JPH0453655Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial field of application) The present invention provides a meandering prevention mechanism for continuous recording paper in a fixing device that fixes images transferred onto continuous recording paper.
More specifically, the present invention relates to a mechanism for preventing continuous recording paper from falling off from the meandering prevention mechanism.

(Prior art) Conventionally, a photoconductor on the surface of a photoconductor drum is exposed to light to form a latent image, toner is attached to this latent image and developed, and the toner is transferred to recording paper and fixed by a fixing device. Image forming apparatuses using so-called electrophotography are mainly used in copying machines, but recently they have also been used in printers and the like that print out computer output.

Copying machines generally use cut paper as recording paper, but printers are desired to use continuous recording paper, which is the same as that used in conventional line printers.

The continuous recording paper that is the same as the conventional paper is a folded continuous paper with sprocket holes (hereinafter simply referred to as continuous paper) called so-called fan-fold paper, and the folded part becomes a perforation so that it can be easily cut. It is something that exists.

Fixing methods include so-called heat roll fixing, in which the unfixed recording paper is sandwiched between a pair of rotating heatable fixing rolls and fixed by applying heat and pressure, and toner is applied to the recording paper by applying pressure with a pair of fixing rolls. A pressure fixing method (pressure roll fixing) is used in which the image is crushed and fixed. In either fixing method, the recording paper is conveyed and driven by the rotation of the fixing roll.

However, when pressure fixing and heat-pressure fixing are applied to continuous paper, the fixing roll pair is damaged due to factors such as poor initial biting into the fixing roll pair, uneven paper thickness, and elongation of the paper due to moisture absorption. The continuous paper held between the rollers becomes skewed or meandering, and the position where the continuous paper is caught by the pair of fixing rolls continuously changes in the lateral direction until it reaches the end of the opposite side of the fixing roll, causing wrinkles, resulting in poor fixing and poor conveyance. will occur.

In order to prevent this situation, a tensioning belt, which has a plurality of protrusions that fit into and engage the feed holes of the continuous paper on the continuous paper introduction side of the fixing roll, is rotated with a predetermined rotational resistance in the continuous paper transport direction. It has been considered that a tensioning belt is rotated as the continuous paper is conveyed, and tension is applied to the continuous paper between the tensioning belt and the fixing roll to prevent meandering. There is.

(Problems with the prior art) However, in pressure fixing and heat-pressure fixing, the continuous paper is pressurized with strong pressure by the fixing roll and is conveyed, so once the continuous paper begins to skew or meander, the skew In extreme cases, the continuous paper may become deformed (wrinkled) and the continuous paper's feed hole may come off the protrusion of the tensioning belt, causing the continuous paper's feed hole to become There are problems in that parts are damaged and skewing or meandering cannot be controlled, resulting in poor conveyance and fixing.

In addition, in a so-called tractor belt in which a belt having the above-mentioned protrusions is installed on the left and right lower sides of the continuous paper so as to be able to rotate around the continuous paper, and the continuous paper is conveyed by the rotational drive of the belt, the belts shown in FIGS. 4 and 5 are used. Gotoku protrusion 50
There is a structure in which a plate 51 with a slit 51A formed in the orbit of A is installed at a predetermined distance from the upper surface of the tractor belt 50 to prevent the continuous paper 9 from falling off the upper surface of the tractor belt 50. Compared to the force that causes the continuous paper 9 to move diagonally when the continuous paper 9 rotates and is driven to be transported as shown in FIG. Since the oblique force exerted by this structure is extremely strong, the structure causes the object to fall off in the lateral direction (Z direction).

(Purpose of the invention) In view of the above-mentioned circumstances, the present invention prevents the continuous paper from falling off from the protrusion of the tensioning belt, prevents skewing and meandering, and ensures restoration to the specified position when it occurs. The purpose is to provide a mechanism for preventing meandering of a fixing device.

(Means for solving the problem) In order to achieve the above object, the meandering prevention mechanism of the fixing device according to the present invention has a protrusion on the upper side of the tensioning belt of the meandering prevention mechanism at a position corresponding to the protrusion of the tensioning belt. A presser belt with a fitting hole formed therein is fixed so that it can be rotated, and the protrusion of the tensioning belt is fitted into the fitting hole of the presser belt through the feed hole of the continuous paper, and the continuous paper is attached to the protrusion of the tensioning belt. The tension applying belt and the presser belt are engaged with each other and are configured to sandwich the continuous paper between the tension applying belt and the presser belt, and are configured to prevent the continuous paper from falling out from the protrusion of the feed hole.

(Example of the invention) Fig. 1 shows a laser beam printer device that uses fan-hold paper as the recording paper, and prints input from a computer etc. on fan-hold paper 9 using electrophotography and outputs it. be.

Around the photosensitive drum 1, a toner cleaning section 2, a static eliminating section 3, a charging section 4, a scanning optical system 5 that guides a laser beam onto the photosensitive drum 1, a developing section 6, and a transfer section 7 are arranged along the drum rotation direction. The fixing unit 8 is arranged in a predetermined order, and the fixing unit 8 is arranged in front of the fan-hold paper 9 in the conveyance direction, and a meandering prevention mechanism unit 30 is installed in the continuous paper conveyance path from the photosensitive drum 1 to the fixing unit 8. ing.

Then, the photosensitive drum 1 is rotated (sub-scanning) and the surface of the photosensitive drum 1 is scanned in the axial direction of the photosensitive drum 1 (main scanning) with a laser beam from the scanning optical system 5, and the formed latent image is transferred to the developing section. 6 to develop it into a toner image, which is transferred by a transfer unit 7 to fan-hold paper 9 that is conveyed at the same speed as the rotational circumferential speed of the photosensitive drum 1 by a fixing unit 8, and is also fixed by the fixing unit 8. This is what is output.

The fixing unit 8 includes a pair of fixing rolls 81 and a back-up roll 82 that presses the pressure roll 81A on the lower side of the pair of fixing rolls 81 from below to above, which are installed in a direction perpendicular to the conveyance direction of the fan-hold paper 9. This is what is being done.

The fixing roll pair 81 includes a pair of upper and lower pressure rolls 8.
1A and 81B, and the distance between the outer peripheries of both pressure rolls 81A and 81B is such that when the fan-hold paper 9 is sandwiched between the two pressure rolls 81A and 81B, the fan-hold paper 9 is pressed with a predetermined pressure. The interval is set.

Further, the upper pressure roll 81B is connected to a drive motor 50 via a chain (not shown), and is rotationally driven by the drive motor 50 to hold the unfixed fan-hold paper 9 between the pair of fixing rolls 81 at a predetermined position. The fan-hold paper 9 is pressed with pressure to crush and fix the toner (so-called pressure fixing), and the fan-hold paper 9 is conveyed and discharged from the apparatus.

Incidentally, as mentioned above, the rotational circumferential speed of the photosensitive drum 1 and the rotational circumferential speed of the pressure roll 81 completely match.
In other words, it is the conveyance speed of the fan hold paper 9.

The meandering prevention mechanism section 30 is composed of a tension applying mechanism 10 and a falling-off prevention mechanism 20, as shown in FIGS. 2 and 3.

The tension applying mechanism 10 is constructed by installing tension belts 11, 11 parallel to the conveyance direction under both left and right ends of the fan-hold paper 9 conveyed from the transfer section 7 to the fixing section 8. There is.

The tension belt 11 is a so-called synchronous belt in which unevenness (teeth) are formed on the inner circumferential surface to engage with the pulleys connected thereto. A plurality of protrusions 11A that fit into the sprocket holes 9A are protruded in a line around the entire circumference at the same pitch (1/2 inch) as the sprocket holes 9A.

Two shafts 1 are provided in parallel in a direction orthogonal to the conveyance direction of the fan hold paper 9.
Pulleys 12A and 13A installed on 2 and 13 respectively
They are connected to each other, and are installed parallel to the conveyance direction of the fan-hold paper 9, and so that the upper surface thereof coincides with the conveyance path of the fan-hold paper 9.

The protrusions 11A are spindle-shaped so that they can be easily inserted into the feed holes 9A of the fan-hold paper 9 and the fitting holes 21A of the presser belt 21, which will be described later.

The pulley 13A is rotatably fitted to the shaft 13 on the side of the fixing unit 8, and the pulley 12A is installed on the shaft 12 on the side of the photosensitive drum 1 via a powder clutch, and is configured to rotate with a predetermined rotational resistance. . That is, it is configured to apply a predetermined rotational resistance to the tension belt 11 that connects both pulleys 12A and 13A.

The drop-off prevention mechanism 20 includes presser belts 21, 21 that are freely rotatable and are supported by a holder 24 above the tension belts 11, 11 of the tension applying mechanism 10.

The presser belt 21 is a synchronized belt like the tension belt 11, and the idling pulleys 22, 2
It connects the two. A fitting hole 21A having a predetermined diameter larger than the diameter of the projection 11A of the tension belt 11 is formed at the same pitch (1/2 inch) as the projection 11A over the entire circumference. It is something.

The idle pulleys 22, 22 are gears that mesh with the unevenness on the inner circumference of the presser belt 21.
A small-diameter portion 22A is formed in which the center portion corresponding to the fitting hole 21A formed in is made smaller in diameter by a predetermined amount. They are rotatably supported by a holder 24 and installed above the pulleys 12A and 13A of the tension applying mechanism, respectively.

The small diameter portion 22A is a so-called escape groove when the protrusion 11A of the tension belt 11 is fitted into the fitting hole 21A of the presser belt 21, as will be described later, and prevents the rotation of the idle pulley 22 and the presser belt. If the configuration is configured to perfectly synchronize the 21 turns of the protrusion 11A...
A hole of a predetermined depth into which the ... is inserted may be formed on the circumferential side.

The holder 24 is installed on a frame 60 of the entire laser beam printer device via a fulcrum 61, and the lower surface of the presser belt 21, which connects the idle pulleys 22, 22, sandwiches the upper surface of the tension belt 11 and the fan hold paper 10. It is configured to be able to swing from a position at a predetermined interval (operating position

Further, a predetermined position between the fulcrum 61 and the idling pulleys 22, 22 and a predetermined position of the frame 60 are connected by a spring 62, and the spring 62 allows the paper to be moved to the action position X side and the paper set position Y, respectively. The holder 24 is configured to be stabilized by biasing it in each direction.

That is, the fall prevention mechanism 20 supports the presser belts 21, 21, which can be rotated freely, on the frame 60 by the holders 24, 24, and also supports the tension applying mechanism 10.
It is configured to be able to swing around a fulcrum 61 between an operating position X on the upper side of the tension belts 11, 11 and a paper setting position Y.

Thus, the laser beam printer configured as described above has the presser belt 21 of the drop-off prevention mechanism 20,
21 are swung around the fulcrums 61 and 61, respectively, to the paper set position Y, and the fan-hold paper 10 introduced from the inlet 61 is passed through the tension mechanism 10 between the photosensitive drum 1 and the transfer section 7. The projections 11A of the tension belts 11, 11 are connected to the sprocket hole 9.
A..., and after the tip is caught between the fixing roll pair 81 of the fixing unit 8, the projection 11A... through the feed hole 9A... of the fan hold paper 10 is held down and the belt 21 is fitted. The drop-off prevention mechanism 20 is set at the operating position X by fitting it into the holes 21A.

Then, when printing, use fan hold paper 10
is conveyed and driven by a pressure roll 81B of the fixing section 8 that rotates in synchronization with the photosensitive drum 1, and is transferred to the transfer section 7.
The toner image on the surface of the photosensitive drum 1 is transferred to the developing section 6 and is conveyed toward the fixing section 8 .

In the fan-hold paper 9 between the photosensitive drum 1 and the fixing section 8, protrusions 11A on the surface of the tension belts 11, 11 of the meandering prevention mechanism section 30 penetrate and engage with the feed holes 9A on both left and right ends. The tension belts 11, 11 are rotated by being pulled by the fan-hold paper 9 being conveyed.

As described above, the tension belts 11, 11 have a predetermined rotational resistance, thereby applying tension to the fan-hold paper 9 between the meandering prevention mechanism section 30 and the fixing section 8.

Further, the protrusions 11A are fitted into and engaged with the fitting holes 21A of the presser belt 21, and as the tension belts 11, 11 rotate, the presser belts 21, 21 are also driven to rotate. It is something.

That is, the tension belts 11, 11 and the presser belts 21, 21 are driven around by the fan hold paper 9 which is conveyed and driven by the fixing section 8, and the tension belts 11, 11 and the presser belts 21, 21
The fan-hold paper 9 is held between the fan-hold paper 9 and the fan-hold paper 9 between the meandering prevention mechanism section 30 and the fixing section 8, and tension is applied by the rotational resistance of the tension belts 11, 11. Become.

In this way, the fan-hold paper 9 introduced into the fixing section 8 is subjected to a predetermined back tension.
The tension belts 11, 11 regulate the left-right position of the fan-hold paper 9 relative to the fixing section 8, thereby preventing the fan-hold paper 9 from skewing or meandering.

In the event that skewing or meandering occurs, it automatically restores the paper to a predetermined position, and the fan-hold paper 9 is deformed and the tension belts 11 are fed from the protrusions 11A of the tension belts 11, 11. hole 9
A... is prevented from falling off by the presser belts 21, 21, which act to ensure that the above-mentioned skew and meandering can be corrected and restored.

In addition, in the above embodiment, the tension belt 1
1 and 11, and the presser belts 21 and 21 are constructed so as to be able to freely rotate.However, conversely, the presser belts 21 and 21 are provided with circulating resistance and the tension belts 11 and 11 are configured to be freely circumferential. Also good.

Furthermore, it goes without saying that the holding belts 21, 21 may be formed with protrusions and the tension belts 11, 11 may be formed with fitting holes.

(Effect of the invention) According to the meandering prevention mechanism of the fixing device according to the invention,
By fitting the plurality of protrusions of the tensioning belt into the presser belt through the feed hole of the continuous paper to apply tension to the continuous paper, it is possible to prevent the continuous paper from falling off from the protrusions of the tensioning belt in the feed hole of the continuous paper. can be prevented.

That is, it is possible to reliably apply tension to the continuous paper, thereby preventing the occurrence of skewing and meandering, and also to ensure automatic restoration to a predetermined position when skewing and meandering occur. be.

[Brief explanation of the drawing]

FIG. 1 is a side view of the configuration of a printer using the meandering prevention mechanism of the fixing device according to the present invention, FIG. 2 is a partial perspective view of the meandering prevention mechanism of the fixing device, FIG. 3 is a cross-sectional view thereof, and FIG. The figure is a perspective view showing a conventional example, and FIG. 5 is a cross-sectional view thereof. 8... Fixing unit (fixer), 81... Fixing roll pair (fixing roll), 9... Fan hold paper (continuous recording paper), 9A... Spread hole, 10... Tension applying mechanism, 11... Ten tension belt (tension belt), 11A...protrusion, 20...drop-off prevention mechanism,
21... Presser belt, 21A... Fitting hole, 30...
...Meandering prevention mechanism section.

Claims (1)

[Scope of utility model registration request] A tension imparting belt having a plurality of protrusions that fit into and engage the feed holes at the left and right ends of the continuous recording paper is placed on the continuous recording paper introduction side of the fixing roll for pressure fixing and heat and pressure fixing. In the meandering prevention mechanism of the fixing device configured to be rotatable in the conveyance direction with a predetermined rotational resistance, a protrusion is provided on the upper side of the tensioning belt of the meandering prevention mechanism at a position corresponding to the protrusion of the tensioning belt. A presser belt having a fitting hole formed therein is installed so as to be able to rotate in the same direction as the tension applying belt, and a protrusion of the tension applying belt is fitted into the fitting hole of the presser belt through the feeding hole of the continuous recording paper. A meandering prevention mechanism for a fixing device, characterized in that the continuous recording paper is engaged with the protrusion, and the continuous recording paper is held between the tension applying belt and the presser belt.