JPH04134390A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the degradation of image quality caused by the soiling of a transfer material due to the soiling of a carrying belt, color slurring, etc., by allowing each of cleaning means to freely uncontact/contact with the carrying belt. CONSTITUTION:In the uncontact/contact mechanism of a first cleaning means 107, a frame body 107a is attached to a rocking shaft 71, the frame body 107a and a fur brush 107b supported by the frame body 107a, can be integrally rocked centering the rocking shaft 71, and simultaneously, a solenoid 74 is attached to the frame body 107a, as a rocking source. Further, a recovering spring 73 whose one end is fixed is attached in the vicinity of the carrying belt 8, as a recovering source. The uncontact/contact mechanism of a second cleaning means 108 is completely similar to that of the first cleaning means 107. The ON/OFF of a voltage to the solenoid is carried out, and the uncontact/contact of the fur brushes 107b and 108b with respect to the front/back surfaces of the carrying belt 8 is carried out, to carry out cleaning. Thus, the the degradation of the image quality caused by image blurring, the color slurring, and the void and irregularities of the transfer, when the image is formed, are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention relates to an image forming apparatus using an electrophotographic method or the like, and in particular, an image forming apparatus in which a plurality of drum-shaped image bearing members are arranged in parallel and transferred onto a transfer material supported on a conveyor belt. The present invention relates to an image forming apparatus suitable for sequentially transferring toner images of each color on an image carrier to obtain a color image.

1. Not yet established and I Various types of image forming apparatuses have been proposed for forming color images, one of which is a drum-shaped image forming apparatus in which image forming units of each color are arranged side by side and each unit is provided with a drum-shaped image forming apparatus. A toner image of each color is formed on a photosensitive drum of a carrier by a well-known image forming process, and these toner images of each color are superimposed and transferred onto a transfer material such as transfer paper supplied from a transfer material supply section. 2. Description of the Related Art An electrophotographic image forming apparatus that forms a color image on a transfer material is known.

The transfer material supplied from the above transfer material supply section is placed on an endlessly moving conveyor belt and conveyed to each image unit, and the toner images formed on the photosensitive drums of each unit are sequentially transferred. Ru.

By the way, in the above-mentioned image forming apparatus, the developer used to visualize the electrostatic latent image formed on the photosensitive drum may be scattered from the developing means such as the developing device that houses the developer, or the developer used to visualize the electrostatic latent image formed on the photosensitive drum may be scattered or transferred onto the photosensitive drum. The remaining developer is cleaned and collected by the cleaning device, and the developer is scattered from the cleaning device, and the scattered developer adheres to the transfer material placement surface of the conveyor belt and causes stains, which causes the transfer material to become stained. There was a problem that caused stains etc.

Furthermore, when the transfer material is a transfer paper, in addition to the stains caused by the developer, paper dust from the transfer paper adheres to the transfer material mounting surface of the conveyor belt, making the stains even worse.

In extreme cases, there is also the problem that scattered toner and paper powder invade the back surface of the conveyor belt opposite to the surface on which the transfer material is placed, adhere to the back surface, and stain the back surface. This dirt on the back side of the conveyor belt reduces the friction with the drive roller that drives the conveyor belt and induces slippage in the direction of movement of the conveyor belt and in a direction approximately perpendicular to it, resulting in various image quality problems such as image shift and color shift. lead to deterioration. Furthermore, there is also the problem that the dirt reduces the transfer efficiency or falls into the transfer charger located on the back side of the conveyor belt, and the dirt adheres to the discharge wire, causing uneven transfer or missing transfer.

To this end, a method has been proposed in which cleaning means such as a fur brush or blade is provided on the transfer material mounting surface of the conveyor belt and its back surface to remove dirt.

However, by providing a leaning means such as the above-mentioned fur brush or blade, it is possible to solve the problem of stains caused by developer and paper dust on the transfer material mounting surface of the conveyor belt and its back surface. Another problem arises regarding the drive of the conveyor belt.

The problem is that the cleaning means places a load on the motor used to drive the conveyor belt.

For this reason, even if PLL control is applied to drive the motor, the wow and flutter of the motor worsens.

The above wow and flutter often has a certain periodicity (
Since the phase of the transfer material passing between each image forming unit is random, this wow and flutter causes slight fluctuations with a certain periodicity in the direction of movement of the transfer material during transfer. Uneven coloring appears. These minute color irregularities are very conspicuous due to their periodicity, leading to the problem of deteriorating image quality and lowering image quality.

In view of the above-mentioned current situation, it is an object of the present invention to prevent the deterioration of wow and flutter in the drive motor of the transfer material conveyance belt, prevent image quality deterioration such as color unevenness associated therewith, and provide a method for loading the transfer material on the conveyance belt. To provide an image forming device which can clean a mounting surface and its back surface and prevent other image quality deterioration such as transfer material stains and color misregistration caused by stains on a conveyor belt due to developer or paper dust. That's true.

for The above object is achieved by an image forming apparatus according to the present invention.

In summary, the present invention provides an endlessly moving conveyance belt that conveys a transfer material for transferring a toner image formed on an image bearing member to the image bearing member, on the side where the transfer material is placed and on the back side opposite thereto. An image forming apparatus is provided with cleaning means for cleaning each side of the image forming apparatus, characterized in that each of the cleaning means is movable toward and away from the conveyor belt.

According to one aspect of the present invention, the cleaning means is attached to a swinging shaft, and a swinging means and a return means are attached to the cleaning means, so that the cleaning means can freely move toward and away from the conveyor belt. . Further, a plurality of the image carriers are arranged in parallel in the moving direction of the conveyor belt, and the toner images of each color formed on each of the image carriers are sequentially transferred onto the transfer material.

Examples of the present invention will be described in detail below.

FIG. 1 is a configuration diagram showing an embodiment of an image forming apparatus of the present invention. The image forming apparatus of this embodiment is a color printer.

As shown in FIG. 1, this image forming apparatus includes an apparatus main body 10.
A transfer material feed mechanism 13 is provided on one side of the apparatus main body 10, that is, on the right side as seen in the figure, and a transfer material discharge port 14 is provided on the left side as seen in the figure, which is the side opposite to the paper feed mechanism 13 in the apparatus main body 10. A fixing device 7 is disposed facing the transfer material discharge port 14.

A driving roller 11 is provided in the vicinity of the fixing device 7 on the lower side between the paper feeding mechanism 13 and the fixing device 7 in the apparatus main body 10, and an idler roller 12, which is a driven roller, is provided in the vicinity of the paper feeding mechanism 13. It is provided. An endless transfer material conveying belt 8 is wound around these driving rollers 11 and idler rollers 12 . An adjustment roller 7b is disposed below the drive roller 11 to freely adjust the tensile force of the conveyor belt 8 by coming into contact with the conveyor belt 8 from the inside back surface side. Furthermore, from the idler roller 12 to the drive roller 1
1, there are image forming units P close to the conveyor belt 8 and serving as image forming units sequentially from the paper feed mechanism 13 side.
a, Pb, Pc, and Pd are arranged in parallel.

More specifically, the conveyor belt 8 is driven by a drive roller 11 in the direction of the arrow in FIG. It is designed to be transported sequentially to each of Pb, Pc, and Pd. The paper feed mechanism 13 includes a paper feed cassette 51 that is detachably attached to the apparatus main body 10, a rotatable paper feed roller 52 that is provided at a portion where the paper feed cassette 51 is attached to the apparatus main body 10, and a paper feed roller 52 that is freely rotatable. A paper feed guide 53 guides the transfer material 6 fed into the apparatus main body lO by the roller 52, and a paper feed guide 53 receives the transfer material 6 guided by the paper feed guide 53 and transfers it to the idler roller 12 side at a predetermined timing. A sensor (not shown) outputs a predetermined detection signal when the leading end of the transfer material 6 moving within the paper feed guide 53 is detected. The paper feeding mechanism 13 is for placing the transfer material 6 onto the conveyor belt 8 from the idler roller 12 side.

The fixing device 7 includes image forming units Pa, Pb, Pc, and Pd.
The transfer material 6 onto which the toner image has been transferred is transferred to the drive roller 11.
This is for receiving the toner image from the side and fixing the toner image on the transfer material 6. A paper discharge tray 117 is attached to the transfer material discharge port 14 and is detachable from the apparatus main body 10 .

Each image forming unit Pa, Pb, Pc, and Pd has substantially the same configuration. Image forming units Pa, Pb
, Pc, and Pd are image carriers that are rotationally driven in the direction of the arrow in FIG.
a, 1b, 1c, ld, and these photosensitive drums 1a, 1
Chargers 15a, 15b, 15c, and 15 are provided around each of b, 1c, and 1d in order in their rotational direction.
d, developing devices 3a, 3b, 3c, 3d, transfer chargers 4a, 4b, 4c, 4d, and cleaning means 5a, 5.
b, 5c, 5d, and photosensitive drums 1a, 1b, 1c, 1
Imaging lenses 17a and 1 provided above each of d
7b, 17c, 17d and laser beam scanner 16a
, 16b, 16c, and 16d.

The magenta toner is stored in the developing device 3a.
cyan toner is stored in b, yellow toner is stored in developer 3c, and black toner is stored in developer 3d.

Laser beam scanner 16a, 16b, 16C116d
is composed of a semiconductor laser, a polygon mirror fθ lens, etc., and receives an input of an electric digital pixel signal and sends a laser beam modulated corresponding to the signal through the above-mentioned imaging lenses 17a, 17b, 17c, and 17d, respectively. Charger 15
a, 15b, 15c, 15d and developing devices 3a, 3b, 3c
, 3d in the drum generatrix direction to expose the drum surface. Laser scanner 1 mentioned above
A pixel signal corresponding to a magenta component image of a color image is transmitted to the laser scanner 6a, a pixel signal corresponding to a yellow component image is transmitted to a laser scanner 16b, and a pixel signal corresponding to a cyan component image is transmitted to a laser scanner 16c. scanner 1.6
A pixel signal corresponding to a black component image is input to each of d.

A suction charger (not shown) is provided between the image forming unit Pa and the paper feed mechanism 13, and the suction charger transfers the transfer material 6 supplied from the paper feed mechanism 13 to the conveyor belt. Corona discharge is performed to ensure adsorption to 8.

On the other hand, a static eliminator (not shown) is provided between the image forming unit Pd and the fixing device 7 at a position substantially directly above the drive roller 11. An alternating current voltage is applied to separate the material 6.

Sensors 60a and 60 are provided on the upstream side in the conveying direction of each of the image forming units Pa, Pb, Pc, and Pd described above.
b, 60c, and 60d are arranged, and these sensors 6
0a, 60b, 60c, and 60d detect when the leading edge of the transfer material 6 conveyed by the conveyor belt 8 passes, and the image forming units Pa, Pb%Pc, and P
The image forming apparatus is configured to output a signal for starting the image forming process in each of d to an electronic circuit control means or control unit (not shown).

Now, when a cut sheet-shaped transfer material as the transfer material 6 moves within the paper feed guide 53 of the paper feed mechanism 13, its leading edge is detected by the sensor described above, and this detection starts the signal output from the sensor. As a signal, the photoreceptor drums la, lb of image forming units Pa, Pb, Pc, Pd
, 1c, , 1d start rotating. The drive roller 11 is also driven at the same time, and the conveyor belt 8 starts driving in the direction of the arrow in FIG. When the transfer material 6 is placed on the conveyor belt 8, it is reliably attracted onto the conveyor belt 8 by corona discharge from the aforementioned attraction charger (not shown). When the leading edge of the transfer material 6 passes through the detection area of each sensor 60a, 60b, 60C160d as the conveyor belt 8 moves, this causes the photosensitive drums 1a, 1b, IC51d
Image formation for each of the images is sequentially started.

That is, a magenta toner image is formed on the photosensitive drum la of the first image forming unit Pa, and a magenta toner image is formed on the photosensitive drum la of the first image forming unit Pa.
A cyan toner image is formed on the photosensitive drum lb of the third image forming unit PC, a yellow toner image is formed on the photosensitive drum lc of the third image forming unit PC, and a yellow toner image is formed on the photosensitive drum 1d of the fourth image forming unit Pd.
A black toner image is formed. The principle of image formation in each of the image forming units Pa, Pb, Pc, and Pd is already well known as the Carlson process, so its explanation will be omitted.

Due to the movement of the conveyor belt 8, the transfer material 6 is conveyed in the direction of the fixing device 7, sequentially passing through the lower portions of the photosensitive drums 18 to 1d of the first to fourth image forming units Pa to Pd, that is, the image transfer area. , transfer dischargers 4a, 4b, 4 of each unit
C14d transfers toner images of magenta, cyan, yellow, and black onto the transfer material 6 one over the other in order, thereby producing a combined color image. Transfer material 6 is the fourth
After passing through the image forming unit Pd, the transfer material 6 is neutralized by the aforementioned static eliminator (not shown) to which an alternating current voltage is applied, and is separated from the conveyor belt 8.

The transfer material 6 separated from the conveyor belt 8 enters the fixing device 7 where the image is fixed, and then passes through the transfer material discharge port 1.
4 onto the paper ejection tray 117, and one print cycle is completed.

Now, in order to clean the dirt adhering to the transfer material placement surface 8a of the conveyor belt 8 of the transfer material conveyance means, a second One cleaning means 107 is provided, and a second cleaning means 108 is similarly provided on the back surface 8b side in order to clean the dirt on the back surface 8b opposite to the mounting surface 8a.

The first and second cleaning means 107 and 108 both include frame bodies 107a and 108a whose sides facing the conveyor belt 8 are open, and fur brushes 107b and 108b rotatably supported by the frame bodies 107a and 108a. are doing. The fur brushes 107b and 108b are arranged with their rotational axes substantially perpendicular to the moving direction of the conveyor belt 8, and are installed so as to be in contact with the transfer material mounting surface and the back surface of the conveyor belt 8, respectively. A motor (not shown) is attached to the rotating shaft.

According to the present invention, the cleaning means 107, 108 include:
As shown in FIG. 2, a mechanism for engaging and separating the conveyor belt 8 is provided.

That is, as shown in FIG. 2, the detachment mechanism of the first cleaning means 107 attaches the frame 107a to the swing shaft 71, and swings the frame 107a and the fur brush 107b supported thereon. While being able to swing integrally around the shaft 71,
A solenoid 74 is attached to the frame 107a as a swing source,
Further, a return spring 73 with one end fixed is attached near the conveyor belt 8 as a return source, and a stopper shaft 72 is provided which sets the position of the fur brush 107b at the cleaning position when the frame 107a comes into contact with it.

In the first cleaning means 107, when the voltage application to the solenoid 74 of the separation mechanism is turned off, the frame body 107a and the fur brush 107b are fixed to the conveyor belt 8 by the return spring 73.
When the frame body 107a comes into contact with the stopper shaft 72, the fur brush 107b is positioned at the cleaning position, and the transfer material placement surface 8 of the conveyor belt 8 is pulled.
Contact on a. Therefore, in this state, the fur brush 107
The fur brush 1 is moved by a motor (not shown) installed on the rotating shaft of b.
By rotationally driving 07b, the transfer material mounting surface 8a of the conveyor belt 8 can be cleaned.

Next, from this state, turn on the voltage application to the solenoid 74.
As shown in FIG. 3, the plunger 74
a retracts and pulls the frame body 107a against the return spring 73, and the frame body 107a swings in the direction away from the conveyor belt 8, and the fur brush 107b supported by the frame body 107a
is separated from the transfer material placement surface 8a of the conveyor belt 8.

The detachment mechanism of the second cleaning means 108 is exactly the same, and as shown in FIG. The solenoid 8 is integrally swingable around the swing shaft 81, and the solenoid 8 is mounted on the frame 108a as a swing source.
4, and a return spring 83 with one end fixed near the conveyor belt 8 as a return source, and a stopper shaft 82 that sets the fur brush 108b at the cleaning position by contacting the frame 108a. It has become.

Similarly, when the voltage application to the solenoid 84 of the separation mechanism is 0FFt, the second cleaning means 108 causes the return spring 83 to
The frame body 108a and the fur brush 108b are pulled in the direction of the conveyor belt 8, and the frame body 108a comes into contact with the stopper shaft 82, so that the fur brush 108b is positioned at the cleaning position, and the transfer material placement surface 8a of the conveyor belt 8 is pulled. and comes into contact with the back surface 8b on the opposite side. Therefore, in this state, if the fur brush 108b is rotationally driven by a motor (not shown) provided on the rotating shaft of the fur brush 108b,
The back surface 8b of the conveyor belt 8 can be cleaned.

Also, when the voltage is turned on to the solenoid 84 from this state, the plunger 84a is turned on as shown in FIG.
retracts and pulls the frame 108a against the return spring 83, the frame 108a swings away from the conveyor belt 8, and the fur brush 108b supported by the frame 108a moves to the back surface 8b of the conveyor belt 8. move away from

Therefore, according to the present invention, when the transfer material 6 is not placed on the conveyor belt 8 during the non-image forming process, the first
Solenoid 74.84 of second cleaning means 107.108
By turning off the voltage application to the fur brushes 107b and 108b, as shown in FIG. can.

Therefore, stains on the conveying belt 8 due to scattering of developer from the developing devices 38 to 3d and scattering of developer collected by the cleaning means 58 to 5d, or paper dust when the transfer material 6 is a transfer paper, can be removed. This prevents stains on the transfer material 6, slippage between the conveyor belt 8 and drive roller 11, and uneven discharge of the transfer chargers 4a to 4d, thereby preventing image shift and color shift during image formation.
Image quality deterioration due to transfer omissions and uneven transfer can be prevented.

Then, in the image forming process, the transfer material 6 is placed on the conveyor belt 8.
Once the fur brush 1 is placed, the application of voltage to the solenoid 74.84 is turned on to remove the fur brush 1 from the transfer material placement surface 8a and the back surface 8b of the conveyor belt 8.
The cleaning operation can be stopped by releasing 07b and 108b.

Therefore, there is no need to put a load on the drive motor of the conveyor belt, and it is possible to prevent wow and flutter from worsening. Therefore, images can be formed without causing color unevenness.

As a result, according to the present invention, high quality and high quality images can be obtained.

In the above embodiment, the first and second cleaning means 107, 108
Although the solenoids 74 and 84 are used as the drive source for the separation mechanism, the drive source may also be configured using a motor and a cam.

Further, although the fur brushes 107b and 108b were used for cleaning, it goes without saying that a blade may be used for cleaning and the same effect can be obtained.

1. As explained above, in the image forming apparatus of the present invention, the cleaning means for cleaning the transfer material mounting surface and the back surface of the transfer material conveying belt are provided so that they can move toward and away from the conveying belt. , prevents deterioration of wow and flutter in the conveyor belt drive motor, prevents image quality deterioration such as color unevenness, and cleans the transfer material mounting surface of the conveyor belt and its back surface, and cleans the developer and It is also possible to prevent other image quality deterioration such as staining of the transfer material and color misregistration caused by staining the conveyor belt with paper dust. As a result, high quality and high quality images can be obtained.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an image forming apparatus of the present invention. FIG. 2 is a configuration diagram showing first and second cleaning means for the transfer material conveying belt provided in the image forming apparatus of FIG. 1. FIG. 3 is an explanatory diagram showing that the first and second cleaning means in FIG. 2 are in a separated state. 8: Transfer material conveyance belt a b 71, 81 72, 82 73, 83 74, 84 107a. 107b. : Transfer material placement surface: Back side: Drive roller: Swing axis: Stop bar axis: Return spring: Solenoid 108b: Frame 108b: Fur brush Fig. 2

Claims (1)

[Scope of Claims] 1) With respect to an endlessly moving conveyor belt that conveys a transfer material that transfers a toner image formed on an image carrier to the image carrier, there are What is claimed is: 1. An image forming apparatus provided with cleaning means for cleaning each back side, wherein each of the cleaning means is movable toward and away from the conveyor belt. 2) The image forming apparatus according to claim 1, wherein the cleaning means is attached to a swing shaft, and a swing means and a return means are attached to the cleaning means, so that the cleaning means can be moved toward and away from the conveyor belt. . 3) A plurality of the image carriers are arranged in parallel in the moving direction of the conveyor belt, and the toner images of each color formed on each of the image carriers are sequentially transferred onto the transfer material. 2
The image forming apparatus described above.