JPS63137284A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent reverse of ejecting rolls to prevent winding of a recording body by providing a one-way rotating clutch or the like in a system which transmits the driving force of an image carrier to a pair of ejecting rolls. CONSTITUTION:After a cleaning blade 50 is separated from the surface of a photosensitive body 2, a motor 55 is reversed and the photosensitive body 2 is reversed to return a remaining developer (r), which is accumulated on the front end of the blade 50, upward from the position of the blade once. At the time of restart, the remaining developer (r) is removed by the blade 50. At this time, the first roll 60 can be rotated only in the ejecting direction of a form P because a one-way rotating clutch 65 is provided between the roll 60 and a revolving shaft 66, and a pair of rolls 46 are not reversed, and consequently, winding of the form P on a tray 47 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to improvements in image forming apparatuses such as electronic copying machines and printers.

(Prior Art) Conventionally, there is one as shown in FIG. 4 as one of the image forming apparatuses. This device is equipped with a drum-shaped photoreceptor a as an image carrier, and around this photoreceptor a, a charging means, an exposing means C, and a developing means d are sequentially arranged along the direction of rotation shown by the solid line arrow. , a developer image forming means e.

Further, on the downstream side of the developing means e, a transfer means f, a peeling means Q, a cleaning means, and a static eliminating means i are arranged in this order.

After the photoreceptor a is uniformly charged by the charging means, an electrostatic latent image is formed by the exposing means C, and this is developed by the developing means d to form a developer image (toner image).

Next, the developer image on the photoreceptor a is transferred onto paper P as a recording medium by a transfer means f, and is peeled off from the photoreceptor a by a peeling means Q and guided to the fixing means j. On the other hand, after the developer (toner) remaining on the photoreceptor a is scraped off by a cleaning blade of a cleaning means to clean it, the latent image is erased by a static eliminator i to complete one process. ing.

In addition, the cleaning blade has a blade driving means m that allows it to freely approach and separate from the surface of the photoreceptor a, and removes it from the surface of the photoreceptor a after the image forming operation is completed and removes the photoreceptor that is generated by remaining in contact with the surface of the photoreceptor a. It has a configuration that can prevent adverse effects on the body a.

On the other hand, the photoreceptor a is driven by a driving means 0 whose driving source is a main motor n which can rotate in both forward and reverse directions.

After the cleaning blade k is separated from the surface of the photoconductor a, the motor n is reversely rotated to rotate the photoconductor a in the reverse direction, that is, in the direction of the broken line arrow.
As shown in Figure (a), the residual developer r on the photoconductor a, which has accumulated at the tip of the cleaning blade,
As shown in Figure (b), return it to the upstream side of the -H cleaning blade arrangement position. Then, as shown in FIG. 5(C), the residual developer r is removed by the cleaning blade at the time of restart, thereby preventing the black streak phenomenon caused by the residual developer r passing through the position where it is placed on the cleaning blade. The structure is as follows.

Furthermore, the MP that has been fixed by the fixing means j is discharged via a pair of discharge rollers S to a tray t, which is a discharge destination section. Further, the discharge roller pair S is composed of a 10th roller consisting of a driving roller and a 20th roller V consisting of a driven roller that rolls into contact with the 10th roller, and the 10th roller U is a driving means for driving the photoreceptor a. 0 and a driving force transmission system W, and the rotational force of the motor n of the driving means 0 in both forward and reverse directions is transmitted to the 10th wheel.

(Problems to be Solved by the Invention) However, since the discharge roller pair S is driven via the drive means 0 and the driving force transmission system W that drive the photoreceptor a, the photoreceptor When body a rotates in the opposite direction,
There was a problem in that each of the rollers U and V of the pair of ejection rollers S rotated in the opposite direction as shown by the broken line arrows in FIG. 6, causing the paper P on top of the tray to be rolled up.

The present invention has been made based on the above-mentioned circumstances, and an object thereof is to reversely rotate an image carrier such as a photoreceptor through a driving means after the cleaning member is separated, so that the cleaning member remaining on the image carrier may be removed. In an image forming apparatus in which residual developer is returned upstream from the position of a cleaning member such as a cleaning blade so that it can be removed by the cleaning member when restarting, the image bearing member can be rotated in reverse despite its simple configuration. It is an object of the present invention to provide an image forming apparatus that can reliably prevent the reverse rotation of a pair of ejection rollers at the time of printing and that does not cause a recording medium such as a sheet ejected to a portion to be ejected such as a tray to become entangled.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an image carrier such as a photoreceptor that is driven in a predetermined direction by a driving means, and this image carrier. an image forming means for forming a developer image thereon; a transfer means for transferring the developer image formed by the image forming means onto a recording medium such as paper; A cleaning member such as a cleaning blade that comes into contact with the image carrier to remove residual developer and separates from the surface of the image carrier after the image forming operation is completed, and a driving force transmission system for the drive means that drives the image carrier. and a pair of discharge rollers that are driven and rotated through the cleaning member to discharge the recording medium after the developer image has been transferred to a discharge destination such as a tray. In an image forming apparatus, the residual developer remaining on the image carrier can be removed by the cleaning member at the time of restart by rotating the image carrier in the opposite direction and returning the residual developer remaining on the image carrier to the upstream side of the arrangement position of the cleaning member. The driving force transmission system for transmitting the driving force of the driving means to the pair of ejecting rollers is provided with a driving force connecting/disconnecting means such as a one-way rotation clutch so that the pair of ejecting rollers does not reverse rotation when the image carrier rotates in the opposite direction. It is something.

(Function) That is, in the present invention, by having the above-described configuration, the pair of discharge rollers can be prevented from rotating in reverse when the image carrier rotates in reverse, thereby preventing the recording medium at the discharged portion from being rolled up.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 3 shows the overall configuration of a two-color copying apparatus to which an embodiment of the present invention is applied, and FIG. 1 schematically shows the basic structure.

Reference numeral 1 in the figure indicates a copying machine main body, and a drum-shaped photoreceptor 2 as an image carrier is arranged in the center of the copying machine main body 1. 4. The surface potential of the band If device 39 as a charging means is sequentially increased along the 4. The exposure position of the exposure device 15, which will be described later, and the first developing device 5 as a developing means. A developer image forming means 25 such as a second developing device 6 is arranged. Furthermore, on the downstream side of the second developing device 6, there is a transfer charger 7 as a transfer means.
．． Peeling charger as first peeling means 8. Peeling equipment @9 as second peeling means, cleaning means 10. and static eliminating means 11 are arranged in this order.

In addition, an electrostatic latent image is formed in the upper part of the copying apparatus main body 1 by scanning a document (not shown) set on a document table 12 and exposing it between the surface potential sensor 4 and the first developing device 5. An exposure device 15 is provided as a means.

The exposure device 15 includes an exposure lamp 17 whose back is surrounded by a reflector 16 and serves as a light source for irradiating the document surface, a lens 18, and a plurality of lenses for guiding reflected light from the document surface to the surface of the photoreceptor 2 through the lens 18. Mirror 19-2
It consists of an optical system with 3.

In addition, a paper feed cassette 30. An upper paper feed section 33 consisting of a paper feed row 531 and a double sheet taking prevention means 32, a paper feed cassette 34, and a paper feed roller 35.
．． A lower paper feed section 37 consisting of a double-sheet prevention means 36 is installed, and the paper P, which is a recording medium, can be selectively fed by selective rotation of the paper feed rollers 31 and 35. There is.

Further, the paper P fed from these paper feed sections 33 and 37 is guided to a pair of registration rollers 40 via a paper supply path 38 and 39, and then stopped once, and then the registration rollers 40 transfer the paper P to the photosensitive material. The image is sent to an image transfer section 41 formed between the transfer charger 7 and the photoreceptor 2 in synchronization with the image forming operation on the body 2 .

Further, the paper P fed into the image transfer section 41 and onto which the image has been transferred is transferred via a paper conveyance path 45 to a pair of ejection rollers 46 disposed on the left side of the main body 1 of the copying apparatus. The paper is discharged onto a tray 47, and is fixed by a fixing means 48 during its conveyance.

Further, the cleaning means 10 includes a cleaning blade 50 as a cleaning member, and a blade driving means 51 for moving the cleaning blade 50 toward and away from the surface of the photoreceptor 2. The structure is such that it is possible to prevent an adverse effect on the photoreceptor 2 caused by leaving it in contact with the surface of the photoreceptor 2 .

Note that the blade driving means 51 has a weight 52 so that the tip of the cleaning blade 50 contacts the surface of the photoreceptor 2.
The blade holder 53 is always biased in a predetermined direction via the blade holder 53.
is forcibly rotated by a solenoid (not shown) to separate the cleaning blade 50 from the surface of the photoreceptor 2.

On the other hand, the photoreceptor 2 is driven by a driving means 56 whose driving source is a main motor 55 which is rotatable in both forward and reverse directions.

Further, the discharge roller pair 46 includes a first roller 60 disposed on the lower surface side of the paper conveyance path 45, and a first roller 60 disposed on the lower surface side of the paper conveyance path 45.
and a second roller 61 that rolls into contact with the first roller.
The roller 60 is connected to the driving means 5 for driving the photoreceptor 2.
6 and a driving force transmission system 62, so that the rotational force in both forward and reverse directions of the main motor 55 of the driving means 56 is transmitted to the first roller 60.

Further, a one-way rotation clutch 65 as a driving force connecting/disconnecting means is incorporated in the terminal end of the driving force transmission system 62 to prevent the discharge roller pair 46 from rotating in reverse when the photoreceptor 2 rotates in the opposite direction. ing. That is, as shown in FIG. 2, a one-way rotational clutch 65 is interposed between the 10-560 and the rotating shaft 66, and the 10-560 rotates only in the direction in which the paper P is ejected. It has a structure that allows it to rotate.

The operation of the thus configured copying apparatus is as follows.

That is, after the photoreceptor 2 is uniformly charged by the charger 3, it is exposed by the exposure device 15 to a static image corresponding to the original! A latent image is formed. This electrostatic latent image is developed by the first developing device 5 or the second developing device 6 which selectively operates, and a developer image is formed on the surface of the photoreceptor 2.

At this time, the paper P is sent to the transfer position 41 in synchronization with the developer image forming operation, and the developer image on the photoreceptor 2 is transferred to the paper P by the action of the transfer charger 7. rear,
The paper P is separated from the photoreceptor 2 by the separation charger 8 and sent to the fixing device 48, and after being fixed, it is ejected to the tray 47 via the ejection roller pair 46.

On the other hand, residual developer r remaining on the photoreceptor 2 without being transferred
is cleaned by the cleaning means 10, and then the static electricity is eliminated by the static eliminating means 11, and the photoreceptor 2 is brought into a clean state.

The cleaning blade 50 then separates from the surface of the photoreceptor 2 as the photoreceptor 2 stops in preparation for the next copying cycle.

Next, as described above with reference to FIG. 5, after the cleaning blade 50 is separated from the surface of the photoreceptor 2, the main motor 55 rotates in the opposite direction to rotate the photoreceptor 2 in the reverse direction, that is, in the direction of the broken line arrow, thereby cleaning the photoreceptor 2. The residual developer r on the photoreceptor 2 accumulated at the tip of the blade 50 is temporarily returned to the upstream side (in the direction of the transfer position 41) of the cleaning blade 50 arrangement position. The remaining developer r can be removed by the cleaning blade 50 at the time of restart, and the black streak phenomenon on the photoconductor 2 can be prevented from occurring due to the residual developer r passing through the location where the cleaning blade 50 is arranged. It becomes.

Further, when the photoreceptor 2 rotates in the reverse direction, the discharge roller pair 46 does not rotate in the reverse direction due to the action of the one-way clutch 65, so that the paper P on the tray 47 is not caught.

In the above-mentioned embodiment, the case where the application is applied to a copying apparatus capable of selectively performing two-color development has been described, but the present invention is not limited to this. What would be an image forming apparatus in which the residual developer remaining on the image carrier can be removed by the cleaning member when restarting by rotating the body in the opposite direction and returning the residual developer remaining on the image carrier to the upstream side of the position where the cleaning member is arranged? Of course, the present invention can also be applied to other configurations.

"Effects of the Invention" As explained above, according to the present invention, after the cleaning member is separated, the image carrier is rotated in the reverse direction via the driving means, and the residual developer remaining on the image carrier is removed by the cleaning member. In an image forming apparatus that can be removed by a cleaning member at the time of restart by returning it to the upstream side of the arrangement position, it is possible to ensure the reverse rotation of the ejection roller pair when the image carrier rotates in reverse despite the simple configuration. This has the advantage that it is possible to provide an image forming apparatus that can prevent the recording medium from being caught in the discharged section.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention,
Figure 1 is an explanatory diagram schematically showing the basic structure of the present invention, Figure 2 is an explanatory diagram schematically showing the basic structure of the present invention.
Figure 3 is a schematic longitudinal sectional front view of the copying machine, Figure 4 is a diagram schematically showing the basic structure of a conventional copying machine, Figure 5 is a black line diagram. FIG. 6 is an explanatory diagram illustrating the phenomenon prevention operation, and FIG. 6 is an explanatory diagram illustrating the state in which the recording medium is engulfed by the reverse rotation of the discharge roller pair. 2... Image bearing member (photoreceptor), 3... Charging means (charger), 5.6... Developing means (developing device), 10... Cleaning means, 15... Electrostatic latent Image forming means (exposure device), 25... Developer image forming means, 46... Discharging roller pair, 47... Discharging section (tray), 50... Cleaning member (cleaning blade), 55.・・・
Motor, 56... Drive means, 62... Drive force transmission system, 65... Drive force connection/disconnection means (one-way clutch), P.
...Recording body (paper), r...Residual developer. Applicant's Representative Patent Attorney Takehiko Suzue Figure 2 Figure 1 Figure 6

Claims (2)

[Claims] (1) an image bearing member driven in a predetermined direction by a driving means; an image forming means for forming a developer image on the image bearing member;
A transfer device that transfers the developer image formed by the image forming device to a recording medium; and a transfer device that contacts the image carrier after the developer image is transferred by the transfer device to remove residual developer and image the image. A cleaning member that separates from the surface of the image carrier after the formation operation is completed, and a driving means that drives the image carrier are driven and rotated via a driving force transmission system, and the recording member after the developer image has been transferred is transferred to a discharged portion. and a pair of discharge rollers for discharging the residual developer on the image carrier by rotating the image carrier in the opposite direction via a driving means after the cleaning member is separated, and removing the residual developer remaining on the image carrier upstream from the position where the cleaning member is disposed. In the image forming apparatus, the image forming apparatus can be removed by a cleaning member when restarting by returning the image bearing member to the side. 1. An image forming apparatus characterized in that a cutting means is provided to prevent a pair of ejection rollers from rotating in reverse when an image carrier is rotated in reverse. (2) The image forming apparatus according to claim 1, wherein the driving force connection/disconnection means is a one-way rotational clutch.