JP4221982B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus used for an electrophotographic copying machine, a printer, or the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image forming apparatus used for an electrophotographic copying machine, a printer, or the like charges a photosensitive member, irradiates the charged photosensitive member with exposure light representing an image to form an electrostatic latent image, and The electrostatic latent image is developed by attaching charged toner, and the developed toner image is directly or indirectly transferred to a recording medium via an intermediate transfer member, and then fixed on the recording medium. Is generally formed.
[0003]
As a developing method for developing an electrostatic latent image, a two-component developing method in which a two-component developer in which a carrier such as iron powder and a toner are mixed at a certain ratio is stirred and frictionally charged, and only toner is used as a developer. The one-component development method to be used is a generally used method.
[0004]
In the two-component development method, it is necessary to control the ratio of the toner in the developer to be constant according to the density target. However, the toner consumption varies depending on the image density, the process speed, and the surrounding environment changes. As a result, the charging characteristics of the two-component developer fluctuate or the sensitivity of the sensor for detecting the toner density fluctuates.
[0005]
On the other hand, since the one-component development method does not use a carrier, there are technical difficulties in charging the toner and transporting the charged toner to the development position. Since the accompanying mechanism becomes unnecessary, there is an advantage that the developing unit can be miniaturized and waste such as a carrier is not generated.
[0006]
The one-component development method further includes contact development in which an electrostatic latent image is developed by bringing it into contact with the surface of the photoreceptor, and non-contact development in which the electrostatic latent image is developed without being brought into contact with the surface of the photoreceptor.
[0007]
Among these, the non-contact development needs to apply the DC voltage and the AC voltage in a superimposed manner in order to maintain the gap accuracy for causing the toner to fly from the developing unit to the photoconductor and to make the toner fly.
[0008]
On the other hand, in the contact development, a DC voltage may be applied between the photoconductor and the developing device, but a mechanism for contacting and separating the photoconductor and the developing device is required.
[0009]
In view of this, there is a power transmission unit in which a plurality of developing units are arranged so as to be able to come in contact with and separate from the photosensitive belt, and a timing belt is provided so as to prevent drive unevenness and jitter (see Patent Document 1). ).
[0010]
Further, in an image forming apparatus in which a plurality of developing units are arranged on a photosensitive belt so as to be able to contact and separate, and each color toner image sequentially formed on the photosensitive belt is transferred to a recording medium via an intermediate transfer belt to form an image. In some cases, the model can be easily changed according to the image formation size by simply replacing the intermediate transfer belt (see Patent Document 2).
[0011]
In today's replenishment of toner to image forming apparatuses, removable toner cartridges are actively used from the viewpoint of preventing toner scattering and ease of replenishment. However, toner stored in toner cartridges is supplied to a developing device. As a method for this, a toner container having a toner cartridge mounted thereon is provided separately from the developing device, and a toner transporter including an auger or the like is provided between them (see Patent Document 3), or a toner cartridge mounting part is provided. Generally, a method (see Patent Document 1) provided directly in the developing unit is used.
[0012]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 11-15275 (paragraph number 006 to paragraph number 009, FIG. 8, paragraph number 0028 to paragraph number 0030, FIGS. 1 to 6).
[Patent Document 2]
JP 2002-99121 A (paragraph number 0018 to paragraph number 0023, FIG. 1).
[Patent Document 3]
Japanese Unexamined Patent Publication No. 2000-231252 (paragraph number 0059 to paragraph number 0061, FIG. 8).
[0013]
[Problems to be solved by the invention]
However, when supplying toner to a developing device that performs development by bringing the developing device into contact with and separating from the developing device, a method of providing a toner cartridge mounting portion directly in the developing device unit (see Patent Document 1) is based on the layout around the developing device. Due to regulations, the capacity of the toner cartridge must be reduced, and there is a problem that it is difficult to downsize the entire image forming apparatus.
[0014]
In addition, the toner container can be separated from the developing device by moving the toner conveying device itself in accordance with the movement of the developing device, or by connecting the joint between the toner conveying device and the developing device to the developing device. A method of sliding according to the movement can be considered.
[0015]
However, when the toner transport device itself is moved, there is a problem that, for example, a coiled auger provided in the transport device is curved, and the toner transport capability is lowered. Further, when the joint portion between the toner transport device and the developing device is slid, there are problems such as an increase in the number of parts and toner leakage.
[0016]
In view of the above circumstances, the present invention smoothly supplies toner to a developing device that performs development by bringing the developing device into contact, approach, or separation (abbreviated as “contact and separation”) without causing toner leakage. An object of the present invention is to provide an image forming apparatus that can be performed and can be downsized.
[0017]
[Means for Solving the Problems]
The image forming apparatus of the present invention that achieves the above object develops an electrostatic latent image on an image carrier with toner to form a toner image, and finally the toner image on the image carrier is transferred onto a recording medium. In an image forming apparatus for forming an image composed of a toner image fixed on the recording medium by transferring and fixing to the recording medium,
A container for storing toner;
A developing device having a toner receiving port for receiving toner, and developing the electrostatic latent image on the image carrier with the received toner;
A toner transporter having a hollow member that connects the storage unit and a toner receiving port of the developing unit, and transports toner in the storage unit through the hollow member and transports the toner from the toner receiving port into the developing unit. And
The developing unit is movable in a contacting / separating direction to / from the image carrier, and the hollow member is moved in the contacting / separating direction of the developing unit as the developing unit moves in the contacting / separating direction. It has a sliding contact surface that is in sliding contact with a surface that forms a toner receiving port.
[0018]
As described above, even when a developing device that performs development by bringing the developing device into and out of contact with each other, the storage device and the developing device are separately arranged, and the toner conveying device that conveys the toner to the developing device is fixed, and the toner conveying Since the developing device and the developing device are separated and the hollow member is brought into sliding contact with the movement of the developing device, the toner can be smoothly conveyed without leaking from the toner receiving port into the developing device.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the image forming apparatus of the present invention will be described.
[0020]
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
[0021]
The image forming apparatus shown in FIG. 1 includes four toner image forming units 10 on which yellow (Y), magenta (M), cyan (C), and black (K) toner images are formed, and Y and M colors. The first intermediate transfer body 11 that receives the transfer of the toner image from the toner image forming portion where the color toner image is formed, and the toner image transferred from the toner image forming portion where the C and K toner images are formed The second intermediate transfer member 12, the third intermediate transfer member 13 that receives the transfer of the two-color toner images from the first and second intermediate transfer members, and the paper fed from the paper cassette that stores the paper. A transport path 15 for transporting, a transfer roller 16 for transferring the four-color toner images transferred to the third intermediate transfer body 13 to the paper transported through the transport path 15, and a four-color toner transferred to the paper The image is fixed on the paper by heating and pressing. And the fixing device 17, the discharge roller 18 with the toner images of four colors by the fixing unit 17 to discharge the image-fixed to the sheet on which the image is formed, and a discharge tray 20 for accommodating the sheet on which the image is formed. In addition, a reverse conveyance path 19 is provided that switches the paper on which an image is formed on one side of the paper to reverse and reverses the paper, and joins the paper fed from the paper cassette to the conveyance path 15. Each of the first to third intermediate transfer members includes an intermediate transfer member cleaner 22 for cleaning toner remaining after the transfer.
[0022]
Each toner image forming unit 10 includes a photosensitive drum 1, a charger 2 for charging the surface of the photosensitive drum 1, an exposure unit 3 for exposing the charged surface of the photosensitive drum 1 to form an electrostatic latent image, The electrostatic latent image formed on the surface of the photosensitive drum 1 is developed by attaching toner to the developing device 4 for forming a toner image, and after the toner image is transferred to the first intermediate transfer member, the photosensitive drum 1 And a photosensitive drum cleaner 5 for cleaning the toner remaining in the toner.
[0023]
In addition, toner cartridges 32 that store toners of the respective colors are detachably mounted, and each of the storage units 31 that stores toner supplied from the mounted toner cartridges 32, and the toner receivers of the storage units 31 and the developing units 4. A toner conveying device 35 disposed on the back side of the figure, which has a hollow member connected to the inlet and conveys the toner in the storage device 31 through the hollow member to the developing device 4 from the toner receiving port. The toner supply device 30 is provided.
[0024]
The image forming apparatus according to the present embodiment further includes a contact / separation motor 7 that contacts and separates the developing device 4. The contact / separation motor 7 is sensitive to the developer 4 when performing an image forming process. When the electrostatic latent image formed on the photosensitive drum is developed with toner, moved to a developing position in contact with or close to the photosensitive drum, and the image forming process is not performed, the electrostatic latent image formed on the photosensitive drum is The latent image is moved to a non-development position separated from the photosensitive drum where the latent image is not developed with toner.
[0025]
An image signal input from the outside or an image signal read from a document is subjected to image processing such as color conversion and gradation correction, pulse width modulation, and the like by an image processing unit (not shown). The image signals that have been subjected to pulse width modulation and separated into the respective colors drive the respective exposure units 3 to emit laser beams. The laser beam emitted from each exposure device 3 is applied to each photosensitive drum 1 uniformly charged by the charger 2 to form an electrostatic latent image. The electrostatic latent image formed on each photoconductor drum 1 is developed with the toner of the developing device 4 that has moved to the development position, and a toner image of each color is formed on each photoconductor drum 1. The Y-color toner image and the M-color toner image formed on the photosensitive drum 1 are transferred to the first intermediate transfer body 11 so as to overlap each other. Further, the C color toner image and the K color toner image formed on the photosensitive drum 1 are transferred to the second intermediate transfer body 11 in a superimposed manner. Then, the first intermediate transfer member transferred by superimposing the Y color toner image and the M color toner image, and the second color image transferred by superposing the C color toner image and the K color toner image. The toner images of all colors YMCK are collectively transferred from the intermediate transfer member to the third intermediate transfer member. The four-color toner images on the third intermediate transfer member are transferred by the transfer roll 16 to the paper P fed from the paper cassette and transported through the transport path 15, and the four-color toner images transferred to the paper P are The image is formed by being fixed by being heated and pressurized by the fixing device 17. The paper P on which the image is formed on the paper P is discharged by the discharge roll 18.
[0026]
When forming images on both sides, the paper P is switched back and reversed by the discharge roll 18, conveyed through the reverse conveyance path 19, and again the toner image is transferred to the back surface by the transfer roll 16. After that, it is discharged by a discharge roll.
[0027]
FIG. 2 is a diagram illustrating the toner supply device.
[0028]
As shown in FIG. 2, the toner supply device 30 includes a container 31 that stores toner of each color, a toner cartridge 31 that is detachably attached to the container 31 and stores toner of each color, and one end thereof. A flexible tube 37 that is fitted in the container 31 and is fitted in a toner discharge member 33 that has a toner discharge opening at the other end, is incorporated in the flexible tube 37, and the toner of each color stored in the container 31 is discharged into the toner. A toner transport device 35 including an auger that does not appear in the drawing is transported toward the member. The toner discharged from the toner discharge opening is conveyed into the developing device 4 from a toner receiving port provided in the developing device 4.
[0029]
The developing device 4 according to the present embodiment moves in the contact / separation direction to / from the photosensitive drum 1, but the toner discharge opening formed in the toner discharge member 33 is narrower than the toner receiving port 9 and receives the toner. It overlaps the entrance 9. Further, the periphery of the toner receiving port 9 of the developing device 4 is covered with a seal member 8, and as the developing device 4 moves in the contact / separation direction, the sealing member 8 covering the periphery of the toner receiving port 9 is provided. The slidable contact surface of the toner discharge member 33 formed with the toner discharge opening is slidably contacted. Therefore, the toner is prevented from leaking from the toner discharge opening.
[0030]
Further, the toner discharge member 33 is fixed by a bracket 38, and the flexible tube 37 has one end fixed to the toner discharge member 33 and the other end fixed to a container 31 fixed to the frame. Since the built-in auger does not bend even when the developing device 4 moves in the contact / separation direction in which the developing device 4 contacts or separates from the photosensitive drum 1, the transport device 35 can smoothly transport the toner to the developing device 4. it can.
[0031]
FIG. 3 is an exploded view showing a configuration of a joint portion between the toner supply member and the toner receiving member.
[0032]
As shown in FIG. 3, the developing device 4 is provided with a toner receiving port 9 for receiving toner. A toner discharge member 33 having a toner discharge opening 33 a having a smaller size than the toner reception port 9 is disposed on the toner reception port 9. Between the toner discharge member 33 and the toner reception port 9, a toner reception member is disposed. A seal member 8 having an opening having the same size as the inlet 9 is disposed, and the seal member 8 seals the toner discharged from the toner discharge member 33 to the toner receiving port 9 so as not to leak.
[0033]
The seal member 8 is fixed and fixed to the toner receiving port 9 with, for example, an adhesive, and the seal member 8 is fixed to the toner discharge member 33 on the sliding contact surface 33c where the toner discharge opening 33a is formed. 8 is in sliding contact so that it can freely slide.
[0034]
As described above, the toner discharge member 33 is fixed to the bracket 38 and is brought into sliding contact with the seal member 8 fixed to the toner receiving port 9 by the sliding contact surface 33c as the developing device 4 moves. When the toner transporter 35 is moved, the toner transporter 35 having the flexible tube 37 and the built-in auger bends, and the built-in auger 36 comes into contact with the inner wall of the flexible tube 37 so that the toner transport capability is reduced. This is to prevent the possibility that the rotation of the toner does not smoothly occur, and a lump of toner is generated in the flexible tube 37 and the toner in the developing device becomes insufficient, which adversely affects the density of the formed image.
[0035]
Here, the seal member 8 includes a commonly used sealing material such as silicon, polyurethane, polyester, etc., surface-treated with a PET film or the like, PES, PAI, etc. In consideration of the mutual relationship, it is preferable to use a member having excellent wear resistance, sealing properties, and sliding contact properties.
[0036]
FIG. 4 is a diagram illustrating the toner discharge member.
[0037]
As shown in FIG. 4, the toner discharge member 33 has a toner discharge opening 33a having a smaller size than the opening of the sealing member 8, and protrudes around the toner discharge opening 33a toward the toner receiving port. Convex ribs 33b.
Except for the portion where the convex rib 33b protrudes, the slidable contact surface 33c slidably contacted with the seal member is made of a flat and smooth member. When the receiving port moves, the seal member can freely slide. Further, since the toner discharge opening 33a is smaller in size than the respective openings of the seal member and the toner receiving port, the convex ribs 33b are constantly in the respective openings of the seal member and the toner receiving port even when the toner receiving port is moved. It overlaps with.
[0038]
Therefore, in addition to the seal member, toner leakage is prevented by the action of the convex rib 33b.
[0039]
Next, the toner transport device of this embodiment will be described.
[0040]
FIG. 5 is a view showing a cross section taken along the line BB ′ of the toner discharge member shown in FIG.
[0041]
As shown in FIG. 5, the toner transporter is formed in a spiral shape with a flexible tube 37 having one end fitted to the toner discharge member 33, and a plate-like member that is in the flexible tube 37 and is driven to rotate by a motor. And an auger 36. The toner discharge member 33 has a toner discharge opening 33a for discharging the toner toward the developing device, and the auger 36 has a conveyance direction in which the toner is conveyed from the central portion of the toner discharge opening 33a indicated by a one-dot chain line. The tip end portion 36a protrudes on the downstream side.
[0042]
In this way, if the tip of the auger protrudes 50% or more into the toner discharge opening 33a, the toner discharge opening 33a is stored in the container even if it is oriented in a direction perpendicular to the toner transport direction. The toner can be reliably conveyed from the toner discharge opening 33a to the toner receiving port.
[0043]
Here, the auger of this embodiment is formed in a spiral shape with a plate-like member. The plate-like member is used because when the toner is rotated and conveyed, the feeding power for conveying the toner becomes large, and even if the flexible tube 37 is bent, the reaction force is small, so that the sliding force with the flexible tube 37 is small. This is because rubbing can be reduced. However, the auger is not necessarily formed in a spiral shape with a plate-like member, and for example, a linear member can be used.
[0044]
FIG. 6 is a diagram illustrating the relationship between the protruding amount of the auger tip and the amount of toner discharged from the toner discharge opening.
[0045]
In FIG. 6, the vertical axis represents the amount of toner (mg / second) discharged from the toner discharge opening, and the horizontal axis represents the protrusion amount (%) of the auger tip.
[0046]
As can be seen from the figure, if the protruding amount of the auger tip is 50% or more, the toner is reliably conveyed.
[0047]
FIG. 7 is a diagram illustrating a toner discharge member.
[0048]
The toner discharge member 33 shown in FIG. 7 includes an open / close member 34 that opens and closes the toner discharge opening 33a, and two slide rails 33d on which the open / close member 34 slides.
[0049]
The opening / closing member 34 has an opening / closing member opening 34a having the same size as the toner discharge opening 33a. When the opening / closing member 34 moves on the slide rail 33d, the toner discharge opening 33a is opened and closed.
[0050]
FIG. 8 is a diagram illustrating an open / close state of the open / close member.
[0051]
As shown in FIG. 8A, when the opening / closing member 34 moves to the back of the slide rail 33d, the opening / closing member opening 34a and the toner discharge opening 33a are matched to open the toner discharge opening 33a. Further, as shown in FIG. 8B, when the opening / closing member 34 moves to the front of the slide rail 33d, the opening / closing member opening 34a and the toner discharge opening 33a do not coincide with each other, and the toner discharge opening 33a is closed.
[0052]
By providing the openable / closable opening / closing member 34 in this manner, for example, when performing maintenance of the developing device 4 or maintenance of the toner transport device 35, the developing device 4 can be easily removed after the opening / closing member opening 34a is closed.
[0053]
9 and 10 are views showing the opening / closing member. FIG. 9 shows a perspective view, and FIG. 10 shows a cross-sectional shape on the plane of AA ′ of FIG.
[0054]
The opening / closing member 34 has an opening / closing member opening 34a, and a protrusion 34b is provided around the opening / closing member opening 34a.
[0055]
The protrusion 34b has, for example, a height of 0.2 mm and a width of 0.4 mm, and comes into contact with a gap for the opening / closing member provided around the toner discharge opening 33a, so that the toner leaks from the gap for the opening / closing member. Is prevented.
[0059]
【The invention's effect】
As described above, according to the image forming apparatus of the present invention, the toner storage unit and the developing unit can be separately arranged to reduce the size of the entire apparatus, and the toner transfer unit is fixed to stabilize the toner transfer. The toner conveying device and the developing device can be brought into sliding contact with the movement of the developing device, and the toner can be smoothly supplied to the developing device without causing the toner to leak out.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to an exemplary embodiment.
FIG. 2 is a diagram illustrating a toner supplier.
FIG. 3 is an exploded view illustrating a configuration of a joint portion between a toner supply member and a toner receiving port.
FIG. 4 is a diagram illustrating a toner discharge member.
5 is a cross-sectional view taken along the line BB ′ of the toner discharge member shown in FIG.
FIG. 6 is a diagram illustrating a relationship between an auger tip protrusion amount and a toner amount discharged from a toner discharge opening.
FIG. 7 is a diagram illustrating a toner discharge member.
FIG. 8 is a diagram showing an open / close state of an open / close member.
FIG. 9 is a view showing an opening / closing member.
FIG. 10 is a view showing an opening / closing member.
FIG. 11 is a diagram illustrating a state in which an opening / closing member provided in each toner discharge member is locked.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 Charging device 3 Exposure device 4 Developing device 5 Cleaner 7 Contacting / separating motor 8 Seal member 9 Toner receiving port 11 First intermediate transfer member 12 Second intermediate transfer member 13 Third intermediate transfer member 15 Path 16 transfer roll 17 fixing unit 18 discharge roll 19 reverse conveyance path 20 discharge tray 22 intermediate transfer member cleaner 30 toner supply device 31 storage unit 32 toner cartridge 33 toner discharge member 33a toner discharge opening 33b convex rib 33c sliding contact surface 33d slide Rail 34 Opening / closing member 34a Opening / closing member opening 34b Protruding portion 35 Toner transporter 36 Auger 36a Tip portion 37 Flexible tube 38 Bracket 40 Cover 40a Locking portion

Claims (8)

The electrostatic latent image on the image carrier is developed with toner to form a toner image, and the toner image on the image carrier is finally transferred and fixed on the recording medium to be fixed on the recording medium. In an image forming apparatus for forming an image composed of a toner image,
A container for storing toner;
A developing device having a toner receiving port for receiving toner, and developing the electrostatic latent image on the image carrier with the received toner;
A toner transporter having a hollow member that connects the storage unit and a toner receiving port of the developing unit, and transports toner in the storage unit through the hollow member and supplies the toner from the toner receiving port into the developing unit. And
The developing device is movable between a developing position in contact with or close to the image carrier by a driving source and a non-developing position separated from the image carrier,
The hollow member overlaps the toner receiving port of the developing device, has a toner discharge opening narrower than the toner receiving port, and moves with the movement of the developing device between the developing position and the non-developing position. An image forming apparatus having a sliding contact surface that is in sliding contact with a surface that forms the toner receiving port of the developing unit.   The image forming apparatus according to claim 1, wherein the storage unit is detachably mounted with a toner cartridge containing toner.   2. The hollow member includes a hollow pipe and a toner discharge member having a sliding contact surface provided at a distal end portion of the hollow pipe on the developing unit side. Image forming apparatus.   The image forming apparatus according to claim 1, wherein the developing unit includes a seal member that covers the periphery of the toner receiving port, and the sliding contact surface is in sliding contact with the seal member. .   The image forming apparatus according to claim 1, wherein the toner transporter includes an auger for transporting toner and having one end extending to the toner discharge opening in the hollow member.   The image forming apparatus according to claim 3, wherein the toner discharge member has a convex rib protruding in a direction of discharging the toner around the toner discharge opening.   6. The image forming apparatus according to claim 5, wherein the auger is formed of a coil member in which a plate-like member is spirally wound, and conveys toner by rotating in a predetermined direction. apparatus.   The image forming apparatus according to claim 3, wherein the toner discharge member includes an opening / closing member that opens and closes the toner discharge opening.

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