JP2004053917A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which eliminates developer processed as a waste agent and therefore is highly environment-friendly. <P>SOLUTION: Unnecessary developer on an intermediate transfer member 10 is reversely transferred to the surface of a photoreceptor 40-X disposed furthest upstream in the traveling direction of the intermediate transfer member, and recovered by a photoreceptor cleaning means 63-X. The developer thus recovered is conveyed to a recovery tank T via a recovered-developer moving means A, and recycled by a developing means 61-X. Alternatively, the developer is reversely transferred to the surface of a photoreceptor 40-Bk disposed furthest upstream in the traveling direction of the intermediate transfer member, and recycled by a developing means 61-Bk on a path which is the same as the above. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile.
[0002]
[Prior art]
At present, as an image forming apparatus using electrophotography, an image forming apparatus employing an intermediate transfer method using an intermediate transfer member is widely known. Advantages of the intermediate transfer method include wide compatibility with paper types and high flexibility in layout of the intermediate transfer member. In recent years, color electrophotographic apparatuses capable of forming color images, such as color copiers and color printers, have become mainstream in response to market demands.
2. Description of the Related Art A color electrophotographic apparatus includes a plurality of color developing devices around a single photoreceptor, and forms toner images on the photoreceptor by attaching toner with the developing devices, and transfers the toner image. A so-called one-drum type in which a color image is recorded on a transfer material, and a plurality of photoconductors arranged side by side, each having a developing device individually, forming a single-color toner image on each photoconductor, and forming the single-color toner image Are sequentially transferred and a composite color image is recorded on a transfer material, which is a so-called tandem type.
[0003]
By the way, in recent years, it is very important to make industrial products recyclable for environmental protection. In the field of color image forming equipment as well, the material, design, and assembly of the main body of the equipment have already reached the technical area where high-level recycling can be realized. In recent years, recycling of developer and other supplies has been attempted. Has been made. In the recycling of the developer, unnecessary residual developer is collected in the apparatus, and is used again as the developer.
From such a background, Japanese Patent Application Laid-Open No. H11-282225 proposes a recyclable color image forming apparatus that collects a developer from an image carrier of the first color, which is the most upstream.
However, the above technique has a problem that the recycling effect is reduced by half in an image forming apparatus using an intermediate transfer member. The problem is that the residual developer on the intermediate transfer body cannot be recycled.
[0004]
Generally, since the amount of the residual developer on the intermediate transfer member is larger than the amount of the residual developer on the image carrier, the need to recycle the residual developer on the intermediate transfer member is high. The reason why the amount of the residual developer is larger on the intermediate transfer member than on the image bearing member is as follows.
First, in the transfer step, from the viewpoint of transfer efficiency, it is said that the relative relationship of the friction coefficient is such that the lower the material, the higher the friction coefficient. Therefore, in an image forming apparatus using an intermediate transfer member, it is general that the relationship of image carrier <intermediate transfer member <transfer material is satisfied. At this time, when the amount of the residual developer on the image carrier after the primary transfer is compared with the amount of the residual developer on the intermediate transfer member after the secondary transfer, the amount of the remaining developer is represented by the absolute value of the friction coefficient. Since the intermediate transfer member having a higher friction coefficient is greatly affected, the residual developer amount is larger.
[0005]
In the primary transfer step from the image carrier to the intermediate transfer member, the image carrier and the intermediate transfer member are combinations unique to the machine, and are not changed by the user. Therefore, the transfer rate of the developer can be generally designed at a high level, so that the state of the residual developer can be kept low. However, in the secondary transfer process from the intermediate transfer member to a transfer material such as paper, various transfer materials are used according to the use of the user, so that the transfer rate of the developer is significantly reduced depending on the type of the transfer material. As a result, the amount of the residual developer increases. In particular, recycled paper, which is often used for environmental protection in recent years, generally has a rough surface compared to non-recycled paper due to the influence of foreign substances contained in used paper as a raw material, and has a secondary transfer property. Tend to further decrease. In other words, a contradictory phenomenon occurs in that the more the recycled paper is used for environmental protection, the more the residual developer that is treated as a waste agent increases.
Therefore, in the image forming apparatus using the intermediate transfer member, if the collection and reuse of the residual developer on the intermediate transfer member is not considered, waste is eventually generated, and the recycling effect is reduced by half. .
[0006]
Further, when the waste agent is generated as described above, it is necessary to provide a mechanism for discarding the waste agent, and for that purpose, a waste agent storage member must be provided. In general, since the size is increased in consideration of long-term use, there arises a problem that a layout margin is lost to secure an installation place, and a cost is increased. Furthermore, as a problem in terms of maintainability, it becomes necessary to periodically replace the waste agent storage member.
[0007]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an image forming apparatus which eliminates a developer to be treated as a waste agent and has extremely excellent environmental protection. It is in.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention according to claim 1 forms an electrostatic image on an image carrier, develops the electrostatic image on the image carrier by a developing unit, and obtains the electrostatic image. An image forming apparatus for transferring a developer on an image carrier to an intermediate transfer body, wherein the image carrier cleaning unit for collecting unnecessary developer on the image carrier and the image carrier cleaning unit collects unnecessary developer. In an image forming apparatus provided with a recycling mechanism that sends a developer to a developing unit and reuses it, a residual developer in which an unnecessary developer on the intermediate transfer body is reversely transferred onto the image carrier and reversely transferred onto the image carrier. The image forming apparatus is provided with a function of collecting an image by an image carrier cleaning unit and reusing the collected image by a recycling mechanism.
According to a second aspect of the present invention, an electrostatic image is formed on an image carrier, and the electrostatic image on the image carrier is developed by a plurality of developing means. An image forming apparatus for transferring an agent to an intermediate transfer member, wherein the image carrier cleaning means for collecting unnecessary developer on the image carrier, and the developer collected by the image carrier cleaning means are transferred to the developing means. In an image forming apparatus having a recycling mechanism for feeding and reusing, one of the plurality of developing units includes a recycling mechanism for collecting and reusing the residual developer on the image carrier, and the recycling mechanism is provided. The developing means provided is an image forming apparatus which is located at the most upstream position in the traveling direction of the intermediate transfer member.
According to the present invention, an electrostatic image is formed on a plurality of image carriers, and the electrostatic images on each of the image carriers are developed by developing means. An image forming apparatus for transferring the developer to an intermediate transfer member, wherein the plurality of image carriers each include an image carrier cleaning unit for collecting unnecessary developer, and an image carrier cleaning unit. An image forming apparatus having at least one of a recycling mechanism for sending the collected developer to the developing unit and reusing the collected developer, wherein an unnecessary developer on the intermediate transfer body is recycled among the plurality of image carriers. Reverse transfer onto an image carrier having an image carrier cleaning means provided with an image carrier, recovering the residual developer reversely transferred onto the image carrier by the image carrier cleaning means, and reusing the developer by a recycling mechanism. Preparative an image forming apparatus according to claim.
According to a fourth aspect of the present invention, among the plurality of image carriers, an image carrier having a cleaning unit provided with a recycling mechanism is located at the most upstream position in the traveling direction of the intermediate transfer member. An image forming apparatus according to claim 3.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of the present invention, which is an image forming apparatus of a tandem type indirect transfer system.
In the figure, reference numeral 100 denotes an image forming apparatus main body, 200 denotes a sheet feeding table on which the image forming apparatus is mounted, 300 denotes a scanner mounted on the image forming apparatus main body 100, and 400 denotes an automatic document feeder (ADF) further mounted thereon.
An endless belt-shaped intermediate transfer body 10 is provided at the center of the image forming apparatus main body 100. The intermediate transfer member 10 includes a base layer 11, an elastic layer 12, and a coat layer 13, as shown in FIG. The base layer 11 is, for example, a base layer made of a low-elongation fluororesin or a high-elongation rubber material and a non-elongation material such as a canvas. A layer 12 is provided. The surface of the elastic layer 12 is coated with, for example, a fluorine-based resin and covered with a coat layer 13 having good smoothness.
[0010]
The intermediate transfer body 10 is wound around three support rollers 14, 15, and 16 in FIG. 1 so that the intermediate transfer body 10 can be rotated and conveyed clockwise in FIG. In FIG. 1, as an example, an intermediate transfer body cleaning unit 17 is provided to the left of the second support roller 15 among the three. The intermediate transfer member cleaning device 17 removes residual toner remaining on the intermediate transfer member 10 after image transfer.
Also, among the three support rollers, black, cyan, magenta, and yellow are arranged on the intermediate transfer member 10 extending between the first support roller 14 and the second support roller 15 along the transport direction. A tandem image forming unit 20 is configured in which the four image forming units 18 are arranged side by side.
On the tandem image forming means 20, an exposing means 21 is further provided as shown in FIG.
[0011]
On the other hand, a secondary transfer unit 22 is provided on the side opposite to the tandem image forming unit 20 with the intermediate transfer body 10 therebetween. In FIG. 1, the secondary transfer unit 22 is configured, for example, by wrapping a secondary transfer belt 24, which is an endless belt, between two rollers 23, and to the third support roller 16 via the intermediate transfer body 10. The image on the intermediate transfer body 10 is transferred to a transfer material such as a sheet.
A fixing unit 25 for fixing a transfer image on a transfer material is provided beside the secondary transfer unit 22. The fixing unit 25 is configured by pressing a pressure roller 27 against a fixing belt 26, which is an endless belt, as an example in FIG.
The above-described secondary transfer unit 22 has a function of transporting the transfer material after image transfer to the fixing unit 25. Of course, a transfer roller or a non-contact charger may be provided as the secondary transfer unit 22, but in such a case, a transfer device for transferring the transfer material needs to be newly provided.
In FIG. 1, as an example, the transfer material is reversed under the secondary transfer means 22 and the fixing means 25 so as to record an image on both surfaces of the transfer material in parallel with the tandem image forming means 20 described above. Transfer material reversing means 28 is provided.
[0012]
When making a copy using the image forming apparatus 100, an original is set on the original table 30 of the automatic original transport apparatus 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed.
When a start switch (not shown) is pressed, when the original is set on the automatic document feeder 400, the original is conveyed and moved onto the contact glass 32, and then the original is set on the other contact glass 32. At this time, the scanner 300 is immediately driven to travel on the first traveling body 33 and the second traveling body 34. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface to the second traveling body 34, is reflected by the mirror of the second traveling body 34, and passes through the imaging lens 35. The original is read by a reading sensor 36 and read.
When a start switch (not shown) is pressed, one of the support rollers 14, 15, and 16 is driven to rotate by a drive motor (not shown), and the other two support rollers are driven to rotate. I do. At the same time, the photoreceptors 40 are rotated by the individual image forming means 18 to form black, yellow, magenta, and cyan monochromatic images on the respective photoreceptors 40, respectively. Then, as the intermediate transfer body 10 is transported, the monochrome images are sequentially transferred to form a composite color image on the intermediate transfer body 10.
[0013]
On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the transfer material is fed out from one of the paper feed cassettes 44 provided in the paper bank 43 in multiple stages. The sheets are separated one by one at 45 and fed into a paper feed path 46, transported by a transport roller 47, guided to a paper feed path 48 in the image forming apparatus main body 100, and stopped against a registration roller 49.
Alternatively, the transfer material on the manual feed tray 51 is fed out by rotating the paper feed roller 50, separated one by one by the separation roller 52, put into the manual feed path 53, and similarly stopped against the registration roller 49.
Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer body 10, and a transfer material is fed between the intermediate transfer body 10 and the secondary transfer unit 22, and the secondary transfer unit 22 transfers the transfer material. To record a color image on the transfer material.
The transfer material after the image transfer is conveyed by the secondary transfer unit 22 and sent to the fixing unit 25, where the fixing unit 25 applies heat and pressure to fix the transferred image, and then is switched by the switching claw 55 to be discharged. The sheet is discharged by rollers 56 and stacked on a sheet discharge tray 57. Alternatively, the sheet is switched by the switching claw 55 to enter the transfer material reversing means 28, where it is reversed and guided again to the transfer position, the image is also recorded on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56.
[0014]
On the other hand, the intermediate transfer member 10 after the image transfer is removed by the intermediate transfer member cleaning unit 17 to remove the residual toner remaining on the intermediate transfer member 10 after the image transfer, and the tandem image forming unit 20 prepares for another image formation.
Here, the registration roller 49 is generally often used while grounded, but it is also possible to apply a bias for removing paper dust from the sheet.
In the tandem image forming means 20 described above, the individual image forming means 18 are, for example, as shown in FIG. 3, a charging means 60 and a developing means around a drum-shaped photoreceptor 40 as an image carrier. And means 61, primary transfer means 62, photoreceptor cleaning means 63, charge removing means 64, and the like.
[0015]
Next, the developer recycling operation, which is the main feature of the present invention, will be described.
FIG. 4 is a schematic configuration diagram of a tandem image forming apparatus according to the present invention. In the center of the drawing, there is an intermediate transfer member 10, and a drum-shaped photosensitive member 40 is provided on the intermediate transfer member 10 from the upstream side in the rotation direction of the intermediate transfer member 10, from a photoconductor 40 -X dedicated to a recovery agent, for black. The photosensitive member 40-Bk, the photosensitive member 40-C for cyan, the photosensitive member 40-M for magenta, and the photosensitive member 40-Y for yellow are arranged in this order.
A primary transfer unit 62 for forming an electric field for transfer is disposed inside the intermediate transfer body 10 at a position facing each photoconductor 40. Around the respective photoconductors 40, a developing unit 61 and a photoconductor cleaning unit 63 are arranged.
[0016]
Further, the intermediate transfer body 10 is provided with an intermediate transfer body cleaning unit 17. The intermediate transfer member cleaning means 17 is basically kept separated from the intermediate transfer member 10 in order to reuse the residual toner. The intermediate transfer member cleaning unit 17 is brought into contact with the intermediate transfer member 10 at a predetermined timing, and is used to remove deposits other than the developer on the intermediate transfer member 10. The deposits other than the developer include paper powder and dust of the transfer material. Of course, it is possible to clean the developer, but since the intermediate transfer member cleaning means 17 does not have a mechanism for reusing the developer, the developer cannot be recycled in that case.
Whether or not to recycle can be selected by software such as the printer driver of the device, or by input device on the operation panel, etc. Selected.
[0017]
When an unnecessary developer is generated on the intermediate transfer body 10 in such an image forming apparatus, the unnecessary developer is carried to the most upstream recovery agent-dedicated photoconductor 40-X and reversely transferred. Of course, at this time, the normal image forming operation can be continued with the photoconductors 40-X and below. The developer reversely transferred to the photoconductor 40-X is collected by the photoconductor cleaning unit 63-X, and is conveyed to the collection tank T where the collected developer is temporarily stored by the collection developer moving unit A. The developer collected in the collection tank T is reused by the developing means 61-X dedicated to the collection agent. Since the developing unit 61-X forms an image with a turbid color developer in which a plurality of developers are mixed, the developing unit 61-X is suitable for printing a character document that does not need to worry about colors and for test printing. It is mainly consumed for these uses.
[0018]
The collection of the photoreceptor 40-X is performed by charging the surface of the photoreceptor 40-X by a charging unit (not shown), and performing reverse transfer electrostatically by the charging electric field. There is also a method in which an electric field having the same polarity as that of the unnecessary developer is applied to the primary transfer means 62-X to perform reverse transfer by electrostatic repulsion.
Further, needless to say, unnecessary developer on the photoconductor 40 generated at the time of transfer from each photoconductor 40 to the intermediate transfer body 10 is also collected by each photoconductor cleaning unit 63, and is collected into the collection tank T by the collection developer moving unit A. Since they are transported and reused, all of the unnecessary developer on the photoreceptor 40 and the unnecessary developer on the intermediate transfer body 10 can be recycled.
[0019]
Next, an example different from FIG. 4 is shown in FIG. FIG. 5 is a schematic configuration diagram of a general tandem-type image forming apparatus that does not have an image forming unit dedicated to a recovery agent.
In the center of the drawing, there is an intermediate transfer member 10. In the intermediate transfer member 10, a photoreceptor 40 is provided from the upstream side in the rotation direction of the intermediate transfer member 10, from a black photoreceptor 40 -Bk and a cyan photoreceptor 40- C, magenta photoconductor 40-M, and yellow photoconductor 40-Y are arranged in this order. In addition, a charging charger 70 is provided on the intermediate transfer member 10 at a position upstream of the photoconductor 40-Bk. The charging charger 70 is used to charge the unnecessary developer on the intermediate transfer member 10.
Further, inside the intermediate transfer body 10, a primary transfer unit 62 that forms an electric field for transfer is disposed at a position facing each of the photoconductors 40. Around the respective photoconductors 40, a developing unit 61 and a photoconductor cleaning unit 63 are arranged.
As in the example of FIG. 4, an intermediate transfer member cleaning unit 17 is provided around the intermediate transfer member 10, but is not used for an unnecessary developer cleaning operation.
[0020]
When an unnecessary developer is generated on the intermediate transfer body 10 in such an image forming apparatus, the unnecessary developer is transported to the most upstream photoreceptor 40-Bk dedicated to the recovery agent and is reversely transferred. Of course, at this time, it is possible to simultaneously form an image using the photoconductor 40-Bk and the photoconductor 40 for another color. In FIG. 5, a charging charger 70 is provided as an auxiliary mechanism for collecting the unnecessary developer at the same time as the transfer, and the unnecessary developer on the intermediate transfer body 10 is separated from the photosensitive body 40-Bk by the charging charger 70. Since the toner is charged to the opposite polarity (the polarity opposite to the developer on the photoconductor 40-Bk), the collection can be performed simultaneously with the transfer. The developer reversely transferred to the photoconductor 40-Bk is collected by the photoconductor cleaning unit 63-Bk, and is conveyed by the collection developer moving unit A to the collection tank T where the collected developer is temporarily stored. The developer collected in the collection tank T is mixed little by little with the developing unit 61-Bk, which is inconspicuous even when mixed, and is reused.
[0021]
Next, examples in which a single photoconductor is used are shown in FIGS.
FIG. 6 shows a type having a developing means 61-X dedicated to a recovery agent. The specific operation according to the present invention is different from that of FIG. 4 only in that the photoconductor 40 and the photoconductor cleaning means 63 are singular. The operation is the same as that described for the tandem type.
That is, the unnecessary developer on the photoreceptor 40 is collected by the photoreceptor cleaning unit 63 or the developing unit 61-X, transported to the collection tank T by the collected developer moving unit A, and then transferred to the text document by the developing unit 61-X. It is developed and consumed for printing and test printing.
Similarly, FIG. 7 shows a type having no developing means dedicated to the recovery agent, and the specific operation according to the present invention is the same as the operation described for the tandem type in FIG.
That is, the unnecessary developer on the photoconductor 40 is collected by the photoconductor cleaning unit 63 or the developing unit 61-Bk, and is conveyed to the collection tank T by the collection developer moving unit A. -Mix small amounts with Bk and reuse.
[0022]
As described above, by applying the present invention, it is possible to provide an image forming apparatus having extremely high recyclability and excellent environmental protection.
Note that the present invention is not limited to the above embodiment, but is applicable to all devices utilizing the technical idea of the present invention. The photoreceptor, the intermediate transfer member, and the secondary transfer unit may have any of a belt shape, a drum shape, and a roller shape. Also, the number of photoconductors and intermediate transfer members is not limited to the above embodiment.
[0023]
【The invention's effect】
As described above, according to the present invention, the unnecessary developer on the intermediate transfer member is reverse-transferred onto the image carrier, and the residual developer which has been reverse-transferred onto the image carrier is collected by the cleaning unit, and the recycling mechanism is used. By providing a function of reusing the developer, it is possible to provide an image forming apparatus which is excellent in environmental protection and can reuse a developer which has been conventionally treated as a waste agent.
[Brief description of the drawings]
FIG. 1 is a schematic view of an image forming apparatus main body according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a layer configuration of an intermediate transfer member.
FIG. 3 is a schematic diagram illustrating an example of a tandem-type image forming unit.
FIG. 4 is a schematic view of a tandem type image forming apparatus showing an example of the present invention.
FIG. 5 is a schematic view of a tandem type image forming apparatus showing an example of the present invention.
FIG. 6 is a schematic diagram of a one-drum type image forming apparatus showing an example of the present invention.
FIG. 7 is a schematic view of a one-drum type image forming apparatus showing an example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Intermediate transfer body 11 Base layer 12 Elastic layer 13 Coat layers 14, 15, 16 Support roller 17 Intermediate transfer body cleaning means 18 Image forming means 20 Tandem image forming means 21 Exposure means 22 Secondary transfer means 25 Fixing means 28 Transfer material reversal Means 40 Photoconductor 42 Feed roller 49 Registration roller 50 Feed roller 60 Charging means 61 Developing means 62 Primary transfer means 63 Photoconductor cleaning means 64 Static elimination means 70 Charging charger 100 Image forming apparatus main body 200 Feeding table 300 Scanner 400 Original Automatic conveyance device A Collection developer moving means T Collection tank

Claims (4)

An image forming apparatus that forms an electrostatic image on an image carrier, develops the electrostatic image on the image carrier by a developing unit, and transfers the developer on the image carrier to an intermediate transfer member. Image forming apparatus having an image carrier cleaning means for collecting unnecessary developer on the image carrier, and an image forming apparatus having a recycling mechanism for sending the developer collected by the image carrier cleaning means to the developing means for reuse. In the device,
A function to reversely transfer unnecessary developer on the intermediate transfer member onto the image carrier, recover the residual developer reversely transferred onto the image carrier by the image carrier cleaning means, and reuse the developer by a recycling mechanism. An image forming apparatus comprising: Image formation in which an electrostatic image is formed on an image carrier, the electrostatic image on the image carrier is developed by a plurality of developing means, and a developer on the image carrier obtained in this manner is transferred to an intermediate transfer body. An apparatus, comprising: an image carrier cleaning unit for collecting unnecessary developer on the image carrier; and a recycling mechanism for sending the developer collected by the image carrier cleaning unit to the developing unit for reuse. In the image forming apparatus,
One of the plurality of developing units includes a recycling mechanism that collects and reuses the residual developer on the image carrier, and the developing unit that includes the recycling mechanism is the most upstream in the traveling direction of the intermediate transfer member. An image forming apparatus characterized in that: An electrostatic image is formed on a plurality of image carriers, the electrostatic images on each image carrier are developed by a developing unit, and the developer on the image carrier obtained in this way is transferred to an intermediate transfer member. An image forming apparatus, comprising: an image carrier cleaning unit for collecting unnecessary developer on each of the plurality of image carriers; and a developer collected on at least one of the image carrier cleaning units. And a recycling mechanism for sending the toner to the developing means for reuse,
Unnecessary developer on the intermediate transfer member is reverse-transferred onto an image carrier having an image carrier cleaning means provided with a recycling mechanism among the plurality of image carriers, and the residual development is reverse-transferred onto the image carrier. An image forming apparatus having a function of collecting an agent by an image carrier cleaning unit and reusing the agent by a recycling mechanism. 4. The image forming apparatus according to claim 3, wherein, among the plurality of image carriers, an image carrier having a cleaning unit having a recycle mechanism is located at the most upstream side in the traveling direction of the intermediate transfer body.

Images