JP2004212568A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus in which an exchange operation is easily carrying out by integrating a third image carrier 100, a cleaning device 250 and a waste toner tank 250B. <P>SOLUTION: In the image forming apparatus, a transfer means 120 is provided in which a plurality of units of first image carriers 1 are lined up along a second image carrier 10. While forming a visual image on the surfaces of each image carrier 1 with toner of colors which are different from each other, these visual images are transferred to be superposed on the second image carrier 10. The visual images which are superposed on the second image carrier 10 is transferred once to a third image carrier 100. After that, the visual images carried on the second image carrier 10 and the visual images carried on the third image carrier 100 are transferred to both sides of the recording medium P. The third image carrier 100, the cleaning device 250 and the waste toner tank 250B are integrated. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus that supplies a double-sided transfer image to a recording medium in an electrophotographic apparatus such as a copying machine, a printer, and a facsimile machine.
[0002]
[Prior art]
An electrophotographic image forming apparatus that performs double-sided printing without using a double-sided reversing device or the like is already known (for example, see Patent Document 1).
[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-352889
[Problems to be solved by the invention]
2. Description of the Related Art In recent electrophotographic apparatuses such as copying machines and printers, double-sided transfer images on a recording medium have already become common. In such a device, as a method of transferring to a recording medium, a process of transferring and fixing the first surface to the recording medium, and then performing transfer and fixing to the second surface of the recording medium using a two-sided reversing device or the like is performed. I have.
However, in both-side printing on a recording medium by the above method, a two-side reversing device or the like is indispensable. One of the transfer paper feeding devices is changed to a two-sided device, and the number of feeding devices is reduced. This causes problems such as an increase in machine size.
Patent Document 1 discloses a technique of performing double-sided printing without using a double-sided inversion device or the like in order to achieve the above object. In this disclosure, an image forming apparatus is used for a first side of a recording medium, and It has each for the second surface.
However, in this conventional example, the machine size has increased in recent years when space saving is required, and the image forming apparatus has to be arranged on each side of the recording medium. Disadvantageous. Therefore, in recent years, a technology that enables double-sided printing without having a double-sided device has been developed.
Therefore, in order to solve the above problems, an object of the present invention is to integrate the third image carrier, the cleaning device, and the waste toner tank, thereby eliminating the necessity of performing the replacement work of each device. Therefore, it is an object of the present invention to provide an image forming apparatus capable of easily performing the replacement work, since the replacement of the generalized apparatus is performed.
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, in the invention according to claim 1, a first image carrier for forming and carrying a visible image and a second image carrier for carrying a visible image formed by the first image carrier are provided. Image carrier, a third image carrier, and a transport unit for transporting a recording medium between the second and third image carriers, wherein the first image carrier is mounted on the second image carrier. While arranging a plurality of images along the body, and forming visible images on the surface of each image carrier with toners of different colors, the visualized images are transferred so as to overlap the second image carrier, and The visible image superimposed on the second image carrier is transferred to the third image carrier at one time, and then the visible image carried on the second image carrier and the third image carrier are transferred. An image forming apparatus including transfer means for transferring a visual image carried on a body to both surfaces of the recording medium, 3 image bearing member and a cleaning device and a waste toner tank and most important features of an image forming apparatus having a configuration in which integrated.
According to a second aspect of the present invention, there is provided an image forming apparatus according to the first aspect, wherein the cleaning device is located above the third image carrier.
According to a third aspect of the present invention, the image forming apparatus according to the first aspect is characterized in that the waste toner tank has a detecting unit for detecting that the waste toner is full.
According to a fourth aspect of the present invention, the image forming apparatus according to the third aspect is characterized in that the waste toner full detecting means faces downward of the waste toner tank.
According to a fifth aspect of the present invention, a main feature of the image forming apparatus according to the third aspect is that a threshold member is provided above the waste toner full detecting means.
According to a sixth aspect of the present invention, the waste toner tank has a sub-tank, and the waste toner full detecting means can be arranged upward below the sub-tank.
According to a seventh aspect of the present invention, the image forming apparatus according to the third aspect is characterized in that the waste toner full detecting means and the connection terminal on the machine main body side are connected by a spring-shaped terminal.
According to an eighth aspect of the present invention, the image forming apparatus according to the third aspect is characterized in that the waste toner full detecting means and the connection terminal on the machine main body side are connected by a drawer connector.
According to a ninth aspect of the present invention, the image forming apparatus according to the first aspect is characterized in that the waste toner tank is formed of a transparent member, and the waste toner full detecting means is provided on the machine body side.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic center sectional view of an image forming apparatus capable of forming an image on both sides of a recording medium at substantially the same time according to the present invention. In FIG. 1, a charge removing device L, a cleaning device 2, a charging device 3, and a developing device 5 are provided on the outer peripheral portion of a first image carrier (photosensitive drum) 1 which is rotatably supported and rotates in the direction of an arrow. Have been.
A space is provided between the charging device 3 and the developing device 5 for receiving optical information emitted from the exposure device 4. Although there are four first image carriers (photoconductors) 1 (a, b, c, d), the configuration of the image forming parts provided around each is the same. Only the color of the color material (toner) handled by the developing device 5 is different.
The first image carrier (photoconductor) 1 is a photoconductor in which an organic semiconductor layer as a photoconductive substance is provided on the surface of an aluminum cylinder having a diameter of about 30 to 100 mm. A part thereof is in contact with the second image carrier (intermediate transfer belt) 10. A belt-shaped photoconductor can also be employed.
The second image carrier (intermediate transfer belt) 10 is supported and stretched between rotating rollers 11, 12, and 13 so as to be movable in the direction of the arrow. Is disposed in the vicinity of each first image carrier 1 (a, b, c, d). Outside the belt loop, a second image carrier cleaning device 25 is arranged. The second image carrier cleaning device 25 wipes off unnecessary toner remaining on the surface after the transfer from the second image carrier 10.
The exposure device 4 irradiates optical information corresponding to full-color image formation on the surface of the uniformly charged image carrier 1 as a latent image by a known laser method. An exposure apparatus comprising an LED array and an image forming means can also be employed.
The second image carrier (intermediate transfer belt) 10 is a belt based on a resin film or rubber having a substrate thickness of 50 μm to 600 μm, and has a resistance value at which toner can be transferred from the first image carrier 1. Have.
[0006]
A belt-shaped third image carrier 100 is disposed on the right side of FIG. The third image carrier 100 is supported and stretched between the rotation rollers 111, 112, and 113 so as to be movable in the direction of the arrow, and a second transfer unit 120 is disposed on the back side (inside the loop). ing.
The third image carrier (intermediate transfer member) 100 is a belt made of a resin film or rubber having a substrate thickness of 50 μm to 600 μm, and has a resistance value at which toner can be transferred from the second image carrier 10. It is a belt equipped.
Outside the belt loop, a third image carrier cleaning device 250, a charger CH and the like are arranged. After transferring the toner to the recording medium (paper), the cleaning device 250 wipes off the remaining unnecessary toner.
The second image carrier 10 and the third image carrier 100 are brought into contact with each other by the transfer means 120, the roller 113, and the roller 11 supporting the second image carrier 10, thereby forming a predetermined transfer nip. . Sheets P as recording media are stored in sheet feeding devices (sheet feeding cassettes) 26-1 and 26-2 below the drawing, and the uppermost sheet is fed by sheet feeding rollers 27 one by one to a plurality of guides 29. And is conveyed to a pair of registration rollers 28.
A fixing heating unit 30, a paper discharge guide pair 31, a paper discharge roller pair 32, and a paper discharge stack unit 40 are provided above the drawing. Above the second image carrier 10 and below the paper discharge unit 40, a storage unit TS that can store toner for replenishment is provided.
The toner has four colors of magenta, cyan, yellow, and black, and is in the form of a cartridge TC. The developing device 5 of the corresponding color is appropriately supplied by a powder pump or the like.
Since a part of the frame 50 of the main body is configured to be rotatable and openable about the opening / closing support shaft 50A, the conveyance path of the recording medium is greatly opened, and the processing of the paper P as the jammed recording medium is performed. Easy going.
[0007]
Next, a case where images are obtained on both sides of a sheet P as a recording medium by the above-described image forming apparatus will be described. First, an image is formed by the first image carrier (photoconductor) 1. By the operation of the exposure device 4, light from an LD light source (not shown) passes through optical components (not shown), and among the first image carrier (photoconductor) 1 uniformly charged by the charging device 3. , A and forms a latent image corresponding to the written information (information corresponding to the color).
The latent image on the first image carrier 1 is developed by the developing device 5, and a visible image by toner is formed and held on the surface of the first image carrier 1. This toner image is transferred by the first transfer means 20 onto the surface of the second image carrier 10 which moves in synchronization with the first image carrier 1.
The remaining toner on the surface of the first image carrier 1 is cleaned by the cleaning device 2 and the charge is removed by the charge removing device L to prepare for the next image forming cycle. The second image carrier 10 carries the toner image transferred to the surface, and moves in the direction of the arrow.
A latent image corresponding to another color is written on the first image carrier (photoconductor) 1 indicated by b, and is developed with a toner of the corresponding color to become a visible image. This image is superimposed on the visible image of the color before it is already on the second image carrier 10, and the third and fourth image carriers c and d are subjected to the same steps, so that the final image is obtained. Four colors are superimposed.
At this time, the third image carrier 100 is moving in the direction of the arrow in synchronization with the surface of the third image carrier 100 and the surface of the second image carrier 10 by the action of the second transfer means 120. The created image is transferred.
While an image is formed on the four first image carriers 1 in a so-called tandem format, the second and third image carriers 10 and 100 move and image formation is advanced, so that the time is shortened. it can.
When the second image carrier 10 moves to a predetermined position, a toner image to be created on another surface of the sheet P as a recording medium is formed again by the first image carrier 1 in the above-described process. The image is formed, and paper feeding is started.
When the paper feed roller 27 rotates in the counterclockwise direction, the paper P, which is the recording medium at the uppermost position in the paper feed devices (paper feed cassettes) 26-1 and 26-2, is pulled out and conveyed to the registration roller pair 28. You.
A toner image on the surface of the second image carrier 10 is provided on one surface of a sheet P, which is a recording medium, sent between the second image carrier 10 and the third image carrier 100 via the registration roller pair 28. Is transferred by the second transfer unit 120.
Further, the sheet P as a recording medium is transported upward, and the toner image on the surface of the third image carrier 100 is transferred to the other surface of the recording medium P by the charger CH. At the time of transfer, the sheet P, which is a recording medium, is conveyed in a timely manner so that the position of the image is normal.
[0008]
In the present embodiment, the polarity of the toner formed on the first image carrier 1 is negative. By applying a positive charge to the first transfer unit 20, the toner formed on the first image carrier 1 is transferred to the second image carrier 10.
By applying a positive charge to the second transfer unit 120, the toner formed on the second image carrier 10 is transferred to the third image carrier 100. Further, the toner on the surface of the second image carrier 10 is also transferred to one surface of the recording medium P.
By applying a positive polarity charge from the charger CH, the negative polarity toner on the surface of the third image carrier 100 is sucked and transferred to the other surface of the sheet P as a recording medium.
The paper P, which is the recording medium on which the toner images have been transferred on both sides in the above steps, is sent to the fixing means 30, and the toner images (both sides) on the paper P, which is the recording medium, are fused and fixed at a time, and the guide pair The sheet is discharged to a sheet discharge stack section 40 at the upper portion of the main body frame by a sheet discharge roller pair 32 after passing through 31.
When the paper discharge unit 40 is configured as shown in FIG. 1, the surface (page) of the two-sided image which is later transferred to the paper P as a recording medium, that is, the paper from the second image carrier 10 to the paper as a recording medium Since the surface directly transferred to P is the lower surface and is placed on the paper discharge stack unit 40, to align the pages, an image of the second page is created first, and the third image carrier is formed. The toner image may be held at 100, and the image of the first page may be directly transferred from the second image carrier 10 to a sheet P as a recording medium.
The image transferred from the second image carrier 10 to the sheet P as a recording medium is made a normal image on the surface of the first image carrier 1 and transferred from the third image carrier 100 to the sheet P as a recording medium. The resulting toner image is exposed to a reverse image (mirror image) on the surface of the first image carrier (photoconductor) 1.
The image forming order for such page alignment is realized by a known technique of storing image data in a memory, and the exposure for switching between a normal image and a reverse image (mirror image) is realized by a known image processing technique.
After the transfer from the third image carrier 100 to the paper P as a recording medium, the cleaning device 250 including a known brush roller, a collection roller, a blade, and the like inside remains on the surface of the third image carrier. Remove unnecessary toner and paper dust.
In FIG. 1, the brush roller 250 is in a state separated from the surface of the third image carrier 100. It has a structure that can swing around the fulcrum 250A and can come and go on and off the surface of the third image carrier 100. Before the image is transferred onto the sheet P as a recording medium, the third image carrier 100 is released when the toner image is carried thereon, and when cleaning is necessary, the third image carrier 100 is swung counterclockwise in FIG. The removed unnecessary toner is collected in the toner storage section 250B.
[0009]
Next, a case where an image is obtained on one side of a sheet P as a recording medium by the image forming apparatus according to the present invention will be described. In the case of single-sided printing, there are two methods. Here, a case where the process of transferring the toner to the third image carrier 100 is omitted and the image is transferred from the second image carrier 10 to the recording medium P will be described.
The toner image formed on the surface of the first image carrier 1 is transferred onto a sheet P as a recording medium while being transferred onto the second image carrier 10. In FIG. 1, a sheet P as a recording medium is synchronized with a toner image formed on a second image carrier 10 by a second image carrier 10 and a third image carrier. 100, and the toner is transferred from the second image carrier 10 to the sheet P as a recording medium by the second transfer unit 120.
The charger CH serving as the transfer unit does not operate, and the sheet P serving as the recording medium moves together with the third image carrier 100, is sent to a certain area of the fixing unit 30, and the toner is fixed. Thereafter, the sheet P as a recording medium is separated from the third image carrier 100, discharged through the guide pair 31 and the discharge roller pair 32 in the direction of arrow A, and with the image surface down (face down). The sheet is placed on the discharge stack unit 40.
With such a configuration, even when originals of several pages are processed in order from one page, when the document is taken out from the paper discharge stack unit 40, the printed matter is in page order.
In the above-described image forming apparatus, the description has been made regarding the formation of a color image using toners of a plurality of colors.
[0010]
FIG. 2 is a schematic center sectional view showing an example showing the first embodiment of the image forming apparatus according to the present invention. 2, except that the third carrier 100, the cleaning device 250, and the waste toner tank 250B are integrally formed, and that the device has a fullness detection device for the reflection type optical sensor 300. Almost the same configuration.
Since the third carrier 100, the cleaning device 250, and the waste toner tank 250B are integrally formed, the replacement operation of the user is performed by an integrated device (the third image carrier 100, the cleaning device 250, the waste Since only the replacement of the toner tank 250B) is sufficient, the replacement operation is easy.
By disposing the cleaning device 250 above the third image carrier 100, the accumulated capacity of the waste toner tank 250B is increased and the replacement interval is lengthened. That is, the load of the replacement work of the user is reduced, and the replacement cost can be reduced.
A fullness detecting device of the reflection type optical sensor 300 is provided in the waste toner tank 250B, and when the toner is accumulated in the waste toner tank 250B, when the toner is accumulated to the position of the reflection type optical sensor 300, the reflection type optical sensor is used. The sensor 300 detects that the user is full of waste toner and that it is time to replace the integrated device (third image carrier 100, cleaning device 250, waste toner tank 250B). Inform.
FIG. 3 is a schematic center sectional view showing a second embodiment of the image forming apparatus according to the present invention. 3, the configuration is almost the same as that of FIG. 1 except that the reflection type optical sensor 300 provided in the waste toner tank 250B is directed downward.
In the second embodiment, the reflection type optical sensor 300 is provided in the waste toner tank 250B in the downward direction, so that the toner that falls freely from the cleaning device 250 is not bathed. That is, since toner does not adhere to the reflective optical sensor 300, erroneous detection can be prevented.
[0011]
FIG. 4 is a schematic center sectional view showing an image forming apparatus according to a third embodiment of the present invention. In FIG. 4, the configuration is almost the same as that of FIG. 1 except that the waste toner tank 250B has a sill member 310 above the reflection type optical sensor 300.
In the third embodiment, since the waste toner tank 250B has the sill member 310 above the reflection type optical sensor 300, the waste toner tank 250B does not receive the toner freely falling from the cleaning device 250. That is, since toner does not adhere to the reflective optical sensor 300, erroneous detection can be prevented.
FIG. 5 is a schematic center sectional view showing a fourth embodiment of the image forming apparatus according to the present invention. 5, the configuration is the same as that of FIG. 1 except that a sub tank 320 is provided in the waste toner tank 250B.
In the fourth embodiment, in the full detection system having the reflection type optical sensor 300, the arrangement in which the reflection type optical sensor 300 is directed upward is exposed to the toner freely falling from the cleaning device 250. However, the detection is made before the waste toner tank 250B becomes full, which is an erroneous detection.
However, if the reflection type optical sensor 300 has to be directed upward due to the arrangement with other components, a sub-tank 320 is provided in the waste toner tank 250B, and the toner inlet of the sub-tank 320 is located above the waste toner tank 250B. , And the toner flows into the sub-tank 320 only when the waste toner tank 250B is full. This prevents toner from adhering to the reflective optical sensor 300, thereby preventing erroneous detection before being full.
[0012]
FIG. 6 is a schematic center sectional view showing a fifth embodiment of the image forming apparatus according to the present invention. In FIG. 6, the structure is almost the same as that of FIG. 1 except that a conductive leaf spring 330 has an electrical contact with the main body under the waste toner tank.
In the fifth embodiment, since the reflection type optical sensor 300 installed in the waste toner tank 250B needs to be supplied with power from the machine main body, a conductive leaf spring 330 is provided below the waste toner tank 250B to form a main body side. With electrical contacts. This makes it possible to make electrical contact only by attaching and detaching the integrated device (third image carrier 100, cleaning device 250, waste toner tank 250B). That is, when a fitting-type connector is used, a cumbersome operation such as attaching and detaching a connector has to be performed. However, since only attaching and detaching an apparatus is performed, workability is improved. Further, similar workability can be obtained by using a drawer connector instead of using the conductive leaf spring 300.
FIG. 7 is a schematic center sectional view showing a sixth embodiment of the image forming apparatus according to the present invention. 7 has almost the same configuration as that of FIG. 1 except that the waste toner tank 250B is formed of a transparent resin member or the like.
In the sixth embodiment, the waste toner tank 250B is formed of a transparent resin member or the like, and the reflection type optical sensor 300 is provided on the machine body side. This eliminates the need for the reflective optical sensor 300 to be replaced, thereby reducing replacement costs. Further, the electric contacts shown in FIG. 6 are unnecessary, and the cost is reduced.
In addition, since the reflection type optical sensor 300 is separate from the waste toner tank 250B, toner does not adhere and erroneous detection can be prevented.
[0013]
【The invention's effect】
As described above, according to the first aspect, since each device is integrated, the replacement work can be easily performed.
According to the second aspect, since the capacity of the waste toner tank can be increased, the life of the replacement cycle can be extended.
According to the third aspect of the present invention, since the waste toner tank has the fullness detecting means, it is possible to prevent the overflow of the toner from the waste toner tank and to inform the user of the replacement time of the apparatus. .
According to the fourth, fifth, and sixth aspects, since the toner is prevented from adhering to the full state detecting means, erroneous detection of the full state detecting means can be prevented.
According to the seventh and eighth aspects, since the electrical contact of the full state detecting means is a contact type, the replacement operation of the apparatus can be easily performed.
According to the ninth aspect, it is possible to prevent erroneous detection of the fullness detecting means by preventing toner from adhering to the fullness detecting means, and since the fullness detecting means is installed on the machine main body side, it is possible to prevent electrical contact. It is possible to reduce the cost because it is not necessary, and it is possible to reduce the replacement cost of the full detection means.
[Brief description of the drawings]
FIG. 1 is a schematic center sectional view of an image forming apparatus capable of forming an image on both sides of a recording medium including the present invention substantially simultaneously.
FIG. 2 is a schematic center sectional view showing an example showing the first embodiment of the image forming apparatus according to the present invention.
FIG. 3 is a schematic center sectional view showing a second embodiment of the image forming apparatus according to the present invention.
FIG. 4 is a schematic center sectional view showing a third embodiment of the image forming apparatus according to the present invention.
FIG. 5 is a schematic center sectional view showing a fourth embodiment of the image forming apparatus according to the present invention.
FIG. 6 is a schematic center sectional view showing a fifth embodiment of the image forming apparatus according to the present invention.
FIG. 7 is a schematic center sectional view showing an image forming apparatus according to a sixth embodiment of the present invention.
[Explanation of symbols]
P Recording medium (paper)
1. First image carrier (photoconductor)
2 First image carrier (photoconductor) cleaning device 10 Second image carrier (intermediate transfer belt)
20 First transfer unit 25 Cleaning device (for second image carrier)
28 registration roller pair (transportation means)
29 Guide (transportation means)
100 Third image carrier (intermediate transfer belt)
120 Second transfer unit 250 Cleaning device (for third image carrier)
250B Waste toner tank 300 Reflective optical sensor (Waste toner full detection means)
310 Sill member 320 Sub tank 330 Leaf spring

Claims (9)

A first image carrier for forming and carrying a visible image, a second image carrier for carrying a visible image formed by the first image carrier, a third image carrier, and the second image carrier. A conveying means for conveying a recording medium between the three image carriers, a plurality of the first image carriers are arranged along the second image carrier, and each image carrier is provided with a toner of a different color. While forming visible images on the surface of the carrier, those visual images are transferred so as to be superimposed on the second image carrier, and the visual images superimposed on the second image carrier are transferred to the third image carrier. And then transfer the visible image carried on the second image carrier and the visible image carried on the third image carrier on both surfaces of the recording medium, respectively. An image forming apparatus provided with a transfer unit for transferring the toner image onto the third image carrier, a cleaning device, and a waste toner tank. Image forming apparatus characterized by a unit was. The image forming apparatus according to claim 1, wherein the cleaning device is located above the third image carrier. 2. The image forming apparatus according to claim 1, wherein the waste toner tank has a detection unit that detects that the waste toner is full. The image forming apparatus according to claim 3, wherein a detection surface of the waste toner full detection unit is disposed downward in the waste toner tank. 4. The image forming apparatus according to claim 3, wherein a sill member is provided above the waste toner full detecting unit. 4. The image forming apparatus according to claim 3, wherein the waste toner tank has a sub-tank that communicates with the waste toner tank, and the full-toner for waste toner detecting means can be arranged upward below the sub-tank. 4. The image forming apparatus according to claim 3, wherein the waste toner full detection unit is connected to a connection terminal on the machine body side by a spring-shaped terminal. 4. The image forming apparatus according to claim 3, wherein the waste toner full detection unit is connected to a connection terminal on a machine body side by a drawer connector. 2. The image forming apparatus according to claim 1, wherein the waste toner tank is formed of a transparent member, and the waste toner full detecting unit is provided on a machine main body side.

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