JP2002108172A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus, especially, a tandem type full color image forming apparatus where a transfer unit can be easily detached from and attached to the inside of a housing main body. SOLUTION: A transfer unit having a transfer belt and a paper feeding/ carrying unit provided with a paper feeding roll are built into a main body housing provided with an image forming area where a photosensitive drum is arranged, and transfer paper is carried from the paper feeding roll of the paper feeding/carrying unit to the transfer unit, and a toner image formed on the photosensitive drum is transferred to the surface of this transfer paper while the transfer paper is carried by a transfer belt of the transfer unit. In this image forming device, a rail shaped groove extended along the paper feeding/carrying direction of the transfer paper is formed in the inside surface of the main body housing, and projections which are engaged with this rail shaped groove and can slide in this groove are formed on the outside surfaces of side parts of the transfer unit and the paper feeding/carrying unit, and these projections are slid in the groove to integrally introduce the transfer unit and the paper feeding/carrying unit into the main body housing and to detach them from the main body housing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer.
More specifically, the present invention relates to an image forming apparatus in which a transfer unit is integrated into a main body housing constituting an image forming apparatus and can be detached from the main body housing.

[0002]

2. Description of the Related Art An electrophotographic image forming apparatus typified by a copying machine has an image forming area in which a photosensitive drum is disposed in a main body housing constituting the image forming apparatus. Peripheral devices such as a main charging device, an optical system for image exposure, a developing device, a static eliminator, and a cleaning device are arranged, and a toner image formed on a photosensitive drum is provided below the image forming area by a predetermined amount. A transfer unit for transferring to paper (transfer paper) is incorporated. Further, in the main body housing, a paper feed / conveyance unit for supplying the transfer paper to the transfer unit and a fixing unit for fixing the toner image transferred on the surface of the transfer paper are also incorporated.

Recently, an image forming apparatus capable of forming a full-color image has also been widely used. As such a full-color image forming apparatus, a plurality of photosensitive drums dedicated to each color are provided side by side along a sheet feeding direction. A so-called tandem arrangement is known. That is,
A full-color image is formed by forming a black toner image, cyan toner image, magenta toner image, yellow toner image, etc. using separate photosensitive drums dedicated to each color, transferring the toner images of each color onto transfer paper and superimposing them It is to do. In such a tandem type full-color image forming apparatus, a transfer unit of a transfer belt type is used,
A transfer belt stretched between a plurality of rollers is disposed below the photosensitive drum of each color described above. Transfer paper is supplied on the transfer belt, and the transfer belt transfers the photosensitive drum. By passing the transfer paper through the area, transfer and superposition of the toner image are performed, and there is an advantage that full-color image formation is performed while the transfer paper is continuously fed.

[0004]

In the tandem-type full-color image forming apparatus described above, a plurality of photosensitive drums are arranged side by side, and a transfer belt is arranged over the entire lower side. Therefore, there is a disadvantage in that it is extremely troublesome to remove the transfer unit from the housing main body for exchanging the transfer belt or the like. That is, in a conventionally known device, the transfer unit is removed from the upper portion of the housing main body after opening the upper cover of the housing main body and removing the photosensitive drum and the like. There is such a problem. Therefore, not only when the transfer belt is replaced, but also when the so-called JA
Even when M (transfer paper jam) occurs, it is necessary to remove the photosensitive drum or the like in order to remove the jammed transfer paper, and its improvement is required.

Accordingly, it is an object of the present invention to provide an image forming apparatus, particularly a tandem type full-color image forming apparatus, in which a transfer unit can be easily removed from the housing main body or mounted in the housing main body. It is in.

[0006]

According to the present invention, a transfer unit having a transfer belt and a paper feeder having a paper feed roller are provided in a main body housing having an image forming area in which a photosensitive drum is arranged. The transfer unit is incorporated, the transfer paper is transferred from the paper feed roller of the paper transfer unit to the transfer unit, and the transfer paper is transferred by the transfer belt of the transfer unit while the toner formed on the photosensitive drum is transferred. In the image forming apparatus for transferring an image to the surface of the transfer paper, a rail-shaped groove extending along a paper feeding and conveying direction of the transfer paper is formed on an inner surface of the main body housing, and the transfer unit and the supply unit are provided. On the outer surface of the side of the paper transport unit,
Each of the protrusions is formed so as to engage with the rail-shaped groove and slide in the rail-shaped groove. By sliding the protrusion into the rail-shaped groove, the transfer unit and the sheet feeding / conveying unit are formed. Are integrally introduced into the body housing and can be detached from the body housing.

According to the present invention, a rail-shaped groove provided on the inner surface of the housing body along the paper feeding direction is used,
Along the rail groove, the transfer unit and the sheet feeding / conveying unit can be integrally pulled out from the inside of the housing main body and can be introduced into the housing main body. Therefore, when pulling out the transfer unit, it is not necessary to remove the photosensitive drum or the like from the inside of the housing main body, and the transfer unit can be mounted while the photosensitive drum is still attached. The operation of removing the transferred transfer paper can be easily performed.

In the present invention, the projection on the outer surface of the side of the transfer unit, which engages with the rail-shaped groove formed on the inner surface of the housing body and slides along the rail-shaped groove, is used as a positioning boss. It is preferable that the protrusion on the outer surface of the side portion is a rail-shaped protrusion which is broken in the middle. That is, the positioning boss formed in the transfer unit is inserted into the broken portion of the rail-shaped protrusion formed in the sheet feeding / conveying unit, so that the transfer unit and the sheet feeding / conveying unit are integrally introduced and detached. Can be easily performed.

The rail-shaped groove formed on the inner surface of the main body housing includes a wide first rail-shaped groove and a narrow second rail-shaped groove formed in the first rail-shaped groove. Preferably, the positioning boss on the outer surface of the transfer unit side portion includes a large-diameter boss that can slide by engaging with the first rail-shaped groove and a positioning boss that engages with the second rail-shaped groove. It is preferable that a small-diameter boss that can slide is used, and the rail-shaped protrusion on the outer surface of the side of the sheet feeding / conveying unit is shaped so as to engage with the wide first rail-shaped groove and slide. . That is, the rail groove of the main body housing has a double structure, and two types of positioning bosses on the outer surface of the side of the transfer unit that can be engaged and slid with the first or second rail groove are used. By setting the shapes of the first and second rail-shaped grooves, the mounted transfer unit can be positioned close to the photosensitive drum, and the transfer can be performed when the transfer unit is pulled out integrally with the sheet feeding / conveying unit. The unit can be separated from the photosensitive drum.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to specific examples shown in the accompanying drawings. FIG. 1 is a schematic side cross-sectional view showing a state in which a transfer unit and a sheet feeding / conveying unit are mounted in a housing main body in the image forming apparatus of the present invention, and FIG. FIG. 3 is a diagram showing a side cross section of a sheet feeding and conveying unit used in the present invention, and FIG. 4 is an enlarged diagram showing a cross section of a rail-shaped groove formed on the inner surface of the housing main body. Yes,
FIG. 5 is a diagram showing a positional relationship between the transfer unit and the sheet feeding / conveying unit when they are integrally attached or detached.

In FIG. 1, in this image forming apparatus, an image forming area indicated by A as a whole is provided in a main body housing (omitted for convenience). 1. Drums (in FIG. 1, in order from the right, photosensitive drum 1a for black toner, photosensitive drum 1b for cyan toner, photosensitive drum 1 for magenta toner
c, a photosensitive drum 1d for yellow toner) is arranged side-by-side, and a transfer unit indicated by 2 as a whole is incorporated below the image forming area A (that is, below each of the photosensitive drums 1a to 1d). On the right side of the image forming area A, a paper feed / conveyance unit indicated by 3 is incorporated as a whole.

Referring also to FIG. 2 showing the structure of the transfer unit 2, the transfer unit 2 includes a pair of belt drive rollers 5, 5 (one is a drive roller and the other is a driven roller). A transfer belt 6 is stretched around the belt driving rollers 5 and 5, and the transfer belt 6 is arranged over the entire lower part of the image forming area A. That is, the transfer belt 6 is located below any of the photosensitive drums 1a to 1d. Further, inside the transfer belt 6, transfer rollers 8 are provided so as to face the respective photosensitive drums 1a to 1d. Each transfer roller 8
As shown in FIG. 1, the transfer belt 6 is urged upward by a spring 9 as necessary.
Abuts. The above-described belt drive roller 5 and transfer roller 8 are held on the side plate 10 of the unit frame.

Referring to FIG. 3 showing the structure of the sheet feeding / conveying unit 3 together with FIG. 1, a sheet feeding roller 12 and a conveyance guide roller 13 are provided, and these are held on side plates 15 of the unit frame. Have been. Although not shown, the sheet feeding roller 12 of the unit frame of the sheet feeding and conveying unit 3 is not shown.
Is provided with a mounting portion for the paper feed cassette.

That is, in FIG. 1, each photosensitive drum 1a
1 to 1d, image forming devices (not shown) such as a main charging device, an optical system for image exposure, a developing device, a static eliminator, and a cleaning device are arranged, respectively. In the photoconductor drum 1a, the photoconductor drum 1a is uniformly charged to a predetermined polarity by a main charging device, image exposure is performed by light irradiation through an optical system, and an electrostatic latent image is formed. The latent image is developed by the developing device to form a black toner image on the photosensitive drum 1a. On the other hand, the transfer paper loaded on the paper feed cassette mounted on the paper feed / conveyance unit 3 is supplied from the paper feed roller 12 to the transfer belt 6 of the transfer unit 2 via the conveyance guide roller 13, and FIG. It is conveyed from the middle and right to the left. When the transfer paper passes below the photosensitive drum 1a, the transfer roller 8 disposed opposite to the drum 1a with the transfer belt 6 interposed therebetween is opposite to the black toner image on the drum 1a. A bias voltage having a polarity is applied, whereby a black toner image is transferred onto the transfer paper surface. After the transfer of the black toner image, the surface of the photosensitive drum 1a is neutralized by a neutralization device, and the toner (black toner) remaining on the drum 1a is removed by a cleaning device. The image forming cycle in 1a is completed. Hereinafter, a similar image forming cycle is performed on the photosensitive drum 1b for cyan toner, the photosensitive drum 1c for magenta toner, and the photosensitive drum 1d for yellow toner, and a black toner image, a cyan toner image, a magenta toner The image and the yellow toner image are superimposed to form a full-color toner image on the transfer paper surface. The transfer paper on which the full-color toner image has been formed in this manner is discharged from the transfer belt 6 to the left side in FIG. 1 and introduced into a fixing unit (not shown) incorporated in the image forming apparatus, and heat, Fixing by pressure is performed, thereby forming a full-color image.

In the present invention, a rail-shaped groove 20 is formed on the inner surface of the housing body along the transfer paper transfer direction (indicated by an arrow X in FIG. 1) as shown by a dotted line in FIG. The transfer unit 2 and the sheet feeding / conveying unit 3 are integrally attached and detached by sliding along the rail-shaped groove 20. This rail-shaped groove 20 has a double structure, and as shown in the side sectional view of FIG.
5 and a narrow second rail-shaped groove 26 formed and extending in the first rail-shaped groove.

As is clear from FIG. 1, the first rail-shaped groove 25 is formed longer than the second rail-shaped groove 26, and its tip (left side in FIG. 1) has an upward direction. An inclined portion 25a is formed, and the first rail-shaped groove 25 ends at a short horizontal portion 25b connected to the inclined portion 25a. On the other hand, the tip end of the second rail-shaped groove 26 is derailed from the first rail-shaped groove 25 and ends with a short inclined portion 26a inclined upward. Note that the rail-shaped groove 20 having the above-described shape or structure is used.
Are formed on the inner surface of the front housing and the inner surface of the rear housing in FIG.

Further, in the present invention, as is apparent from FIGS. 1 and 2, the outer surface of the side plate 10 of the transfer unit 2 is
A large-diameter boss 30 and a small-diameter boss 31 for positioning are formed. The large-diameter boss 30 engages with and slides in the wide first rail-shaped groove 25 formed on the inner surface of the main body housing.
1 engages with a narrow second rail-shaped groove 26 extending in a wide first rail-shaped groove 25 and slides in the groove 26. Therefore, the height of the small diameter boss 31 is
It is set higher than the large diameter boss 30. The distance D between the large-diameter boss 30 and the small-diameter boss 31 is set so as to correspond to the distance between the terminal ends of the first rail-shaped groove 25 and the second rail-shaped groove 26. In addition, such a large-diameter boss 30
The small-diameter boss 31 is also formed on the rear side plate 10 not shown in FIG.

Further, in the present invention, an extension 2a extending toward the transfer unit 2 is formed in a lower portion of the side plate 15 of the sheet feeding and conveying unit 3, and the lower portion including the extension 2a is formed. A rail-shaped protrusion 35 extends over the entire outer surface. The rail-shaped protrusion 35 engages with the wide first rail-shaped groove 25 formed on the inner surface of the main body housing and slides in the groove 25. As is clear from FIG. 3, a disconnection portion 36 is formed near the tip of the rail-shaped protrusion 35, and a cutout 38 is formed in the side plate 15 so as to include the disconnection portion 36. I have. The disconnection portion 36 has such a size that at least the small-diameter boss 31 described above can enter, and the notch 38 has a small diameter on the rail-shaped protrusion 35 on the right side in FIG. The boss 31 has a size or a shape such that the boss 31 can ride on and be held. The rail-shaped protrusion 35 and the notch 38 described above are used.
Are also formed on the rear side plate 15 not shown in FIG.

According to the present invention, by using the transfer unit 2 and the paper feed unit 3 having the above-described structures,
In a state where these units 2 and 3 are integrated, the units 2 and 3 can be introduced into a predetermined position in the main body housing constituting the image forming apparatus, and can be detached from the main body housing. That is, referring to FIG. 5, which shows the positional relationship between the transfer unit 2 and the sheet feeding / conveying unit 3 at the time of such mounting (introduction) or detachment, the small diameter boss 31 of the transfer unit 2 is connected to the rail The transfer unit 2 is inserted into the disconnection portion 36 of the projection 35 so that the transfer unit 2
Hold it on top, and in this state, attachment and detachment are performed.

For example, in the state shown in FIG. 5, the large-diameter boss 30 of the transfer unit 2 and the rail-shaped projection 35 of the sheet feeding / conveying unit 3 are connected to the wide first boss extending on the inner surface of the main body housing.
1 and slide from right to left in FIG. Thus, the small-diameter boss 31 that has entered the disconnection portion 36 slides in the narrow second rail-shaped groove 26. As described above, when the transfer unit 2 and the sheet feeding / conveying unit 3 are integrally pushed into the main body housing, the large-diameter boss 3 of the transfer unit 2 is moved.
0 stops after passing through the inclined portion 25a at the end of the wide first rail-shaped groove 25 and entering the horizontal portion 25b. On the other hand, the small-diameter boss 31 enters and stops in the inclined portion 26 a formed at the tip of the second rail-shaped groove 26, but the rail-shaped protrusion 35 slides in the first rail-shaped groove 25. Therefore, the small-diameter boss 31 stopped in the inclined portion 26 a is stably held while riding on the rail-shaped protrusion 35. In this manner, the transfer unit 2 is finally held in a state of being lifted upward, and as shown in FIG.
The transfer unit 2 is positioned in a state where the photoconductor drums 1a to 1d are close to each other, and the above-described image formation is performed.

On the other hand, when the transfer unit 2 and the paper feed unit 3 are detached from each other, when the paper feed unit 3 is pulled to the right in FIG. 1 in the state shown in FIG. Since the small-diameter boss 31 of the transfer unit 2 held on the rail-shaped protrusion 35 is slid into the disconnection portion 36 of the rail-shaped protrusion 35 to slide to the right in the rail-shaped groove 25. Into the second rail-shaped groove 26
In order to slide to the right, the large-diameter boss 30 of the transfer unit 2 also slides to the right through the first rail-shaped groove 25 through the inclined portion 25a. That is, the transfer unit 2
Is pulled down integrally with the paper feed / conveyance unit 3 in a state where the distance between the transfer belt 6 and the photosensitive drums 1a to 1d is increased as a whole.

[0022]

As described above, according to the present invention, the transfer unit 2 and the sheet feeding / conveying unit 3 can be easily integrated from the inside of the main body housing without removing the photosensitive drums 1a to 1d from the inside of the main body housing. , And these can be integrally mounted in the main body housing. Therefore, JAM on the transfer belt 6
The operation of removing the transfer paper can be performed extremely easily by removing the transfer unit 2, and the operation of replacing the transfer belt 6 provided in the transfer unit 2 can be performed extremely easily. The present invention is particularly useful for a large-sized image forming apparatus in which a large number of photosensitive drums are arranged on a transfer belt, such as a tandem-type full-color image forming apparatus, and in which it is troublesome to take out a transfer unit having the transfer belt. It goes without saying that the present invention can be applied to other types of full-color image forming apparatuses having only one photosensitive drum or image forming apparatuses dedicated to monochrome images.

[Brief description of the drawings]

FIG. 1 is a schematic side cross-sectional view showing a state in which a transfer unit and a sheet feeding / conveying unit are mounted in a housing main body in the image forming apparatus of the present invention.

FIG. 2 is a diagram showing a side cross section of a transfer unit used in the present invention.

FIG. 3 is a diagram showing a side cross section of a sheet feeding and conveying unit used in the present invention.

FIG. 4 is an enlarged view showing a cross section of a rail-shaped groove formed on an inner surface of a housing main body.

FIG. 5 is a diagram showing a positional relationship between a transfer unit and a sheet feeding / conveying unit when they are integrally attached or detached.

[Explanation of symbols]

 1a to 1d: photosensitive drum 2: transfer unit 3: paper feed unit 6: transfer belt 8: transfer roller 10: side plate of transfer unit 12: paper feed roller 15: side plate of paper feed unit 20: rail-shaped groove 25 : Wide first rail groove 26: Narrow second rail groove 30: Large diameter boss 31: Small diameter boss 35: Rail-shaped projection 36: Disconnection 38: Notch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) G03G 15/16 G03G 15/00 554 F-term (reference) 2H030 AA07 AB02 AD05 BB44 BB46 BB71 2H032 AA05 AA15 BA18 BA19 BA23 2H071 BA03 BA13 BA14 BA16 BA19 BA22 BA36 DA09 DA15 DA22 DA23 EA04 EA18 3F049 AA04 BA00 CA31 DA03 DA12 DB05 DB06 LA04 LA05 LA07 LB03 3F343 FA02 FC08 HA16 JA01 KB03 KB04 KB05 KB06 KB13 LA04 LA13 LC02

Claims (5)

[Claims] 1. A transfer unit having a transfer belt and a paper feed unit having a paper feed roller are incorporated in a main body housing having an image forming area in which a photosensitive drum is arranged. The transfer paper is transported from the paper feed roller of the unit to the transfer unit, and the toner image formed on the photosensitive drum is transferred onto the surface of the transfer paper while the transfer paper is transported by the transfer belt of the transfer unit. In the forming apparatus, a rail-shaped groove extending along a paper feeding and conveying direction of the transfer paper is formed on an inner surface of the main body housing, and a side outer surface of the transfer unit and the paper feeding and conveying unit is Protrusions which are respectively engaged with the rail-shaped grooves and are slidable in the rail-shaped grooves are formed. By sliding the protrusions into the rail-shaped grooves, transfer is performed. An image forming apparatus characterized in that the unit and the sheet feeding / conveying unit can be integrally introduced into and detached from the main body housing. 2. The projecting portion of the transfer unit is a positioning boss, the projecting portion of the paper feeding and conveying unit is a rail-shaped projecting portion broken in the middle, and the positioning boss is provided on a broken portion of the rail-shaped projecting portion. 2. The image forming apparatus according to claim 1, wherein the transfer unit and the sheet feeding / conveying unit are integrally introduced and detached in a state where the sheet enters. 3. The rail-shaped groove formed on the inner surface of the main body housing includes a first rail-shaped groove having a wide width and a second rail-shaped groove having a narrow width formed in the first rail-shaped groove. On the outer surface of the transfer unit side portion, as the positioning boss,
A large-diameter boss that is slidable by engaging with the first rail-shaped groove, and a small-diameter boss that is slidable by engaging with the second rail-shaped groove; The rail-shaped protrusion formed on the transfer unit is engaged with the first rail-shaped groove and can slide. The image forming apparatus according to claim 2, wherein the image forming apparatus is integrally introduced and detached from the sheet feeding / conveying unit. 4. The first rail-shaped groove has a leading end portion inclined and rises, and ends with a short flat portion connected to the rising portion. The second rail-like groove has a leading end portion of the first rail-like groove. When the transfer unit and the sheet feeding / conveying unit are mounted on the housing body, the large-diameter boss terminates the first rail-shaped groove. The small-diameter boss is held at a terminal portion of the second rail-shaped groove, and is detached from a broken portion of the rail-shaped protrusion and held on the rail-shaped protrusion. 4. The image forming apparatus according to 3. 5. The image forming area according to claim 1, wherein a plurality of photosensitive drums are arranged side-by-side, and a transfer belt of a transfer unit is located over and below these photosensitive drums. An image forming apparatus according to claim 1.