JPH11327317A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of easily processing a jam and positioning an image forming unit and a transfer belt unit with high accuracy. SOLUTION: When an image forming frame 35 is pulled out of the image forming device main body, a guide roller 76 for a transfer belt frame 74 is moved along a guide rail 77. When the guide roller 76 is moved up to a fixed position on the front side in the pulling out direction of the image forming frame 35, the transfer belt frame 74 starts to leave the image forming frame 35, to form a space where jam can be processed, with respect to the image forming frame 35. Thus, the removal (jam processing) of a transfer body jammed between the transfer belt frame 74 and the image forming frame 35 is easily executed. Further, a positioning projection 81 is arranged on the top surface 74a of the transfer belt frame 74, and a positioning hole 82 engaged with the projection 81 is formed on the bottom surface 35a of the image forming frame 35.

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 printer, a copying machine, and a facsimile for forming an image on a transfer member such as paper or a plastic sheet. The present invention relates to an image forming apparatus configured to be able to be pulled out from a main body.

[0002]

2. Description of the Related Art For example, laser printers for forming a color image on a sheet material (transfer member) such as paper are generally classified into four types of recording systems: a transfer drum system, an intermediate transfer system, a tandem system and a multiple development system. You. Of these, in response to the recent demand for high-speed recording, a tandem method that is superior to other methods in recording speed has been often adopted. In this tandem type laser printer, black, cyan, magenta, and yellow image forming units are appropriately arranged in a sheet conveying direction, and toner images of respective colors formed by these image forming units are transferred to a sheet member. A fixing device (fixing means) fixes a desired color image to a sheet material.

[0003]

In such a tandem laser printer, when a paper jam occurs between the image forming unit and the transfer belt unit, the image forming unit and the transfer belt unit are separated from each other, and between the two. After removing the jammed transfer body, the transfer belt unit is pressed against the image forming unit, and the printing operation is continued. Therefore, in order to perform the printing operation smoothly, it is necessary to facilitate the jam processing.

In such a tandem type laser printer, a color shift occurs unless an image of each color is transferred to a sheet material with high accuracy. Therefore, it is necessary to accurately position the transfer belt unit with respect to the image forming unit. is there. In particular, it is necessary to maintain high parallelism between the photosensitive drum of the image forming unit and the transfer roller of the transfer belt unit. Therefore, when separating and joining the image forming unit and the transfer belt unit at the time of maintenance of the image forming unit or at the time of jam clearance, it is necessary to accurately position the image forming unit and the transfer belt unit.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of easily performing a jam processing and accurately aligning an image forming unit and a transfer belt unit.

[0006]

According to the present invention, there is provided an image forming unit which detachably accommodates an image forming means and which is detachably mounted on an image forming apparatus main body, and the image forming unit accommodated in the image forming unit. A transfer belt unit that conveys the transfer body to the transfer unit and transfers the toner image created by the image forming unit to the transfer body. The image forming unit is mounted on the image forming apparatus main body so that the image forming unit can be pulled out in a direction orthogonal to the transfer body transport direction. Further, the transfer belt unit is rotatably mounted on a lower surface side of the image forming unit and at a position on the back side in the pull-out direction of the image forming unit via a support shaft. When the image forming unit is pulled out from the image forming apparatus main body by a predetermined amount, the transfer belt unit is rotated around the support shaft as a rotation fulcrum, and the transfer belt unit is separated from the image forming unit. While the transfer belt unit is opened to the front side in the pull-out direction, when the image forming unit is pushed into the image forming apparatus main body, the transfer belt unit is rotated around the support shaft as a rotation fulcrum, and the transfer belt unit is rotated. And a transfer belt unit opening / closing means for pressing the transfer belt unit against the image forming unit.

According to the present invention, when the image forming unit is pulled out from the image forming apparatus main body, the transfer belt unit is automatically separated from the image forming unit by the transfer belt unit opening / closing means. As a result, the transfer belt unit opens toward the drawing direction and forms a sufficient space between the transfer belt unit and the image forming unit so that the operator's hand can be inserted. Therefore, the work (jam removal) of the transfer member jammed between the transfer belt unit and the image forming unit is easily performed.

In the above invention, the transfer belt unit opening / closing means is fixed to the image forming apparatus main body so as to oppose both side surfaces of the transfer belt unit, and the transfer is performed along the guide rail. And a guide member for guiding the belt unit, wherein the guide rail is gradually inclined downward from a predetermined position on the near side in the drawing direction of the image forming unit.

According to the present invention having such a configuration, when the image forming unit is pulled out of the image forming apparatus main body, the guide member of the transfer belt unit moves along the guide rail. Then, when the guide member moves to a predetermined position on the near side in the drawing direction of the image forming unit, the transfer belt unit starts to separate from the image forming unit.

Here, in the above invention, the guide member is constituted by a guide roller mounted on the transfer belt unit and rolling along the guide rail or a guide block slidably engaged with the guide rail. can do.

Further, the present invention is characterized in that a positioning means is arranged on a mating surface between the image forming unit and the transfer belt unit.

According to the present invention having such a configuration, when the transfer belt unit is separated from the image forming unit and then pressed again by the image forming unit, the transfer belt unit and the image forming unit are positioned by the positioning means. Positioned with high precision. As a result, the image forming apparatus of the present invention forms a high-accuracy image without color shift.

The positioning means may include a positioning projection arranged on one of the image forming unit and the transfer belt unit, and a positioning projection arranged on the other of the image forming unit and the transfer belt unit. And a positioning hole that engages with the positioning protrusion.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Schematic Configuration of Image Forming Apparatus) FIG. 1 shows a color printer (image forming apparatus) according to an embodiment of the present invention.
2 is a schematic configuration diagram of FIG.

First, a schematic configuration of the color printer 2 will be described with reference to FIG. The color printer 2 includes a sheet feeding unit 4 for feeding sheet materials 3 as transfer members one by one, a conveying unit 6 for conveying the sheet material sent from the sheet feeding unit 4 to an image forming unit 5 described later, An image forming unit 5 for forming a toner image to be transferred onto the sheet material conveyed by the conveying unit 6
A transfer conveyance unit 7 that receives the sheet material conveyed by the conveyance unit 6, conveys the sheet material in a predetermined direction, and transfers the toner image formed by the image forming unit 5 to the sheet material; A fixing unit 8 for fixing the toner image on the sheet material conveyed by the transfer conveyance unit 7 to the sheet material;
The image forming unit 5 includes a paper discharge unit 10 that receives the sheet material discharged from the fixing unit 8 and an optical unit 11 that irradiates the image forming unit 5 with laser light for exposure.

The paper feed unit 4 feeds the sheet material 3 stacked on the first paper feed tray 12 to the paper feed roller 13 and the reverse roller 1.
4 and a second paper feed unit 18 that feeds a sheet material (not shown) on the manual feed tray 16 by a paper feed roller 17.

The conveying section 6 includes a conveying path 20 for guiding the movement of the sheet material 3 sent from the first sheet feeding section 15, a conveying roller 21 arranged in the middle of the conveying path 20, and a conveying roller 21. The registration roller pair 22 receives the sheet material from the printer, corrects the skew of the sheet material, and sends the sheet material to the image forming unit 5.
And a manual feed path 23 that is connected to the feed path 20 upstream of the registration roller pair 22 in the sheet feed direction.

The image forming unit (image forming unit) 5 includes a first image forming unit 24 having black toner (hereinafter, abbreviated as black) and a toner containing cyan pigment (hereinafter, referred to as black) in order from the upstream side in the sheet conveying direction. A second image forming section 25 having cyan (abbreviated as cyan), a third image forming section 26 having magenta pigment-containing toner (hereinafter abbreviated as magenta), and a toner containing yellow pigment (hereinafter abbreviated as yellow). And a fourth image forming unit 27. And the first to fourth
Each of the image forming units (image forming means) 24 to 27 includes a cylindrical photosensitive drum 28, a developing device 30 for forming a toner image on the outer peripheral surface of the photosensitive drum 28, and a residual image on the photosensitive drum 28. The cleaning device includes a cleaning device 33 including a fur brush 31 for removing toner and a cleaning blade 32, and a charging device 34 for applying a charge to the photosensitive drum 28 to charge the photosensitive drum 28.
Note that the image forming unit 5 can be pulled out of the image forming apparatus main body 36 integrally with the image forming frame 35.

The transfer conveyance section (transfer belt unit) 7
An endless transfer belt 37 made of a fluororesin material, a driving roller 38 and a tension roller 40 around which the transfer belt 37 is wound, and transfer rollers 41a, 41b, and 41c disposed at positions facing the respective photosensitive drums 28. ,
41d, and also functions as a transfer body transporting device. The transfer rollers 41 a to 41 d have a predetermined pressing force, and the transfer belt 37 and the photosensitive drum 28.
Is sandwiched between them. Further, belt guide rollers 42 and 43 are disposed at appropriate positions on the inner peripheral side of the transfer belt 37.

The fixing section 8 includes a heating roller 44 having a built-in heater, a fixing roller 45, and a metal endless belt 4 wound around the heating roller 44 and the fixing roller 45.
6, and a pressure roller 47 pressed against the fixing roller 45
And Then, a donor roller 48 for supplying oil to the outer surface of the endless belt 46 and the donor roller 4
An oil roller 50 and a cleaning roller 51 that are in rolling contact with the roller 8 are arranged.

The paper discharge section 10 guides the sheet material discharged from the fixing section 8 to the upper portion of the image forming apparatus main body 36 through a discharge path 53, and the paper discharge tray 54 on which the image forming surface is stacked.
have. The paper discharge cover 52 is pulled out of the image forming apparatus main body 36 when the jam is cleared, and is stored in the image forming apparatus main body 36 when the jam is not cleared.

The optical unit 11 has a polygon scanner mirror 55, image forming lenses 56, 57 and a mirror 58 arranged corresponding to each photosensitive drum 28, and a laser beam is formed on an optical unit support plate 60. Slit 61
Irradiates the photosensitive drum 28 toward the photosensitive drum 28.

The color printer 2 configured as described above
When a sheet material is sent out from the first paper supply unit 15 or the second paper supply unit 18, the sheet material is sent to the first
It is fed between the photosensitive drum 28 of the image forming unit 24 and the transfer belt 37 of the transfer / conveyance unit 7. And the sheet material is
While being conveyed by the transfer belt 37 between the photosensitive drum 28 and the transfer rollers 41a to 41d, black, cyan,
The toner images formed on the magenta and yellow photosensitive drums 28 are sequentially transferred. Then, the sheet material on which the transfer of the color image has been completed is sent by the transfer belt 37 between the fixing roller 45 and the pressing roller 47 of the fixing unit 8, where the sheet material is heated and pressed to fix the color toner image. You. The sheet material on which the fixing operation has been completed is discharged to the discharge tray 54.

(Connecting Structure of Image Forming Unit and Transfer Belt Unit) Next, the structure of the connecting portion of the image forming unit 5 and the transfer belt unit 7 will be described in detail with reference to FIGS. In these drawings, FIG. 2 is a side view of the image forming unit 5 and the transfer belt unit 7. FIG. 3 is a front view of the image forming unit 5 and the transfer belt unit 7 partially cut away. The image forming unit 5 includes the first to the first.
The fourth image forming units 24 to 27 are housed inside the image forming frame 35.

As shown in these figures, the image forming frame 3
5 are provided on both sides of the frame 7 of the image forming apparatus main body 36.
A rail 72 slidably engaged with the zero guide 71 is fixed. As shown in FIG. 2, the image forming frame 35 is slidable along a guide 71 on the image forming apparatus main body 36 side in a direction (A direction) orthogonal to the transfer body transport direction. A transfer belt unit connecting portion 73 is formed on the lower surface side of the image forming frame 35 and on the inner side in the pull-out direction (left side in FIG. 2). The transfer belt unit connecting portion 73 includes a transfer belt frame 7.
4 is mounted so as to be rotatable via a support shaft 75.

The transfer belt frame 74 includes the transfer belt 3
Rollers 38, 40, 41a-41 around which 7 is wound
d, 42 and 43 are rotatably supported. A plurality of guide rollers (guide members) 76, 76 are rotatably mounted on both side surfaces of the transfer belt frame 74. The guide roller 76 of the transfer belt frame 74 is attached to the image forming apparatus main body 3.
6 is rotatably engaged with the guide rail 77 of the frame 70. Therefore, the transfer belt frame 74 is
As shown in FIG. 2, when the image forming unit 5 is pulled out of the image forming apparatus 2, the image forming unit 5 is guided by the guide rail 77 and is pulled out together with the image forming frame 35. The frame 70 of the image forming apparatus main body 36 is provided with openings 78 and 79 that allow transfer of the transfer body.

When the image forming frame 35 is pulled out from the image forming apparatus main body 36 by a predetermined amount as shown by a two-dot chain line in FIG. 2, the transfer rail frame 74 rotates the support shaft 75. So that the transfer belt frame 74 rotates away from the image forming frame 35 as a fulcrum,
The image forming frame 35 is gradually tilted downward from a predetermined position on the front side in the pull-out direction A. The guide rail 77 constitutes a transfer belt unit opening / closing means 80 together with the guide roller 76 of the transfer belt frame 74.

The transfer belt unit opening / closing means 80 is
When the image forming frame 35 is pulled out from the image forming apparatus main body 36 by a predetermined amount, the transfer belt frame 74 is rotated about the support shaft 75 as a rotation fulcrum, and the transfer belt frame 74 is separated from the image forming frame 35 to transfer the transfer belt. Unit 7
When the image forming unit 5 is pushed into the image forming apparatus main body 36 while the image forming apparatus main body 36 is opened toward the drawing direction (direction A) of the image forming apparatus main body 36, the transfer belt frame 74 is rotated around the support shaft 75 as a rotation fulcrum. The transfer belt frame 74 is pressed against the image forming frame 35. The predetermined position at which the guide rail 77 is inclined as described above is appropriately changed in accordance with the amount of pull-out of the image forming frame 35, the rotation angle (opening angle) θ of the transfer belt frame 74, and the like.

FIG. 4 is an enlarged sectional view of a main part showing a positioning state of the image forming unit 5 and the transfer belt unit 7.
As shown in FIG. 4, a positioning projection 81 is disposed on the upper surface 74a of the transfer belt frame 74. The positioning projection 81 engages with a positioning hole 82 formed on the lower surface 35 a side of the image forming frame 35, and
5 and the transfer belt frame 74 are positioned.

The opening of the positioning hole 82 and the tip of the positioning projection 81 are chamfered, and the positioning projection 81 and the positioning hole 82 are designed to be easily engaged. Here, in the present embodiment, the positioning projections 81 are arranged on the upper surface 74a of the transfer belt frame 74, and the positioning holes 82 are formed in the lower surface 35a of the image forming frame 35. You may. That is, the positioning projection 81 is provided on the lower surface 35a of the image forming frame 35.
And a positioning hole 82 may be formed in the upper surface 74 a of the transfer belt frame 74. As described above, the positioning projection 81 and the positioning hole 82 are arranged on the mating surface of the image forming frame 35 and the transfer belt frame 74,
It constitutes a means for positioning the image forming frame 35 and the transfer belt frame 74.

According to the present embodiment having the above-described configuration, the transfer belt frame 74 is automatically separated from the image forming frame 35 by pulling out the image forming frame 35 from the image forming apparatus main body 36, and the image forming A space is formed between the frame 35 and the transfer belt frame 74 to enable jam clearance. Therefore, a transfer member (for example, a paper sheet or a plastic sheet) jammed between the transfer belt frame 74 and the image forming frame 35 can be easily removed, and the jam processing becomes extremely easy.

In this embodiment, since the positioning projection 81 and the positioning hole 82 as positioning means are provided on the mating surface of the image forming frame 35 and the transfer belt frame 74, the image forming frame 35 and the transfer belt frame 74 are provided. Can be positioned with high accuracy, and high-precision image formation without color shift can be achieved.

Further, in this embodiment, since no mechanism is provided as a means for raising and lowering the transfer belt unit 7, a space for raising and lowering the transfer belt unit 7 becomes unnecessary, and the structure of the image forming apparatus 2 is simplified. Image forming apparatus 2
Can be reduced in size and weight.

In the above embodiments, the color printer 2 as an image forming apparatus has been described as an example. However, the present invention is not limited to this and can be widely applied to facsimile machines, copiers, and the like.

In the above embodiment, the first image forming units 24 to
Although the fourth image forming unit 27 is arranged in the transfer body transport direction to form a color image on the transfer body, the present invention is not limited to this.
The present invention can also be applied to an image forming apparatus that forms a monochrome image with a single image forming unit.

Further, in the above-described embodiment, the configuration in which the guide roller 76 is used as the guide member has been described. However, the present invention is not limited to this, and a guide block made of a low friction resistance material can be used as the guide member.

[0038]

As described above, according to the present invention, the transfer belt unit is automatically separated from the image forming unit by the transfer belt unit opening / closing means by pulling out the image forming unit from the image forming apparatus main body. Since a space that allows jam processing is formed between the image frame and the transfer belt frame, a transfer member clogged between the transfer belt frame and the image forming frame can be easily removed, Jam processing becomes extremely easy.

Further, according to the present invention, there is provided a guide rail fixed to an image forming apparatus main body such that the transfer belt unit opening / closing means is opposed to both side surfaces of the transfer belt unit, and the transfer belt unit is moved along the guide rail. Since the guide rail is gradually inclined downward from a predetermined position on the near side in the drawing direction of the image forming unit, the transfer belt unit is moved when the image forming unit is pulled out from the image forming apparatus main body. Automatically separate from the imaging unit. That is, according to the present invention, no special mechanism is provided as a means for elevating and lowering the transfer belt unit.
Since the space for elevating and lowering the transfer belt unit is not required and the structure of the image forming apparatus is simple, the size and weight of the image forming apparatus can be reduced.

Further, according to the present invention, since the positioning means is provided on the mating surface between the image forming frame and the transfer belt frame,
The image forming frame and the transfer belt frame can be positioned with high accuracy, and a high-accuracy image without color shift can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a side view showing a connection state between the image forming frame and the transfer belt frame according to the embodiment of the present invention.

FIG. 3 is a front view of the image forming frame and the transfer belt frame with a part cut away.

FIG. 4 is a diagram illustrating a positioning state of an image forming frame and a transfer belt frame.

[Explanation of symbols]

2 color printer (image forming apparatus), 5 image forming unit (image forming unit), 7 transfer transfer unit (transfer belt unit), 24, 25, 26, 27 image forming means (first To the fourth image forming unit), 36 ... the image forming apparatus main body, 75 ...
... Support shaft, 76 ... Guide roller, 77 ... Guide rail, 80 ... Transfer belt unit opening / closing means, 81 ... Positioning protrusion (Positioning means), 82 ... Positioning hole (Positioning means)

Claims (6)

[Claims] An image forming unit that removably houses an image forming unit and is detachably attached to an image forming apparatus main body; and a transfer body that is conveyed to the image forming unit housed in the image forming unit. A transfer belt unit for transferring the toner image created by the image forming means to a transfer body, wherein the image forming unit is capable of being pulled out in a direction orthogonal to the transfer body transport direction. The transfer belt unit is attached to an image forming apparatus main body, and the transfer belt unit is rotatably mounted via a support shaft on a lower surface side of the image forming unit and at a position on a back side in a pull-out direction of the image forming unit. Is pulled out from the image forming apparatus main body by a predetermined amount, the transfer belt unit is rotated around the support shaft as a rotation fulcrum, and the transfer belt unit is When the image forming unit is pushed into the image forming apparatus main body while the transfer belt unit is opened to the front side in the drawing direction while being separated from the image unit, the transfer belt unit is rotated around the support shaft as the rotation fulcrum. An image forming apparatus, comprising: a transfer belt unit opening / closing means for moving the transfer belt unit against the image forming unit. 2. A guide rail fixed to the image forming apparatus main body so that the transfer belt unit opening / closing means faces both side surfaces of the transfer belt unit, and guides the transfer belt unit along the guide rail. 2. The image forming apparatus according to claim 1, further comprising: a guide member configured to tilt the guide rail from a predetermined position on the near side in a drawing direction of the image forming unit. 3. 3. The image forming apparatus according to claim 2, wherein the guide member is a guide roller attached to the transfer belt unit and rolling along the guide rail. 4. The image forming apparatus according to claim 2, wherein the guide member is a guide block attached to the transfer belt unit and slidably engaged with the guide rail. 5. An image forming apparatus according to claim 1, wherein a positioning means is disposed on a mating surface between said image forming unit and said transfer belt unit. 6. A positioning projection disposed on one of the image forming unit and the transfer belt unit, and a positioning projection disposed on one of the image forming unit and the transfer belt unit. 6. A positioning hole which engages with the hole.
The image forming apparatus as described in the above.