JPH05261994A - Sheet conveying device - Google Patents

Abstract

PURPOSE:To prevent generation of gap in a sheet conveying passage so as to convey sheets stably. CONSTITUTION:An upper guide 20 which also serves as an armoring section is connected by a connecting member 21 consisting of elastic material provided at a lower guide 19 fixed to a device body frame integrally. When a hook 22 of an openclose section B is to be caught by a stopper 23 of a device body A so as to fix and when a moving range of the upper guide 20 in the horizontal direction is larger than or equal to a gap between the open-close section B and the device body A, the gap can be eliminated by the elastic force of the connecting member 21. Accordingly, a connecting part D of a first conveying passage 16 and a second conveying passage 15 can be stuck all the time.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a laser printer, LE
The present invention relates to a sheet conveying device applied to an image forming apparatus such as a D printer.

[0002]

[Prior Art]

(1) Conventionally, as shown in FIG. 9, a sheet conveying apparatus applied to an image forming apparatus such as a laser printer, an LED printer, etc., conveys a sheet 51 when the conveyed sheet 51 jams (paper jam). In order to remove or replace the cartridge 52 in which the image forming means is integrated, the apparatus main body 53 can be divided into the fixed side A and the opening / closing portion 54 can be divided into the opening / closing side B.

The structure of the positioning portion of the opening / closing portion 54 with respect to the apparatus main body 53 will be described with reference to FIG. In FIG. 10, the one-dot chain line shows the open / close side B in the open state, and the solid line shows the position when the open / close side B is fixed to the fixed side A at the final position. When fixing the opening / closing side B from the open state to the fixed side A, the opening / closing side B is rotated counterclockwise around the fulcrum M, and the hook 55 provided on the opening / closing side B is fixed to the stopper portion 56 of the fixed side A. Hit against. The hook 55 is urged clockwise by a spring 57 about the fulcrum N, and the hook 55 is stopped by the stopper portion 56.
When it hits against, it is rotated counterclockwise against the urging force of the spring 57, gets over the stopper portion 56, and is rotated to the state shown by the chain double-dashed line. Thereafter, the opening / closing side B is rotated by the spring 58 provided on the fixed side A so as to be pushed back clockwise around the fulcrum M, and the hook 55 and the stopper 56 are rotated.
Is locked and fixed at the position shown by the solid line in the figure.

FIG. 11 shows a sheet discharging section in which the opening / closing section 54 is fixed to the apparatus main body 53. The conveyance path 59 formed on the fixed side A of the apparatus is composed of a main body frame 60 and an upper cover 61, and the upper cover 61 is fixed to the main body frame 60 by a rigid body connection with a screw 62.

Further, in the above-mentioned image forming apparatus, the sheet after the image transfer has the transferred image fixed by the fixing device 62, and then is conveyed by the conveying rollers 63, and the conveying path 64 on the opening / closing side B, and further the fixed side A. Discharge roller 65 through the transport path 59 of
Is discharged to a discharge tray 66 outside the apparatus.

[0006]

[Problems to be Solved by the Invention]

(1) However, in the above-mentioned conventional technique, as shown in FIG. 10, when fixing the opening / closing side B, the hook 55 is rotated to the position shown by the chain double-dashed line in order to engage with the stopper 56. Therefore, a gap d is always formed between the connecting portion between the opening / closing side B and the fixed side A. This has caused the following problems.

As shown in FIG. 11, since a gap d is formed at the connecting portion between the opening / closing side B and the fixed side A conveying paths 64 and 59, smooth sheet conveyance may be hindered. Further, as shown in FIG. 11, the upper cover 61 located above the fixed side A often doubles as a conveyance path, and when a gap d is created between the fixed side A and the opening / closing side B, play occurs. Therefore, it is difficult to keep the interval between the transport guides constant.

(2) Further, since the sheet on which the transferred image is fixed by the fixing device 62 is heated by a heater or the like, if there is an obstacle during conveyance or the sheet is not smoothly introduced into the discharge roller 65, the sheet is wavy. Since there is a risk of loosening or jamming, it is desirable that the interval between the transport guides (the main body frame 60 and the upper cover 61) be narrowed so that they can be smoothly introduced into the discharge roller 64. Further, it is necessary to keep the intervals of the transport guides uniform so that the transfer image surface of the sheet is not rubbed by the transport guides.

Particularly, in the sheet discharging portion, the heat of the fixing device 62 easily deforms the conveyance guides, and it is difficult to keep the intervals uniform. If the interval between the transport guides is too wide, the sheet may not be guided to the nip portion of the discharge roller pair 65 and the leading end may be caught, causing a jam. Further, if the interval between the above-mentioned conveyance guides is too narrow, there is a possibility that a jam will occur or the transfer image surface will be rubbed by the conveyance guides and the image quality will deteriorate.

(1) An object of the present invention is to solve the above-mentioned problem (1) in the prior art and to prevent a gap from being formed in the sheet conveying path and to smoothly convey the sheet.

(2) An object of the present invention is to solve the above-mentioned problem (2) in the prior art and to stably convey the sheet while keeping the interval between the guide members constant.

[0012]

[Means for Solving the Problems]

(1) A typical means according to the present invention for solving the above-mentioned problem (1) of the related art is to convey a sheet, and to guide the sheet conveyed by the conveying means. And a connecting member for pressing a connecting portion provided on at least one of the first and second conveying paths.

(2) A typical means according to the present invention for solving the problem (2) shown in the above-mentioned prior art is a conveying rotary body for conveying a sheet, and both ends of a rotary shaft of the conveying rotary body. A shaft support member for supporting the sheet, a transport guide provided above and below for guiding the sheet transported by the transport rotating body, and correcting the transport guide deformation formed on at least one of the transport guides. And an abutting member for.

[0014]

According to the above-mentioned means (1), since a connecting member is provided on at least one of the first and second conveying paths so as to press the connecting portions thereof, a gap is formed at the connecting portion of the conveying path. Therefore, the sheet can be smoothly conveyed.

According to the above-mentioned means (2), the abutting member is formed on at least one of the conveying guides, so that even if the conveying guide is deformed by heat or the like, the abutting member corrects the deformation of the conveying guide. As a result, the interval between the transport guides can be kept constant, and the sheet can be stably transported.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the sheet conveying apparatus to which the above means is applied will be described with reference to the drawings. In this embodiment, a laser beam printer will be used to explain the sheet discharge portion of this printer. FIG. 1 is a sectional explanatory view showing a schematic configuration of a laser beam printer, FIG. 2 is an enlarged explanatory view of a sheet discharging portion, FIG. 3 is an enlarged explanatory view showing another example of the sheet discharging portion, and FIG. 4 is a sectional explanatory view of the sheet discharging portion. 5, FIG. 5 is an explanatory view showing a modification of the transport guide of FIG. 4, FIG. 6 is an explanatory view showing another example of FIG. 4, and FIG. 7 is an explanatory view showing a modification of the transport guide of another example.
FIG. 8 is an explanatory diagram showing another example of FIG.

First, a schematic structure of a laser beam printer will be described with reference to FIG. The printer apparatus in this embodiment is configured by combining an apparatus main body A and an opening / closing section B which can be opened / closed around a fulcrum M. Reference numeral 1 denotes a cassette on which a plurality of sheets P such as cut sheets can be stacked. The sheets P stored in the cassette 1 are separated and fed one by one from the uppermost one at a predetermined timing by the feeding roller 2 and the separating claw 3, and the sheet guide 4 provided in the cassette 1 and the apparatus main body. The registration roller pair 7 is guided by the sheet guides 5 and 6 provided on the A side.
Be led to. A sheet detection sensor S is provided immediately in front of the registration roller pair 7, and the rotation control of the registration roller pair 7 and the control of the emission timing of the laser light from the laser oscillation unit 8 are performed by the detection signal of the sensor S. Done.

The sheet P sent out by the registration roller pair 7 at a predetermined timing transfers an image when passing between a photosensitive drum 9 which is an image carrier and a transfer roller 10 which is provided so as to face the photosensitive drum 9. Is applied to the sheet P to transfer the image. A plurality of process units for image formation including the photosensitive drum 9 are
The process cartridge C is housed in the process cartridge C, and the process cartridge C is detachably attached by opening and closing the opening / closing portion B fixed to the apparatus main body A.

The sheet P after the image transfer is guided by the fixing frame 11a and guided to the fixing device 11 arranged on the downstream side to fix the transferred image. The fixing device 11 is made of an aluminum fixing roller 12 heated to a predetermined temperature (about 200 ° C.) by a heater 12a and a temperature sensor (not shown).
And a rubber pressure roller 13 arranged opposite to the pressure roller 13 so that the pressure roller 13 is pressed against the fixing roller 12 with a constant pressure by a spring or the like (not shown) so as to be driven to rotate. It is configured.

Further, the sheet P after the image fixing is a fixing roller.
The separation roller 12b provided on the downstream side of the fixing roller 12
It is separated from 12 and is conveyed to the downstream side by a conveying roller pair 14 which is a conveying rotator, and passes through the second conveying path 15 of the opening / closing section B and the first conveying path 16 on the apparatus main assembly A side so that the image surface is downward. The sheet is guided in the reverse direction and is discharged by the discharge roller 17 to the discharge tray 18 arranged outside the apparatus.

Next, the structure of the sheet discharging portion will be described with reference to FIGS. The first conveying path 16 on the side of the apparatus main body A is composed of a lower guide 19 integrally fixed to the apparatus main body frame and an upper guide 20 which also serves as an exterior part.

The upper guide 20 is held by the fitting frame 20b in the main frame of the apparatus so as to be movable in the horizontal direction (direction of arrow X). The upper guide 20 is the lower guide 19
And a connection member 21 made of an elastic material. The connecting member 21 is formed in an L-shaped cross section, is fixed to the lower guide 19 with a screw 21a, and is made of a metal material such as a stainless steel plate for spring, a phosphor bronze plate, or a polyacetal resin. The synthetic resin material is used.

Therefore, the upper guide 20 is attached so as to be movable in the arrow X direction within the elastic limit of the connecting member 21. In FIG. 2, reference numeral 22 denotes a hook provided on the opening / closing portion B, which is attached so as to be rotatable around a fulcrum N. Reference numeral 23 denotes a stopper provided on the apparatus main body A side, which locks the hook 22 when the opening / closing portion B is fixed to the apparatus main body A.

When the hook 22 of the opening / closing section B is locked and fixed to the stopper 23 of the apparatus main body A, the upper side is larger than the gap d between the apparatus main body A side and the opening / closing section B side shown in the conventional example. When the moving range of the guide 20 is equal or large,
As shown in FIG. 2, the opening / closing part B can fix the connecting part D in a predetermined position while keeping the connecting part D in close contact with the apparatus body A side by the elastic force of the connecting member 21, and eliminate the gap d. It becomes possible to do.

As a result, the connecting portion between the first conveying path 16 and the second conveying path 15 can be brought into close contact with each other, and the sheet P can be smoothly conveyed.

When the connecting member 21 is made of plastic resin as shown in FIG. 3, it may be integrally formed on a part of the upper guide 20. In this case, it is possible to reduce the number of parts and manufacture at a lower cost.

Next, the structure in the vicinity of the discharge roller 17 will be described with reference to FIGS. As shown in FIG.
The discharge rollers 17 are attached at a plurality of positions in the axial direction of the rotary shaft 24, and the rotary shaft 24 is attached to the frame 25 of the main assembly A of the apparatus.
Is rotatably supported by a bearing 26.

Further, the upper guide 20 is provided with a discharge roller 17
In order to improve the position accuracy with respect to the above, it is fixed to the frame 25 so as to support the protruding portion 20a in the vicinity of the bearing 26. If the upper guide 20 is configured so that the protruding portion 20a directly abuts on the bearing 26, the positional accuracy is further improved.

The lower guide 19 is integrally fixed to the frame 25. At a position facing the discharge roller 17, a discharge roller 27 is supported by springs 29 fixed on the frame 25 at both ends of a rotary shaft 28 and is in pressure contact with the discharge roller 17.

In addition, at the central portion of the upper guide 20, an abutting member arranged close to the rotary shaft 24 of the discharge roller 17 is provided.
30 is projected. The abutting member 30 is connected to the rotation shaft 24 of the discharge roller 17 while the upper guide 20 is not warped.
They are arranged with a gap of about 2 mm.

For example, when the upper guide 20 is deformed so as to warp downward as shown in FIG. 5 due to heat of the sheet P after image fixing, heat of the fixing device 11, etc., the upper and lower guides 20, 19
The space between them and the position of the upper guide 20 with respect to the discharge roller 17 cannot be maintained. Therefore, by correcting the warp of the upper guide 20 by the abutting member 30 and maintaining the interval and position between the upper and lower guides, the sheet P can be smoothly guided to the discharge roller 17.

Further, as the abutting member 30, it is preferable to use a bearing material or the like having good slidability without causing noise or the like. For example, as shown in FIG.
Even if the freely rotatable roller 31 is attached to the tip of the, the same effect can be obtained. Furthermore, the abutting member 30
In the case where the upper guide 30 is warped, it is more preferable to provide not only one location but a plurality of locations in the axial direction, so that the abutting force can be dispersed, which is more preferable for the safety of parts.

According to the above structure, the abutting member 30 is provided on the upper guide 20 so that even if the upper guide is deformed by heat or the like, the abutting member 30 corrects the deformation of the upper guide 20. As a result, the interval between the upper and lower guides can be kept constant, and the sheet P can be stably conveyed.

Next, another embodiment of the abutting member 30 will be described with reference to FIGS. 7 and 8. In the above embodiment, the correction method in the case where the upper guide 20 is convexly warped downward (to the discharge roller 17 side) has been described. However, as shown in FIG. ) Has a convex warp, it has no effect. Therefore,
As shown in FIG. 8, a hook 32 that rotatably engages the rotating shaft 24 of the discharge roller 17 can be formed at the tip of the abutting member 30. In this case, it is possible to correct the upper guide 20 even if the upper guide 20 warps in any of the upper and lower directions, and the reliability of the device can be further improved.

Although this embodiment has been described by using the laser beam printer as the image forming apparatus, it can be applied to other image forming apparatuses such as a copying machine and an LED printer.

[0036]

As described above, according to the present invention, since a connecting member for pressing the connecting portions of both the first and second conveying paths is provided on at least one of the conveying paths, a gap is formed in the connecting portions of the conveying paths. It is possible to prevent the occurrence and to smoothly convey the sheet.

Further, by forming an abutting member on at least one of the conveying guides, even if the conveying guide is deformed due to heat or the like, the abutting member corrects the deformation of the conveying guides, so that the gap between the conveying guides is corrected. Can be kept constant, and the sheet can be stably conveyed.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view showing a schematic configuration of a laser beam printer.

FIG. 2 is an enlarged explanatory diagram of a sheet discharging unit.

FIG. 3 is an enlarged explanatory diagram illustrating another example of the sheet discharging unit.

FIG. 4 is a cross-sectional explanatory diagram of a sheet discharging unit.

FIG. 5 is an explanatory diagram showing a modification of the transport guide of FIG.

6 is an explanatory diagram showing another example of FIG. 4. FIG.

FIG. 7 is an explanatory diagram showing a modification of the conveyance guide of another example.

FIG. 8 is an explanatory diagram showing another example of FIG. 4.

FIG. 9 is an explanatory diagram of a conventional image forming apparatus.

FIG. 10 is an explanatory view showing a conventional fixing structure for an opening / closing section.

FIG. 11 is an enlarged explanatory diagram of a conventional sheet discharging unit.

[Explanation of symbols]

 A ... Device body B ... Opening / closing part C ... Process cartridge M, N ... Support point P ... Sheet S ... Sheet detection sensor 1 ... Cassette 2 ... Feeding roller 3 ... Separation claws 4, 5, 6 ... Sheet guide 7 ... Registration roller pair 8 ... Laser oscillation unit 9 ... Photosensitive drum 10 ... Transfer roller 11 ... Fixing device 11a ... Fixing frame 12 ... Fixing roller 12a ... Heater 13 ... Pressure roller 14 ... Conveying roller pair 15 ... Second conveying path 16 ... First conveying path 17 ... Ejection roller 18 ... Ejection tray 19 ... Lower guide 20 ... Upper guide 20a ... Projection part 20b ... Fitting part 21 ... Connecting member 22 ... Hook 23 ... Stopper 24, 28 ... Rotating shaft 25 ... Frame 26 ... Bearing 27 … Ejection roller 29… Spring 30… Abutment member 31… Roller 32… Hook

Claims (5)

[Claims] 1. A conveyance means for conveying a sheet, and a dividable first and second conveyance paths for guiding the sheet conveyed by the conveyance means, wherein the first and second conveyance means are provided. A sheet conveying device, comprising a connecting member for pressing a connecting portion provided on at least one of the paths. 2. The sheet conveying apparatus according to claim 1, wherein the connecting member presses the connecting portions of the first and second conveying paths by using an elastic member. 3. A transport rotary body for transporting a sheet, a shaft support member for supporting both ends of a rotary shaft of the transport rotary body, and an upper and lower for guiding the sheet transported by the transport rotary body. A sheet conveying device, comprising: a guide member provided on the guide member; and an abutting member that is formed on at least one of the guide members and corrects the deformation of the rotation axis of the conveying rotating body. 4. The sheet conveying apparatus according to claim 3, wherein the abutting member is made of a bearing material such as resin. 5. The sheet conveying apparatus according to claim 3, wherein the abutting member is a rotating roller.