because The guide portion 23 includes the lower guide portion 2.
4 and the transfer paper
A portion on the upstream side of the transfer portion 22 with respect to the transport direction of 100
Transfer paper 100 transported to the transfer section 22
To do something inside. As described above, depending on the unit case itself,
The guide portion 23 for guiding the transfer paper 100 is configured.
It is necessary to provide an independent member as the upper guide
The number of parts of the image forming apparatus and the cost
Reduction can be achieved. FIG. 5 shows the image forming unit 1.
3 shows the case body 3 of the unit case 2 shown in FIG.
FIG. You can see from this figure
As described above, the unit case 2, the case body 3 in this example,
A part of the photoconductor 7 is cut out from the notch 25 formed in the bottom wall 21 of the photoconductor 7.
It projects outside the unit case 2. Also in FIG.
The arrow B in FIG. 1 is the same as the arrow B in FIG.
The transfer direction of the transfer paper 100 sent toward 1) is shown.
I have. Further, the symbol W indicates a paper passing area through which the transfer paper 100 passes.
The transfer paper 100 having the maximum width also passes through the area W.
I do. In this example, as shown in FIGS.
The guide part 23 constituted by the knit case lower part,
Projecting from the bottom wall 21 of the case body 3 in the unit case 2
And along the transfer direction B of the transfer paper 100
It is constituted by a plurality of guide ribs 26 extending.
These ribs 26 move in the transfer direction B of the transfer paper 100.
Are separated from each other in a direction orthogonal to
Is provided in the paper passing area W through which the rib 26 passes.
The transfer paper 100 of the maximum size is surely proposed by the edge.
It is configured to be able to. Instead of the guide rib 26 described above, a unit
On the flat surface at the bottom of the case, for example, on the lower surface of the bottom wall 21
Therefore, the transfer paper 100 conveyed to the transfer unit 22 is guided.
A guide portion can also be configured. However, this guide
If the part is flat, the electrostatic force of the transfer paper 100
Therefore, the transfer paper 100 comes into close contact with the flat guide surface,
The transportability of the transfer paper 100 may be reduced. Such transport
When the transportability decreases, the toner transferred on the transfer paper 100
There is a possibility that an abnormal image may occur due to extension and shrinkage of the
is there. In addition, toner adheres to the guide section consisting of a flat surface
If this occurs, the adhered area increases,
Is re-adhered to the leading edge of the transfer paper in a large amount and the transfer paper becomes extremely dirty.
May occur. On the other hand, the embodiment shown in FIGS.
The guide part 23 is constituted by the guide rib 26 as shown in FIG.
The free edge of the guide rib 26 causes the transfer paper 10
0 is guided to the guide portion 23.
Even if the copying paper 100 touches, the contact area is extremely small
The transfer paper 100 is guided to the guide portion 23 by electrostatic force.
Adherence can be prevented and abnormal images can be prevented.
You. Moreover, it is constituted by the free edge of the guide rib 26.
Even if toner adheres to the guide portion 23, the guide portion 23
The contact area between the transfer paper 100 and the transfer paper 100 is small.
0 can prevent a large amount of toner from adhering.
Prevents significant toner contamination at 00
it can. Also, as shown in FIG. 1 and FIG.
26 protrudes from the unit case bottom wall 21.
From the upstream side to the downstream side in the transfer paper transport direction of the guide rib
The transfer paper transport
The upstream side in the direction shall be rounded with its free edge rounded.
It protrudes from the bottom wall 21 of the knit case. In the image forming apparatus of this embodiment,
As shown in FIG. 1 and FIG. 5, paper passing through which the transfer paper 100 passes
The lower part of the unit case 2 other than the area W, in the example of the figure
Is attached to the lower part of the case body 3 by the transfer paper 100.
Projected outward (below in FIG. 1) from the id portion 23
A protrusion 27 is provided. Inhibits transfer of transfer paper 100
The protrusion 27 protrudes from the lower part of the unit case 2
It is being done. In the example of FIG. 1 and FIG.
The width of the paper passing through the transfer paper 100 guided by 23
At the bottom of the unit case on both sides of the range, the case book
Protrusions 27 formed integrally with the body 3 are provided, respectively.
A total of four protrusions 27 are provided. And these
Projecting from the bottom wall 21 of the unit case 2
The height H is determined by each guide rib 26 which is a guide portion of the transfer paper.
It is higher than the height h protruding from the bottom wall 21. Ma
Also, as is clear from FIGS. 1 and 5, the transfer paper transport direction
The upstream projection 27 and the downstream projection 27 in the transfer paper transport direction
The intermediate portion between them is more unitary than these projections 27,27.
Formed on the bottom wall 21 side of the case 2
The projections 27, 27 and the intermediate portion are
It extends substantially parallel to the valve 26. Also the unit
The case 2 is directly moved from outside to the transfer paper transport direction.
When viewed in the intersecting direction, the guide rib 26 is
So that it is covered by the middle part
And the bottom wall of the unit case 2 at the intermediate portion
The projection height from 21 is set. Here, the image forming unit 1 is imaged as described above.
When taken out of the image forming apparatus main body, the unit 1
On a flat floor surface with the bottom side of the unit case facing down.
It is placed on a placement surface such as a desk top. At that time, the unit
The lower part of the case 2 projects outward from the guide part 23.
Are provided, so that these protrusions 27
Contact the mounting surface. That is, it exists between the protrusions 27
The free end of the guide portion 23, in this example, the guide rib 26 is placed.
It does not touch the surface. According to the above configuration, even if foreign matter is present on the mounting surface,
Is present, the foreign matter adheres to the guide portion 23
The guide portion 23 may be damaged by the foreign matter.
It is not. Therefore, the image forming unit 1 is re-imaged.
The transfer paper can be used even if the paper
No foreign matter adheres to the guide portion 100 and the guide portion 23 is supported.
It can perform the function of guiding the transfer paper 100 without obstruction.
You. Also, even if foreign matter on the mounting surface adheres to the protrusion 27
The projection 27 is somewhat damaged by the foreign matter.
However, the image forming unit 1 is set in the image forming apparatus main body.
When the transfer paper 100 is
Since the transfer paper 100 is located outside the area W,
There is no risk that the transfer will be hindered. In the embodiment shown in FIG. 5, the transferred transfer
Although the protrusions 27 are provided on both sides of the paper 100,
If it is the lower part of the unit case outside,
May be provided with a projection 27. FIG. 6 shows a transfer paper to be conveyed.
And the upstream side of the paper passing area W in the transfer paper transport direction.
A guide rib 26 is attached to the unit case bottom wall 21
Projecting outside the unit case from the guide portion 23
The example which provided each protrusion 27 was shown. The bottom of the projection 27 shown in FIGS. 1, 5 and 6
The protruding height H from the wall 21 is determined by setting the imaging unit 1 on the mounting surface.
So that the photoconductor 7 does not touch the mounting surface
Is set to a reasonable size. Next, in order to understand the present invention, the illustrated image forms
Each device that composes the device and its components in more detail
Will be described. First, the photosensitive member 7 illustrated in FIG.
Fig. 7 is a schematic enlarged view of the cross-sectional structure.
FIG. The laminated photoreceptor 7 shown in FIG.
An electric charge having a thickness of 0.1 to 1 μm is generated on the substrate 28.
It has a raw layer (CGL) 29 and a thickness of 10 to 30 μm
Charge transfer layers (CTLs) 30 are sequentially stacked.
The charge generation layer 29 and the charge transfer layer 30 form a photosensitive layer.
31. Laser incident on the photoconductor 7
The light L2 passes through the translucent charge transfer layer 30 to generate charges.
The excited energy is absorbed by the layer 29 and
Carriers are generated by gi. Generated carrier
Is injected into the charge transfer layer 30 by an external force, and the charge transfer
Moves in layer 30 to reach photoreceptor surface and neutralizes surface charge
I do. The charge transfer layer 30 shown in FIG.
Indicates the state when the battery is negatively charged. Next, the charging roller 8 shown in FIGS.
Has a structure in which conductive rubber is wound around the outer peripheral surface of a metal cored bar.
The surface of the photoconductor 7 is charged when the photoconductor 7 is charged.
Touch the surface. Each of the charging rollers 8 has a lengthwise direction.
The ends are respectively connected to the bearing 33a shown in FIG.
It is rotatably supported, and each bearing 33a is a charging roller.
Longitudinal direction of the charging roller case 33 extending parallel to 8
Contact the photosensitive member 7 with the charging roller 8
It is supported so that it can move within a predetermined range in the direction of approaching or separating.
ing. Also, the charging roller 8 of the charging roller case 33 is
On the facing surface, a belt extending long along the charging roller 8 is provided.
Cleaning pad 32 which is an example of an electric roller cleaning member
Is affixed. Each of the bearings 33a and the charging roller case
Between each end in the longitudinal direction of the
One compression spring is press-fitted, whereby each bearing 3
3a is pressed so as to approach the photoconductor 7, and is charged.
The roller 8 can be pressed against the surface of the photoconductor 7. Ma
In addition, the charging roller case 33 is also attached to the surface of the photoconductor 7.
The cable can be moved in a direction approaching or moving away from a predetermined area.
Each end of the base 33 in the longitudinal direction is a case of the unit case 2.
Each notch 36 formed in the main body 3 (only one notch is shown in FIG. 3)
To). Such a charging roller case 33
Is a case body by a case cover 4 (FIGS. 1 and 2).
Exit from 3 is prevented. In addition, a case book
Between the body 3 and each end in the longitudinal direction of the charging roller case 33
In addition, a second pressure different from the first compression spring described above is used.
The compression spring 37 (only one is shown in FIG. 3)
As a result, the charging roller case 33 is
It is urged away from the surface. The case cover 4 includes a photosensitive member 7 and a charging roller.
Function of protective cover to prevent human hands from touching
However, as described above, the second
The charging roller case urged by the compression spring 37
To prevent the device 33 from coming off the case body 3.
He also works as a pa. With this, the charging roller
It is not necessary to provide an independent stopper member for the case 33.
In addition, simplification of the configuration can be achieved. On the other hand, as shown in FIG.
An electromagnetic clutch 39 for controlling the rotation of the cam 38 is provided on the body.
The cam 38 is fixed to the rotating shaft of the electromagnetic clutch 39.
The electromagnetic clutch 39 is turned 120 ° in one operation.
It is configured to rotate. Also, this cam 38 has
Swingably supported on the image forming apparatus main body via the pivot pin 40
If one end 41a of the pivoted arm 41 is not shown
The arm 41 is brought into pressure contact by the action of a spring.
Charging roller case 33 through opening 34 of base cover 4
Is in contact with the upper surface of the Upper surface of charging roller case 33
By the pressurizing action of the second compression spring 37 described above.
Then, it comes into pressure contact with the other end 41 b of the swing arm 41. When the cam 38 occupies the rotational position shown in FIG.
And the symbol a₁The cam surface portion indicated by
When the charging roller case 33 is in contact with one end 41a,
1 occupies the position shown in FIG.
8 is pressed by the first compression spring described above.
It is pressed against the surface of the photoreceptor 7 and the core of the charging roller 8 is marked.
The applied voltage causes the photosensitive member 7 to have a predetermined polarity as described above.
Charge. As described above, the charging roller 8 makes the photosensitive member 7
During the charging operation of charging, the contact with the surface of the photoconductor 7 is continued.
Is charged by the minute toner attached to the photoconductor 7
Roller 8 becomes dirty, causing uneven charging of photoconductor 7
There is a possibility that. For this reason, in the image forming apparatus of this embodiment,
Is a timely operation other than the charging operation by the charging roller 8.
The clutch 39 is actuated and the cam 38 rotates 120 °.
Symbol a for 1_TwoThe cam surface portion indicated by is one of the swing arms 41.
It is pressed against the end 41a. Thereby, other than the swing arm 41
The end 41b holds the charging roller case 33 on the surface of the photoconductor 7
Press and move in the approaching direction. At this time,
8 remains pressed against the surface of the photoreceptor 7, and
The leaning pad 32 is pressed against the peripheral surface of the charging roller 8
You. At that time, the charging roller 8 is driven by the rotation of the photosensitive member 7.
The cleaning pad 32 rotates and the peripheral surface of the charging roller 8 is rotated.
To clean. In this way, the charging roller 8 is turned into toner.
Therefore, the charging operation of the photoconductor 7 is performed while the photoconductor 7 is soiled.
Is prevented, and the occurrence of uneven charging of the photoconductor 7 can be prevented.
You can. When the operation of the image forming apparatus is stopped,
By the operation of the electromagnetic clutch 39, the cam 38 is shown in FIG.
a_ThreeIs pressed against one end 41a of the swing arm 41.
You. Thereby, the other end 41b of the swing arm 41 is shown in FIG.
The charging roller case 3
Reference numeral 3 denotes a photosensitive member by the action of the second compression spring 37 described above.
7 in a direction away from it. This allows charging low
The roller 8 is also separated from the surface of the photoconductor 7. Operation of image forming device
In the stopped state, the charging roller 8 contacts the photoconductor 7 for a long time.
If left unattended, the photoconductor 7 will be contaminated and an abnormal image will occur.
However, in the image forming apparatus of the present example,
As described above, when the operation is stopped, the charging roller 8 is exposed to light.
The image is separated from the body 7 and an abnormal image occurs during the image forming operation.
It is preventing that. Instead of the charging roller 8, a corona discharger is used.
A charging device can be used.
When the roller 8 is employed, the use of a corona discharger
Reducing the amount of generated zon to 1/100 to 1/1000
This makes it possible for ozone
There is no need to attach a processing member. Next, the charging mechanism by the charging roller 8 will be described.
explain about. FIG. 8 schematically shows the photoconductor 7 and the charging roller 8
FIG. 9 is a schematic diagram showing a charging model.
3 shows an equivalent circuit. Here, the center of the charging roller 8
The voltage applied to the metal core is assumed to be Va and applied to the charging roller 8.
The voltage is Vr, and an empty space near the contact portion between the charging roller 8 and the photosensitive member 7 is provided.
The discharge starting voltage in the gap 42 is Vg, and the surface voltage of the photoreceptor 7 is
Assuming that the order is Vd, these relationships are Va = Vr + Vg + Vd (1) It is expressed as Here, the voltage Vr applied to the charging roller 8
Is R, the resistance of the charging roller 8 is I, and the value of the flowing current is I.
Then Vr = IR (2) And the firing voltage Vg in the gap is
7 is d, and the relative dielectric constant of the photosensitive layer 31 is K.
If d     Vg = 312 + 6.2 × d / Kd + √ (7737.6 × d / Kd) (3) Is represented by The surface potential Vd of the photoconductor is supplied to the photoconductor 7.
Let Q be the supplied charge and C be the capacitance of the photosensitive layer 31.
Then Vd = Q / C (4) Becomes Here, the peripheral speed of the photoconductor 7 is Vp, the charging roller 8
Is L and its dielectric constant is K₀Then     Q = I / L · Vp C = (K₀・ Kd) / d     Vd = (Id ·) / (K₀・ Kd ・ L ・ Vp) (5) Therefore, equation (1) is     Va = I · R + 312 + 6.2 × d / Kd + √ (7737.6 × d / Kd)          + (Id) / (K₀・ Kd ・ L ・ Vp) (6) Becomes The above is the charging model formula. Next, a method of controlling charging by the charging roller 8
Considering this, there are two methods, constant voltage control method and constant current control method.
Any of the control methods can be adopted. The constant voltage control method is based on the equation (1) and (6).
This is a control method that makes a constant. In this case, in equation (1)
Actually, the charge potential of the photosensitive member 7 is used in the term of Vd.
is there. Therefore, when Vr and Vg change, Vd is affected.
give. Looking at each term, the term of Vr is
The resistance value of the charging roller 8 is a variable factor. Therefore, the environment
When the resistance value of the charging roller 8 increases due to the fluctuation, the Vr value increases.
As a result, Vd decreases. Therefore, this effect is suppressed.
It is necessary to provide temperature detecting means to correct Va
You. Also, the charging roller resistance value rises remarkably at low temperature and humidity.
Since it is time, a heater etc. not shown is provided,
It is desirable not to drop below the temperature. Next, in the term of Vg, the film of the photosensitive layer 31
It is affected by the thickness d.
= 28 µm, decreased by 4 µm over time, Kd = 3.2
Vg (28) = 626, Vg (24)
= 599, which is a change amount of the difference 27V. About this
Because of the change, the charge potential (usually 800 to 1000 V)
Impact is small. Note that the charging roller resistance
Since the value of the current flowing at the value fluctuation is small,
If the electric roller resistance value is low (for example, 10⁷Ω or less)
For example, the influence on Vd can be reduced. In the case of the constant current method, I is constant according to the equation (6).
Is not affected by the terms of Vr and Vg.
No. However, the influence of the change in the photosensitive layer thickness d in the Vd term
The sound directly extends to Vd and the initial 28 μm shown in the previous example.
When it changes by 4 μm with time, Vd becomes Vd × 24 with time.
/ 28, and if Vd is initially 850V,
With the passage of time, it becomes 728 V and drops by 100 V or more.
And charging performance may not be guaranteed. this
To prevent this, a change in the thickness of the photosensitive layer 31 is detected and corrected.
In practice, such a detection mechanism is expensive and very expensive.
Can not be installed. Therefore, the hardness of the photoconductor surface is increased,
Countermeasures are currently difficult except using a photoreceptor that does not wear.
No. For the above reasons, in this embodiment, the charging roller 8
Voltage correction for resistance fluctuation of
The pressure control method is adopted. Then, the temperature of the charging roller 8
As the degree detecting means, as shown in FIG.
Is used. This service
The mister 43 detects the surface temperature of the charging roller 8 and detects it.
Of the charging roller 8 has changed in temperature and its electric resistance has changed.
Signal to the circuit for correcting the applied voltage for
You. The thermistor 43 is configured such that the charging roller 8
Contacts the charging roller 8 when separated from the surface of the
Position. As described above, the thermistor 43 is
Since it was attached to bar 4, it was a special installation for this thermistor.
There is no need to provide a separate attaching member, and the image forming apparatus,
Can be simplified. Ma
When the charged roller 8 is separated from the photoconductor 7,
Thermistor when no voltage is applied to the charging roller 8
The roller 43 contacts the peripheral surface of the charging roller 8 and
Because it is configured to detect temperature,
Is changed by the influence of the voltage applied to the charging roller 8.
There is no danger of breaking. Next, the developing device 10 will be described. Figure
1, as described above with reference to FIGS.
The case 12 includes a carrier made of, for example, a small iron ball.
A two-component developer 101 having toner and
The first and second developers 101 and 102 are described in detail later.
The developer in the developing case 12 is controlled by the developer stirring members 44 and 45.
The developing sleeve 1 is stirred while being circulated and transported in the chamber 90.
1 is supplied. Developer supplied to developing sleeve 11
Is provided around the developing sleeve 11 as described above.
The layer thickness is regulated by the doctor blade 14 thus set.
A portion of the peripheral surface of the developing sleeve 11 facing the photoconductor 7
The minute is exposed from the developing case 12 to the outside. Here, the outer diameter of the developing sleeve 11 is
For example, a non-magnetic circle made of aluminum of 16 to 20 mm
Consists of a cylindrical body, whose peripheral surface is formed smoothly or
Outer peripheral surface of the developing sleeve 11 to enhance the transportability of the image agent
For example, irregularities such as V-grooves are formed on the substrate. As shown in FIG. 4, the inside of the developing sleeve 11 is
A shaft 46 penetrates the portion, and the magnet 13 described above is
Fixed. The front end 46a of the shaft 46 is
To the case body 3 of the
The rear end 46b of the developing sleeve 11 is
The sleeve end member 47 fitted and fixed to the rear end is provided with a bearing.
And are fitted so as to be relatively rotatable. Also this sleeve end
The shaft portion 47a of the member 47 is a case body of the unit case.
3 rotatably supported as described later. Development
The front end of the leave 11 is turned around a shaft 46 via a bearing.
Rollably supported. The “back side” here
"Front side" is an image forming unit for the image forming apparatus main body.
1 is based on the attachment / detachment direction. As described above, the shaft 46 moves together with the magnet 13.
The shaft 4 is fixedly supported with respect to the unit case 2.
6, a developing sleeve 11 is rotatably supported. So
Then, the sleeve end member 47 is connected to the coupling attached thereto.
48 and a cup on the image forming apparatus main body side that engages with the
By being rotationally driven through a ring 49 (FIG. 2),
The developing sleeve 11 rotates counterclockwise in FIG.
Driven. The bias voltage to the developing sleeve 11 is
Image forming apparatus via the couplings 48 and 49 described above
Applied from the main unit side. FIG. 10 shows the developing sleeve 11 and the inside thereof.
Between the magnet 13 and the photoreceptor 7 that are not rotatably arranged
FIG. As shown here, the magnet 13
Individual magnets, that is, first to fifth magnets 13a to 13a
3e are arranged in the circumferential direction of the developing sleeve 11 and
The sleeve 11 is fixed to the shaft 46 so as to be stationary.
It extends in the direction. Then, these magnets 13a to 13
e in the circumferential direction of the developing sleeve 11 and in the normal direction
Of magnetic force P₁Or P₆Is formed. The first magnet 13a is substantially opposed to the photosensitive member 7.
The magnetic force distribution in the photosensitive member 7 and the developing sleeve 11
A peak θ = 3 ° to 10 ° above the line connecting the centers
Have The peak magnetic flux density is 80-100
(MT millitesla). Small peak magnetic flux density
The carrier of the developer can be held in the developing sleeve 11
Scratched developer scatters. On the contrary, if it is too large,
Ear traces in the circumferential direction of the developed toner are likely to occur.
In addition, the toner adhering to the low potential portion of the photoreceptor 7 is
May be collected in the developing sleeve 11. Angle θ
If it is too large, the developing ability will be reduced. The magnetic force distribution P by the second magnet 13b_TwoIs
A 50-80 (mT) pin near the opening of the developing case 12
It has a magnetic flux density. This magnetic force is generated in the developing case 12.
The developer is conveyed, and the developer is
It has a function to carry air into the developing case 12. this
As a result, the toner can be prevented from scattering outside the developing case 12.
it can. To increase the efficiency of air conveyance,
Develop the shape of the developing case part 12a corresponding to the bundle density part
It is good to slightly inflate in a direction away from the sleeve 11.
As a result, the developer ears can be formed smoothly.
You. The third magnet 13c has a magnetic force distribution P_ThreeForm
And transports the developer into the developing case 12 by the magnetic force.
And the magnetic force distribution P in cooperation with the fourth magnet 13d.
_Four(A magnetic flux density of 10 mT or less). by this
The developer after being subjected to development is separated from the developing sleeve 11.
It is. The magnetic force of the fourth magnet 13d will be described later in detail.
Supplied by the second agent stirring member 45 (FIG. 4).
The developer is held on the developing sleeve 11. Doc
The magnetic flux density is reduced in the region of the
The developer is allowed to pass while being in close contact with the developing sleeve 11.
With this, the layer thickness of the developer can be regulated stably.
You. The fifth magnet 13e has a magnetic force distribution P₆Form
And the developer held by the magnetic force of the fourth magnet 13d.
To the area of the first magnet 13a, but stabilizes the developer and
Control the air flow around the developing sleeve 11
Therefore, the developer may be brought into contact with an inlet seal 50 described later.
The magnetic force distribution P₆The peak magnetic flux density of
You. The gap Gp between the developing sleeve 11 and the photosensitive member 7
Is the gap G between the developing sleeve 11 and the doctor blade 14.
Gp = Gd × (0.8-1.
0), Gp−Gd = (0 to 0.15) mm.
You. The peripheral speed of the developing sleeve 11 is set to vs (mm / se).
c), assuming that the peripheral speed of the photoconductor 7 is vp (mm / sec),
Is as follows. vs = (1 to 2.5) × vp As shown in FIG. 4 and FIG.
Shaft of the sleeve end member 47 protruding from the rear end of the sleeve 11
The portion 47a is rotatably fitted to the back side support member 57,
The front end 46a of the front end 46a is relatively rotated with respect to the front support member 58.
It is fitted so that it cannot roll. These support members 57, 58
Are inserted into the long holes formed in these as shown in FIG.
To the screw 59 which is passed through and screwed into the doctor blade 14
Therefore, it is connected to the doctor blade 14. Follow
Then, if these screws 59 are loosened, the doctor blade 14
Is adjusted with respect to the developing sleeve 11 in the direction substantially in the normal direction.
can do. After the adjustment, tighten the screw 59 to secure the door.
Is fixed to the developing sleeve 11.
You. The doctor blade 14 is raised with respect to the developing sleeve 11.
The value moved as described above and the gap between the two are one-to-one.
Corresponding. In addition, such adjustment work is
With the code 14 and the developing sleeve 11 removed from the developing device
Can be easily performed. As shown in FIG. 3 and FIG.
The case body 3 of the device 2 has a front side outer plate 51
And a front side inner plate 52, and a back side outer plate 53
It has a back inner plate 54. The front and rear inner plates 52, 54
The front and rear side plates of the developing case 12 are configured. Photoconductor 7
Is a flange member 8 fixed to each longitudinal end thereof.
6, 87 are a positioning plate 55 on the near side and a positioning plate on the back side
56, the front inner plate 52 and the rear outer plate of the case body
And 53 are rotatably supported respectively. Also shaft 4
6, a near-side support member 58 fitted to the near-side end 46a.
Also, the unit case 2 is
It is non-rotatably supported by the near inner plate 52. further,
The shaft portion 47a of the sleeve end member 47 is also
To the outer skin 53 on the rear side of the unit case 2 through the
Supported. The support member 57 on the back side includes the inner plate 54 on the back side.
Removably fits into the concave groove. As described above, the photosensitive member 7 and the developing sleeve 1
1 is a positioning plate 5 whose front side and back side are respectively common.
5 and 56, which are supported by the unit case.
The distance between the center of the developing sleeve 11 and the center of the photoconductor 7 is constant
Thus, the gap Gp between them is always kept constant. Further, as shown in FIG.
Each of the support members 57 and 58 on the side has an inlet seal cover 60.
1 and FIG.
As shown, the above-mentioned entrance seal 50 is stuck.
The inlet seal cover 60 is, as shown in FIG.
Located on the upstream side of the developing area between the photosensitive drum 7 and the photosensitive member 7.
To cover the upper portion of the developing sleeve 11 and
It regulates the developer and regulates the flow of air. entrance
The seal 50 is made of a thin resin such as PET or PUR.
To prevent toner from scattering to the outside of the developing device 10
I have. As shown in FIG. 11, the back side and the near side
Each support member 57, 58 has a side made of thin resin or the like.
Seals 61 and 62 are attached, respectively,
The seals 61 and 62 are at respective longitudinal ends of the developing sleeve 11.
Toner and carrier fly from each end.
Prevents scattering. Next, the first and second stirring members 4
4, 45, as shown in FIG.
A plurality of elliptical plates 65, 66 fixed to each shaft 63, 64
It is composed of In FIG. 3, the figure is easy to understand.
Therefore, the illustration of the elliptical plate is omitted,
The disks 65 and 66 are formed in a shape in which an ellipse is partially cut out.
Have been. In place of the elliptical plate, screws are used for each shaft 63, 64
The stirring members 44 and 45 can be configured by fixing
You. The first stirring member 44 has a longitudinal axis 63
Each end in the direction is in the case body 3 of the unit case 2
The support wall 67 on the near side and the inner plate 54 on the back side
The shaft 64 of the second stirring member 45 is
Of the unit case 2 on the front side inner plate 52
And the back inner plate 54 are rotatably supported respectively.
You. In addition, each shaft 63, 64 of these agitating members 44, 45
Drive gears 68 and 69 are provided at the rear end of the
And the sleeve end member 47
The driving gear 70 is also fixed. These gears 7
0, 69, 68 are mutually connected via an intermediate gear (not shown).
Are engaged. The developing case 12 has first and second
In the region between the stirring members 44 and 45, these stirring members 4
A partition wall 71 extending in parallel with 4, 45 is provided.
The front side and the back side of the cut wall 71 are notched, and the passage 71
a and 71b are respectively formed. As described above, the sleeve end member 47 has an image shape.
When it is rotationally driven by the drive unit on the
As the image sleeve 11 rotates, its sleeve end member
The rotation of 47 is performed via the drive gears 70, 69, 68 and the intermediate gear.
And transmitted to the first and second stirring members 44 and 45,
These members are each driven to rotate in a predetermined direction. This
As a result, the developer contained in the developing case 12 is
The developer is transported while being agitated in the X direction, and the developer is
71, the passages 71a,
Circulate through 71b. This allows the developer toner
And the carrier are frictionally charged to different polarities. Such present
An image agent is supplied to the developing sleeve 11 and
The developer from 11 is returned to the side of the stirring member. Each oval plate
65 and 66 have a shape in which a part of an ellipse is cut out.
Therefore, when the developer hits the edge of the notch, the current
The effect of stirring the image agent is enhanced. Here, the ellipse in each of the stirring members 44 and 45 is used.
The pitch of the disks 65 and 66 is P, and the minor axis of the ellipse is Y.
When P = (1/3 to 4/5) × Y It is desirable to satisfy Pitch P is higher than this
If it is small, the conveying force of the developer is reduced.
4, 45 rotation speed becomes high, and the developer tends to deteriorate
You. When the pitch P is larger than the above formula, the developer
The agitation performance on the other hand decreases. Rotation of first and second stirring members 44 and 45
The numbers are equal to each other, and the outer diameter Y of each of the elliptical plates 65 and 66 is
The pitches P are also equal to each other. In addition, each of the elliptical plates 65, 6
6 and the peripheral speed of the developing sleeve 11
The relationship with vs is vs = (1.1 to 1.5) × v It is desirable to satisfy The peripheral speed v of the elliptical plates 65 and 66 is expressed by the above equation.
If the speed is faster than the
When the speed is low, the speed on the developing sleeve 11
It takes a long time to replace the image agent, and it is formed on the photoreceptor 7.
Density unevenness occurs in the toner image. The elliptical plates 65, 66 of the stirring members 44, 45
And the gap between the partition wall 71 and the developing case wall is 0.1 mm.
It is desirable to set it to 5 to 2 mm. This gap is more than this value
Too large, the developer cannot be transported reliably, and
If this gap is narrower than the above value,
The developer rubs the partition wall 71 and the developing case wall too strongly.
And may deteriorate early. The elliptical plate 66 of the second stirring member 45 and the current
Set the gap with the image sleeve 11 to 1.5 to 3 mm.
Then, the developer can be smoothly supplied to the developing sleeve 11.
And recovers the developer smoothly from the developing sleeve 11
can do. If the gap between them is too large,
Sufficient supply and recovery of developer to sleeve 11
If it is too small, it will deteriorate due to the stress of the developer.
And toner supply unevenness occurs. FIG. 1 and FIG. 4 show the developing case 12.
A sensor for detecting the toner concentration of the developer 101,
In this example, a magnetic permeability measurement sensor 72 is provided. Also
The toner bottle shown in FIG. 1 and FIG.
The tor 73 is detachably mounted. The developer housed in the developer chamber 90 in the developing case 12
That the toner concentration of the developer 101 falls below the reference value.
Is detected by the sensor 72, the detection signal
The toner bottle 73 by the toner supply signal based on the
It is rotationally driven via a drive shaft 74, thereby
Toner is supplied from the supply port 73a of the
Through the opening 6a (FIG. 2) formed in the upper wall of the
Toner supply section 75 (FIG.
3, FIG. 4). Toner bottle 73 containing replenishment toner
Has a spiral projection on its inner wall,
Internal toner supply from back to front by rotation
The toner is supplied to the opening 73 a and supplied to the toner supply unit 75. So
Between the toner bottle 73 and the toner supply unit 75
Is equipped with a hopper (not shown) for guiding the supply toner.
As a result, toner from the toner bottle 73 is scattered.
The toner is supplied to the toner supply unit 75 without being used. Toner bottle 7
An electromagnetic clutch (not shown) is
When the toner supply signal is output,
When the electromagnetic clutch is turned on, the drive shaft 74 for the toner bottle is turned on.
Rotates. As shown in FIGS. 3 and 4, the toner supply section
75 and a developer chamber 90 containing a two-component developer.
Consists of a thin resin sheet with many small holes
A shielding plate 76 is provided.
Toner consisting of a thin resin sheet having a base end fixed to 77
-A delivery member 78 is arranged and fixed to its shaft 77.
Gear 79 is fixed to the shaft 63 of the first stirring member 44.
Gear 80. Formed on the shielding plate 76
The diameter of the small hole is, for example, about 0.5 to 1 mm. axis
77 is rotatably supported by the case body 3. As described above, the first stirring member 44 rotates.
Then, the rotation is transmitted to the shaft 77 via the gears 80 and 79.
As a result, the toner delivery member 78 rotates,
It comes into sliding contact with the shielding plate 76. Thereby, the toner replenishing unit 75
Of the stirring member 44 passes through the small hole of the shielding plate 76.
Is fed into the developer chamber 90 provided with As described above, the toner bottle 73
Is temporarily stored in the toner supply unit 75, and
Since the developer is fed into the developer chamber 90 little by little through the hole, the toner
-Unless a certain amount of toner is discharged from the bottle 73,
Also, the toner is supplied to the developer chamber 90 by a constant amount.
And The toner supplied to the developer chamber 90 is supplied to the stirring section.
By the materials 44 and 45, the two-component developer existing here can be used.
Stir and mix. Even if the toner supply operation described above is performed,
If the sensor 72 continues to detect a decrease in toner density, the toner
Assuming that the toner in the bottle 73 has run out, the toner
Display that the end is near is displayed on the display, and notify the user to that effect.
Inform. Despite this display,
If the bottle is not replaced, A4
When 50 image forming operations are performed on transfer paper of size
Then, the operation of the image forming apparatus is stopped. The replacement operation of the toner bottle 73 is performed by the image forming operation.
Determined by the opening / closing time of the front door (not shown) of the device body
After the toner bottle 73 has been replaced,
Operation and the detection voltage of the sensor 72 reaches a certain value.
Is confirmed, the operation prohibition of the image forming apparatus is released. As shown in FIG. 2, the developing case cover 5
An opening 102 is formed in the opening 102, as shown in FIG.
The illustrated developer cartridge 81 is mounted. Brand new
When the imaging unit 1 is shipped from a manufacturing factory or a store,
The lower opening of the developer cartridge 81 is not shown.
Covered with a flexible sealing member
Two-component development having toner and carrier inside the die 81
The agent is contained. At this time, the developer is stored in the developer chamber 90.
Does not exist. The image forming unit 1 has been delivered to the user.
Sometimes, by rotating a roller not shown,
The seal member is wound around the roller, and the developer
The opening of the ridge 81 is opened. This allows
The developer falls into the developer chamber 90. In this way,
Until the knit 1 is delivered to the user, the developer cart
Since the developer is sealed and stored in the ridge 81,
Prevents deterioration of developer due to moisture absorption during storage of image forming unit 1
Can be stopped and also prevents developer from leaking out of the developing device
it can. Next, a developing mechanism using a two-component developer
Mechanism, especially a two-component system focusing on the force acting on the toner
Explains the basic concept of magnetic brush development with image agent
I do. [0088]About development electric field A shape is formed between the photosensitive member 7 and the developing sleeve 11 shown in FIG.
The developing electric field generated is generally represented by the following equation. E = ε (Vd−Vb) / Gp (7) E = developing electric field (V / mm) ε: dielectric constant of developer V
d: image part potential (V) of photoconductor Vb: developing bias voltage
Pressure (V) Gp: Development gap (photoreceptor and development three
Gap with the loop) (mm) From the equation (7), the developing electric field is controlled by the developing bias voltage.
It turns out that it is possible to roll. Therefore,
The image density control changes the developing bias voltage to reduce the developing electric field.
We do this by controlling. [0089]Power to work on toner a) Adhesive force between developer carrier and toner Model of adhesion force of toner particles adhering to carrier particles C
The figure is shown in FIG. The toner particles T are on the surface of the carrier C.
And several charge exchanges by contact and friction
Has a negative charge of q and a positive charge corresponding to it.
It is on the rear side. The adhesive force Ft at the contact point between the two is the charge q
Coulomb force and short-range van der Waals force Fv
And is represented as follows: Ft = Fv + αq^Two/ 4πε₀r^Two(8) Where r is the radius of the toner particle, ε₀Is the dielectric constant of vacuum, α
Is a constant (1 to 1.9) depending on the dielectric constant of the toner.
You. B) Model of insulating magnetic brush development In two-component development, the development driving force (static
(Power) (qE) becomes larger than the adhesive force with the carrier
Is developed. qE> Fv + αq^Two/ 4πε₀r^Two(9) Equation (9) can be easily understood by describing FIG. here
Is E₁<E_TwoAnd the straight line is
The respective developing powers are shown. E₁Development occurs in the electric field
QE above the Ft curve_TwoIs q₁And q_TwoBetween
Therefore, all toners with charges in this range can be developed.
It will work. The above is the description of the developing device 10 and its related structures.
This is an explanation of the configuration, but at least the photoconductor and the developing device are assembled
In a conventional image forming unit, the developing device
Use one-component developer without carrier
Was mainstream. In this case, the toner particles are transferred to the developing sleeve.
When attaching to the photoreceptor from the
Since there is no medium such as
Must be in contact with each other, and the distance is usually 0 to 0.3 mm
It is a minute thing. Therefore, it is adopted in this embodiment.
Recycle the toner as described later, and
If you try to delete parts such as ink
Recycled toner that arrives and is collected by the cleaning device
Contains foreign matter such as paper dust, so the photoconductor and developing roller
If the gap between them is narrow, foreign matter such as paper dust
And abnormal images such as white stripes are likely to occur.
Therefore, in the one-component developing method, the toner recycling is
Not suitable. In addition, toner recycling with one-component development method
Is implemented, but in this case, the imaging unit
Life is around 10K (K = 1000) copies
And short. On the other hand, in this embodiment, the developing method is a two-component developing method.
By adopting the image system, the photosensitive member 7 and the developing sleeve 11
Can be 0.5 mm or more, and the toner
Foreign matter such as paper dust is trapped even after recycling
The life of the imaging unit is determined by the number of copies.
For example, it can be extended to 30K sheets or more. Therefore,
Cost of using a carrier compared to one-component development
But the life of the imaging unit 1 is more than doubled
As a result, costs are reduced as a whole and
Maintenance intervals are reduced because the replacement interval of
It is. Next, the transfer device will be described. As shown in FIG.
Transfer roller 15 is formed by winding conductive resin around a metal cored bar.
Attached to a compression spring not shown here.
The entire bearing is pressed toward the photoconductor. This roll
A constant current is applied to the transfer roller 15 to transfer the toner on the photoconductor.
Transfer to paper. This transfer roller 15 is also
With the same mechanism, it is possible to make contact and separation with the photoconductor 7.
You. The transfer mechanism will be described with reference to FIG.
4, the photosensitive member 7 having the photosensitive layer 31 having a thickness of dm
There is a charged toner layer dt having a volume charge density ρ, under which
The transfer paper 100 having the thickness dp is located. This toner layer
Let g be the gap with the paper. Further, on the transfer paper 100,
A charge σc having a polarity opposite to that of the charged toner is given. In this state
Having a charge qt at x from the photoreceptor surface.
The force Fe (x) acting on the recording paper in the recording paper direction is expressed by the following equation.
Is done.     Fe (x) = qt {-σc-ρ (dt-x)} / (ε₀・ Kt) (10) Where ε₀Is the dielectric constant of vacuum, Kt is the relative dielectric constant of the toner layer
It is. Charged toner T located at a distance x from the photoreceptor surface
The electrostatic force Fe (x) acting on the balance with the mechanical adhesive force Fa
At this point, the toner layer is divided and has a thickness of (dt-x).
Assuming that only the toner layer of
The rate η is represented by the following equation.     η = (dt−x) / dt       = ∫₀ ¹−1 / (ρ · dt) ｛σc + (ε₀・ Kt) Fa / qt｝ (11) In addition, regarding the expression (10), the volume charge density ρ is
The density is δ, the filling ratio of the charged toner layer is p, and the toner specific charge is
If Tp, it can be expressed as ρ = δ · p · Tp. Also, toner
The charge amount qt is qt = Tp, where m is the mass of one toner.
・ It can be expressed as m. Therefore, equation (10) is   Fe (x) = ｛− σc · m · Tp−δ · pm (dt−x) Tp^Two｝ / (Ε₀・ Kt) (12) Can also be expressed. The above is the transfer model formula. Next, the transfer control method will be described.
The maximum copy width size paper contains toner.
15 and 16 show equivalent circuits as transfer models.
You. Thus, the image portion transfer current Ib is obtained. Ib = (V-Vl) / (R + Zb) (13) Where Zb = (1 / Cd + 1 / Cp + 1 / Ct) Cd = K₀・ Kd ・ L ・ Vp / d Cp = K₀・ Kp ・ L ・ Vp / dp Ct = K₀・ Kt ・ L ・ Vp / dt V: transfer voltage, Vl: image portion surface potential, R: transfer roller
Resistance value, K₀: Dielectric constant, Kd: relative permittivity of photosensitive layer, Kp:
Relative permittivity of transfer paper, Kt: relative permittivity of toner layer, d: photosensitive layer
Film thickness, dp: transfer paper thickness, dt: toner layer thickness, L: paper passing width,
Vp: photoconductor peripheral speed (13) Substituting each value into the expression, an expression representing the term of V-Vl
Then   V−Vl = Ib · R + (Ib · dp) / (K₀・ Kp ・ L ・ Vp) + (Ib ・ dt) / ( K₀・ Kt ・ L ・ Vp) + (Ib ・ d) / (K₀・ Kd ・ L ・ Vp) (14) From equation (14), if the transfer control method is a constant current method,
Transfer charge acting on transfer described in the transfer mechanism
.sigma.c is the same as Ib / L.Vp in the term of the transfer paper in equation (14).
Therefore, by controlling Ib to be constant,
Transfer charge is always given, and the transfer
The matter stabilizes. On the other hand, in the case of constant voltage control,
When V is constant, the resistance value R of the transfer roller 15 is
The value changes greatly due to environmental changes, and the resistance changes when the resistance value increases.
The voltage of the transfer roller increases, and the voltage applied to the transfer paper
The transferred voltage decreases, the transfer charge changes, and stable
Shooting conditions cannot be obtained. Therefore, the resistance of the transfer roller 15
For a value change, constant current control is advantageous. Next, transfer paper is present but toner is present.
Area is small, and the transfer paper size is small,
When the contact area between the body 7 and the transfer roller 15 is large,
I will consider it. 17 and 18 show that the transfer paper 100
If there is no toner layer, FIG. 19 and FIG.
This is a case where the photoconductor 7 and the transfer roller 15 are in contact with each other.
Here, assuming that the respective flowing currents are Iw and Id, Iw = (V−Vd) / (R + Zw) (15) However, Zw = (1 / Cd + 1 / Cp) Id = (V−Vd) / (R + Zd) (16) Where Zd = (1 / Cd) Vd: Photoreceptor non-image area surface potential Becomes Here, in the case of constant current control, small size (A6, etc.)
Most of the applied current flows to the photoreceptor 7
As a result, Ib is not a sufficient value, and the transfer charge is small.
Transfer failure. As a means to prevent this, once
Measure the resistance value of the transfer roller, and then obtain the proper transfer charge
To apply a voltage suitable for this resistance value
There is. Explaining this, the current during non-image formation
I₁Is the voltage flowing through₁Then I₁= (V₁−Vd) / (R + Zd) (17) The resistance value R of the transfer roller is determined from the following relationship. sand
By the way,     R = 1 / I₁・ ｛V₁−Vd− (I₁・ Id) / Cd｝ (18) Here, Vd is the charging potential, and Cd is the capacitance of the photosensitive layer.
This is a known value. Next, at the time of image formation, Ib is set to the proper current value I._TwoWhen
Voltage value is V_TwoThen I_Two= (V_Two-Vl) / (R + Zb) (19) Substituting equation (18) into equation (19), V_TwoAnd ask for     V_Two= (I_Two/ I₁) × (V₁−Vd) + I_Two(Zb−Zd) + Vl (20) And V obtained during non-image formation.₁For (20)
The voltage value V derived by the equation_TwoTo apply a constant voltage during image formation.
In this way, an appropriate voltage is always set according to the resistance value R of the transfer roller.
Transfer is possible with the pressure V. Consider the effect of the linear velocity. Photoconductor peripheral speed
To see the relationship between Vp and transfer roller resistance R, (1
Equations 3), (14), and (15) are solved for R.
When,     R = (V−Vl) / (Qb · L · Vp) −Yb / Vp (21)     R = (V−Vd) / (Qw · L · Vp) −Yw / Vp (22)     R = (V−Vd) / (Qd · L · Vp) −Yd / Vp (23) Where Yb / Vp = 1 / Cd + 1 / Cp + 1 / Ct Yw / Vp = 1 / Cd + 1 / Cp Yd / Vp = 1 / Cd Here, Qb, Qw, and Qd represent an image portion, a non-image portion,
This is the amount of charge per unit area of the paper. That is, Qb = Ib
/ L · Vp, Qw = Iw / L · Vp, Qd = Id / L · Vp
is there. Therefore, when changing the photoconductor peripheral speed, it is inversely proportional to the peripheral speed.
It can be seen that the transfer roller resistance value should be changed. In the expression (16), the band of the charging roller is obtained.
Discharge starting voltage (V
Although the term of g) is omitted, the equation of Vg is expressed by Vg = 31.
2 + 6.2 × d / Kd + √ (7737.6 × d / Kd)
Where d is the thickness of the photosensitive layer and Kd is the relative dielectric constant of the photosensitive layer.
Omitted because it can be regarded as a nearly constant value determined from the rate
did. Next, the cleaning device 17 shown in FIG.
Will be described. Cleaning of the cleaning device 17
The blade 18 is made of an elastic material such as a flat polyurethane rubber.
Made of a metal body, an adhesive or
It is fixed with double-sided tape. The blade boulder 82
As shown in FIG. 3, an inclined surface formed on the case body 3
The two positioning pins 83 provided at
The position in the direction parallel to the surface 84 is regulated,
In the counter direction opposite to the direction of rotation of the
The screw 85 is fixed to the screw body 3. This screw 85
Is in the same direction as the surface to which the cleaning blade 18 is attached.
And the inclined surface 84 formed on the case body 3
The holder 84 is brought into close contact with the
In the direction perpendicular to the inclined surface 84.
The position of the leaning blade 18 is regulated. As described above, the cleaning of the photosensitive member 7 is performed.
The contact angle and pressure of the blade 18 are completely guaranteed,
This prevents problems such as poor cleaning and abnormal noise.
You. Further, the blade holder 82 is fixed to the case body 3.
The position of the screw 85 in the thrust direction is the flange member of the photoconductor.
Be set further outside both ends including 86 and 87
In this case, the photoconductor 7 should not be removed.
And only the cleaning blade can be replaced.
can get. Next, the toner recycling apparatus will be described.
You. The cleaning device 1 shown in FIGS. 1 and 3
7 from the photoreceptor 7 by the cleaning blade 18.
The removed toner is cleared by the toner conveying member 20.
Is transported to the near side in the
Discharge to the outside through a pipe 88 protruding integrally with 19
Is done. At the far end of the toner conveying member 20,
Gear is fixed, and this gear is
Meshes with a gear formed integrally with the flange member 87,
The rotation of the photoconductor 7 is transmitted to the toner conveying member 20, and
The toner conveying member 20 is driven to rotate. As shown in FIG. 3, FIG. 21 and FIG.
Toner conveying member 20 protruding outside cleaning case 19
The roller 91 is provided at the front end of the
A pair of pins 89 are provided.
-The recycle belt 92 is wound around. This
The bolt 92 has the same length along the circumferential direction at the same pitch.
Are formed, and each pin 89 described above is
Each of the slots 93 enters one of the slots 93. Toner resai
The clever belt 92 is a part of the case body 3 as shown in FIG.
On the toner conveying path in the gutter-like portion 94 formed by
The upper portion of the toner conveying path is covered with the upper cover 6 as described above.
(See also FIG. 2). As shown in FIGS. 3 and 22, the gutter 94
A driven roller 95 is rotatably supported on the
95 is wrapped around the toner recycling belt 92 described above.
Have been. The toner conveying member 20 is driven to rotate as described above.
As a result, the roller unit 91 integrated therewith rotates, and
Each pin 89 is a long hole 93 of the toner recycling belt 92.
One after the other, thereby recycling toner.
The belt 92 is driven in the direction indicated by the arrow in FIG.
The outer surface of the toner recycling belt 92 is
A large number of elastic fins 96 arranged in
-When the recycle belt 92 is driven, each elastic fin 96
Is in sliding contact with the gutter-like portion 94 and the inner wall surface of the upper cover 6. The cleaning by the toner conveying member 20 is performed.
To the outside of the cleaning case 19 of the
With a transfer section for the toner recycling belt 92
While moving in an unstable manner nearby, the long hole of the belt 92
After passing through 93, it falls on the inner wall surface of the gutter-like portion 94. Soshi
Of the driven toner recycling belt 92.
The developer 96 is transported in the toner transport path by the
The developer is fed into the developer chamber 90 of the “0”. At this time,
The toner 96 comes into pressure contact with the inner wall surface of the gutter-like portion 94, so that the toner
Is transported toward the developing device 10 without any residual toner.
Can be prevented from being overstressed
You. Further, the gutter-shaped portion 94 near the driven roller 95
An inclined surface 94a is formed on the inner wall surface portion by a protrusion.
When the elastic fins 96 rub against the inclined surface 94a,
When the elastic fin 96 is elastically bent and deformed,
a, each elastic fin 96 is in a natural state.
It returns elastically to the state. For this reason, the elastic fins 96
Is transported by the second stirring unit shown in FIG.
It is skipped to the material 45. This ensures that the toner
The developer can be conveyed to the developer chamber 90. In the developer chamber 90
The transported toner is stirred by the developer 101 existing here.
Mixed and reused. As shown in FIG. 21, the toner recycle
The thickness of the bolt 92 is t₁, Each elastic fin 96 integral therewith
The thickness of t_TwoAnd t₁<T_TwoIs set to
As a result, the stiffness of the elastic fins 96 is reduced by the toner lisa.
The bullet that is stronger than the waist strength of the
As shown in FIG. 22, the sex fin 96 is formed on the inner wall surface of the gutter 94.
When the toner is conveyed by pressing against the elastic fins 96,
There is no large bending deformation itself. And this bullet
When the fin 96 starts to contact the inclined surface 94a, the fin 96
９６96 bends greatly and then returns elastically
At times, the toner is rushed. Using the toner recycling device as described above
As a result, waste containing the toner collected from the photoconductor 7 is eliminated.
The toner tank can be eliminated, and the collected toner can be used in the developing device 1
0 can be efficiently reused. The gutter-like portion 94 constituting the toner conveying path
Is constituted by a part of the case body 3,
This gutter-shaped portion 94 and the other case body are separated from each other.
As in the case where the toner is
Prevents leaks and prevents toner leakage
It is not necessary to provide a sealing material such as a sponge for use. Also
The gutter 94 and the other case body are integrated.
Therefore, the assemblability of the image forming unit 1 is improved. By the way, as shown in FIG. 3 and FIG.
And the shafts 63, 64 of the second stirring members 44, 45
Drive gears 68 and 69 are provided at the rear end of the shafts 63 and 6 respectively.
4 and are fitted so as not to rotate relative to each other. Gigi like this
Conventionally, when supporting a shaft on a shaft, the gear is
In order to prevent it from moving in the direction
A lock ring consisting of a ring or a C-ring is fitted to the shaft.
And the gear is disengaged from the shaft by the locking ring
Was configured to block. Locking ring out of gear
It is used as a stopper to prevent this. Place
However, if such a locking member is used, the number of parts
Increases, and costs increase. In contrast, the embodiment shown in FIGS.
In the above, the drive gears 68 and 69 are outside the drive gears 68 and 69.
The back side outer plate 53 of the knit case 2 is located,
By the plate 53, each driving gear 68, 69 is connected to each shaft 63, 6
4 is provided with a stopper for preventing the shaft 4 from deviating in the axial direction.
Has been established. That is, the case book of the unit case 2
The body 3 includes a rear inner plate 5 that rotatably supports the shafts 63 and 64.
4 and a back side outer plate 53 located further outside thereof,
Drive gears 68, 69 are arranged between the plates 53, 54,
The drive gears 68 and 69 are driven by the rear side
Constitutes a stopper for preventing it from coming off from
It is. As described above, the outer plate 53 has its original function.
In addition, it also functions as a stopper for gears 68 and 69
By using the structure described above, the conventionally required locking ring
Can be omitted, the number of parts is reduced accordingly,
Cost can be reduced. Further, each of the gears 68 and 69 is provided with a rear outer plate.
The gears 68 and 6 are located between the inner plate 53 and the inner plate 54.
It is possible to eliminate the possibility that a person touches the 9. Also
Since it has a double wall structure of the inner plate 54 and the outer plate 53,
The toner of the image forming device 10 may leak out of the image forming unit 1.
Can be more reliably prevented. As shown in FIG. 23 or FIG.
The surface of the rear outer plate 53 facing the moving gears 68 and 69 has a rib shape.
Alternatively, a protrusion 97 having a cylindrical shape is formed, and the protrusion 9 is formed.
7 so that the end faces of the drive gears 68 and 69 come into contact with each other.
Then, the respective drive gears 68 and 69 come into contact with the rear side outer plate 53.
The area can be reduced, which allows
The frictional force used can be reduced, and the gears 68 and 69 and the unit case
Can reduce the wear of the base 2 and extend its life
You. As described above, the case portion in contact with the gear
It is provided adjacent to the outside of the gear, and the case part
The configuration that prevents the gear from slipping off the shaft
It can be widely applied to various machines and devices other than
is there. The drive gears 68 and 69 are connected to the shafts 63 and 63, respectively.
64 is prevented from shifting inward in the axial direction.
Various configurations can be adopted. For example, as shown in FIG.
Each gear 68,
69 is prevented from moving in the axial direction of the shafts 63 and 64.
Can be Alternatively, as shown in FIG.
A step portion 163 is formed in each of the third and the third portions 64.
That each gear 68, 69 is shifted inward in the axial direction.
May be prevented. Also, as shown in FIG.
Or each gear by a locking ring 164 comprising a C-ring.
63, 64 may be prevented from shifting inward in the axial direction.
No. Incidentally, the image forming unit 1 described above has a
From the light body 7, the charging roller 8, and the cleaning blade 18
Has many parts such as cleaning members, and
The two-component developer 101 is stored in the developer chamber 90 and used.
Is done. Each of these factors degrades over time and eventually
It becomes a state that cannot be used. Usually these elements are
Replace it with a new one just before it can no longer be used
Is done. This replacement time is the life of each element. that time,
Each element is configured to have a completely different life span.
Each time the element reaches its end of life,
And the replacement work becomes very complicated. Therefore, a plurality of components of the image forming unit 1
Are configured so that their life spans are approximately the same.
Is preferred. In this way, multiple
Can be replaced at the same time, and the entire imaging unit 1
It is also possible to exchange for a new one. For example, the life of the photosensitive member 7 and the developer 101
Configure each of them to match. in this way
Then, when the photoconductor 7 and the developer 101 reach the end of their life,
These can be replaced at the same time, or the entire imaging unit 1 can be replaced
The replacement does not significantly impair the economics. The photosensitive member 7, the developer 101, and the clear
The life of the cleaning blade 18 and the charging roller 8
When they reach the end of their service life,
Replace them simultaneously or replace the entire imaging unit 1 with a new one.
Can be exchanged for Here, the life of each component of the image forming unit 1 is described.
Life can be set as follows. First, the life of the developer, more precisely, its
The life of the rear depends on the stirring and circulation of the developer.
The coating layer on the carrier surface is peeled off over time,
Determined by the deterioration of the triboelectric charging characteristics of the carrier
It is. That is, the thickness of the carrier coating layer and the development
The entirety of the developer 101 stored in the developer chamber 90 of the apparatus 10
By selecting the amount, the approximate life of the developer 101 is
Can be determined. The life of the photosensitive member 7 mainly depends on the photosensitive layer 31.
But is shaved over time by the cleaning blade 18.
And the film thickness decreases, making it impossible to obtain a proper charging potential.
It is determined by That is, the thickness of the photosensitive layer 31 is
The life of the photoconductor 7 can be set by selecting
You. The service life of the cleaning blade 18 is
The contact pressure against the photoreceptor 7 and the pressure
It is determined by the amount of wear of the blade edge. In general,
As the amount of abrasion increases, residual toner on the photoreceptor is reduced.
Cleaning performance deteriorates. However, Cleanin
The higher the contact pressure of the blade 18 against the photoreceptor 7 is,
A cleaning blade 18 with a large amount of wear
Of the cleaning brush
The life of the blade 18 is extended. However, the contact pressure is high
Then, there is a problem that the load torque of the photoconductor 7 increases. This
As described above, the cleaning
By selecting the contact pressure of the
The approximate life of the blade 18 can be set. The life of the charging roller 8 depends on the surface of the charging roller.
A cleaning pad that cleans the adhered minute toner
For pressing the pad 32 (FIG. 1) against the charging roller 8
If the pressing pressure is large, the charging roller 8
Cleaning performance is good, but the charging roller surface
The surface is scratched, resulting in image unevenness. Also, the pressing pressure
If it is small, the cleaning property for the charging roller 8 will be poor.
You. For this reason, the cleaning for the charging roller 8 is performed.
By selecting the pressing force of the
The approximate life of the electric roller 8 can be set. The above is the description of each element constituting the image forming unit 1.
Factors that determine the life are as follows: the photoconductor 7 and the developer 1
A more specific example when matching the lifespans of No. 01 will be described. First, a new image forming unit 1 is started to be used.
After that, when an image is formed on S sheets of transfer paper,
When the number of copies reaches S, the photosensitive member 7 and the developer 10
Has reached the end of its service life. At this time, the entire imaging unit 1 is replaced.
Shall be. The developer 101 deteriorates
If you decide to use it until it becomes unusable,
Immediately after completing S image formation, the carrier is charged
Carrier coating layer thickness and its
Is determined. The triboelectric charge polarity of the carrier is
Expressed by toner specific charge (charge amount per unit weight Q / M)
FIG. 28 shows the toner specific charge and the number of copies.
Shows the relationship. Toner specific charge (Q / M) out of tolerance
If it also decreases, it will cause background stains and image density,
Immediately before such a state occurs, the number of copies becomes S.
The thickness of the coating layer of the carrier and the amount of the developer
Set it. For example, 30K sheets of the above-mentioned S sheets, 40K sheets
Sheets or 50K sheets (K = 1000), developer
Life is a substitute for the carrier's triboelectric charging characteristics as described above.
Is determined by the value of the toner specific charge (Q / M),
This value is 30K, 40K or 50K after each sheet has passed
But as it is in the range of 10 to 40 μc / g, and
Immediately after reaching this number of copies, the toner specific charge becomes this value.
Lower than the carrier coating layer thickness
By selecting the amount of developer, the developer life can be set correctly.
Wear. Specifically, the coating layer thickness is set to, for example, 0.5
Select from the range of μm to 1.5 μm and the amount of developer
(Weight) is selected from the range of 2.45N to 4.41N
I do. Note that if the amount of the developer 101 is small,
Costs can be reduced.
When the amount of developer is smaller than 50K sheets
To set the combination with the carrier coating layer thickness
It is desirable. Next, the photosensitive member 7 also deteriorates.
If the number of copies is S,
So that an appropriate charging current cannot be obtained immediately after
The thickness of the photosensitive layer 31 is set. As an example,
Due to the change in the thickness of the photosensitive layer 31 with time, its charging potential
Considering the case where the width of change is 20V or less,
In the equation shown for the charging mechanism of the charging roller 8,
, The firing voltage (band) affected by the thickness of the photosensitive layer 31
So that the fluctuation of the term of power start voltage) Vg becomes 20 V or less.
Then, the thickness of the photosensitive layer 31 may be selected. S copies
Since the subsequent wear amount of the photosensitive layer is known in advance, this is set to l. First
The film thickness of the photosensitive layer in the initial period is d, and its relative dielectric constant is Kd.
Is the charging start voltage of Vgs, and the charging start voltage after copying S sheets
Is Vge,     Vgs = 312 + 6.2 × d / Kd + √ (7737.6 × d / Kd)     Vge = 312 + 6.2 × (dl) / Kd + {{7737.6 × (dl) / Kd}     Vgs-Vge = 1.931 + 49.17 {d-{(dl)}} Here, if l is 3 μm,     Vgs-Vge = 5.79 + 49.17 {d-{(d-3)}} And the change width is 20 V or less,     Vgs-Vge = 5.79 + 49.17 {d-{(d-3)} ≤20                 √d-√ (d-3) ≦ 0.289 Becomes Here, √d = D, d−3 = D^Two-3
When, D-√ (D^Two-3) ≦ 0.289 √ (D^Two-3) ≦ D−0.289 And squaring both sides, D^Two-3 ≦ D^Two-0.578D + 0.0835 0.578D ≦ 3.0835 ∴D ≦ 5.33 From d = D, d = D^Two ∴d = 5.33^Two= 28.4 μm Therefore, after S sheets have been copied, the photosensitive layer 31 is temporarily
If 3 μm wear is required, a 28.4 μm thick photosensitive
By selecting the layer, the fluctuation width can be reduced to 20 V or less.
It becomes possible. For example, if the photosensitive member 7 has 30K copies,
In order to extend the life, the photosensitive layer after passing 30K sheets
So that the potential drop due to the film thickness change of
In addition, he continued using the photoconductor as it was.
Sometimes, immediately after that, the potential drop will be greater than 20V
Thus, the thickness of the photosensitive layer 31 is set. 30K copies
Assuming that the amount of wear of the photosensitive layer 31 later is 2 μm,
From the calculation formula, the initial film thickness is around 13 μm. Similarly, the life of the photosensitive member 7 is extended up to 40K sheets.
In this case, the amount of wear of the photosensitive layer 31 is 2.5
μm, so the initial film thickness should be around 20 μm.
I just need. Further, the life of the photoreceptor 7 reaches 50K sheets.
At this time, the wear amount of the photosensitive layer 31 is 3 μm.
The initial film thickness is set to around 28.4 μm. As described above, the life of the developer and the photoreceptor
And the developing device can be
The integrated imaging unit can be replaced collectively. This
Service parts at different times.
Maintenance costs can be significantly reduced.
You. When the cleaning blade 18 is S sheets
To extend the life of the copy, the blade 18
Pressure of the cleaning blade 18 on the photosensitive member surface
As can be seen from the graph of FIG. 29 showing the relationship between the amounts of wear,
For example, when the contact pressure of the cleaning blade 18 decreases,
Cleaning failure still occurs at the end of S copies
Cleaning blade 18 without further cleaning.
If you continue to use the printer with the
Set the contact pressure so that
You. Even when the contact pressure of the cleaning blade 18 is large
The same is true. If the contact pressure is set to a high value, the cleaning
Although the wear amount of the blade 18 increases, the cleaning
The photoreceptor can be cleaned with the card 18 in good condition.
And the cleaning blade 18
The prolongation of life can be better understood from FIG. However
When the contact pressure is large, the load
The torque increases, and a large load is applied to the drive motor.
And the drive motor capacity must be increased.
The cost of the image forming apparatus increases. Therefore, cleaning
The contact pressure of the blade 18 against the photoconductor 7 is set too high.
It is more economical to not specify. As described above, the cleaning blade
18, the life of the photosensitive member 7 and the developer can be determined.
These can be replaced simultaneously by matching the life
And maintenance costs can be further reduced. For example, as described above, the developer and the photosensitive member 7
When the life of the photoconductor is 30K copies,
The contact pressure of the cleaning blade 18 is 0.1176
N / cm vicinity and life expectancy of 40K copies
At this time, the cleaning blade 18 is
The contact pressure is set near 0.1568 N / cm. Also life
When the number of copies is
The contact pressure of the cable 18 should be set near 0.196 N / cm.
And the life of each element can be almost matched
You. The charging roller 8 is driven by the number of S copies.
When the roller reaches the end of its service life,
8 can be configured as follows. FIGS. 30 and 31 show the surface of the charging roller 8.
Cleaning pad that cleans fine toner adhering to the top
32 is a pressing force (pad) for contacting the surface of the charging roller 8.
Pressure), the cleaning properties of the pad 32, and the charging.
The image unevenness due to the scratches generated on the surface of the roller 8 is shown.
are doing. The range indicated by “OK” in these figures is
Cleaning of the charging roller 8 by the cleaning pad 32
This is a range where the properties are good and image unevenness is small. As shown in FIGS. 30 and 31, after S sheets have been copied.
Good cleaning performance with the cleaning pad 32
Good and no image unevenness
Immediately after copying S sheets if you continue to use
Also, make sure that cleaning performance and image unevenness are poor.
Select the head pressure. In this way, the developer 101,
Of the optical member 7, the cleaning blade 18, and the charging roller 8
The lifetimes can all be matched. For example, if the number of copies S until the end of its life is 3
0K, the pad 32 with respect to the charging roller 8
Set the pressure contact force (pad pressure) to around 5.88N,
When the number of peaks S is 40K, the pad pressure is close to 7.84N.
Set nearby. Similarly, if the life copy number S is 50K,
In this case, the pad pressure is set near 9.8N. The pad pressure is also applied to the pad 32.
If the cleaning property of the charging roller 8 can be satisfied,
It is preferable to set the eyes so that the photoconductor 7 can be driven.
Since the dynamic load can be reduced, the driving motor has a small capacity
Can be used, and the cost can be reduced. [0147] As described above, the unit case 2
Replacement elements, ie, photoreceptor 7, developer 101, and clear
Copy a certain number of cleaning blades 18 and charging roller 8
After that, make sure that each element
By selecting materials and setting characteristic values,
An economical and lean unit can be configured on the
Replacement by exchanging one imaging unit at the time of product exchange
When the work is completed, maintenance is greatly improved,
The cost of maintenance can be significantly reduced. On the other hand, the use of low-cost high-durability parts
If possible, change the life of its individual components
It is also possible to configure. As described above, the photosensitive member and the developing device are contained in the unit case.
And the image forming element of the cleaning device and the charging roller
The imaging unit was configured, but these imaging elements, or other
Combining the imaging elements of
Assemble the imaging unit with the unit case
You can also. Normally, at least the photoconductor and the developing device are
Can be assembled to a knit case to form an imaging unit
Many. Thus at least one imaging element and unit
By constructing an imaging unit by assembling the case
And the assemblability is improved, and the
The operability during replacement is improved. [0150] According to the image forming apparatus of the first aspect,
For example, the lower part of the unit case guides the transfer paper
As an independent member for the guide part
There is no need to provide this, reducing the cost of the image forming apparatus.
You. In addition, under the unit case other than the paper passing area
Protruding parts that protrude outward from the guide part are provided in the part
Therefore, remove the imaging unit from the image forming
When the unit is placed on the mounting surface,
The guide section may be damaged by
The condition can be prevented. Further, the guide portion is constituted by a guide rib.
Is formed on the guide part by electrostatic force.
Prevents paper from sticking together and prevents abnormal images
it can. Also, when toner adheres to the guide ribs,
The contact area between the ribs and the transfer paper is small, so the toner
It does not adhere to the transfer paper in large quantities, preventing the transfer paper from becoming dirty.
Can be stopped.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of an image forming unit mounted on an image forming apparatus main body. FIG. 2 is an external perspective view illustrating an image forming unit without a developer cartridge and a toner bottle. FIG. 3 is a perspective view showing the image forming unit with a case cover, a developing case cover, and an upper cover removed. FIG. 4 is a partial cross-sectional plan view in the same state as FIG. 3; FIG. 5 is a perspective view showing a state where a case body is inverted. FIG. 6 is a perspective view similar to FIG. 5, showing another example. FIG. 7 is an enlarged schematic cross-sectional view of a photoconductor. FIG. 8 is a schematic diagram of a photoconductor and a charging roller. FIG. 9 is a diagram illustrating an equivalent circuit of a charging roller, a photoconductor, and a power supply. FIG. 10 is an explanatory sectional view illustrating a relationship between a developing device and a photoconductor. FIG. 11 is an exploded perspective view of a doctor blade, a developing sleeve, a support member, and an inlet seal cover. FIG. 12 is an explanatory diagram showing a development model. FIG. 13 is a graph showing an example of a relationship between toner charge and force acting on toner. FIG. 14 is an explanatory diagram showing a transfer model. FIG. 15 is an explanatory diagram illustrating a relationship between a photoconductor and a transfer roller. FIG. 16 is a diagram showing an equivalent circuit of FIG. FIG. 17 is an explanatory diagram illustrating a relationship among a photoconductor, a transfer roller, and a transfer sheet. FIG. 18 is a diagram showing an equivalent circuit of FIG. 17; FIG. 19 is an explanatory diagram illustrating a relationship between a photoconductor and a transfer roller. FIG. 20 is a diagram showing an equivalent circuit of FIG. 19; FIG. 21 is an enlarged perspective view of a toner recycling belt. FIG. 22 is a vertical sectional view of the toner recycling belt. FIG. 23 is a perspective view showing another example of the back side outer plate of the unit case. FIG. 24 is a perspective view showing still another example of the back side outer plate of the unit case. FIG. 25 is a horizontal cross-sectional view showing one configuration example for preventing the drive gear from shifting inward in the axial direction of the shaft. FIG. 26 is a horizontal sectional view showing another configuration example for preventing the drive gear from shifting inward in the axial direction of the shaft. FIG. 27 is a horizontal sectional view showing still another configuration example for preventing the drive gear from shifting inward in the axial direction of the shaft. FIG. 28 is a graph showing an example of the relationship between the number of copies and the toner specific charge. FIG. 29 is a graph showing an example of the relationship between the number of copies and the amount of wear of the cleaning blade. FIG. 30 is a graph showing an example of the relationship between the number of copies and the cleaning property of the charging roller. FIG. 31 is a graph showing an example of the relationship between the number of copies and image unevenness. [Description of Signs] 1 Image forming unit 2 Unit case 21 Bottom wall 23 Guide part 26 Guide rib 27 Projection 100 Transfer paper W Paper passing area

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-92883 (JP, A) JP-A-3-100665 (JP, A) JP-A-2-213857 (JP, A) JP-A-6-92 110264 (JP, A) JP-A 4-120962 (JP, U) JP-A 1-153564 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/18

Claims (1)

(57) An image forming apparatus for obtaining a recorded image by transferring a toner image formed on an image carrier to transfer paper conveyed toward the carrier. An image forming apparatus comprising: an image forming unit configured by attaching at least one of the image forming elements including the image carrier to a unit case, and detachably mounting the image forming unit to an image forming apparatus main body. ,
The unit case of the image forming unit is positioned so that the lower part of the unit case of the image forming unit mounted on the main body of the image forming apparatus constitutes a guide portion of the transfer paper to be conveyed, and the paper passing width through which the transfer paper passes. A projection whose height from the bottom wall of the unit case is higher than the projection height of the guide portion of the transfer paper is provided at a lower portion of the unit case on both outer sides of the range, and the guide portion is provided in the unit case. And a plurality of guide ribs protruding from the bottom wall of the unit case and extending along the transfer paper transport direction. It is set so as to gradually decrease from the side to the downstream side, and the upstream side in the transfer paper transport direction projects from the bottom wall of the unit case with its free edge rounded, An intermediate portion between the projection on the upstream side in the copying paper transport direction and the projection on the downstream side in the transfer paper transport direction is formed as a concave portion recessed toward the bottom wall of the unit case from these projections. The protrusion and the intermediate portion extend substantially parallel to the guide rib, and
When viewed from the outside in a direction perpendicular to the transfer paper transport direction, the guide ribs, the protrusions, and the bottom of the unit case of the intermediate portion are so covered that the guide ribs are covered by the protrusions and the intermediate portion. An image forming apparatus, wherein a height of protrusion from a wall is set.