JPH1184785A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an image forming device excellent in quality by holding at least one side of a rotary member with a guide pivotally supported so that it is freely turned and enabling a sheet mipping and holding part to be opened by the turning action of the guide. SOLUTION: A roll 51 interposingly carrying a heated recording paper P is held by the upper ejection guide 50. Besides, the device is provided with an energizing member (spring) 56 arranged at the upper part of the guide 50 and set for pressing the outside surface of the guide 50 so as to energize it in a direction that the turning direction thereof is regulated. When the guide 50 is turned by resisting to the energizing force of the energizing member 56 in the case that the sheet is jammed, the holding part formed by the roll 51 and an ejecting roller 41 is opened. Thus, since an operation space related on jam processing is widened, the jam processing can be easily and surely executed when the leading edge of the paper P is jammed before an ejecting nip part or jammed just after the ejecting nip part.

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 printer, or a facsimile machine, provided with a discharging means for discharging a sheet after forming an image on the sheet.

[0002]

2. Description of the Related Art Conventionally, as this type of image forming apparatus, for example, there are a copying machine, a printer, a facsimile machine and the like.

A copying machine generally has a function of reading an image of an original or the like and forms an image on a sheet based on the read image information. Some copiers have a function of inputting image information to be sent.

[0004] A printer is generally an external device,
For example, an image is formed on a sheet based on image information sent from an apparatus such as a computer, and a facsimile apparatus generally has a function of reading an image of a document,
Further, it has a communication function, sends read image information to the outside, and forms an image on a sheet based on information sent from the outside.

[0005] As described above, each apparatus forms an image on a sheet based on the obtained image information.

[0006] These apparatuses are provided with discharge means for discharging the sheet to the outside of the apparatus after forming an image on the sheet.

Referring to FIG. 8, a description will be given of a discharging means provided in an image forming apparatus according to the prior art.

FIG. 8 is a schematic structural view of a conventional image forming apparatus in the vicinity of the area where a discharge unit is provided.

As shown in the figure, a sheet S having an unfixed toner image T formed on its surface is conveyed from the right side in FIG. To the nip N formed by the

The fixing roller 101 has a heater 101a and a heat-resistant film F, and the pressing roller 102 is configured to press the fixing roller 101.

With this configuration, the unfixed toner image T is melted and fixed by applying pressure and heat to the sheet S conveyed in the nip portion N.

Then, the pressure roller 102 rotates in the direction of the arrow in the drawing to convey the sheet S downstream.

The film F is driven by the rotation of the pressure roller 102.

The conveyed sheet S is delivered to the upper discharge guide 10.
5 and guided by the lower discharge guide 106, guided to the holding portion of the roller 103 and the discharge roller 104, further conveyed downstream, and discharged outside the apparatus.

The interval between the upper discharge guide 105 and the lower discharge guide 106 on the upstream side of the holding portion between the roller 103 and the discharge roller 104 is gradually narrowed so that the sheet S can be easily guided to the holding portion. I have.

Here, the roller 103 is held by an upper discharge guide 105 fixed to the apparatus main body, and the discharge roller 104 is held by a lower discharge guide 106.

[0017]

However, in the case of the above-described prior art, the following problems have occurred.

When a sheet jam occurs near the discharge unit of the image forming apparatus according to the prior art described above, the space around the discharge unit is very small, so that it is difficult to remove the jam.

In particular, when a part of the sheet passes through the holding portion of the discharging means and the remaining portion becomes an accordion-shaped jam at a position before passing through the holding portion, the sheet has passed through the holding portion. In some cases, the sheet was torn and the remaining portion was left at a position before passing through the holding portion when the portion was pulled to be processed.

The remaining sheet may cause a further jam or cause a failure of the apparatus body.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide an image forming apparatus which is capable of easily and surely performing jam processing and which has excellent quality. Is to do.

[0022]

According to the present invention, there is provided an image forming apparatus having a discharge means for discharging a sheet on which an image has been formed to the outside of the apparatus while nipping the sheet between the pair of rotating members. , Wherein at least one of the rotating members is held by a rotatably supported guide, and the rotation of the guide can open the holding portion of the sheet.

Therefore, when a jam occurs, the jam sheet can be easily removed by rotating the guide to open the holding portion of the sheet, and the sheet is not broken and remains.

It is preferable to provide an urging means for urging the guide in a direction for holding the sheet.

Therefore, in a normal state, the guide is urged by the urging means, and the holding portion is formed by the pair of rotating members.

The urging means may be a spring which presses and urges the outer surface of the guide.

It is also preferable that the urging means is a spring which applies a rotational force to the center of rotation of the guide to urge the guide.

It is also possible to provide a locking means for locking the guide at a position for holding the sheet.

Therefore, in a normal state, the guide is locked by the locking means, and the holding portion is formed by the pair of rotating members.

The locking means may be provided with a snap-fit portion on the guide, and the snap-fit portion may be locked and unlocked in a predetermined notch.

It is preferable to provide a heating means for heating the sheet on which the unfixed toner image is formed while pressing the sheet, and convey the sheet to the discharge means while fixing the toner image by the heating means.

[0032]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The material, shape, relative arrangement, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) An image forming apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic structural view of an image forming apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing a main part (discharge means) of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a schematic configuration diagram, FIG. 3 is a partially cutaway perspective view of a main part (discharge unit) of the image forming apparatus according to the first embodiment of the present invention, and FIG. 4 is a first embodiment of the present invention. FIG. 3 is a schematic configuration diagram of a main part (discharge unit) of the image forming apparatus according to the embodiment.

In the present embodiment, a laser beam printer utilizing an electrophotographic process will be described as an example of an image forming apparatus.

First, an outline of the image forming apparatus will be described with reference to FIG.

Reference numeral 1 denotes a rotating drum type electrophotographic photosensitive member (hereinafter, referred to as a drum) as an image carrier.

The surface of the drum 1 is first uniformly charged by the primary charger 2 during the rotation process.

Next, a scanning exposure with a laser beam L modulated in accordance with a time-series electric digital pixel signal of target image information is performed on the charged surface of the rotating drum 1 by scanning exposure.
Output from the laser scanner 3, an electrostatic latent image corresponding to target image information is formed on the surface of the rotating drum 1.

Next, the electrostatic latent image is reversal-developed with the negative toner T by the developing device 4 (toner is adhered to the laser exposed portion) to be visualized.

On the other hand, a recording sheet P as a sheet is separated and fed from a sheet feeding cassette 20 by a sheet feeding roller 21 and passes through a registration roller pair 22 at a pressure nip between the drum 1 and the transfer roller 5. The toner image on the rotating drum 1 surface side is sequentially transferred to the surface of the recording paper P by being conveyed and introduced to a certain transfer portion at a predetermined timing.

The recording paper P that has passed through the transfer section is
Is transferred to an image fixing / ejecting device 7 having a heating unit, and is subjected to a fixing process of a transferred toner image, and is ejected outside the machine as a print by an ejecting unit.

After the recording paper is separated, the surface of the rotary drum 1 is cleaned by the cleaning device 23 after removing residual contaminants such as transfer residual toner and the like, and the work is repeatedly performed.

Incidentally, the printer shown in the present embodiment comprises a drum 1, a primary charger 2, a developing device 4, and a cleaning device 23.
The four process devices are collectively configured as a process cartridge 24 that can be detached and replaced in the printer body.

Next, the image fixing and discharging device 7 will be described with reference to FIGS. 2, 3 and 4. FIG.

The image fixing and discharging device 7 has a heating means and a discharging means of a tension-free type film heating method, and these will be described in detail below.

For convenience, JP-A-63-313182, JP-A-1-263679, and JP-A-2-157
No. 878, JP-A-4-44075-444083,2
An image forming apparatus having an image fixing and discharging device having both a heating means of a film heating method and a discharging means of a heated recording sheet disclosed in Japanese Patent No. 04980-204498 or the like will be described as an example.

First, the heating means will be described.

The heating means includes a substantially planar heater having a heat-generating portion, a pressure roller for forming a heating nip by pressing the heater and a heat-resistant film member therebetween, and a pressure roller facing the pressure roller of the heater. It has a heater folder that covers the surrounding area, introduces the material to be heated into the heating nip part, and heats it with the heat of the heater through a heat-resistant film.It has a low heat capacity and fast temperature rise. Using a heater, the heating nip portion can be heated intensively, and has a quick start property and features such as power saving.

Such a film heating type heating means can be used, for example, in an image forming apparatus such as a copying machine, a laser beam printer, a facsimile, a micro film reader printer, an image display (display) device, and a recording machine. Indirectly to the surface of a recording medium (transfer material sheet, electrofax sheet, electrostatic recording sheet, printing paper, etc.) by using a toner made of a heat-meltable resin or the like by an appropriate image forming process means such as electric recording and magnetic recording. The present invention can be used as an image fixing device that heats and fixes an unfixed toner image corresponding to target image information formed by a (transfer) method or a direct method as a permanently fixed image.

As the heating element having a low heat capacity and a rapid rise in temperature, a ceramic material substrate having heat resistance, insulation, and good thermal conductivity and a heat-generating portion formed on the substrate by printing, baking, etc., as a heat-generating portion are provided. Generally, a ceramic heater which has a low heat capacity and a high temperature as a whole, which has a resistance portion as a basic component and supplies electric power to a heating resistance portion to generate heat, is generally used.

The heating means described in the present embodiment is disclosed in
-44075 to 44083, 204980 to 20498
No. 4, gazette, and the like, a cylindrical film is used as a heat-resistant film, and the film is rotated and driven by a pressing roller as a pressing means, a pressing roller driving method, a tension-free type (do not apply tension to the film) That drives the film).

In the figure, reference numeral 14 denotes a horizontally elongated thin plate-shaped heating element (hereinafter, referred to as a heater) whose longitudinal direction is perpendicular to the drawing.

The heater 14 is generally a low-heat-capacity ceramic heater having a ceramic substrate and a heating resistor printed and fired on the substrate surface as a basic component.

The heater 14 has heat resistance, insulation,
TaSiO ₂ , AgPd, TA ₂ N, Ru formed on a high thermal conductive alumina substrate by screen printing, for example.
It has a thin-film heat-generating resistor such as O ₂ or nichrome, and the surface facing the inner surface of the fixing film 9 is overcoated with heat-resistant glass or the like.

Reference numeral 10 denotes a heater support which also serves as a film guide of a horizontally long gutter type having a substantially semicircular cross section. The heater 1 extends along the length of the support at the center of the lower surface of the heater support 10.
4 is fixedly supported by a heat-resistant adhesive or the like.

Reference numeral 9 denotes a cylindrical (endless belt), thin heat-resistant film (hereinafter referred to as a fixing film or a film) loosely fitted on a heater support 10 supporting a heater 14.

The fixing film 9 is a single layer film having heat resistance, toner release property and toughness, or a composite layer film subjected to a desired surface treatment or lamination.

The fixing film 9 is made of polyimide (P
I) Film is preferred, heat-treated 50 um Z
no monolayer film or tetrafluoroethylene (PTF
A composite layer film subjected to the release property imparting treatment in E) can be obtained.

Numeral 15 denotes flange members provided at both ends of the heater support 10 for receiving the ends of the fixing film and restricting the shift of the fixing film 9.

Numeral 11 denotes an elastic pressure roller as a pressure member, which presses the lower surface of the heater 14 of the heater support 10 and the fixing film 9 against each other with a predetermined contact pressure against the roller elasticity. Thus, a heating nip portion N as a heating portion having a required width is formed.

That is, the heater 14 and the pressure roller 11 are pressed against each other with a predetermined pressure (for example, A4 width and a total pressure of 4 to 10 kg) with the fixing film 9 interposed therebetween.

The pressure roller 11 is driven to rotate in a counterclockwise direction indicated by an arrow by a driving means (not shown).

The rotational force acts on the film 9 by the frictional contact between the outer surface of the pressure roller 11 and the outer surface of the film 9 due to the rotation of the pressure roller 11 at the heating nip portion N. While contacting and sliding on the lower surface of the heater 14, the outer periphery of the heater support 10 is driven to rotate clockwise as indicated by the arrow.

The heater support 10 also serves as a guide for the rotating film 9.

The rotation of the pressure roller 11 causes the film 9
Is rotated, and in a state in which the heater 14 is heated to a predetermined temperature (for example, 150 deg or more) by energizing the heat generating resistance portion, the unfixed toner is supplied to the heating nip portion N between the film 9 and the pressure roller 11. The recording paper P on which the image T is formed and carried is conveyed.

At this time, the recording paper P is introduced with the toner image surface through the guide member with the film 9 side, and is moved together with the film 9 to the heating nip portion N. P is heated by the heater 14 via the film 9, and the unfixed toner image T is softened and fused.

The recording paper P that has passed through the heating nip N is separated from the surface of the film 9, and passes through a discharge upper guide 50 and a discharge lower guide 40 to form a pair of rotating members 51.
The sheet is nipped and conveyed by a discharge roller 41 and discharged outside the image forming apparatus.

This apparatus comprises a pressure roller 11 for the film 9.
In the rotating state by the driving of, substantially no tension acts on the film 9 except for the heating nip portion N,
Therefore, the heater support 10 accompanying the rotation of the film
There are advantages in that the moving force for moving the film along the length of the film is small, the means for controlling the movement of the film can be simplified, and the ease of assembly and the cost can be reduced.

Reference numeral 8 denotes an upper cover for preventing the user from touching the components of the device that become hot.

Next, the discharging means will be described.

As shown in the figure, the upper discharge guide 50 is
It is rotatably attached to the frame 30 by a boss 50a formed integrally with the upper discharge guide 50, and guides the recording paper P above.

Reference numeral 51 denotes a roller for nipping and conveying the heated recording paper P, which is held by the upper discharge guide 50.

Reference numeral 50b denotes a rib provided to maintain the position of the upper discharge guide 50.

Reference numeral 56 is provided above the upper discharge guide 50,
The outer surface of the discharge upper guide 50 is pressed to
Direction in which the rotation direction of the roller
It is an urging member (spring) as urging means for urging in the direction of being pressed to one side and nipping the recording paper.

By providing the urging member 56 in this manner, the discharge upper guide 50 that has been rotated against the urging force of the urging member 56 can be automatically returned to the original state during a jam clearance or the like. .

Reference numeral 41 denotes a discharge roller which forms a discharge nip with the roller 51, and is held by a discharge lower guide 40 which guides a lower portion of the recording paper.

The interval between the upper discharge guide 50 and the lower discharge guide 40 on the upstream side of the holding portion between the roller 51 and the discharge roller 41 is gradually narrowed so that the recording paper P can be easily guided to the holding portion. ing.

With such a configuration, the recording paper P after the heating and fixing is nipped and conveyed by the rollers 51 and the discharge rollers 41.
The sheet is discharged outside the image forming apparatus through the discharge upper guide 50 and the discharge lower guide 40.

Reference numeral 30 denotes a frame provided with the flange member 15, the pressure roller 11, the upper discharge guide 50, and the lower discharge guide 40.

With the above configuration, when a sheet jam occurs, the upper discharge guide 50 is moved against the urging force of the urging member 56 (in the clockwise direction in the drawing) as shown in FIG. Rotate.

Then, as shown in the figure, the holding portion between the roller 51 and the discharge roller 41 is opened.

Accordingly, the operation space (discharge space of the recording paper P) relating to the jam processing is widened, so that a jam occurs at the leading end of the recording paper P before the discharge nip, a jam occurs immediately after the discharge nip, or In addition, even when the recording paper P has been subjected to accordion jam, the jam can be easily and reliably processed.

(Second Embodiment) FIGS. 5 and 6 show a second embodiment of the present invention. In the first embodiment, the configuration is described in which the outer surface of the guide (discharge upper guide 50) is pressed by the urging means (spring) to pinch the pair of rotating members (the roller 51 and the discharge roller 41). In the present embodiment, a configuration is shown in which a biasing means (spring spring) applies a rotating force to the center of rotation of a guide (upper discharge guide 50) to pinch a pair of rotating members.

Since other configurations and operations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and description thereof will be omitted.

FIG. 5 is a schematic structural view of a main part (discharge means) of an image forming apparatus according to a second embodiment of the present invention.
FIG. 6 is a partially cutaway perspective view of a main part (discharge unit) of the image forming apparatus according to the second embodiment of the present invention.

In the drawing, reference numeral 57 denotes a direction provided at the center of the rotation of the boss 50a to regulate the direction of rotation of the upper discharge guide 50 (the roller 51 is urged toward the discharge roller 41 to pinch the recording paper). A biasing member (rolling spring) as a biasing means for applying a turning force in the direction (direction).

By providing the urging member (rolling spring) in this manner, the discharge upper guide 50 that has been rotated against the urging force of the urging member 56 during a jam clearance or the like is automatically returned to its original position. be able to.

Further, as compared with the configuration in which the outer surface (upper surface) of the upper discharge guide 50 is pressed as described above, in the configuration of the present embodiment, a biasing member (spring) is provided above the upper discharge guide 50.
Since the space for disposing the recording paper P is not required, the apparatus can be made compact, and the operation space (discharge space of the recording paper P) related to the jam processing can be sufficiently widened.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention. In the above-described embodiment, the configuration has been described in which the urging means is provided to sandwich the pair of rotating members (the roller 51 and the discharge roller 41), but in the present embodiment, the locking means is provided to The structure which clamps a rotating member is shown.

The other configuration and operation are the same as those of the first embodiment, so that the same components are denoted by the same reference characters and description thereof is omitted.

FIG. 7 is a partially cutaway perspective view of a main part (discharge means) of an image forming apparatus according to a third embodiment of the present invention.

In the description of the above-described embodiment, in a normal state, the discharge upper guide 50 is urged by the urging means, so that the pair of rotating members (the roller 51 and the discharge roller 41) are sandwiched. The configuration has been shown in which the discharge upper guide 50 is rotated against the urging force of the urging means at the time of the jam clearance to open the holding portion formed by the pair of rotating members.

However, the point is that in normal times,
It is sufficient that the holding portion is formed by a pair of rotating members and the holding portion is opened at the time of jam clearance. For example, the holding portion is locked by the holding member in a state where the holding portion is formed by the pair of rotating members. It is also possible to adopt a configuration in which the holding portion is fixed and released when the jam is cleared, and the holding portion is opened.

Various locking mechanisms and the like can be considered as the locking means, one example of which will be described with reference to FIG.

As shown in the drawing, the snap fit shape is formed integrally with the rib 50c,
Is configured to be detachable from the notch portion 30a provided at the bottom.

With such a configuration, the notch 30a
, The pair of rotating members (the roller 51 and the discharge roller 41) are fixed in a sandwiched state, and when jam is cleared, the lock is released, and the upper discharge guide 50 is rotated to hold the holding portion. Can be opened.

Therefore, without providing the urging means,
By adopting a configuration in which the user performs the operation of removing and attaching the jam, the configuration is simplified, and the recording paper P
Jams can be cleared even when a jam occurs before the tip of the discharge nip or when a jam occurs immediately after the discharge nip.

[0099]

According to the present invention, at least one of the rotating members is held by a rotatably supported guide and the holding portion of the sheet can be opened by the rotation of the guide. By rotating the guide and opening the sheet holding portion, the jammed sheet can be easily removed, and the sheet can be easily and reliably jammed without tearing and remaining. Excellent in nature.

If the urging means is provided, in a normal state, the guide is urged by the urging means, and the holding portion is formed by the pair of rotating members. Therefore, the holding portion is automatically formed after the jam clearance. it can.

The biasing means can be a spring that presses and biases the outer surface of the guide, or a spring that biases by applying a rotating force to the center of rotation of the guide. It becomes possible.

Further, if the locking means is provided, in a normal state, the guide is locked by the locking means, and the holding portion can be formed by the pair of rotating members.

The locking means is provided with a snap-fit shape portion on the guide, and this snap-fit shape portion can be locked and unlocked at a predetermined notch.

A heating means is provided for heating the sheet on which the unfixed toner image is formed while applying pressure, and the sheet can be conveyed to the discharge means while the toner image is fixed by the heating means.

[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 schematic configuration diagram of a main part (discharge unit) of the image forming apparatus according to the first embodiment of the present invention.

FIG. 3 is a partially cutaway perspective view of a main part (discharge unit) of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a schematic configuration diagram of a main part (discharge unit) of the image forming apparatus according to the first embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a main part (discharge unit) of an image forming apparatus according to a second embodiment of the present invention.

FIG. 6 is a partially cutaway perspective view of a main part (discharge unit) of an image forming apparatus according to a second embodiment of the present invention.

FIG. 7 is a partially cutaway perspective view of a main part (discharge unit) of an image forming apparatus according to a third embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of the vicinity of a conventional image forming apparatus provided with a discharge unit.

[Explanation of symbols]

 7 Image Fixing and Ejecting Device 9 Film 11 Pressure Roller 14 Heater 30a Notch 40 Discharge Lower Guide 41 Discharge Roller 50 Discharge Upper Guide 51 Roller 56, 57 Urging Member N Heating Nip P Recording Paper

Claims (7)

[Claims] 1. An image forming apparatus comprising: a discharge unit for discharging an image-formed sheet to the outside of the apparatus while sandwiching the sheet between the pair of rotation members, wherein at least one of the rotation members is rotatably supported by a shaft. An image forming apparatus, wherein the holding unit is held by a guide, and the holding portion of the sheet can be opened by rotating the guide. 2. An image forming apparatus according to claim 1, further comprising an urging means for urging said guide in a direction for nipping a sheet. 3. An image forming apparatus according to claim 2, wherein said biasing means is a spring which presses and biases an outer surface of said guide. 4. The image forming apparatus according to claim 2, wherein said biasing means is a spring which biases the guide by applying a rotating force to the center of rotation of the guide. 5. An image forming apparatus according to claim 1, further comprising a locking means for locking said guide at a position for holding a sheet. 6. The locking means according to claim 5, wherein said guide is provided with a snap-fit shape portion on said guide, and said snap-fit shape portion is locked and unlocked in a predetermined notch. Image forming apparatus. 7. A heating means for heating a sheet on which an unfixed toner image is formed while applying pressure to the sheet, and conveying the sheet to the discharge means while fixing the toner image by the heating means. Item 7. The image forming apparatus according to any one of Items 1 to 6.