JP3101016B2 - Multicolor image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor image forming apparatus, and more particularly, to a transfer paper transport structure for an intermediate transfer pair.

[0002]

2. Description of the Related Art As is well known, in a multicolor image forming apparatus capable of forming images of full color or two or more colors, a visible image formed for each color on a photosensitive member is transferred to an intermediate transfer member. Once, and superimpose images of each color on the intermediate transfer body.
Thereafter, as a structure in which the visible image carried on the intermediate transfer body is collectively transferred to transfer paper, for example, Japanese Patent Laid-Open No.
No. 456 discloses this.

According to this, when a full-color image is obtained, for example, a belt-shaped photosensitive member is used, and an electrostatic latent image corresponding to the color of a document image color-separated on the photosensitive member is placed on an intermediate belt on the belt. A visible image is processed using a developer of a color complementary to the color of the color-separated image of the image sequentially transferred to the transfer body, and when the visible image has been superimposed, the visible image is transferred to a transfer paper. Are transferred at once.

[0004]

By the way, in the above-mentioned structure, particularly in the structure using a belt-shaped transfer member stretched as an intermediate transfer member, the transfer path of the transfer paper to the intermediate transfer belt is Specifically, when a paper jam occurs on the upstream side in the transport direction until the transfer position is reached, that is, when a so-called jam occurs, a hand is inserted near the transfer position on the intermediate transfer belt to remove the jammed transfer paper. You need to take it out.

However, when the intermediate transfer belt is extended in the vertical direction and the transfer position is set at the lower part of the intermediate transfer belt, if the hand is inserted from the upper part of the apparatus due to the layout, The hand may touch the surface of the intermediate transfer belt. Therefore, the intermediate transfer belt, which is configured so that the surface resistance and flatness affecting the transfer characteristics are in a predetermined state in advance, causes the above-described transfer characteristics due to the adhesion of hand oil and the occurrence of scratches when touched by a hand. May be changed. In particular, in recent years, in order to reduce the installation space of the image forming apparatus, a front loading structure has been adopted in which a paper feed cassette can be inserted and removed from the front side of the apparatus. Since the paper feed cassette is disposed below the intermediate transfer belt, if a jam of the transfer paper is to be eliminated, a guide plate or a feeding roller disposed on the transfer path of the transfer paper is required. Needs to be moved upward to open the transport path, whereby the risk described above is likely to increase stochastically. Therefore, there is a risk that a required image cannot be obtained due to a change in the transfer characteristics of the intermediate transfer pair.

Accordingly, an object of the present invention is to solve the problems in the above-described conventional multicolor image forming apparatus, and particularly to the problem of the jam when the transfer position between the intermediate transfer member and the transfer paper is set below the intermediate transfer member. An object of the present invention is to provide a multicolor image forming apparatus having a structure capable of preventing a hand from touching an intermediate transfer body at the time of resolution and preventing image characteristics from deteriorating.

[0007]

According to the first aspect of the present invention, visible images of different colors sequentially formed on a photoreceptor are sequentially superimposed and transferred on an intermediate transfer member, and the superimposed image on the intermediate transfer member is transferred. Full color transfer by batch transfer at the image transfer position to transfer paper
In a multicolor image forming apparatus for obtaining an image, a registration roller consisting of a pair of rollers located on the upstream side in the conveyance direction of the transfer paper with respect to the image transfer position, and guiding the transfer paper to the image transfer position, A guide member rotatably supporting a roller of the registration roller facing the upper surface of the transfer paper, and swinging in a direction capable of coming into contact with and separating from the roller facing the lower surface of the transfer paper; An intermediate transfer member disposed on a surface of the intermediate transfer member facing the guide member and covering the surface with a slight gap between the intermediate transfer member and the surface of the intermediate transfer member. It is characterized by having.

According to a second aspect of the present invention, in the multicolor image forming apparatus according to the first aspect, a paper feeding means is disposed below the intermediate transfer body, and a transfer position on a transfer sheet fed from the paper feeding means is adjusted. It is characterized in that it is set below the intermediate transfer member.

According to a third aspect of the present invention, visible images of different colors sequentially formed on a photosensitive member are sequentially superimposed and transferred on an intermediate transfer member, and the superimposed image is transferred onto transfer paper at an image transfer position of the intermediate transfer member. In a multicolor image forming apparatus for obtaining a full-color image by collective transfer, a guide member for guiding the transfer paper to the image transfer position and a surface of the intermediate transfer body facing the guide member are provided. Having a small gap between the surface of the intermediate transfer body and a protection means for the intermediate transfer body covering the surface, and a paper feeding means disposed below the intermediate transfer body. The transfer position to the transfer paper fed from the paper feeding means is set at a lower portion of the intermediate transfer body.

According to a fourth aspect of the present invention, visible images of different colors sequentially formed on a photoreceptor are sequentially superimposed and transferred onto a belt-shaped intermediate transfer body, and the superimposed image of the intermediate transfer body is transferred at an image transfer position. In a multicolor image forming apparatus for obtaining a full-color image by batch-transfer onto a transfer sheet, a transfer bias pulley and a tension pulley disposed at a position of the intermediate transfer member facing the photosensitive member; And a side plate rotatably supporting the tensioner and the tension pulley, and arranged to cover the intermediate transfer body with a slight gap from the surface of the intermediate transfer body, and open a range corresponding to the image transfer position. And an intermediate transfer member cover, wherein the intermediate transfer member cover is separable from the side plate. According to a fifth aspect of the present invention, visible images of different colors sequentially formed on a photoreceptor are sequentially transferred onto a belt-shaped intermediate transfer member at a first image transfer position, and the superimposed image of the intermediate transfer member is transferred. In a multicolor image forming apparatus for obtaining a full-color image by collectively transferring images to transfer paper at a second image transfer position, a transfer bias pulley and a tension disposed at a position of the intermediate transfer member opposed to the photosensitive member Pulley and
A side plate rotatably supporting the transfer bias pulley and the tension pulley; and a first image transfer position disposed so as to cover the intermediate transfer member with a slight gap from the surface of the intermediate transfer member. And an intermediate transfer body cover having an open area corresponding to the above-mentioned condition, wherein the intermediate transfer body cover is separable from the side plate. According to a sixth aspect of the present invention, visible images of different colors sequentially formed on a photoreceptor are sequentially transferred onto a belt-shaped intermediate transfer body at a first image transfer position, and the superimposed image of the intermediate transfer body is transferred. In a multicolor image forming apparatus for obtaining a full-color image by collectively transferring images to transfer paper at a second image transfer position,
A transfer bias pulley and a tension pulley arranged at a position facing the photoconductor, a side plate rotatably supporting the transfer bias pulley and the tension pulley, and a slight gap from the surface of the intermediate transfer body. An intermediate transfer body cover disposed so as to cover the intermediate transfer body, and opening an area corresponding to a first image transfer position and an area corresponding to a second image transfer position; The body cover is separable from the side plate.

[0011]

According to the present invention, the guide member located on the upstream side in the transport direction of the transfer paper to the intermediate transfer member is connected to the other registration roller.
The transfer path of the transfer paper can be opened by swinging and opening in a direction away from the roller, and even if the hand is inserted in this state, the intermediate transfer body is protected by the protection means. So that touch is prevented.

Further, according to the present invention, the area other than the transfer position with the photosensitive member and the transfer position with the transfer paper in the intermediate transfer body is covered with the intermediate transfer body cover, so that the intermediate transfer body can be moved along the transfer path of the transfer paper. Even when a hand is inserted, the hand can be prevented from touching the surface of the intermediate transfer member located in the middle of the hand.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a layout diagram showing the overall configuration of a multicolor image forming apparatus according to an embodiment of the present invention. (From here) In FIG. 1, the multicolor image forming apparatus 1 according to the present embodiment includes an original reading unit 1A and an image recording unit 1B,
Hereinafter, each unit will be described.

The above-mentioned original reading section 1A constitutes a scanner for reading a color original placed on an original placing table by a photoelectric conversion element.
B, a photoelectric conversion element including a document table 2, an illumination light source 3, an optical path forming mirror-4, an imaging lens 5, and a CCD for receiving reflected light from a color-separated document. And a color sensor 6 comprising:

In the above-described original reading section 1A,
The reflected light from the original is color-separated, for example, in the order of blue, green, and red, and then read as color image information by the color sensor 6, and an image signal corresponding to this information is sent to an image processing unit (not shown). Output. In the above-described image processing unit, based on the signal regarding the intensity level of the image output from the color sensor 6, the cyan, magenta, yellow, and gradation improvement and the black-and-white image having a complementary relationship with the color separation are performed. The color conversion processing for black at that time is performed, and a processing signal in an image recording unit 1B described later is output.

On the other hand, the image recording section 1B includes a writing section 7,
A photoconductor 8, a developing unit 9 and a transfer unit 10 are provided.

The writing section 7 converts the color image data from the color scanner 6 into an optical signal, performs optical writing according to the original image, and forms an electrostatic latent image on the photosensitive member 8. Specifically, the apparatus includes a laser light source 7A, a polygon mirror 7B serving as an optical scanning unit, an fθ lens 7C, and a reflection mirror 7D.

In the case of this embodiment, the photosensitive member 8 is constituted by a drum rotatable in the direction of the arrow shown in the figure, and is surrounded by a charging device 11 for executing a copying process along the rotating direction. The optical path from the writing section 7, the developing section 9, the transfer section 10, the cleaning device 12, and the charge removing lamp 13 are arranged.

The developing unit 9 described above, as shown in FIG.
In addition to the black developing device 9A, a cyan developing device 9B, a magenta developing device 9C, and a yellow developing device 9D for supplying a developer having a color complementary to the color separated in the document reading section 1A are provided. A developing sleeve 9E capable of causing the developer to stand on the photosensitive member, and a rotatable developing paddle 9F for assembling and transporting and stirring the developer. And a density detection sensor 9G for detecting the density of the stored developer. In the developing unit 9, only a developing device that stores a developer of a color corresponding to the color of the electrostatic latent image formed on the photosensitive drum 8 operates, and the developer is When the developer is supplied, the developer is spiked in the form of a developing sleeve and electrostatically adheres to the electrostatic latent image. During this time, the developing device containing the developer which is not present is kept in a standby state without causing the developer to stand.

As shown in FIG. 2, a belt-shaped transfer member is used for the transfer section 10.
A is a pump disposed at a position facing the photosensitive drum 8.
It is hung on a plurality of pulleys including the tension pulley 10A2 disposed at a position opposite to the pulley 10A1. Of the pulleys described above, the pulley denoted by reference numeral 10A3 indicates a drive pulley.
As shown in FIG. 3, 0A3 can be driven by a drive motor 10A5 via a reduction gear 10B. The drive motor 10A5 can be rotated forward or backward by a servo motor or a stepping motor. Data is used. A bias for transferring a visible image on the photosensitive drum 8 is applied to the pulley 10A1 disposed at a position facing the photosensitive drum 8 among the plurality of pulleys described above. The pulley 10A1 and the drive pulley 10A1
A facing pulley 10A4 facing the belt cleaning device 14 is arranged between the pulley 10A4 and A3.

On the other hand, a transfer paper transfer device 15 is disposed at a position facing the above-described drive pulley 10A3 with the transfer belt 10A interposed therebetween.
A transfer bias roller 15A to which a bias for image transfer is applied is provided at a position facing the drive pulley 10A3 in the support portion having a structure capable of coming in contact with and separating from the transfer belt 10A. Paper feeder 16 (FIG. 1)
The transfer belt 1 is held while nipping and transporting the transfer paper fed at a timing synchronized with the image leading end position.
The image on 0A is transferred.

In FIG. 2, reference numeral 17 denotes a transport belt.
In FIG. 1, reference numerals 18 and 19 indicate a fixing device and a paper discharge tray, respectively.

By the way, in the multicolor image forming apparatus of the present embodiment, the sheet feeding device 1 is provided below the transfer belt 10A.
A paper loading cassette 20 constituting a part of the paper feeding cassette 6 is disposed, and a front loading method is adopted in which the paper feeding cassette 20 can be inserted and removed in a direction perpendicular to the paper surface shown in FIG. The transfer position with the transfer sheet is set below the transfer belt 10A, and the transfer path of the transfer sheet is set toward this position. That is, the transfer path of the transfer sheet described above is set so that the transfer sheet fed from the paper feed cassette 20 is brought to the transfer position in a state of being bypassed, and the transfer direction with respect to the transfer position of the transfer sheet is set in the transfer direction. In front of the transfer position corresponding to the downstream side, a registration roller 21 for setting the paper feed timing of the transfer paper is disposed.

That is, the registration rollers 21 are a pair of rollers 21 which are vertically opposed to each other across the transfer paper transport path.
A and 21B, of which the roller 21A on the side facing the upper surface of the image transfer surface of the transfer paper is the roller 21B on the side facing the lower surface of the transfer paper by a guide member 22 described later. It is swingably supported so as to be able to come and go with respect to.

As shown in FIG. 3, the guide member 22 is composed of a pair of guide plates 22A and 22B located on the upstream side in the transport direction of the transfer sheet with respect to the transfer position. The guide member 22A located on the upper side corresponding to the opposing side is constituted by a swinging member having an end that rotatably supports the registration roller 21A as a swinging end, and an end on the fulcrum side is provided. , Which are fixed to a support shaft 22a supported by an immovable bracket (not shown). The guide member 22 is in contact with the other registration roller 21B as shown by a solid line in FIG. 3 to allow the transfer of the transfer sheet, and is separated from the other registration roller 21B so as to be separated from the transfer roller. The transfer path of the transfer paper can be selectively rocked to a position where the transfer path is opened and exposed, and the normal position is a position where the transfer of the transfer paper is allowed. Therefore, in the case where the transfer sheet is jammed in the transfer path on the upstream side in the transfer direction of the transfer sheet with respect to the transfer position, the transfer path is exposed by opening one of the guide members 22A and the clogged transfer is performed. The paper can be removed.

On the other hand, a protection means 23 for covering the surface of the transfer belt 10A is provided on the side of the transfer belt 10A opposite to the guide member 22. That is, the protection means 2
Reference numeral 3 designates one end of the guide member 22 formed integrally with a side plate 24 rotatably supporting the transfer bias pulley 10A1, the tension pulley 10A2 and the drive pulley 10A3 on which the transfer belt 10A is hung. 22A
A small gap is set between the sheet metal member and the surface on the opposite side to cover the sheet metal member. Therefore, the transfer belt 10A is connected to one of the guide members 22A.
Is opened to expose the transfer path of the transfer paper, and when the operator's hand enters the transfer path, the surface facing the entry path of the operator's hand is kept closed.

In FIG. 3, reference numeral 25 denotes a photosensitive drum 8 and a supporting face plate of a developing device disposed around the photosensitive drum 8, and a part of the face plate 25 is fixed together with the side plate 24 on the transfer belt 10A side. By doing so, positioning between the two can be performed. Also, in FIG.
Indicates an opening formed in the apparatus main body, and each member can be inserted and removed from the opening 26.

Since the present embodiment has the above configuration,
At the time of image formation, the guide member 22 is set to the normal position, and the transfer paper is fed out from the paper feed cassette 20, so that the batch transfer of images at the transfer position is performed. On the other hand, when the transfer paper is jammed on the way to the transfer position, the guide member 22 is swung in a direction to separate the one 22A from the other 22B to expose the transport path. In this state, the operator inserts his hand from the top of the apparatus, but the operator's hand is placed between the transfer belt 10A and the protection means 2 until the operator reaches the transport path.
3, so that touching the transfer belt 10A is prevented.

On the other hand, the above-mentioned protection means 23 may have the structure shown in FIGS.

That is, the protection means 27 shown in FIGS. 4 and 5 is composed of a cover provided at a position where a slight gap is set with respect to the surface of the transfer belt 10A. Is detachably attached to the side plate 24 on the transfer belt 10A side. The cover 27 includes a drive pulley 10A3 disposed at a transfer position with respect to the transfer paper and a transfer bias pulley provided at a transfer position with the photosensitive drum 8 with respect to the peripheral surface of the transfer belt 10A. The size is set such that the surface of the belt wound around 10A1 can be exposed.

In the above configuration, the transfer belt 10
The surface on the side facing the guide member 22 in FIG.
The cover 27 prevents the operator's hand from coming into contact with the surface of the belt, and should be removed from the side plate 24 of the transfer belt 10A during maintenance work on the transfer belt 10A. The maintenance work becomes possible.

[0033]

As described above, according to the present invention, in a structure in which the transfer position between the intermediate transfer member and the transfer paper is set on the transport path located below the intermediate transfer member, the transfer position By opening a part of the transfer path leading to the transfer belt, the transfer path is exposed to enable removal of the jammed transfer paper. By providing a protective means for covering this surface, it is possible to prevent the contact between the hand of the transfer belt and the hand when the hand of the operator is inserted for taking out the transfer paper. Therefore, it is possible to prevent the image characteristics from deteriorating due to the change in the electrical surface resistance characteristics and the mechanical surface characteristics that affect the transfer characteristics due to the damage of the surface of the intermediate transfer member. .

[Brief description of the drawings]

FIG. 1 is a layout diagram illustrating an overall configuration of a multicolor image forming apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged layout view of a part of the apparatus shown in FIG.

FIG. 3 is a schematic perspective view for explaining a configuration of a part of the main part shown in FIG. 2;

FIG. 4 is a schematic diagram for explaining a modification of the configuration shown in FIG. 2;

FIG. 5 is a perspective view showing a part of the modification shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Multicolor image forming apparatus 8 Photosensitive drum 10A Transfer belt as an intermediate transfer body 10A1 Transfer bias pulley 10A2 Tension pulley 20 Paper feed cassette 21 Registration roller 21A Roller 21B facing the upper surface of transfer paper 21B Roller 22A on the side facing the lower surface of the transfer paper 22A Guide member 23 Protecting means 24 Side plate 27 Cover

Claims (6)

(57) [Claims] 1. A method according to claim 1, wherein visible images of different colors sequentially formed on a photoreceptor are sequentially transferred onto an intermediate transfer member, and the superimposed images on the intermediate transfer member are collectively transferred to transfer paper at an image transfer position. A multi-color image forming apparatus that obtains a full-color image by: a registration roller including a pair of rollers positioned upstream of a transfer direction of the transfer sheet with respect to the image transfer position; and transferring the transfer sheet to the image transfer position. The transfer roller guides and rotatably supports a roller on the side of the registration roller facing the upper surface of the transfer sheet, and swings in such a direction as to be able to contact and separate from the roller on the side of the registration roller opposite to the lower face of the transfer sheet. A guide member, protection means for the intermediate transfer body, which is disposed on a surface of the intermediate transfer body facing the guide member and covers the surface with a slight gap between the surface of the intermediate transfer body; Characterized by having That the multi-color image forming apparatus. 2. A multi-color image forming apparatus according to claim 1, wherein a sheet feeding means is disposed below said intermediate transfer body, and a transfer position on a transfer sheet fed from said sheet feeding means is set to a position of said intermediate transfer body. A multicolor image forming apparatus, which is set at a lower part. 3. The method according to claim 1, wherein visible images of different colors sequentially formed on a photosensitive member are sequentially superimposed and transferred onto an intermediate transfer member, and the superimposed images are collectively transferred to transfer paper at an image transfer position of the intermediate transfer member. A multicolor image forming apparatus for obtaining a full-color image, a guide member for guiding the transfer paper to the image transfer position; and an intermediate transfer member disposed on a surface of the intermediate transfer member facing the guide member; A protection means for the intermediate transfer member that covers the surface with a slight gap between the intermediate transfer member and a paper supply means disposed below the intermediate transfer member. A multi-color image forming apparatus, wherein a transfer position to the transfer paper fed from the means is set below the intermediate transfer member. 4. A visible image of different colors sequentially formed on a photosensitive member is sequentially transferred onto a belt-shaped intermediate transfer member, and the superimposed image of the intermediate transfer member is collectively transferred to transfer paper at an image transfer position. A multi-color image forming apparatus that obtains a full-color image by performing a transfer bias pulley and a tension pulley disposed at a position of the intermediate transfer body facing the photoconductor, and the transfer bias pulley and the tension pulley. A side plate rotatably supported, and an intermediate transfer body cover arranged to cover the intermediate transfer body with a slight gap from the surface of the intermediate transfer body, and opening a range corresponding to the image transfer position Wherein the intermediate transfer body cover is separable from the side plate. 5. A visible image of different colors sequentially formed on a photosensitive member is sequentially transferred onto a belt-shaped intermediate transfer member at a first image transfer position, and a superimposed image of the intermediate transfer member is transferred to a second image transfer member. Batch transfer to transfer paper at the image transfer position
In the multicolor image forming apparatus for obtaining an image, a transfer bias pulley and a tension pulley disposed at a position of the intermediate transfer body facing the photoreceptor, and rotatably supporting the transfer bias pulley and the tension pulley. And an intermediate transfer member cover disposed so as to cover the intermediate transfer member with a slight gap from the surface of the intermediate transfer member, and opening an area corresponding to the first image transfer position. A multicolor image forming apparatus, wherein the intermediate transfer member cover is separable from the side plate. 6. A visible image of a different color sequentially formed on a photosensitive member is sequentially transferred onto a belt-shaped intermediate transfer member at a first image transfer position, and a superimposed image of the intermediate transfer member is transferred to a second image transfer member. Batch transfer to transfer paper at the image transfer position
In the multicolor image forming apparatus for obtaining an image, a transfer bias pulley and a tension pulley disposed at a position of the intermediate transfer body facing the photoreceptor, and rotatably supporting the transfer bias pulley and the tension pulley. And a side plate that covers the intermediate transfer body with a slight gap from the surface of the intermediate transfer body, and corresponds to a range corresponding to the first image transfer position and a second image transfer position. An intermediate transfer body cover having an open area, wherein the intermediate transfer body cover is separable from the side plate.