JPS59212865A - Recording paper guiding device of fixing device - Google Patents

Abstract

PURPOSE:To introduce recording paper having thin thickness through thick one into a fixing device stably and convey it smoothly without wrinkling by varying a recording paper introduction position to the fixing device responding to the thickness of the recording paper. CONSTITUTION:An entrance guide plate 20 which mounts and guides recording paper P1 to a heat roller 13 is fixed to an inclinable plate 21. The plate 20 has a highly slanted or curved surface at the sliding center part to bend and send the paper P1 vertically to its moving direction. When the paper P1 to be fed is thin paper or normal paper, the plates 21 and 20 are inclined and the paper P1 is curved by abutting on the peripheral surface of the roller 13 to be fed with no ruggedness nor wrinkle. The angle phi1 of inclination at this time is 10- 23 deg. and preferably 15 deg.. When the paper is thick, a lever 23 is rotated and a cam 24 is turned by the rotation of a cam shaft 23 to elevate the right end of the plate 21, which is held almost in level. The angle at this time is 0-10 deg. and preferably about 15 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a roller fixing device used in an electrostatic recording device, and more particularly to a guide device for introducing recording paper into the fixing device.

2. Description of the Related Art In general, a fixing device having a clamping mechanism in an electrostatic recording device, such as an electrophotographic copying machine, uses a pressure roller fixing method, a heat roller fixing method, or the like. An electrophotographic copying machine will be described as an example of a conventionally known electrostatic recording device having the above fixing device.

FIG. 1 is a diagram schematically showing a recording paper conveyance path of an electrophotographic copying machine. A drum-shaped photoreceptor 1 is rotatably driven in the direction of an arrow by a drive source (not shown), and a charger 2 is attached to its circumferential surface.
An electrostatic latent image is formed by the exposure device and the developing device 3.
to create a visible image (toner image). On the other hand, skein, To 4
The recording paper P fed by the feeding roller 5 is guided by a guide plate 6 to a pair of upper and lower registration rollers 7 .

The recording paper P, which has passed through the registration rollers 7 which are synchronized with the photoconductor 1, is also sent out toward the photoconductor 1 by the guide plate 8. From then on, the recording paper P is brought into close contact with the circumferential surface of the photoconductor 1.
The visible image on the photoreceptor 1 is transferred onto the recording paper P by the transfer pole 9 . After transfer, the recording paper P has a separation pole l
The photoreceptor is separated from the photoreceptor 1 by a conveyor belt 11 and conveyed toward a fixing device 12 by a conveyor belt 11 . The fixing device 12 is
It consists of a heat roller 13 having a heat source, a pressure roller 14 that comes into pressure contact with this roller, and a fixed guide plate 15 on the recording paper introduction side.

In this fixing device 12, the recording paper P is attached to the introduction guide plate 1.
5, the toner image on the recording paper P is introduced into the pressure contact position of the two rollers, and here the toner image on the recording paper P is applied with heat and pressure, and the toner image on the recording paper P is
The image forming process is completed when the image is fixed on the top. After the recording paper P is fixed, it is ejected out of the copying machine by a paper ejection roller 16 and onto a paper ejection tray 17.

In the above, wrinkles are particularly likely to occur when recording paper such as thin paper that is relatively film-free is used.

This is because the recording paper is thin, stiff, and has a small stiffness and funes. In addition, recording paper is hygroscopic, and especially when it is thin, it is easily affected by humidity (this is because it causes wavy unevenness and curling of the leading edge).

Of course, similar unevenness phenomena may also occur due to external factors other than humidity. For example, unevenness also appears when recording paper is conveyed on a plurality of conveyor belts spaced apart while being suctioned or electrostatically attracted.

In any case, if such uneven recording paper is introduced directly to the position where the heat roller 13 and the pressure roller 14 are in pressure contact with each other in the pressure-heating type fixing device, the longitudinal length of the recording paper will be Permanent wrinkles are likely to occur in the direction, resulting in a loss of copy quality.

Note that the term "pressure heating type fixing device" as used herein specifically refers to a heating roller fixing device as shown in FIG. That is,
In the figure, 13 is a driving heat roller, the surface of which is coated with a C-coated layer 13A such as Teflon, and 13B is a heater built into the roller. Reference numeral 14 denotes a pressure roller which can be driven in pressure contact with the heat roller 13, and a silicone rubber liner layer 14A having a thickness of about 5 rtttn is provided on its surface.

The heat roller 13 and the pressure roller 14 are brought into pressure contact with each other by a pressure bonding mechanism (not shown) only during the fixing operation or all the time to form a contact width N.

FIG. 2 shows a technique disclosed in Japanese Patent Publication No. 53-35731. In this method, a fixed guide plate 15 provided on the recording paper introduction side is placed at a pressure contact position of both rollers 13 and 14.
In other words, it is maintained at a height higher than the horizontal line extending from the nip N, and is placed close to the heat roller 13 to maintain a slight distance therebetween.

Once the recording paper P has completed the transfer and is fed while being sucked onto the conveyor belt, it slides on the fixed guide plate 15, and its leading edge first hits the surface of the heat roller 13, and then, as the roller 13 rotates, it slides on the fixed guide plate 15. and is guided to a slit l-S formed between the surface of the roller 13 and the front end surface of the fixed guide plate 15. The recording paper P is bent when passing through the slit section S, and the unevenness of the recording paper P is thereby uniformly regulated, and the recording paper P is turned into a substantially straight line toward the nip N.

According to the guide device of the fixing device described above, ordinary recording paper P□
For example, if it is around 40kg17~55kg, it is fine, but thick recording paper P! For example, when using 9 paper or a thick letter such as a postcard for 70, recording may occur due to relative speed deviation or left/right deviation between the first heat roller 13 and the recording paper conveyance when it passes through the slit section S and is bent. Image disturbance on paper P or recording paper P2
In extreme cases, it may become impossible to transport due to the occurrence of bumps on the running surface.

As mentioned above, the conventional recording paper guide device guides the ordinary recording paper P1.
When using the printer, a normal introduction guide is provided, but when the thick recording paper P2 is fed in, it has the above-mentioned drawbacks.

Purpose of the Invention The present invention was proposed in view of the above-mentioned drawbacks, and it is an object of the present invention to stably introduce recording paper, from thin to thick, into a fixing device, and to transport it smoothly without wrinkles or the like. It is an object of the present invention to provide a recording paper guide device for a fixing device that can perform fixing satisfactorily.

SUMMARY OF THE INVENTION The above object is to provide a guide device for introducing recording paper into a fixing device where it is fixed by fixing rollers that rotate while being pressed against each other, in which the guide device introduces the recording paper into the fixing device according to the paper thickness of the recording paper. This is achieved by a recording paper guide device in a fixing device that is characterized by changing its introduction position.

EXAMPLES Hereinafter, the present invention will be explained in detail by showing specific examples thereof.

FIG. 3 is a front view showing an example of the recording paper guide device in the fixing device of the present invention.
3 (B) is a diagram showing the state of the recording paper guiding device when feeding thick paper (for example, 70 kg paper or FIG. 4 is a diagram showing the state of the guide device when feeding document P2. FIG. 4 is an exploded perspective view of the recording paper guide device.

In these figures, the entrance guide plate on which the recording paper P1 is placed and introduced to the circumferential surface of the heat roller 13 of the fixing device is fixed to the tiltable plate 21. The recording paper sliding surface of the input log guide plate has a high slope or curved surface in the center,
The recording paper P is fed while being curved in a direction perpendicular to the direction of travel. Both end portions 21A and 21B of the tiltable plate 21 are bent downward or are integrated by groove welding, which are separate parts, and have through holes. A shaft n is fitted into the through hole, and is rotatably attached to a device main body (not shown).

On the other hand, on the lower right side of the tilting plate 21, a cam shaft is rotatably supported by the device main body (not shown), and a cam row is fixed in contact with the lower surface of the tilting plate 21. Furthermore, one end of the cam shaft is extended and has an operating lever 6.

When feeding thin or normal recording paper P1, the tilting plate 21 and the input guide plate are inclined as shown in FIG. 3 (4), and the recording paper P1 is heat roller 1
At this time, the recording paper P
After the unevenness and wrinkles of 1 are removed, the sheet becomes almost straight and advances to position 6 where both rollers 13 and 14 come into pressure contact, and fixing is performed.

Incidentally, the inclination angle θ1 of the tilting plate 21 is effective at 10° to 23°, and in particular, good fixing results were obtained for commonly used recording paper when it was set to about 15°.

Next, when introducing thick recording paper Pt, the operating lever 5 is rotated clockwise or counterclockwise to bring it down. As a result, the cam shaft rotates, and the right end of the tiltable plate 21 is raised by the rocking of the cam row that is integral with the cam shaft, and the entry guide plate is set almost horizontally. When the thick recording paper P2 is fed in this state, the recording paper P reaches the circumferential surface near the pressing position of the heat roller 13 without being almost bent, and is subsequently pressed, heated and fixed. The thick recording paper P2 does not easily form unevenness or wrinkles, so it does not require the above-mentioned bending to straighten it, and since the paper is stiff, if the above-mentioned bending is performed, there is a risk that the paper will hit the heat roller 13 and cause a feeding failure. This is because there is. Incidentally, the inclination angle θ2 in FIG. 3(B) is O~
10°, preferably about 5°.

FIG. 5 is a schematic sectional view showing another embodiment of the recording paper guiding device according to the present invention. The input roller guide plate is rotatable around a shaft 31, and the left end is close to the heat roller 13.
The other end forms an operating lever 32. In this case as well, by operating the operating lever 32 left and right as described above, the upper surface of the input log guide plate is tilted, and switching is controlled in accordance with the thickness of the recording paper.

In FIG. 6, the entrance guide plate 40 can be rotated about a shaft 41 by operating a solenoid by operating a switch S.

Figure 7 shows the lever 53 that controls the input guide plate.

This is an embodiment in which the flexible wire 52 is operated by pulling and pulling, and is rotatable about a shaft 51.

The above is a guide device that changes the approach angle and contact position of the recording paper with respect to the heat roller according to the paper thickness of the °C recording paper by making the entrance guide plate tiltable. The object of the invention can also be achieved by moving the earthwork in parallel.

FIG. 8 is a front view showing an example of such a recording paper guide device, and FIG. ) is a diagram showing the state of the guide device when feeding thick letters. FIG. 9 is an exploded perspective view of the guide device.

In these figures, the entrance guide plate 60 on which the recording paper is placed and introduced to the circumferential surface of the heat roller 13 of the fixing device has the same shape as the input log/f drive plate 30, and the upper surface thereof A certain recording paper sliding surface has a high slope or curved surface in the center.Thereby, the recording paper is fed while being curved in a direction perpendicular to its traveling direction.Artificial guide plate 300
Both ends are fixed to a slide plate 61 and are integrally movable up and down parallel to the fixed plate 62.

These are two guide pins 63 fixed on the fixed plate 62.
The slide plate 610, which slides on the guide pin 63, can be moved up and down by the long grooves 04 at two locations. Furthermore, a fixing pin 65 is installed in the center of the slide plate 6I, and a fulcrum pin 66 is installed in the fixing plate 62, which are fitted into the long end of the operating lever 67 and fixed in the rotating shaft hole of the operating lever 670. ing. When the right end of the operating lever 67 is lifted, the operating lever 67 rotates around the fulcrum pin 66, and the other end pushes the fixed bin 65 downward, whereby the slide plate 61 is guided by the long lug and the guide pin 63. It descends in parallel and becomes the state shown in Figure 8 CB). Note that the slide plate 61 and the operating lever 67 are normally lifted upward by a spring (not shown) and are in the state shown in FIG. It is lowered by the operation lever 67.

FIG. 10 is a schematic front view showing another embodiment of the guide device, in which the entrance guide plate 70 is moved up and down in parallel by a parallel link mechanism that rotates about a fulcrum 71. This changes the introduction position of the recording paper into the fixing device.

FIG. 11 shows a guide device in which an entrance guide plate 80 is moved vertically in parallel by a link mechanism of a rotation support shaft 81 and an operating lever 82.

The third example is a guide device that moves an entrance guide plate 90 vertically in parallel by linearly moving an operating lever 92 having a cam surface 91.

The above are various embodiments in which a solid entrance guide plate is moved up and down in parallel, but FIG. 13 is an embodiment using a flexible artificial guide plate 100. The flexible entrance guide plate 100 is made of a hard stainless steel plate or a phosphor bronze plate, etc., has appropriate elasticity, and is pushed upward by a push-up member 101 to hold a thin or ordinary recording paper P1 as described above. Bend it while making a slight curve and insert it into the pressure contact position of the fixing device.

When feeding the thick recording paper P2, the push-up member 10
1 is lowered, the entrance guide plate 100 becomes nearly flat due to its own restoring spring force, and the contact position of the recording paper P and the heat roller 13 is lowered. Note that 102&-1 is a long and fixed bin that slidably presses both ends of the artificial guide plate 1000.

In the above-described embodiments of the present invention, the tilting or parallel movement of the entrance guide plate was mainly performed manually according to the paper thickness of the recording paper, but the entrance guide plate was driven automatically by automatic detection of the paper thickness. Converting or converting the entrance guide plate electrically or the like by operating a changeover switch according to the paper thickness can be done by using known means (the recording paper guide device according to the present invention is easily described in detail in the embodiments). Therefore, the inclination angle or height of the guide plate can be easily changed according to the thickness of the recording paper, thereby stably feeding recording paper from thin to thick against the pressure roller of the fixing device. It does not cause wrinkles on the recording paper, folded edges, poor feeding (jams), or image disturbances (it maintains flatness and performs good fusing, and it also withstands high-speed copying machines, etc.). You can make a profit.

[Brief explanation of drawings]

FIG. 1 is a front view showing an outline of a recording paper conveyance system of an electrophotographic copying machine, FIG. 2 is a front view of a recording paper guide device using a fixed guide plate, and FIGS. 3 and 4 are recording paper according to the present invention. A front view and an exploded perspective view of the guide device, FIGS. 5 to 7 are schematic front views showing other embodiments, and FIGS. 8 and 9 are front views of still other embodiments of the guide device according to the present invention. and an exploded perspective view, and FIGS. 10 to 12 are schematic front views showing other embodiments. FIG. 13 is a perspective view showing still another embodiment. 12... Quagmire fjffi 13°°° Heat roller 14... Pressing roller 15... Fixed guide plate 2L), 30, 40, 50, 60, 70, 80, 90
．． 100-Population guide plate 21... tiltable plate U
...Cam 42...Nlenoid 61...Slide plate P1...Thin or normal recording paper P2...Thick 6-self recording paper agent Yoshimi Kuwahara Figure 2/ @)y

Claims (3)

[Claims] (1) In a guide device that introduces recording paper into a fixing device where it is fixed by fixing rollers that rotate while pressing against each other, the position of introducing the recording paper into the fixing device of the guide device is determined depending on the paper thickness of the recording paper. A recording paper guide device in a fixing device characterized by being variable. (2) The recording paper in the fixing device according to claim 1, characterized in that the introduction angle of the recording paper guide plate of the guide device into the fixing device is changed depending on the paper thickness of the recording paper. Guidance device. (3) Raise the recording paper guide plate of the guide device parallel to the
1. The recording paper that can be inserted into the fixing device according to claim 1, wherein the recording paper is not movable downward, and the introduction position into the fixing device is changed up and down depending on the paper thickness of the recording paper. Guidance device.