JP3705348B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile using an electrophotographic method, and more particularly to an apparatus for cutting off various driving power sources when an opening / closing cover of the apparatus main body is opened.
[0002]
[Prior art]
The image forming apparatus includes a driving power source for a laser light emitting unit, a high voltage power source for charging, developing and transferring, a photoconductor, a transfer belt, a fixing device, a transfer material conveying system, and the like. This image forming apparatus is provided with an interlock circuit that shuts off a predetermined power source for the safety of the user when the opening / closing cover of the apparatus main body is opened during printing. Conventionally, this interlock circuit is usually constituted by one system.
[0003]
[Problems to be solved by the invention]
By the way, in an image forming apparatus, there is a system in which a photosensitive member, a developing device, a transfer device, and the like are unitized and an opening / closing cover of the device main body is opened and closed to be detachable. At that time, the developing device is separated from the photosensitive member. At the same time, the tension of the belt of the photosensitive member or the transfer device is released.
[0004]
However, as shown in FIG. 6, when the user opens the front cover (opening / closing cover) during printing in step S51, the interlock circuit is turned off in step S52, and the drive system, the high voltage power supply, and the laser are de-energized. Then, as shown in step S53, the developing unit comes into contact, and the transfer belt tension remains stretched. This state is the same as the state during printing. Next, when the developing device lock lever or the photoconductor lock lever is released in step S54, as shown in step S55, the photoconductor is damaged when the developing device is pulled out, and the photoconductor is damaged when the photoconductor is pulled out. In this way, when the interlock circuit is activated and all the power is shut off, the developing device comes into contact with the photoconductor and the belt is tensioned. However, when the toner is pulled out, there is a problem that the photosensitive member and the belt are damaged.
[0005]
The present invention solves the above-described conventional problems, and prevents damage to the photoreceptor and belt when the user tries to pull out the photoreceptor unit and the development unit by opening the opening / closing cover of the apparatus main body during printing. An object of the present invention is to provide an image forming apparatus capable of performing the above.
[0006]
[Means for Solving the Problems]
For this purpose, the image forming apparatus according to claim 1 of the present invention is configured to open and close the open / close cover of the apparatus main body so that a plurality of image forming units can be attached and detached, and to supply and shut off power by opening and closing the open / close cover. In an image forming apparatus that supplies power to an image forming member via a circuit, power that is different from the interlock circuit is supplied to an image forming unit that makes contact and separation between the image forming units. As a feature,
According to a second aspect of the present invention, in the first aspect, the image forming unit is a developing unit, a photosensitive unit, and a transfer unit, and the photosensitive unit or the transfer unit includes a belt, and the belt has a tension. A tension / release mechanism is provided.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall configuration diagram showing an embodiment of an image forming apparatus of the present invention. This image forming apparatus is a color electrophotographic printer capable of forming a full color image with four color toners. However, the present invention is not limited to this, and all image forming apparatuses such as copying machines and facsimiles can be used. It is applicable to.
[0008]
In the image forming apparatus 1, a photoconductor 2 is disposed in the apparatus main body, and is driven to rotate in a direction indicated by an arrow by a driving motor M1. Around the photosensitive member 2, along the rotation direction, a charging roller 3 as a charging unit, an exposure unit 4 for forming an electrostatic latent image on the photosensitive member 2, and a photosensitive member 2 are formed. A developing unit U1 for developing the electrostatic latent image, a transfer unit U2 for transferring the toner image formed on the photoconductor 3 onto the intermediate transfer belt 5, and a toner remaining on the photoconductor 3 are removed. Cleaning means 6 is arranged for this purpose. The photoconductor 2, the charging roller 3, and the cleaning unit 6 are unitized as a photoconductor unit U3. The developing unit U1 and the transfer unit U2 are opened together with the opening / closing cover 31 (FIG. 3) of the apparatus main body so as to be detachable from the apparatus main body. It is configured to be wearable.
[0009]
The developing unit U1 includes a yellow developing unit 7Y, a cyan developing unit 7C, a magenta developing unit 7M, and a black developing unit 7K. Each developing unit includes a developing roller 7a and is driven by driving motors M2 and M3. Is done. The developing units 7Y, 7C, 7M, and 7K are arranged so as to be able to come into contact with the photosensitive member 2 by the separate contact clutches C1 to C4. Only the developing roller 7a of one developing device can be brought into contact with the photosensitive member 2.
[0010]
The transfer unit U2 includes an intermediate transfer belt 5, a primary transfer electrode roller 7 for uniformly charging the intermediate transfer belt 5, a drive roller 9 for rotating the intermediate transfer belt 5 by a drive motor M1, and an intermediate transfer belt 5. A tension roller 10 for tensioning, a secondary transfer roller 11 for transferring a toner image on the intermediate transfer belt 5 to a transfer material, a cleaning means 12 for removing residual toner on the intermediate transfer belt 5, A primary transfer roller 13 for transferring the toner image on the photosensitive member 2 to the intermediate transfer belt 5 is constituted. The secondary transfer roller 11 and the cleaning unit 12 can be brought into and out of contact with the intermediate transfer belt 5 as shown by the arrows in the figure by the driving motor M4 and the separation and contact clutches C5 and C6. The primary transfer roller 13 is movable inward of the intermediate transfer belt 5 by a driving motor M4 and a tension clutch C7 as shown by the arrow in the figure, and is configured to stretch or release the belt tension.
[0011]
A main body paper feed cassette 14 is disposed in the main body of the apparatus, an auxiliary paper feed cassette 15 is disposed on the side of the main body of the apparatus, and an upper portion of the main body of the apparatus is configured to store a transfer material on which an image is transferred. A paper tray 16 is provided, and a transfer material conveyance path 17 is formed between the paper feed cassettes 14 and 15 and the paper discharge tray 16. In the transfer material conveyance path 17, a gate roller 19 that controls the conveyance timing of the transfer material is disposed on the upstream side of the secondary transfer roller 11, and is driven by the drive motor M <b> 5 on the downstream side of the secondary transfer roller 11. A fixing unit U4 is provided.
[0012]
The main body paper feed cassette 14 and the auxiliary paper feed cassette 15 are provided with a pick-up roller 20 and a transport roller 21 for feeding a transfer material to the transfer material transport path 17 one by one. It is driven by turning on and off the clutch. The main body paper feeding cassette 14 and the auxiliary paper feeding cassette 15 are unitized as a main body paper feeding unit U5 and an auxiliary paper feeding unit U6, respectively, and are configured to be detachable from the apparatus main body.
[0013]
The operation of the image forming apparatus having the above configuration will be described. When an image forming signal from a computer (not shown) is input, the photosensitive member 2 and the intermediate transfer belt 5 are rotationally driven. First, the surface of the photosensitive member 2 is uniformly charged by the charging roller 3 and uniformly charged. The exposure unit 4 selectively exposes the surface of the photoreceptor 2 in accordance with the image information of the first color (for example, yellow) to form a yellow electrostatic latent image.
[0014]
Next, only the developing roller 7a of the yellow developing unit 7Y comes into contact with the photosensitive member 2, whereby a yellow electrostatic latent image toner image is formed on the photosensitive member 2. A primary transfer voltage having a polarity opposite to the charging polarity of the toner image is applied to the side end portion of the intermediate transfer belt 5 by the primary transfer electrode roller 7, and the toner image formed on the photoreceptor 2 is transferred by the primary transfer roller 13. The image is transferred onto the intermediate transfer belt 5. At this time, the secondary transfer roller 11 and the cleaning unit 12 are separated and retracted from the intermediate transfer belt 5. Residual toner on the photosensitive member 2 is removed by the cleaning unit 6 each time, and then the surface of the photosensitive member 2 is discharged by a discharging unit (not shown).
[0015]
In response to the second color, the third color, and the fourth color of the image formation signal, the above operation is repeated to form a latent image, develop, and transfer by one rotation of the photosensitive member 2 and the intermediate transfer belt 5, and the image formation is performed. Four color toner images corresponding to the contents of the signals are superimposed and transferred on the intermediate transfer belt 5. Then, at the timing when this full-color image reaches the secondary transfer roller 11, the gate roller 19 is driven and the transfer material is supplied to the secondary transfer roller 11 through the transfer material conveyance path 17, and at this time, the secondary transfer roller 11 and The cleaning unit 12 is brought into contact with the intermediate transfer belt 5 and a secondary transfer voltage is applied to the secondary transfer roller 11 so that the full-color toner image on the intermediate transfer belt 5 is transferred onto the transfer material. Residual toner on the intermediate transfer belt 5 is removed by the cleaning means 12. The transferred image transferred onto the transfer material is fixed by the fixing unit U 4 and discharged to the paper discharge tray 16.
[0016]
FIG. 2 is a view for explaining the abutment contact and belt tension stretching / releasing operation of the developing device in FIG.
[0017]
FIG. 2A shows a state during printing. The separation / contact clutch C4 is turned on, the K developing unit 7K moves to the arrow shown in FIG. 2 and comes into contact with the photosensitive member 2, and the tension clutch C7 is turned on. The primary transfer roller 13 moves in the direction of the arrow shown in the figure, and tension is applied to the intermediate transfer belt 5.
[0018]
FIG. 2B shows a standby state until printing is completed and the next printing operation is performed. The separation / contact clutch C4 is turned off, the K developing device 7K moves to the illustrated arrow and is separated from the photosensitive member 2, and the tension clutch C7. Is turned off, and the tension roller 10 and the primary transfer roller 13 are moved in the direction of the arrows in the figure to release the tension on the intermediate transfer belt 5. Accordingly, the belt can be prevented from creeping or deforming by loosening the belt tension.
[0019]
FIG. 3 is a schematic view of the appearance of the image forming apparatus. A front cover (open / close cover) 31 is provided on the front surface of the apparatus main body 30 so as to be openable and closable, and the developing unit U1, the transfer unit U2, and the photosensitive unit U3 are detachable from the apparatus main body 30. An interlock switch S1 that supplies and cuts off power by opening and closing the front cover 31 and interlock switches S2, S3, and S4 that supply and cut off power by attaching and detaching the units U1, U2, and U3 are provided. Also, a fixing unit U4 is detachably disposed on the side surface of the apparatus main body 30, and an interlock switch S5 that supplies and shuts off power by opening and closing a cover of the fixing unit U4 and a power supply and shutting off by sliding the fixing unit U4. An interlock switch S6 is provided.
[0020]
Further, an auxiliary paper feeding unit U6 is disposed on the side surface of the apparatus main body 30, and an interlock switch S7 is provided to supply and shut off power by sliding. Further, on the side surface of the apparatus main body 30, a main body paper supply cover 32 and a paper discharge cover 33 are provided so as to be openable and closable, and interlock switches S8 and S9 for supplying and shutting off power by opening and closing the respective covers are provided. . Further, an upper cover 34 is provided on the upper surface of the apparatus main body 30 so as to be openable and closable, and an interlock switch S10 that supplies and shuts off power by opening and closing the cover is provided.
[0021]
4 and 5 show an embodiment of the image forming apparatus of the present invention. FIG. 4 is a configuration diagram of a control system, and FIG. 5 is a diagram for explaining the operation.
[0022]
In FIG. 4, the AC 100V power source of the power source unit 35 is connected to the fixing unit (heater) 36, and the DC 24V, 5V power source is the first interlock circuit 37 (the interlock switch 37a and the relays R1 and R2 are collectively interlocked). The circuit 37 is connected to a paper feed / paper transport unit (paper feed drive / electromagnetic clutch) 38, a high voltage power source (charging, development, transfer bias application) 39, and an exposure unit (laser irradiation) 40. .
[0023]
The 24V power source of the power supply unit 35 is connected to the developing unit (developer drive / development in FIG. 1) via the second interlock circuit 41 (the interlock switch 41a and the relay R3 are collectively referred to as the interlock circuit 41). Device separation contact mechanism drive) 42 and transfer portion (transfer belt drive / transfer belt tension tension / release mechanism drive) 43. Specifically, the developing unit 42 is the developing device driving motors M1 and M2 / separation clutches C1 to C4 of FIG. 1, and the transfer unit 43 is the transfer belt driving motor M1 and transfer belt tension tension / Release clutches C5 to C7.
[0024]
The interlock switch 37a of the first interlock circuit 37 is supplied with the interlock switch S1 that supplies and shuts off the power by opening and closing the front cover 31, and the power by opening and closing the cover of the fixing unit U4, as described in FIG. Interlock switch S5 that shuts off, interlock switch S6 that feeds and shuts off power by sliding the fixing unit U4, interlock switch S7 that feeds and shuts off power by sliding the auxiliary paper feeding unit U6, the paper feed cover 32 and the drain Interlock switches S8 and S9 that supply and shut off power by opening and closing the paper cover 33 and an interlock switch S10 that supplies and shuts off power by opening and closing the upper cover 34 are connected in series. The second interlock circuit 41 has a configuration in which interlock switches S2, S3, and S4 that supply and cut off power by attaching and detaching the developing unit U1, the transfer unit U2, and the photosensitive unit U3 are connected in series.
[0025]
Next, the operation of the present invention will be described with reference to FIG. When the user opens the front cover (open / close cover) during printing in step S41, the first interlock circuit 37 is turned off in step S42, and the feed / paper transport unit 38, the high-voltage power source 39, and the exposure unit 40 Energization is cut off. In step S43, the developing device is separated and the transfer belt tension is released. This state is the same as the standby state from the end of printing until the next printing operation. Next, when the developing device lock lever or the photoconductor lock lever is released in step S44, as shown in step S45, the photoconductor is not damaged even if the developing device is pulled out, and the photoconductor is not damaged even if the photoconductor is pulled out. . Note that the second interlock circuit 41 is turned off simultaneously with the drawing and the power supply is cut off.
[0026]
Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications are possible. For example, in the above embodiment, a photosensitive drum is used as the photosensitive member and a transfer belt is used as the intermediate transfer member. However, a photosensitive belt and a transfer drum may be used.
[0027]
Further, in the above-described embodiment, the two interlock circuits are targeted for the developer contact and belt tensioning / releasing, but the transfer materials of the main body paper feeding unit U5 and the auxiliary paper feeding unit U6 are used. The separation contact may be targeted.
[0028]
【The invention's effect】
As is clear from the above description, when the user opens the opening / closing cover of the apparatus main body and pulls out the photosensitive unit and the developing unit during printing, damage to the photosensitive member and the belt can be prevented.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram showing an embodiment of an image forming apparatus of the present invention.
FIG. 2 is a view for explaining a developer unit separation contact and belt tension tensioning / releasing operation in FIG. 1;
3 is a schematic view of the appearance of the image forming apparatus of FIG.
FIG. 4 is a configuration diagram of a control system showing an embodiment of the image forming apparatus of the present invention.
FIG. 5 is a diagram for explaining the operation of FIG. 4;
FIG. 6 is a diagram for explaining the problem of the present invention.
[Explanation of symbols]
2 ... photosensitive member 5 ... intermediate transfer belts 7Y, 7C, 7M, 7K ... developer 31 ... opening / closing cover 37 ... first interlock circuit 41 ... second interlock circuit U1 ... developer unit U2 ... transfer unit U3 ... Photoreceptor units C1 to C4 ... separation / contact clutch C7 ... tension clutch

Claims (2)

An image forming apparatus configured to open and close an open / close cover of the apparatus main body so that a plurality of image forming units can be attached and detached, and to supply power to an image forming member via an interlock circuit that supplies and shuts off power by opening and closing the open / close cover The image forming apparatus according to claim 1, wherein a power source different from the interlock circuit is supplied to the image forming units that contact and separate from each other. The image forming unit is a developing unit, a photoconductor unit, and a transfer unit, and the photoconductor unit or the transfer unit is constituted by a belt, and the belt is provided with a tension stretching / releasing mechanism. The image forming apparatus according to claim 1.

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