JPH054757A - Resist conveyor device for image forming device - Google Patents

Abstract

PURPOSE:To prevent the generation of wrinkles in an envelope passing region by reducing the diameter, in the envelope passing region, of one roller between a resist roller pair, and adjusting in such a way as to make the resist timing reference position of an envelope equal to that of normal recording paper. CONSTITUTION:The diameter, in an envelope passing region, of a drive roller 3a' between a pair of resist rollers is smaller by alpha than the diameter in the other region part. In this case, the value of alpha is to be 0.1-1m in order to make the resist timing reference position of normal recording paper, so-called cut paper, equal to that of an envelope 21, but this is determined by the thickness of the envelope 21 based on the paper quality and the like of the envelope 21. The mutual pressure contact between the roller pair in the envelope passing region is thereby released to prevent the wrinkle of the envelope 21 in that place.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist conveying device for an image forming apparatus such as a laser printer, a copying machine or a facsimile which uses an electrophotographic process.

[0002]

2. Description of the Related Art FIG. 8 is a schematic configuration diagram of a conventional laser printer.

The recording paper 2 which is pressed against the pickup roller by the bottom plate raising lever from the paper feeding device 1 and is fed in the direction of the registration roller pair, is composed of a drum-shaped photosensitive member 4 at a timed timing by the registration roller pair 3. It is conveyed to the image carrier. The photoconductor 4 is rotationally driven counterclockwise as viewed in the figure, and at that time, the surface is charged by the charging charger 5.
A laser beam from the laser optical system 6 is irradiated to form an electrostatic latent image on the photoconductor. This latent image is visualized by toner as it passes through the developing device 7, and this visible image is transferred by the transfer charger 8 to the recording paper 2 conveyed to the photoconductor 4, and the visible image on the transferred recording paper is transferred. Is fixed by the fixing device 9. On the other hand, the residual toner on the photoconductor 4 after the transfer of the visible image is removed by a cleaning device having a cleaning blade 11. The toner removed from the photoconductor 4 is collected and stored in the toner recovery tank 12.
The recording paper 2 discharged from the fixing device 9 is directly stored in the paper discharge unit 10 in the case of single-sided recording, and guided to the double-sided conveying roller pair 14 by the rotatable double-sided entrance guide 13 in the case of double-sided recording. . The recording paper 2 is conveyed by the pair of double-sided conveyance rollers 14 to the pair of reversing rollers 15 rotating so as to feed the recording paper 2 toward the sheet feeding device, and the reversal sensor 16
Pass through. After a lapse of a predetermined time after the recording paper 2 passes the reversing sensor 16, the reversing roller pair 15 changes the rotation direction, and the rotatable reversing guide 17 is switched to convey the recording paper 2 in the registration roller pair direction. The recording paper 2 again fed to the registration roller pair 3 is conveyed to the photoconductor 4 at a timing by the registration roller pair 3, and the toner image is transferred and fixed onto the recording paper 2 through the same procedure as above. . At this time, the opposite side of the sheet fed from the sheet feeding device 1 contacts the photoconductor 4, so that double-sided recording is performed on the recording sheet 2. The recording paper 2 on which double-sided recording has been performed passes through the fixing device 9 and is then discharged to the paper discharge unit 10 by the double-sided entrance guide 13 and stored therein.

[0004]

In the above apparatus, when the envelope 21 is fed instead of the recording sheet, the following problems occur at the registration roller pair 3 of the registration conveying device.

(1) Compared with the case of making a copy using a normal recording paper, the writing position is delayed and displaced.

The thickness of a normal recording paper is about 0.1 mm, whereas an envelope has a folded portion of the paper, an air layer, a glued portion, etc., and the sheets are stacked in multiple layers. Therefore, the thickness is about 1 mm. Due to its thickness, in the nip region of the registration roller pair 3 (3a, 3b), the envelope 21 is faster by xmm than the cut sheet 22 which is a normal recording sheet by xmm, as shown in FIG. Hit 3b. This means that the reference position of the registration timing is a position delayed by xmm from the normal position. The defective state of the copy result due to the delay of the registration position by xmm is shown in the upper part of FIG.

(2) As a result of passing the paper, wrinkles occur at the rear end portion of the envelope.

The pair of registration rollers 3a and 3b are in pressure contact with each other when no paper is passed. As shown in FIG. 11, between the pair of pressure-contacting registration rollers,
When the envelope 21 having a non-uniform thickness is passed, the expansion of the envelope gradually moves toward the latter half of the envelope on the upstream side in the sheet passing direction as the sheet passes, and finally, as shown in the lower part of FIG. , Wrinkles occur at the trailing edge of the envelope.

In view of the above, the present invention solves the above-mentioned problems and allows the same registration timing as that of normal recording paper when an envelope is passed through, and also it is possible to prevent wrinkles at the registration roller pair. An object of the present invention is to provide a resist transfer device that prevents the occurrence of the occurrence.

Conventionally, as shown in Japanese Patent Application Laid-Open No. 3-26633, in at least one of the pair of registration rollers, an area through which a corner of a sheet material such as an envelope passes,
A sheet that provides a means for releasing pressure contact such as a notch to reliably prevent the occurrence of so-called "pre-register jam" that winds up the corners of an envelope etc. and smoothly conveys an uneven sheet such as an envelope Although a material conveying device has been proposed, such a device does not solve the above problem.

[0011]

SUMMARY OF THE INVENTION According to the present invention, there is provided a resist transport apparatus having at least one pair of registration roller pairs for performing registration timing and skew correction of recording paper, in which at least one of the registration roller pairs has a diameter of The problem was solved by reducing the registration timing reference position of the envelope so as to be equal to the registration timing reference position of normal recording paper by reducing the size only in the envelope sheet passing area.

If a large number of concave and convex lines are provided along the axial direction in the area where the diameter of the registration roller pair is reduced in the envelope sheet passing area, the contact of the envelope with the roller can be ensured. Is preferred.

A roller having a region of reduced diameter is
It is more preferable if the roller can be switched to a roller having a uniform diameter over the entire paper passing length.

Further, it is more preferable that the region width having a reduced diameter can be changed.

It is further preferable to provide a groove in the envelope sheet passing area of at least one of the pair of registration rollers.

[0016]

According to the present invention, the diameter of at least one of the pair of registration rollers is reduced only in the envelope sheet passing area so that the registration timing reference position of the envelope becomes equal to the registration timing reference position of normal recording paper. Since the adjustment is made, the same registration timing as that of normal recording paper can be taken even when the envelope is passed. Since the mutual pressure contact of the roller pair is released in the envelope sheet passing area, the formation of wrinkles that has conventionally occurred at that portion is prevented.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on the embodiments shown in the drawings.

As shown in FIGS. 1 and 2, of the pair of registration rollers, the diameter of the drive roller 3a 'in the envelope sheet passing area is smaller than the diameter in the other area by α. . In this case, the value of α is 0.1 to 1 m in order to make the registration timing reference position of normal recording paper, so-called cut paper, equal to the registration timing reference position of envelope.
m, which is determined by the thickness of the envelope based on the paper quality of the envelope and the like. By adjusting the roller diameter in this way, the registration timing becomes the same between the cut sheet and the envelope, and when the envelope is passed in place of the cut sheet from the paper feeding device, there is no need to pay any attention. The writing position deviation as shown in FIG. 10 is eliminated.

Since the diameter of the registration roller is reduced to partially release the pressure contact of the roller pair, a large number of uneven lines are provided along the axial direction at the reduced diameter portion, and the envelope is pressed against the roller. The contact may be achieved by this convex portion.

When the envelope-passing region is widened to accommodate envelopes of various sizes, as shown in FIG. 3, one of the registration roller pairs has a roller 3a 'having a region having a reduced diameter, and the roller 3a'. The roller 3a having a uniform diameter over the entire length of the sheet passing portion is configured to be switchable by rotation of the rotary solenoid 18. As shown in FIG. 4, the two rollers 3a ′ and 3a ″ having different widths in the reduced diameter region can be switched by the rotation of the rotary solenoid 18.

Further, as shown in FIG. 5, in a roller having a partially reduced diameter, the roller is constituted by a rubber member so as to cover the divided shaft, and at two points in the middle of the reduced diameter region. When it is necessary to pass the envelope having a width larger than the bulge portion 23 by passing the bulge portion 23, the roller is pulled in the lengthwise direction to reduce the diameter of the region. Try to use effectively. By doing so, it is possible to correspond to envelopes of various sizes as in the above example.

Further, as shown in FIGS. 6 and 7, by further reducing the diameter of, for example, the central portion of the drive roller having a smaller diameter in the envelope sheet passing area, the portion is formed as a groove. With this configuration, when the envelope is passed, the wrinkles at the rear end portion of the envelope, which have been conventionally generated due to the bulge of the envelope, can be more reliably prevented.

[0023]

According to the resist conveying apparatus of the present invention, the diameter of at least one of the rotating bodies, which are the pair of registration rollers, is reduced only in the envelope paper passage area, and the registration timing reference position of the envelope is the normal position. Since it is adjusted so as to be equal to the registration timing reference position of the recording paper, even when passing envelopes instead of normal recording paper,
It is possible to take the same registration timing as normal recording paper without any treatment. Further, since the mutual pressure contact between the roller pairs is released by reducing the diameter in the envelope sheet passing area, the formation of wrinkles that has conventionally occurred at that portion is prevented.

In the resist transfer device according to the second aspect,
Since a large number of uneven lines are provided along the axial direction in the portion where the diameter of the registration roller pair is reduced in the envelope sheet passing area, the contact of the envelope with the roller becomes more reliable, A certain registration timing is secured.

In the resist conveying apparatus according to the third or fourth aspect, the roller having the area with the smaller diameter is
It is configured so that it can be switched to a roller with a uniform diameter over the entire paper passing length, or it can be configured to change the area width with a smaller diameter, so it can handle cut paper and envelopes of various sizes as needed. Can be made.

Further, in the resist transporting device of the fifth aspect, at least one groove is further provided in the envelope sheet passing region of at least one of the pair of rollers, so that the effect of the first aspect can be prevented from forming wrinkles. , Will be more certain.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing a state in which an envelope passes through a pair of registration rollers according to an embodiment of the present invention.

FIG. 2 is an end view of the registration roller pair of FIG.

FIG. 3 is a schematic view of a pair of registration rollers according to another embodiment of the present invention.

FIG. 4 is a schematic diagram of a pair of registration rollers according to another embodiment of the present invention.

FIG. 5 is a schematic view of a pair of registration rollers according to still another embodiment of the present invention.

FIG. 6 is a schematic view of a registration roller pair according to still another embodiment of the present invention.

FIG. 7 is an enlarged partial view of the case where an envelope passes through the registration roller pair of FIG.

FIG. 8 is a schematic configuration diagram of a conventional laser printer.

FIG. 9 is a schematic view showing a state in which a registration timing reference position is deviated between a cut sheet and an envelope in a conventional registration roller pair.

FIG. 10 is a schematic diagram showing the occurrence of writing misalignment and wrinkles when printing is performed using a conventional resist transport device.

FIG. 11 is a schematic diagram showing a state in which an envelope is passed through a pair of conventional registration rollers.

[Explanation of symbols]

2 Recording paper 3 Registration roller pair 3a, 3a 'drive roller 21 envelopes

Claims (5)

[Claims] 1. A registration conveying device having at least a pair of registration roller pairs for recording paper feeding timing and skew correction, wherein at least one of the registration roller pairs has a small diameter only in an envelope sheet passage area. A resist conveying device, wherein a registration timing reference position of an envelope is adjusted to be equal to a registration timing reference position of a normal recording sheet. 2. The resist conveying device according to claim 1, wherein a large number of concave and convex lines are provided along an axial direction in a portion of the registration roller pair where the diameter is small in the envelope sheet passing region. 3. A roller having a region with a reduced diameter is configured to be switchable with a roller having a uniform diameter over the entire length of the paper passing.
Alternatively, the resist transfer device according to claim 2. 4. The resist transfer apparatus according to claim 1, wherein the width of the area having a reduced diameter is changeable. 5. The resist conveying device according to claim 1, wherein at least one groove is provided in an envelope paper passing area of at least one of the pair of resist rollers.