JPH05341687A - Sheet of paper carrying device for image forming device - Google Patents

Abstract

PURPOSE:To process a jammed paper in a sheet of paper carrying path means of a fixing roller in a clamshell type image forming device such as a printer, composed of upper and lower units pivotally attached each other by the end part of the paper ejecting side of a fixing device. CONSTITUTION:A form upper surface guide 26b fixed on the frame 29 of an upper unit 10b, is provided so that it is smoothly and continuously extended, the top end part 26 of the guide 26b is intruded into the fixing device 18 in a state where the upper and lower units are closed, to make the top end nearer to the fixing roller 21, and when the upper unit is opened, the guiding part 26b is greatly retreated from the fixing device, the lower side guiding member of a carrying path, and carrying rollers 22 and 23. It is further, preferable that the driven rollers 24 and 25 of the carrying rollers 22 and 23 are provided on the upper unit 10b, as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device after fixing an image forming apparatus.

[0002]

2. Description of the Related Art In a small-sized image forming apparatus such as a laser printer or an electrophotographic copying machine, an apparatus main body is divided into an upper unit and a lower unit for the purpose of facilitating maintenance, replacement of parts, and removal of jammed paper. A so-called clamshell type device is adopted in which the upper and lower units are pivotally attached to each other at one edge, and the upper unit is flipped up on the opposite side to open a large mouth.

FIG. 9 is a diagram showing the overall construction of an example of a clamshell type laser printer. The printer body 10 is divided into a lower unit 10a and an upper unit 10b with a chain line XX as a boundary, and the upper and lower units 10b and 10a are pivotally attached to each other by a shaft 28 provided at an end of the fixing device 18 on the sheet discharge side. On the opposite side, that is, on the right side in the drawing, the upper unit 10b can be flipped up to the position of 10b 'shown by the chain line to open the mouth greatly.

The upper unit 10b is provided with an endless belt type photoconductor unit 13, a charging charger 14, a laser writing optical system 15, a developing device 16 and a cleaning device 20.
A paper discharge receiver 19 is formed on the top surface of the top plate of the exterior cover.

A paper feed cassette 11 is provided below the lower unit 10a, and a pair of registration rollers 12 are provided above the paper feed cassette 11.
A transfer charger 17 and a fixing device 18 are provided.

The sheet 50 fed from the sheet feeding cassette 11 in the direction of arrow A is fed to the endless belt photosensitive member 13 by the registration roller pair 12 at a certain timing, and is uniformly charged by the charging charger 14 and laser. Writing optical system 1
The toner image formed on the photoconductor 13 by the optical writing by 5 and the developing device 16 is transferred onto the sheet by the action of the transfer charger 17, and is fixed by the fixing device 18.

The fixing device 18 is a heat roller fixing device comprising a fixing roller 21 having a built-in heater and a pressure roller which comes into pressure contact with the fixing roller 21, and the sheet after fixing is separated by a separating claw 30 whose tip abuts against the fixing roller. The sheet is separated from the fixing roller 21, and is conveyed through the sheet conveyance path after fixing by the sheet discharge roller 22 after fixing and the driven roller 24 that is pressed and driven by the sheet discharge roller 22.

In the example of the printer shown in the figure, the paper discharge section is provided in addition to the paper discharge tray 19 provided at the top of the upper unit.
A paper discharge receiver 19 ′ that is discharged without being deflected from the paper discharge side of the fixing device 18 is provided, and the discharge direction can be selectively switched by the switching claw 41.

When the sheet is discharged to the upper sheet discharge tray 19, the sheet is discharged from the upper sheet discharge roller 40 in the direction indicated by the arrow through the reverse conveyance path formed in the upper unit, and then the sheet is discharged to the lower side. When the paper is discharged to the paper receiver 19 ', the switching claw 4
By the lower paper discharge roller 23 provided on the upstream side of 1 and the driven roller 25, the paper is discharged to the paper discharge receiver 19 ′ in the direction of arrow C. The lower paper discharge roller 23 functions as a transport roller when the paper is discharged to the upper paper discharge receiver 19.

In the image forming apparatus having the heat roller fixing device having the above structure, when a jam occurs inside the fixing device or after fixing, the jammed paper is removed and the separation claw is replaced.
It is necessary to open the separation claw, the upper and lower conveyance guides, and the pair of paper ejection rollers after fixing. As means for this, for example, in Japanese Utility Model Laid-Open No. 60-150571, as shown in FIG. 10, upper and lower guide members 42 and 43 from the fixing roller 21 to the post-fixing paper discharge roller 22, the separation claw 30, and the post-fixing paper discharge. The pair of rollers 22 and 24 are integrally attached to one member 44 pivotally attached to the machine frame on the discharge side of the fixing device, and this member is attached to a pivot shaft 44a.
When the separation claw 30 is brought into pressure contact with the fixing roller 21 by rotating it around, the guide members 42 and 43 and the post-fixing discharge roller pair 22 and 24 come to a predetermined operating position, as shown in FIG. There is disclosed a fixing device separating claw releasing device which is configured so as to be disengaged from the fixing device and movable when the guide members 42 and 43 can open their mouths. Japanese Patent Application Laid-Open No. 2-234179 and Japanese Utility Model Application Laid-Open No. 60-168158 disclose almost the same mechanism.

However, it is considered that the jam processing mechanism having such a structure can carry out the jam processing without any trouble in the clamshell type apparatus in which the pivot shaft is provided at the end portion on the developing device side or the back side of the apparatus. However, as shown in FIG. 9, in the clamshell type image forming apparatus having a pivot shaft at the discharge side end of the fixing device, the opening of the upper and lower units on the downstream side of the fixing device becomes small, and the separation claw, It is difficult to raise and lower the guide member and the mounting member 44 integrally provided with the pair of post-fixing paper discharge rollers, and even when the guide member is tilted, the separation claws, the mounting member, the guide member, etc. interfere with the jammed paper. There is a problem that it is very difficult to remove or replace the separation claw.

[0012]

SUMMARY OF THE INVENTION The present invention has solved the above-mentioned problems of the conventional sheet conveying device of the clamshell type image forming apparatus in which the pivotal shaft of the upper and lower units is at the discharge side end of the fixing device. An object of the present invention is to provide a paper transporting device that facilitates jam clearance work and separation nail replacement work.

[0013]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is an image composed of an upper and lower unit pivotally mounted to be openable and closable by a hinge located at the end of the heat roller fixing device on the paper discharge side. The portion of the sheet conveying path after fixing of the forming device in the upper unit is formed in the first guide portion formed on the inner surface of the upper unit exterior cover and the sheet discharge unit attached to the machine frame of the upper unit. A sheet guide device including a guide surface of the first guide portion and a second guide portion having a guide surface opposed to the first guide portion at a distance,
The paper discharge unit is smoothly connected to a portion inside the upper unit of the second guide portion, and a part of the upper guide unit enters the inside of the heat roller fixing device when the upper and lower units are closed. A part that cooperates with the above part to form a sheet conveyance path up to the conveyance path in the upper unit of the sheet after fixing, and is separated from the lower guide section with the upper and lower units open, and the tip of which retracts from the fixing device. Is provided.

[0014]

As described above, since the pivot shafts of the upper and lower units are located at the ejecting end of the fixing device, by opening the upper unit of the device, the fixing unit is moved toward the fixing device from the lower end of the upper unit of the second guide portion. The extended portion has a large gap between it and the lower guide portion of the lower unit, which facilitates jam processing and separation claw replacement.

A separating claw and a driven roller of a paper discharge roller provided in the lower unit are provided at a portion of the second guide portion extending toward the fixing device so as to come to a predetermined operating position with the upper and lower units closed. In this case, when the upper unit is opened, they move together with the second guide member, and a gap between the other unit with which they abut is widened, so that the jam clearance operation and the separation claw replacement work become much easier.

The problems of the present invention and the means for solving the same other than the above will be made clear by the description of the embodiments described in detail below with reference to the drawings.

[0017]

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

FIG. 1 is a diagram showing a state in which an upper unit 10b of the entire structure of an embodiment to which the present invention is applied to the laser printer 10 described in FIG. 9 is opened. FIG. 2 is an enlarged view of the sheet conveying device after the fixing device.

The conveying path of the sheet after fixing to the upper sheet discharge receiver 19 is composed of a plurality of ribs formed on the inner surface of the outer cover 27 of the upper unit 10b, and a first guide surface is formed by their edges. A plurality of guide portions 27a and a plurality of guide surfaces formed by heat-resistant resin attached to the frame 29 of the upper unit and formed on the discharge unit 26 and spaced apart from the guide surface of the first guide portion are formed by edges. It is composed of a second guide portion 26b composed of a rib. This point is no different from the conventional image forming apparatus.

However, in the embodiment of the present invention, the second guide portion 26b is smoothly connected to the inner portion of the upper unit 10b, and when the upper and lower units are closed, as shown in FIG. There is provided a portion for guiding the sheet discharged from the nip portion between the fixing roller 21 and the pressure roller in cooperation with the lower guide provided in the lower unit, the leading end of which enters the sheet. If the distance A between the fixing roller 21 shown in FIG. 3 and the tip of the portion 26a of the second guide portion 26b that has entered the fixing device is 0.5 to 10 mm, the guide member 42 shown in FIG. 10 can be omitted. You can

As shown in FIGS. 4 and 5, the separation claw 30 and the pressure spring 34 for bringing the tip of the separation claw into contact with the fixing roller are attached to and detached from the tip of the intrusion part 26a of the second guide part 26b into the fixing device. It is installed freely. If the point where the tip of the separation claw 30 abuts the fixing roller 21 and the sheet guide surface of the separation claw are made higher than the sheet passing surface of the fixing roller 21 and the pressure roller, the sheet is smoothly conveyed.

As shown in FIG. 1, when the upper unit 10b is flipped up around the pivot shaft 28 and opened, the fixing device 18
The second guide portion 26b into which the inside of the
The separation claw 30 is also largely separated from the fixing roller 21. Therefore, the replacement jam paper of the separation claw 30 and the spring 34 can be easily removed.

As shown in FIG. 6, the fixing device housing 33 has a passage notch 33a so that the tip end portion 26a of the second guide portion and the separating claw can be smoothly moved in and out of the fixing device 18. It is necessary to install it in the position.

As shown in FIGS. 1 and 2, the lower unit 10
When the driven rollers 24 and 25 for the post-fixing paper discharge roller 22 and the lower paper discharge roller 25 provided in a are attached to the paper discharge unit 26, the upper unit 10b is opened to drive these driven rollers 24 and 25. Is greatly separated from the rollers 22 and 23 of the respective counterparts, and it becomes easier to remove the jammed paper.

In order to detect the occurrence of a jam, as shown in FIG. 7, the upper paper ejection jam sensor 32 and the lower paper ejection jam sensor 31 are ejected near the upstream side of the upper paper ejection roller 40 and the lower paper ejection roller 23, respectively. It is attached to the unit 26. These sensors 32 and 31 are, as shown in FIG.
Mounting socket hole 3 provided in advance at a predetermined position of
If the mounting foot that also serves as the terminal of the sensor is inserted into 5 and locked, the attachment / detachment wiring becomes easy.

[0026]

As described above, according to the present invention, in a clamshell type image forming apparatus having a hinge at the discharge side end of the fixing device, the jammed paper is fixed and the paper is peeled from the fixing roller. The separation claw can be easily replaced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an entire configuration of a clamshell type image forming apparatus of an embodiment of the present invention with an upper unit opened.

FIG. 2 is an enlarged cross-sectional view of the sheet conveyance device after fixing.

FIG. 3 is a cross-sectional view illustrating a positional relationship between an end portion of a second guide portion provided in the paper discharge unit that has entered the fixing device and a fixing roller.

FIG. 4 is a cross-sectional view showing a state in which a separation claw and its spring are attached to the end portion of the second guide portion.

FIG. 5 is an exploded perspective view thereof.

FIG. 6 is a perspective view showing a separation claw passage notch provided in the fixing device housing.

FIG. 7 is a cross-sectional view showing an arrangement of an upper paper ejection jam sensor and a lower paper ejection jam sensor.

FIG. 8 is an exploded perspective view showing a jam sensor and its mounting portion.

FIG. 9 is a sectional view showing an overall schematic configuration of an example of a known clamshell type laser printer.

FIG. 10 is a separation claw of a conventional fixing device, a discharge guide member,
FIG. 6 is a side sectional view showing a retracting mechanism of a post-fixing paper discharge roller pair from a fixing roller.

[Explanation of symbols]

 10 Image Forming Device 10a Lower Unit 10b Upper Unit 18 Heat Roller Fixing Device 21 Fixing Roller 22 Fixing Paper Ejection Roller 23 Lower Paper Ejection Roller 24, 25 Driven Roller 26 Paper Ejection Unit 26a Penetration of the second guide into the fixing device Part 26b Second guide part 27 Upper unit exterior cover 27a First guide part 28 Hinge 29 Upper unit frame 30 Separation claw 31 Lower ejection jam sensor 32 Upper ejection jam sensor 35 Socket hole for mounting jam sensor 40 Upper ejection roller 41 Output direction switching claw

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location G03G 15/00 110 7369-2H 112 7369-2H

Claims (5)

[Claims] 1. A portion in the upper unit of a sheet conveying path after fixing of an image forming apparatus, which comprises an upper and lower unit pivotably mounted by a hinge located at an end of the heat roller fixing apparatus on the sheet discharge side. Is formed on the first guide portion formed on the inner surface of the upper unit exterior cover and on the paper discharge unit attached to the machine frame of the upper unit, and is opposed to the guide surface of the first guide portion at a distance. In a sheet conveying device configured by a second guide portion having a guide surface, the sheet discharge unit is smoothly connected to a portion inside the upper unit of the second guide portion, and a part of the upper and lower units is closed. Enters the inside of the heat roller fixing device and cooperates with the lower guide part provided in the lower unit to form a paper conveyance path up to the conveyance path in the upper unit of paper after fixing, and when the upper and lower units are open. Up Apart from the lower guide portion, the sheet conveying apparatus characterized by its leading end provided with a portion to be retracted from the fixing device. 2. The second guide portion is constituted by a plurality of ribs, and a separation claw for separating the sheet after fixing from the fixing roller is detachably provided at the tip of the portion extending inside the fixing device. The sheet conveying device according to claim 1. 3. The second guide portion is provided with a driven roller which is pressed against a post-fixing discharge roller provided in the lower unit when the upper and lower units are closed and is separated from the post-fixing discharge roller when the upper and lower units are opened. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is provided. 4. The image forming apparatus has, in addition to the sheet conveying path after fixing provided in the upper unit, a lower sheet discharging conveying path that extends substantially in the sheet discharging direction of the fixing device and is switchable. The lower unit has a lower discharge roller for discharging the paper to the paper conveyance path, and the second guide portion is pressed against the lower discharge roller when the upper and lower units are closed, and is separated from the lower discharge roller when the upper and lower units are opened. The sheet transporting device according to claim 1, further comprising a driven roller that rotates. 5. A paper discharge unit provided in the upper unit, an upper paper discharge jam sensor for detecting a jam generated in the upper unit conveyance path, and a jam generated in the lower paper discharge conveyance path. 6. The sheet conveying apparatus according to claim 5, further comprising a means for attaching a lower sheet discharge jam sensor for detecting the.