JPH086328A - Recording device - Google Patents

Abstract

PURPOSE:To provide a recording device having a paper conveying guide guiding the paper not to be twined on a roller. CONSTITUTION:This paper conveying guide is constituted of the first paper conveying guide 24 provided on the frame 8a of a cleaner 8 cleaning the toner left on the surface of a photosensitive drum 6 and having a tip section 24a in the upstream of paper conveyance near the surface of the photosensitive drum 6 to the utmost possible and a tip section 24b in the downstream extended toward a fixing unit 12 and the second paper conveying guide 25 provided on the frame 12c of the fixing unit 12 and having a tip section 25a in the downstream of paper conveyance near the pinch section 12d between a heating roller 12a and a pressing roller 12b to the utmost possible and a tip section 25b in the upstream of paper conveyance extended toward the photosensitive drum 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer and a facsimile having a paper feed guide for feeding paper from a photosensitive drum to a fixing unit and a paper separating pawl for preventing the paper from being wound around a heating roller constituting the fixing unit. , A recording device such as a copying machine.

[0002]

2. Description of the Related Art A paper on which a toner image is transferred from a photosensitive drum of a recording device such as a printer, a facsimile, a copying machine, etc. by the action of a transfer unit is securely placed in a nipping portion between a heating roller and a pressure roller which constitute a fixing unit. In order to convey the sheet to the sheet, a sheet conveying guide is provided between the photosensitive drum and the fixing unit.

FIG. 7 is a side view showing a schematic structure of a recording device such as a general printer in the past.
Is a pick roller for feeding the papers in the paper cassette one by one, 3 is a paper size sensor, 4 is a first guide roller, 5 is a second guide roller, 6 is a photosensitive drum,
Reference numeral 7 is a pre-charger, 8 is a cleaner, 9 is an exposure unit using, for example, a laser, 10 is a developing device, 11 is a transfer unit, 12 is a fixing unit, 13 is a third guide roller, and 14 is a first paper discharge. Roller, 15 is a paper ejection sensor,
Reference numeral 16 is a second paper discharge roller, 17 is a manual paper feed tray for manually feeding paper, 18 is a manual paper sensor, and 19 is a manual paper roller.

The recording apparatus as described above starts a recording cycle when one page of data is accumulated in a page buffer in a control unit (not shown). At the time of recording, the photosensitive drum 6 is rotated counterclockwise in the figure, the surface of the photosensitive drum 6 is uniformly charged by the pre-charger 7, and the charged surface is exposed by the exposure unit 9 in a pattern corresponding to the image information. Is exposed to form an electrostatic latent image, and the electrostatic latent image is developed by the developing device 10 to form a toner image.

On the other hand, the paper 20 is sent one by one from the paper cassette 1 by the pick roller 2 and is sent to the transfer unit 11 by the first and second guide rollers 4 and 5 at the timing when the toner image is formed. The toner image on the photosensitive drum 6 is transferred to the paper. After that, the paper is guided by the paper conveyance guide 21 and is fixed in the fixing unit 1.
2 and the toner image is fixed on the paper. The paper on which the toner image has been fixed is the guide 22, the third guide roller 13, the first paper discharge roller 14, the paper discharge sensor 1.
5, the sheet is ejected to the stacker 23 via the second sheet ejection roller 16.

In order to reliably convey the paper separated from the photosensitive drum 6 to the sandwiched portion between the heating roller 12a and the pressure roller 12b which constitute the fixing unit 12, the sheet is separated between the photosensitive drum 6 and the fixing unit 12. Is provided with a paper transport guide 21. In particular, when the sheets are not separated promptly, the leading edge of the sheet is conveyed by the sheet conveyance guide 21
Therefore, the shape of the paper transport guide 21 is formed into a curved line in consideration of softening the paper collision.

As shown in FIG. 8, the leading end 21a of the sheet conveying guide 21 on the fixing unit 12 side is fixed to the fixing unit 1.
Since the space between the heating roller 12a and the heating roller 12a that compose the sheet 2 must be maintained accurately,
Integrates with the frame 12c of the fixing unit 12 to improve the dimensional accuracy.

At the time of transfer, the paper wound around the photosensitive drum 6 enters the inside of the cleaner 8, so various paper separating means are used. However, as shown in FIG. 9, as shown in FIG. One of the means is to guide the leading end of the sheet to be wound in the direction of the sheet transport guide 21 by accurately bringing the leading end 21b of the sheet 21 on the side of the photosensitive drum 6 close to the surface of the photosensitive drum 6.

Further, as shown in FIG. 8 and FIG. 10, the toner is fixed while being pinched by the heating roller 12a and the pressure roller 12b constituting the fixing unit 12 and the sheet is conveyed, and the sheet after fixing is heated by the heating roller. 12a is discharged in the tangential direction, and the tip 26a abuts on the outer periphery of the heating roller 12a by a spring pressure (not shown) to separate the paper so as not to wind around the heating roller 12a. A plurality of them are arranged along the longitudinal direction of.

[0010]

When the sheet conveying guide 21 is provided on the fixing unit 12 side as shown in FIG.
Further, when the sheet conveyance guide 21 is provided on the photosensitive drum 6 side as shown in FIG.
Since it is necessary to have dimensional accuracy on the side of the photosensitive drum 6 and on the side of the photosensitive drum 6, it is desirable to integrate the paper transport guide 21 with the frame of the fixing unit 12 and the frame of the photosensitive drum 6, but then the fixing unit 12 and the photosensitive drum 6 are integrated. Since the distance between and becomes constant, there is no freedom in designing the recording device.

Further, as shown in FIG. 8, the fixing unit 1
The leading end 21c of the paper conveyance guide 21 integrated with the second frame 12c on the photosensitive drum 6 side is extended to
It is difficult to accurately approach c to the photosensitive drum 6. Further, as shown in FIG. 9, the leading end 21d of the paper transport guide 21 integrated with the frame of the cleaner 8 on the fixing unit 12 side is extended, and the leading end 21d is accurately brought close to the heating roller 12a of the fixing unit 12. Is also difficult.

Further, the fixed sheet is heated by the heating roller 12.
Since the edge 26b is formed on the sheet separating claw 26 provided in the fixing unit 12 so as not to be wound around the outer periphery of the edge a, as shown in FIG.
There is a problem that the toner image fixed on the paper is peeled off in 6b, and the quality of the toner image is deteriorated.

[0013]

In order to solve the above problems, the present invention provides a cleaner 8 for wiping off the toner remaining on the surface of the photosensitive drum 6, which is provided on a frame 8a of the cleaner 8 on the upstream side of sheet conveyance. The front end portion 24a of the sheet is provided as close to the surface of the photosensitive drum 6 as possible, and the front end portion 24b on the downstream side is provided on the first sheet conveying guide 24 extending toward the fixing unit 12 and the frame 12c of the fixing unit 12. , The downstream end portion 25a of the sheet conveyance is as close as possible to the nipping portion 12d between the heating roller 12a and the pressure roller 12b, and the upstream end portion 25b of the sheet conveyance extends toward the photosensitive drum 6. The recording apparatus is characterized in that it is provided with a sheet conveyance guide composed of two sheet conveyance guides 25.

Further, the front end portions 24b and 25b of the first sheet conveying guide 24 and the second sheet conveying guide 25 are
The recording apparatus is characterized in that it is provided with a sheet conveyance guide that intersects in a shape intersecting with teeth of a comb alternately in a direction perpendicular to the conveyance path.

Further, ribs 24 are provided on the paper contact surface sides of the first paper transport guide 24 and the second paper transport guide 25.
The recording apparatus is characterized in that it is provided with a sheet conveyance guide on which c and 25c are formed.

Further, the leading end portions 24b, 25 of the first sheet conveying guide 24 and the second sheet conveying guide 25 intersecting each other.
b only on the paper contact surface side, or both paper transport guides 24,
This is a recording apparatus characterized in that it is provided with a paper transport guide in which all of the paper contact surface side of 25 are ribs 24c, 25c.

Further, the frame 8a of the cleaner 8 provided with the first paper transport guide 24 and the photosensitive drum 6
The recording device is characterized in that it is provided with a paper conveyance guide which is integrated with the frame 6a.

Further, the toner is fixed while being sandwiched between the heating roller 12a and the pressure roller 12b constituting the fixing unit 12 and the paper is conveyed, and the paper after fixing is discharged in the tangential direction of the heating roller 12a, Heat roller 12a to prevent paper from wrapping around 12a
Edge 2 of the sheet separating claw 26 whose tip is in contact with the outer periphery of the sheet
The recording device is characterized by including a fixing unit 12 having a curved surface 6c.

[0019]

The front end 24a of the cleaner 8 for wiping off the toner remaining on the surface of the photosensitive drum 6 is located as close to the surface of the photosensitive drum 6 as possible, and the front end 24a of the downstream side is as close as possible to the surface of the photosensitive drum 6. The first paper conveyance guide 24 having the reference numeral 24b extending toward the fixing unit 12 and the downstream end 25a of the paper conveyance provided on the frame 12c of the fixing unit 12 include the heating roller 12a and the pressure roller as much as possible. By approaching the nipping portion 12d with 12b, the leading end portion 25b on the upstream side of the sheet conveyance serves as a sheet conveyance guide including the second sheet conveyance guide 25 extending toward the photosensitive drum 6, and The paper on which the toner image on the surface is transferred by the action of the transfer unit 11 is the front end portion 2 of the first paper transport guide 24 on the upstream side of the paper transport.
It is separated by 4a so as not to be wound around the photosensitive drum 6, and is guided toward the fixing unit 12 by the first paper transport guide 24.

The sheet is further guided toward the fixing unit 12 by the second sheet transport guide 25, and the heating roller 12 is driven by the front end portion 25a of the second sheet transport guide 25 on the downstream side of the sheet transport.
It is guided toward the nip 12d between the a and the pressure roller 12b.

Further, the leading end portions 24b, 25 of the first sheet conveying guide 24 and the second sheet conveying guide 25 intersecting each other.
b only on the paper contact surface side, or both paper transport guides 24,
Since the ribs 24c and 25c are formed on the entire sheet contact surface side of 25, the sliding friction of the sheet is small and the sheet is smoothly guided.

Further, in order to prevent the paper from wrapping around the heating roller 12a of the fixing unit 12 composed of the heating roller 12a and the pressure roller 12b, the paper whose front end is in contact with the outer periphery of the heating roller 12a. By forming the edge 26c of the separation claw 26 into a curved surface, the toner image fixed on the paper is not peeled off by the edge 26c of the paper separation claw 26, and the quality of the toner image is deteriorated. Disappears.

[0023]

Embodiments of the present invention will be described below by attaching the same reference numerals to the same members as those of the conventional example. FIG. 1 is a schematic view showing a first embodiment of a sheet conveying guide provided in the recording apparatus of the present invention, and 24 is a first sheet conveying guide, which is a cleaner 8 for wiping off the toner remaining on the surface of the photosensitive drum 6. Is provided on the frame 8a, the upstream end portion 24a of the sheet conveyance is as close to the surface of the photosensitive drum 6 as possible, and the downstream end portion 24b extends toward the fixing unit 12.

Reference numeral 25 denotes a second paper conveyance guide, which is provided on the frame 12c on the heating roller 12a side of the fixing unit 12 and has the leading end 25a on the downstream side of paper conveyance as far as possible between the heating roller 12a and the pressure roller 12b. The leading end portion 25b on the upstream side of the sheet conveyance extends toward the photosensitive drum 6 as it approaches the sandwiching portion 12d.

FIG. 2 is a schematic view showing a second embodiment of the sheet conveying guide provided in the recording apparatus of the present invention, and the front end portion 24b of the first sheet conveying guide 24 and the second sheet conveying guide 25. , 25b are paper feed guides having a shape in which the teeth of the combs are bite alternately in the direction perpendicular to the feed path.

FIG. 3 is a schematic view showing a third embodiment of the sheet conveying guide provided in the recording apparatus of the present invention, and the sheet contact surface side of the first sheet conveying guide 24 and the second sheet conveying guide 25. Is a sheet conveyance guide on which ribs 24c and 25c for reducing sliding friction of the sheet are formed.

The ribs 24c and 25c may be formed only on the paper contact surface side of the front end portions 24b and 25b where the first paper transport guide 24 and the second paper transport guide 25 intersect, or both. It may be formed on the entire sheet contact surface side of the sheet transport guides 24, 25.

FIG. 4 is a schematic view showing a fourth embodiment of the sheet conveying guide provided in the recording apparatus of the present invention. The frame 8a of the cleaner 8 provided with the first sheet conveying guide 24 and the photosensitive drum. The frame 6a of 6 serves as an integrated sheet conveyance guide.

FIG. 5 is a vertical sectional side view of the improved fixing unit 12 provided in the recording apparatus of the present invention.
2, a heating roller 12a and a pressure roller 12b
The toner is fixed while being sandwiched by and the paper is conveyed, and the paper 20 after fixing is discharged in the tangential direction of the heating roller 12a,
The tip 26a abuts on the outer circumference of the heating roller 12a by a spring pressure (not shown) and separates the paper so that it does not wind around the heating roller 12a. Therefore, a plurality of paper separating claws 26 are provided along the longitudinal direction of the heating roller 12a. It is arranged. The leading edge 26a of the sheet separating claw 26 is flatly pointed, and the edge 26 extending from the leading edge 26a to the base edge.
c is formed into a curved surface.

[0030]

As described above, according to the present invention, the front end portion on the upstream side of sheet conveyance, which is provided on the frame of the cleaner for wiping off the toner remaining on the surface of the photosensitive drum, approaches the surface of the photosensitive drum as much as possible, and the front end portion on the downstream side. The first sheet conveyance guide whose section extends toward the fixing unit and the leading end on the downstream side of the sheet conveyance provided on the frame of the fixing unit are as close as possible to the nip between the heating roller and the pressure roller. Since the recording apparatus is provided with the paper transport guide including the second paper transport guide whose front end on the upstream side of the paper transport extends toward the photosensitive drum, the paper does not wind around the photosensitive drum. The sheet conveyance guide smoothly guides the nip between the heating roller and the pressure roller that constitute the fixing unit.

Further, there is provided a paper conveyance guide in which tip ends of the first paper conveyance guide and the second paper conveyance guide intersect in a direction perpendicular to the conveyance path in a shape in which comb teeth bite alternately. As a result, even when the distance between the photosensitive drum and the fixing unit changes due to a design change, it can be applied without changing the design of the first paper transport guide and the second paper transport guide.

Further, only the sheet contact surface side of the leading end portion where the first sheet transport guide and the second sheet transport guide intersect with each other,
Alternatively, by using a sheet conveyance guide in which all of the sheet conveyance guides on the sheet contact surface side are ribs, the sliding contact friction of the sheet is reduced, and the sheet can be smoothly guided.

Further, the toner is fixed while being sandwiched between the heating roller and the pressure roller which constitute the fixing unit and the paper is conveyed, and the paper after fixing is discharged in the tangential direction of the heating roller, and the paper is wound around the heating roller. In order to prevent the toner from sticking, the edge of the paper separation claw whose tip is in contact with the outer periphery of the heating roller is a curved fixing unit, so that the toner image fixed on the paper at the edge of the paper separation claw is It is not peeled off and the quality of the toner image is not deteriorated.

[Brief description of drawings]

FIG. 1 is a schematic view of a first embodiment of a sheet conveyance guide provided in a printing apparatus of the present invention.

FIG. 2 is a schematic view of a second embodiment of the paper transport guide provided in the printing apparatus of the present invention.

FIG. 3 is a schematic view of a third embodiment of the paper transport guide provided in the printing apparatus of the present invention.

FIG. 4 is a schematic view of a fourth embodiment of the paper transport guide provided in the printing apparatus of the present invention.

FIG. 5 is a schematic view of an embodiment of a fixing unit included in the printing apparatus of the present invention.

FIG. 6 is a perspective view of a sheet separation claw that constitutes a fixing unit included in the printing apparatus of the present invention.

FIG. 7 is a side view showing a schematic structure of a conventional general recording apparatus.

FIG. 8 is a schematic view of an example of a paper transport guide provided in a conventional general recording apparatus.

FIG. 9 is a schematic view of another example of a sheet conveyance guide provided in a conventional general recording apparatus.

FIG. 10 is a perspective view of a sheet separation claw that constitutes a fixing unit included in a conventional general printing apparatus.

[Explanation of symbols]

 1 Paper Cassette 2 Pick Roller 3 Paper Size Sensor 4 First Guide Roller 5 Second Guide Roller 6 Photosensitive Drum 6a Frame 7 Pre-Electrifier 8 Cleaner 8a Frame 9 Exposure Unit 10 Developing Device 11 Transfer Unit 12 Fixing Unit 12a Heating Roller 12b pressure roller 12c frame 12d nip 13 third guide roller 14 first paper ejection roller 15 paper ejection sensor 16 second paper ejection roller 17 manual paper tray 18 manual paper sensor 19 manual paper roller 20 paper 21 paper transport Guide 21a Tip 21b Tip 22 Guide 23 Stacker 24 First paper transport guide 24a Tip 24b Tip 24c Rib 25 Second paper transport guide 25a Tip 25b Tip 25c Rib 26 Paper separating claw 26a End 26b edge 26c edge

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 15/20 102 21/10

Claims (6)

[Claims] 1. A front end portion (24a) on the upstream side of sheet conveyance, which is provided on a frame (8a) of a cleaner (8) for wiping off the toner remaining on the surface of the photosensitive drum (6), is as photosensitive as possible. 6) near the surface of the downstream end (2
4b) is provided on the first paper conveyance guide (24) extending toward the fixing unit (12) and the frame (12c) of the fixing unit (12),
The leading end portion (25a) on the downstream side of the sheet conveyance approaches the sandwiching portion (12d) between the heating roller (12a) and the pressure roller (12b) as much as possible, and the leading end portion (25a) on the upstream side of the sheet conveyance (25a).
A recording apparatus, characterized in that b) is provided with a paper transport guide including a second paper transport guide (25) extending toward the photosensitive drum (6). 2. A first sheet conveying guide (24) and a second sheet conveying guide (24).
Paper transport guide (25) and the leading end (24b, 25
2. The recording apparatus according to claim 1, wherein b) is provided with a paper conveyance guide that intersects in a direction orthogonal to the conveyance path in a shape in which the teeth of the comb are bite alternately. 3. A first sheet conveying guide (24) and a second sheet conveying guide (24).
2. The recording apparatus according to claim 1, further comprising a sheet conveyance guide having ribs (24c, 25c) formed on the sheet contact surface side of the sheet conveyance guide (25). 4. The first sheet conveying guide (24) and the second sheet conveying guide (24).
Paper transport guides (25) at the intersecting tip portions (24b,
25b) only on the paper contact surface side, or on both the paper contact surface sides of both paper transport guides (24, 25) ribs (24c,
The recording apparatus according to claim 1, further comprising a sheet conveyance guide having a size of 25 c). 5. A paper transport in which a frame (8a) of a cleaner (8) provided with the first paper transport guide (24) and a frame (6a) of a photosensitive drum (6) are integrated. The recording apparatus according to claim 1, further comprising a guide. 6. A fixing unit (12) is sandwiched by a heating roller (12a) and a pressure roller (12b) to fix the toner while conveying the sheet, and the fixed sheet is fixed on the heating roller (12a). The edge (26c) of the sheet separating claw (26) whose tip is in contact with the outer periphery of the heating roller (12a) is curved so that the sheet is discharged in a tangential direction so that the sheet does not wind around the heating roller (12a). A recording apparatus comprising the formed fixing unit (12).