JPH11202728A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make recoverable toner in a recovery container without leaking or scattering the recovered toner by arranging a means for recovering residual toner particles which have not been transferred by a transfer medium and the recovery container in an integrated unit. SOLUTION: The toner and carrier which have not been transferred to a record medium (p) remain on a photoreceptive layer passing through a transfer position. The residual toner is peeled from the surface of the photoreceptive layer by a cleaning roller 31 and dispersed in the residual carrier. After the residual toner and the residual carrier are dammed by a cleaning blade 32, they flow in a specified direction, flow into a waste liquid guide 33 and are recovered in a waste liquid tank 34. Since the tank 34 is arranged in a processing unit 2 together with a cleaning means 30, a waste liquid route from the cleaning means 30 to the tank 34 is connected when the unit 2 is taken in/out, whereby the waste liquid does not spill.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for recovering toner particles remaining on an image carrier after transferring toner particles developed on the image carrier to a transfer medium.

[0002]

2. Description of the Related Art An image forming apparatus using an electrophotographic method or the like
An electrostatic latent image is formed by irradiating light on the surface of an image carrier such as a photosensitive drum or a photosensitive belt according to print information, and the electrostatic latent image is developed using toner particles. After the toner image obtained by developing the electrostatic latent image is transferred to a transfer medium such as paper, film, or an intermediate transfer member, the toner remaining on the image carrier is collected by a blade, a brush, or the like. The collected toner is collected in a collection container such as a bottle, and when the bottle is full, this is detected and a sign indicating that the bottle is full is displayed. With this sign, the user replaces the full bottle with a new empty bottle. As a method of detecting the full state, a method of detecting the weight of the collection container, a method of detecting the upper surface of the collection toner in the collection container by a light emitting and receiving method, and the like are known.

[0003]

In an image forming apparatus for recovering residual toner as described above, the recovery portion is generally formed as a detachable unit to facilitate replacement of components such as blades and brushes. Further, since the collection container is provided in the main body of the image forming apparatus, a joint is required in a path for conveying the collected toner to the collection container. Due to toner leakage at the joint, the inside of the apparatus is soiled, scattered outside the apparatus to deteriorate the environment, and expensive parts are required to improve the sealing performance. In particular, in the case of liquid toner, since the collected toner is liquid, a particularly strict seal is required.
In the case of leakage, not only the inside of the apparatus but also a recording medium such as a paper mounted below the apparatus and a floor on which the apparatus is installed may be soiled.

[0004] Further, there is an error in detecting the weight of the container due to vibrations or the like, and a malfunction of the light emitting and receiving system sensor due to contamination of the collection container. Even when the bottle overflowed, the full sign was not displayed.

[0005]

According to the present invention, there is provided an image carrier, means for forming a latent image on the image carrier, and developing the latent image with toner particles to form a toner image. A developing unit for forming, a transfer unit for transferring the toner image from the image carrier to a transfer medium, a unit for collecting residual toner particles remaining on the image carrier without being transferred to the transfer medium, and a collecting container. An image forming apparatus comprising:

According to a preferred aspect of the present invention, there is provided an image forming apparatus in which the unit also integrally holds the image carrier.

Further, according to a preferred aspect of the present invention, there is provided an image forming apparatus in which the collection container is disposed in front of the image forming apparatus.

Further, according to a preferred aspect of the present invention, there is provided an image forming apparatus in which at least a part of the collecting container is formed of a transparent member so that the amount of collected toner particles can be visually checked. Is done.

According to a preferred aspect of the present invention, there is provided an image forming apparatus in which the image forming method is a wet electrophotographic system.

According to a preferred aspect of the present invention, there is provided an image forming apparatus wherein the developing means is capable of developing a plurality of color toners.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A full-color wet electrophotographic printer (image forming apparatus) according to an embodiment of the present invention will be described below with reference to FIG. The electrophotographic printer 1 develops, for each color, a toner image created by image data separated into four colors of cyan, magenta, yellow, and black, on a recording medium p held on a transfer drum 5. After the transfer of the final color, the transfer belt 5 is peeled off from the transfer drum 5 by the peeling claw 23, and is conveyed to the fixing device 50 by the conveyor belts 24 and 25 to be fixed.

Reference numeral 3 in the figure denotes a photosensitive drum (image carrier) having a photosensitive layer 4 on its surface, which rotates in the direction of arrow a in the figure. Photosensitive layer 4
Materials include amorphous silicon, selenium, cadmium sulfide, and organic photoconductor (OPC).
r) and the like, but in this embodiment, OPC is used. The photosensitive layer 4 is uniformly charged by the primary charger 7. The charged photosensitive layer 4 is first exposed by a laser beam to an optical pattern corresponding to the image data of the first toner image by an exposure device (not shown), and an electrostatic latent image corresponding to the image data of the first toner image is formed. It is formed. In this embodiment, the reversal development method is used in which the absolute value of the surface potential of the image area to which the toner adheres is lower than that of the non-image area. As the exposure device, an exposure device that modulates a semiconductor laser on and off and scans the surface of the photosensitive layer 2 with a polygon mirror is used. Then, a developing device 10 disposed at the lower left of the photosensitive drum 3 is driven by a driving unit (not shown) with an arrow. The electrostatic latent image corresponding to the first image data formed on the photosensitive layer 4 and moved horizontally in the C direction is transferred to a first developing unit in the developing device 10.
Developed by 10a. The developing unit 10a is a developer tank
12a, a supply developer tank 11a, a developing tank 13a, a developing roller 14a, and a squeeze roller 15a. At the time of development, a pump mechanism (not shown) moves the developer tank 12a to the developing tank 13a.
The developer is pumped up, and the developing roller 14a comes into contact with the photosensitive drum 3 to supply the developer to the surface of the photosensitive layer 4 to perform development. The developed toner image moves clockwise due to the rotation of the photosensitive drum 3, and the excess liquid carrier on the photosensitive layer 4 is removed by the squeeze roller 15a as a liquid carrier removing means. In FIG. 1, the developing roller 14a rotates counterclockwise, and the squeeze roller 15a rotates clockwise. Each of the squeeze rollers 15a is urged toward the photosensitive drum 3 by a spring (not shown), and adjacent rollers (not shown) attached to both ends of the roller. ) Keeps a certain gap from the photosensitive member 2. In the present embodiment, the peripheral speed of each developing roller is 0.5 to the peripheral speed of the photosensitive drum 3 (160 mm / s).
The gap with the photosensitive layer 4 is three times, and the squeeze roller is two to five times and 50 to 100 μm, respectively.

The developer concentration in the developer tank is detected by a developer concentration sensor (not shown), that is, the ratio of the toner particles to the liquid carrier. Based on the detection signal, the developer concentration becomes a predetermined value. If it is lower, the replenishment developer is dropped from the upper replenishment developer tank to return the developer concentration to a predetermined value. When the developer concentration is higher than a predetermined value, the developer unit 10 is moved to a predetermined position, and the liquid carrier stored in the carrier tank 43 is moved out of the developing tanks 13a to 13d by the carrier supply electromagnetic valve 44. A certain amount is replenished to the predetermined tank.

As the developer concentration sensor, a sensor having a light emitting element and a light receiving element and measuring the amount of light transmitted by the developer is used. In this case, for example, it is preferable to adjust the spectral characteristics of the light emitting element and the light receiving element to the absorption wavelength of the component of the toner particles because the sensitivity can be improved.

The developing roller and the squeeze roller are connected to a common bias power source (not shown), and an intermediate potential (bias potential) between the image portion and the non-image portion is applied.

On the other hand, before the development of the first toner image is started, the head of the recording medium p sent from the recording medium tray 26 through the transport path R ₁ is transferred to the recording medium head gripper 21 of the transfer drum 5. When the gripper 21 is gripped and the recording medium leading gripper 21 passes the position of the gripping assist roller 27, the gripping assist roller 27 that has been separated from the transfer drum 5 is pressed against the transfer drum 5 by a separation mechanism (not shown) to transfer the recording medium p. While being pressed against the drum 5, it is wound around the transfer drum 5 from the top and held.

On the surface of the transfer drum 5, an underlaying material 6 for a recording medium is provided.
Is mounted so as to be wound around the transfer drum 5.
The underlaying material 6 for the recording medium is 0.5 to 10 mm thick on a stainless steel or aluminum base material (0.01 to 0.3 mm thick).
The conductive foamed rubber sheet is provided. The conductive foamed rubber sheet is made of a conductive material such as chloroprene, urethane, or fluororubber, and has a material hardness ranging from 5 to 30 degrees (Asker C). Conductivity is 10 ⁴ to 10 ¹⁰ Ωc
m.

The rear end of the recording medium p is a gripping assist roller 27.
Immediately before approaching the position, after the recording medium rear end gripper 22 grips the recording medium rear end, the gripping assist roller 27
Is separated from the transfer drum 5.

The first toner image developed on the photosensitive layer 4 is transferred onto the recording medium p on the surface of the transfer drum 5.

Immediately before the transfer, the surface of the photosensitive layer 4 is charged to the same polarity as the charge polarity of the toner image together with the toner image developed by the pre-transfer charger 20. Due to the pre-transfer charging, the toner image is pressed against the photosensitive layer 4 by an electric field force, and the attraction between the photosensitive layer 4 and the toner image is increased. At the same time, a transfer electric field is formed from the surface of the photosensitive layer 4 to the surface of the transfer drum 5, and a repulsive force acts between the surface of the photosensitive layer 4 and the toner particles. The transfer of the toner image from the photosensitive layer 4 to the recording medium p is performed by forming an electric field between the photosensitive layer 4 and the transfer drum 5, and moving the toner in the liquid carrier in the nip portion by the electric field force. It is more preferable to apply a bias having a polarity opposite to that of the surface of the photosensitive layer 4 to the transfer drum for the purpose of forming an electric field because the transfer rate increases. Further, by changing the bias value of the reverse polarity according to the recording medium, it is possible to set the optimal transfer conditions.

The untransferred toner and liquid carrier slightly remain on the photosensitive layer 4. The residual toner and liquid carrier are removed from the photosensitive layer 4 by the cleaning means 30 and placed in front of the developing device 10. Collected in the waste liquid tank 34. This cleaning and waste liquid recovery will be described later in detail.

Further, the residual electrostatic latent image is also erased by the static elimination lamp 40 disposed downstream of the cleaning means 30, for example, the static elimination lamp as in this embodiment.
Is started.

When forming the second toner image, the developing device 10
Moves in the horizontal direction indicated by arrow c by one developing unit, and the developing unit 10b of the second toner image
It is arranged at the position facing. A second toner image is developed on the photosensitive layer 4 in the same process as the first toner image, is superimposed on the first toner image already existing on the recording medium p, and is transferred onto the recording medium p. Is done.

The above process is further repeated for the third and fourth toner images. The order in which the toner images are formed on the recording medium p is, for example, yellow, magenta, cyan, and black. This image forming sequence is preferable because the mixing of other color toners into the yellow developer can be minimized.

On the other hand, when the image forming order is black, cyan, magenta, and yellow, a toner layer having high transparency is superimposed on the recording medium on the upper layer, and the color reproduction range is preferably expanded. In addition, the order of forming images of cyan, magenta, yellow, and black is preferable because the color reproduction range of the superimposed portions of cyan, magenta, and yellow is widened in a state where the mixing of the multicolor toner into the yellow developer is reduced.

During the transfer of the last toner image, immediately before the leading end of the recording medium p comes to the position of the peeling claw 23, the recording medium leading gripper 21 on the surface of the transfer drum 3 is released, and the peeling claw 23 contacts the transfer drum 5. The recording medium p comes under the leading end of the recording medium p and comes into contact with the transfer drum 5. Here, after the development of the final color is completed, the recording drum p can be peeled off by rotating the transfer drum once. This is preferable because mechanical vibrations and the like accompanying the separation of the recording medium p do not affect the transfer of the final color toner image. After the rear end of the recording medium p has passed the transfer position, the recording medium rear end gripper 16 at the rear end of the recording medium p is released immediately before the peeling claw 23, and the recording medium p is discharged onto the transport belt. On the other hand, the recording medium p
The position corresponding to the tip of the underlay material cleaning roller 42
Immediately before passing through, the underlaying material cleaning roller 42 that has been separated is pressed against the recording medium underlaying material 6, and at least the toner among the developer adhered to the surface of the recording medium underlaying material 6 during one rotation of the transfer drum 5. Remove particles. Developing device while cleaning recording medium underlay material 6
10 returns to the original position, and when the cleaning is completed, the underlay material cleaning roller 42 is separated. In parallel with this operation, the leading end of the next recording medium p is gripped by the recording medium leading gripper 21, and image formation on the next recording medium p is started.

Here, the photosensitive drum 3, the transfer drum 5, the primary charger 7, the pre-transfer charger 20, the cleaning means 30, the neutralizing lamp 40, and the waste liquid tank 34 constitute a process unit (drawable unit) 2. I have. The process unit 2 can be pulled out to the front side of the electrophotographic printer 1 by a slide rail (not shown) without changing the relative positional relationship between the individual members (that is, integrally). .

The recording medium p separated from the transfer drum 5
Is transported to the fixing device 101 by the transport belts 24 and 25 and is fixed. The paper transport speed during fixing is 50mm / s
It is.

The recording medium p peeled off from the transfer drum 5 is conveyed by the conveyor belt 24 at a conveying speed of 160 mm / s to the position indicated by A in FIG. Conveyor belt 24
At about the same time as the rear end of the recording medium p is peeled off from the transfer drum 3, the recording medium p is rotated counterclockwise around a shaft 24a to a position shown by a broken line in the figure by a rotating device (not shown). When the transport belt 24 reaches the position shown by the broken line in the figure, the transport belt 24 rotates in the reverse direction and
The transfer starts at the transfer speed of 0 mm / s to the right in the figure. The recording medium p is delivered from the conveying belt 24 to the conveying belt 25, and the leading end of the recording medium p is conveyed to a position B in FIG. At almost the same time as the trailing end of the recording medium p is delivered to the transport belt 25, the transport belt 25 is rotated clockwise about a shaft 25a by a rotating device (not shown) to a position shown by a broken line in the drawing. . Thereafter, the recording medium p is conveyed to the left in the drawing at a speed of 50 mm / s, and is sequentially heated and pressed by a pair of fixing rollers 51, 52, and 53 of the fixing device 50.
It is fixed at a speed of 50mm / s.

The recording medium p on which the fixing is completed is discharged out of the fixing device 50, and the printing is completed.

In the electrophotographic printer 1 constructed as described above, the present invention is characterized by at least the cleaning means 30 and the waste liquid tank described above.
Reference numeral 34 denotes a process unit 2 integrally held, and FIG. 2 shows a front view and FIG. 3 shows a right side view. The left side in FIG. 3 is the front side direction of the electrophotographic printer 1. The front side refers to a side where a user mainly performs a normal operation of the apparatus, a normal maintenance operation such as a paper supply, a paper jam processing, a cleaning and a component replacement.

The cleaning means 30 comprises a cleaning roller 31, a cleaning blade 32, and a waste liquid guide 33. The cleaning roller 31 is pressed against the surface of the photosensitive layer 4 on the downstream side of the cleaning roller 31 while rotating in a direction indicated by an arrow in FIG. The cleaning blade 32 has a thickness of 1.5 mm on a phosphor bronze plate having a thickness of 0.2 mm,
It is made by bonding urethane rubber with Asuka A hardness 70 degrees,
The urethane rubber is arranged so that the edge of the urethane rubber is pressed against the photosensitive layer 4. A waste liquid guide 33 is disposed below the cleaning blade 32 at an angle to the front side of the electrophotographic printer 1 as shown in FIG.
34 have been installed. The waste liquid tank 34 is provided with a transparent window for checking a waste liquid level.

On the photosensitive layer 4 having passed the transfer position, toner and carrier not transferred to the recording medium p (hereinafter referred to as residual toner and residual carrier, respectively) remain. This residual toner is peeled off from the surface of the photosensitive layer 4 by the cleaning roller 31, and is dispersed in the residual carrier. After the residual toner and the residual carrier are dammed by the cleaning blade 32, the arrow k in FIG.
, Flows into the waste liquid guide 33, and is collected in the waste liquid tank. This waste liquid tank 34 is used for the electrophotographic printer 1.
The liquid level can be easily and reliably checked from the transparent window simply by opening a front door (not shown).
Further, as described above, the waste liquid tank 34 is disposed in the process unit 2 together with the cleaning means 30, so that the waste liquid route from the cleaning means 30 to the waste liquid tank 34 is not divided even when the process unit 2 is taken in and out. It is connected and does not require a joint and does not spill waste liquid. Further, since the photosensitive drum 3 is also included in the process unit 2 and is configured to be integrally pulled out when the process unit 2 is pulled out, the cleaning blade 32 is pressed against the photosensitive layer 4 even when the process unit 2 is taken in and out. The residual toner and the residual carrier damped by the cleaning blade 32 do not drop along the photosensitive layer 4 and drop downward, thereby contaminating the inside of the apparatus and the floor surface.

Further, the process unit 2 integrally holds the transfer drum 5, the primary charger 7 and the pre-transfer charger 20, so that the relative positional relationship between the members is not changed and the front side of the apparatus is changed. Therefore, a change in image quality and the like due to mechanical misalignment due to the drawer can be minimized.

[0035]

The means for collecting the residual toner particles not transferred to the transfer medium and the collecting container are arranged in an integrated unit, so that there is no need to provide a joint in the path for transporting the collected toner. As a result, the inside of the apparatus is not contaminated by the toner leakage, and the environment is not deteriorated by scattering outside the apparatus, and expensive parts are not required for improving the sealing performance.

By arranging the collection container in front of the image forming apparatus, the amount of the collected toner can be visually and easily and reliably confirmed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a wet electrophotographic full-color printer which is one of embodiments of the present invention.

FIG. 2 is a front configuration diagram of a waste liquid recovery unit which is one of the embodiments of the present invention.

FIG. 3 is a right side configuration diagram of a waste liquid collecting unit which is one of the embodiment examples of the present invention.

[Explanation of symbols]

 1: electrophotographic printer 2: process unit 3: photosensitive drum 4: photosensitive layer 5: transfer drum 6: underlaying material for recording medium 7: primary charger 10: developing units 10a to 10d: developing units 11a to 11d: supply developer tank 12a to 12d: developer tank 13a to 13d: developing tank 14a to 14d: developing roller 15a to 15d: squeeze roller 20: pre-transfer charger 21: recording medium head gripper 22: recording medium rear end gripper 23: peeling claw 24, 25: conveyor belt 24a, 25a: shaft 26: recording medium tray 27: gripping assist roller 30: cleaning means 31: cleaning roller 32: cleaning blade 33: waste liquid guide 34: waste liquid tank 40: static elimination lamp 41: recording medium pressing roller 42 : Underlay material cleaning roller 43: Carrier tank 44: Carrier replenishment solenoid valve 50: Fixing device 51, 52, 53: Fixing roller pair

Claims (6)

[Claims] An image carrier, a means for forming a latent image on the image carrier, a developing means for developing the latent image with toner particles to form a toner image, and a method for developing the toner image from the image carrier. An image forming apparatus comprising: a transfer unit for transferring to a transfer medium; a unit for collecting remaining toner particles remaining on the image carrier without being transferred to the transfer medium; and a drawable unit integrally holding a collection container. . 2. An image forming apparatus according to claim 1, wherein said unit also integrally holds said image carrier. 3. The image forming apparatus according to claim 1, wherein the collection container is disposed in front of the image forming apparatus. 4. The image forming apparatus according to claim 1, wherein at least a part of the collection container is formed of a transparent member, and the amount of the collected toner particles can be visually checked. . 5. The image forming apparatus according to claim 1, wherein the image forming method is a wet electrophotographic method. 6. An image forming apparatus according to claim 1, wherein said developing means is capable of developing a plurality of color toners.