JPS5890659A - Copying machine - Google Patents

Abstract

PURPOSE:To prevent the formation of creases of transfer paper without increasing the size of a copying machine by making the interval between a photoreceptor and pressure roller couple with a lower peripheral speed shorter than transfer paper length, and forming the sag of the transfer paper curving upward through a conveyance guide. CONSTITUTION:Transfer paper 5 separated forcibly from a photoreceptor 17 by a separating roller 101, etc., abuts on a guide 102 provided in an interval shorter than the transfer paper 5 between the roller 101 and a couple of pressure rollers 46 and 48 having a lower peripheral speed than the roller 101, thereby forming a sag. Further, the sag of the transfer paper 5 curves upward throug a guide 102 for upward guiding from the contacting point between the rollers 46 and 48 to feed the transfer paper to a couple of rollers 46 and 48. This constitution absorbs uneven force due to one-side forcible separation excellently without increasing the size of the copying machine, and the transfer paper is made firm enough to prevent the occurence of trouble of creases.

Description

DETAILED DESCRIPTION OF THE INVENTION In general, in a 1W photocopier, in order to fix an image, a transfer paper with an unfixed image placed on the surface is moved by a pair of pressure rollers whose surface is non-transferable, or by In this way, when weak paper such as transfer paper is passed between a pair of pressure and heating rollers, it is likely to wrinkle, resulting in a very unsightly copy. Therefore, in a copying machine using such a pressure roller, it is necessary to adopt a structure that prevents wrinkles.

The cause of wrinkles is that when the transfer paper is being fed between a pair of pressure rollers, an uneven force is applied to the trailing edge of the copy paper, especially a component force in a direction perpendicular to the direction of travel. In some cases, the person may have been subjected to such force. In particular, when using a transfer type copying machine, as shown in the example below, when only the -@ end of the transfer paper is restrained and separated from the photoreceptor, the part that is restrained and forcibly separated from the photoreceptor is Uneven force is generated on the transfer paper due to the relationship between the side edge, the other end that is adsorbed to the photoreceptor and is about to advance, and the tip that is bitten by the roller.
Causes wrinkles. ' To prevent wrinkles due to this cause, it is necessary to prevent uneven force from being transmitted to the transfer paper near the rollers. To this end, it is only necessary to allow the leading edge of the A4 transfer paper to be gripped by the pressure μm gap only after the separation from the photoreceptor is completed. However, this requires a long distance from the separating section to the pair of pressure rollers, which increases the size of the copying machine and is not practical.

Therefore, an object of the present invention is to provide a simple method for solving the above problems.

First, an example of a copying machine to which the present invention is applied will be explained.

This copying machine is a powder development transfer type copying machine.

In FIG. 1, 1 is a machine case, 2 is a document table on which a document is placed, and is covered with a document holding cover 3.

4□h#iTransfer paper of different sizes5. #5. 6 is a tray on which the transfer paper discharged outside the machine is placed after the transfer has been completed.

A document to be copied is placed on the document glass 16 with its leading edge aligned with the leading edge 161 of the glass, and is held down by the document holding cover 3. Next, if you press copy methane, the electrophotographic photosensitive drum 1
7 begins to rotate clockwise as shown in the figure. When the photosensitive drum 1 reaches a predetermined position and a signal to start illumination is issued, the illumination 2 ring 18, which is a movable part of the optical system, is activated. The first mirror 1i9-19 starts moving rightward in the drawing at the same speed as the circumferential speed of the photosensitive drum 17, and the second mirror 20 starts moving rightward in the drawing at half the speed. Illuminated from below by an illumination lamp 18, the image of the nine originals is captured by a fiil mirror 19, a second mirror 20. Lens 21. 3rd mirror 22° 4th mirror 23
An image is formed on the photosensitive drum F in the exposure section 24 by an optical system consisting of the following. When the exposure is completed, the optical system movable part stops moving to the right and immediately moves in the opposite direction, that is, to the left, and returns to its initial position.

The photosensitive drum 1 has a three-layer structure in which a photosensitive layer on a conductive substrate is covered with a transparent insulating layer, and rotates clockwise in the drawing. The drum 17 is first charged by a positive charger 26 which is supplied with a high voltage current e from a high voltage power source. Subsequently, when reaching the exposure section 24, the image of the document described above is exposed to the slit, and at the same time, the shim is charged (
static electricity removal). Then, the entire surface is exposed by the entire surface exposure lamp 28, and the photosensitive drum 11 is exposed.
It forms an electrostatic latent image on the surface and enters developer 29. In the developing device 29, 1 of the magnet 30! When the carrier on the rotating sleeve 31 comes into contact with the magnetic brush made of toner, the electrostatic latent image on the photosensitive drum 1 is developed and visualized. At the next step, the transfer paper fed from the paper feed section is brought into close contact with the photosensitive drum 17, and the 1 transfer charger 3
At step 2, the developed image (toner image) on the photosensitive drum F is transferred onto the transfer paper by charging with a high voltage current from the high voltage power source 34. After the transfer, the transferred knitted paper is restrained at one end by a separation belt and separated from the photosensitive drum 17, and then fixed at 34.
guided by. The remaining toner is wiped from the photosensitive drum by a cleaning blade 35 that is pressed against the photosensitive drum, and the next cycle is repeated again.

When the photosensitive drum reaches a predetermined position and issues a paper feed signal, the paper feed rollers 391 or 39 . Nyota transfer paper 5. or 5. is the 0th order 1#Nl register roller pair 40. which is fed to the right in the figure. or 40. The paper is prevented from being skewed and sent in the correct direction. Next, #h2 register roller pair 43
After synchronizing with the image on the photosensitive drum E using a signal from the optical system movable part, the transfer paper is brought into close contact with the photosensitive drum E, as described above, and the wI image is transferred thereto. After completing the transfer, attach the separation belt to the photosensitive drum. The removed transfer paper then enters a constant intensifier 34. Fixation@34 has heat 44 inside.
Transfer paper with an unfixed image on its surface is passed between the peeling elastic fixing roller 46 heated by a heating roller 245 having When it passes through and is heated, the toner is thermally fused and the image is fixed on the transfer paper. The transfer paper that has left the fixing device 34 is discharged onto the tray 6 by a pair of paper discharge rollers 51.

In FIG. 2, the transfer paper 5 (the above-mentioned transfer paper 51 or 5.) which has been transferred is sandwiched at its negative end 5m between a separation belt (not shown) and a separation roller 101. Being restrained,
The photosensitive drum 1 is separated from the photosensitive drum 1 in a separating section 104 . At this time, the five end members on the separation belt side are directed downward and pressed against the guide 102 from above. On the other hand, the opposite side end 5B is separated from the photosensitive drum 1 by drawing a large curve, as shown by the solid line in the figure, because although the separating belt exerts a separating force, it also has an adsorption force to the photosensitive drum 1. Then, it reaches the guide 102 from above and comes into contact with the device guide 102 at the 106th position as shown in the figure. Thereafter, the leading edge 50 of the transfer paper advances along the guide 102, is passed to the entrance guide 103 of the fixing device 34, and enters between the fixing roller 46 and the opposing roller 48 under the guidance of this guide 103. .

In FIG. 2, the transfer paper 5 whose leading edge 50 is held by the rollers 46 and 4B is 1. The rotation of the opposing row 248 sends it to the next process, but at this time, the feeding speed of the opposing row 248 is also made slower than the feeding speed of the photosensitive drum F. In other words, the circumferential speed of the opposing roller is increased, and the circumferential speed of the photosensitive drum is increased! When l speed is V, Ma is determined so that. In this way, the front side of the transfer paper 5 is fed more slowly than the rear side, so
In the transfer paper, a slack 105 is inevitably generated upward between the position 106 pressed against the guide 102 and the roller pair 46,48. At this time, if the tip 1031 of the entrance guide 103 of the fixing Wj 34 is set at a slightly 1Ii-position with respect to the tangential plane at the contact point of the rollers 46 and 48 within a range that does not cause poor bite, the problem can be prevented. This is preferable in that the slack that starts is guided by this tip 103, and the slack 105 grows stably upward.

- Regardless of the misalignment, in this slack 105 part, the transfer paper 5
is floating in the air, unrestrained by anything, in the shape of K.

Therefore, the above-mentioned non-uniform force generated at the separation section 104 is resolved by a displacement in the shape of slack at the slack section 105, the contact section Ka of the rows 246 and 48 is hardly transmitted, and wrinkles are eliminated. Does not occur. According to experiments, the value of 1 above is
Good results were obtained with a concavity of about 091 to 097.

Further, as described above, due to the action of the separation belt and the separation roller 101, the paper is once pressed from above the guide 102K before reaching the pair of transfer paper rollers 46 and 48.

Therefore, as shown in the figure, the transfer paper forms a curved slack 105 between the position 106 pressed against the guide 102 and the roller pair 46, 48, so the radius of curvature of this slack 105 increases or decreases. Therefore, the stiffness of the paper is fully utilized, further contributing to the prevention of wrinkles.

Note that when the rear end of the transfer paper 5 leaves the separating section 104, the slack 105 disappears, but at that time, the rear end of the transfer paper 5 becomes free, so the uneven force described above does not occur. No problem will occur.

As described above, according to the present invention, the distance between the separation section that restrains one side edge of the transfer paper and forcibly separates it from the photoreceptor and the pair of fixing pressure rollers can be made shorter than the length of the transfer paper. , the transfer paper is once pressed against the guide means from above and then sent to the pressure roller pair by a conveyance means that separates the transfer paper from the photoreceptor and conveys it, and at this time, the conveyance speed of the pressure roller pair is adjusted to the above-mentioned conveyance means. The transfer speed is also slowed down to form a curved slack in the transfer paper between the position where the transfer paper is pressed against the guide means and the two pairs of pressure rollers, and this slack causes one-sided forced separation. The paper absorbs force as uniformly as possible, reduces the radius of curvature of the slack, makes the paper sufficiently stiff, and effectively prevents wrinkles in the transfer paper with a simple structure.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining a copying machine according to one embodiment of the present invention, and Fig. 2 is a diagram for explaining a transfer material conveying section of the same embodiment, respectively, where 5 is a transfer paper, and 5B is a copying machine of the transfer paper. At both ends, 46 and 48 are pressure roller pairs, 101 is a separation roller, and 102 and 103 are guides. Applicant Canon Co., Ltd.

Claims (1)

[Scope of Claims] A movable photoreceptor; means for forming an electrostatic latent image on the photoreceptor; a developing means for developing the electrostatic latent image formed on the photoreceptor; y) a transfer means for transferring the visible image formed on the photoreceptor onto a transfer paper; a processing pressure roller pair for fixing the visible image transferred to the transfer paper to the transfer paper; and a processing pressure roller pair for transferring the visible image transferred to the pressure roller pair. A guide means for guiding the paper is arranged on the fi11 side of the pressure roller pair, with the guide means in between, and a distance shorter than the length of the transfer paper, and the transfer paper is formed into a pressure loaf pair. a conveyance means for conveying the transfer paper while restraining it toward the guide means, the conveyance means for conveying the transfer paper while restraining one end thereof and forcibly separating it from the photoconductor, and conveying the transfer paper so as to press it against the guide means from above; The conveyance speed of the pair of pressure rollers 1 is set to be lower than the conveyance speed of the conveyance means Q, and the position where the transfer paper is pressed against the guide means by the conveyance means and the pressure roller 2 1. A copying machine characterized in that an upwardly curved slack is formed in the transfer paper by means of an oven between the copying machine and the copying machine.