JPS58137864A - Paper feed guiding device of copying machine - Google Patents

Abstract

PURPOSE:To obtain a good whole surface body of a government postcard and ordinary copying paper by making the aperture between the tip of a paper guide member and a photosensitive drum different at the center and both sides of the paper guide member. CONSTITUTION:A paper guide member 13' is made by bending a metallic band to L-shape and attaching elastic thin plates 18a, 18b on both sides of direction (arrow F), of guiding of the paper leaving a specified width W in the upper face. The width W is made wide enough to pass a government postcard 20 but not enough to pass copying paper of B5 size. The tip of members 18a, 18b is more projected than the tip 13a of the paper guide member 13'. When ordinary copying paper of B5 size and A4 size is used, the paper gets on the members 18a, 18b and the rear part is lifted up, and good whole surface copy is obtained. In the case of a government postcard, it passes through the aperture between the members 18a, 18b and goes to the transferring section smoothly, and good whole surface copy can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a paper feed guide device for an electrostatic transfer copying machine, and more particularly, to a device for guiding paper fed from a paper feed section such as a paper feed cassette to a transfer section. It is something.

The present invention will be described below based on illustrated embodiments, but first, in order to facilitate understanding of the present invention, the general structure of an electrostatic transfer copying machine will be explained with reference to FIG. , a conventional paper feed guide device will be explained with reference to FIGS. 2 and 3. In Figure 1, copy start switch (
(not shown), the photosensitive drum 1 made of amorphous selenium rotates in the direction of the arrow, and the static elimination lamp 2
lights up. At the same time, the paper feed roller 3 rotates, the paper is fed from the paper cassette 4, and the leading edge of the paper enters between the pair of timing rollers 5a, 5b. Then, a high voltage power source (not shown) is activated a little later than the rotation of the photosensitive drum 1, and a charger 6. A high voltage is applied to the transfer charger 7 and the paper separation charger 8. In this case, a positive DC high voltage is applied to the chargers 6 and 7, and an AC high voltage is applied to the charger 8.

A lamp for exposing the document (not shown) lights up slightly after the operation of the high voltage power supply mentioned above, and the light image (indicated by arrow B)
is imaged on the surface of the photosensitive drum 1. At almost the same time, the magnet roll 10 in the developing device 9 rotates in the direction of arrow C, and the developer 11 is rubbed against the surface of the photosensitive drum 1 to develop it.

On the other hand, timing rollers sa and sb rotate so that the leading edge of the paper fed from the paper feed cassette 4 coincides with the leading edge of the document, and the paper is fed in the direction indicated by the arrow.

The leading edge of the fed paper comes into contact with the paper guide 12 attached to the lower part of the developing device 9, and then moves along the paper guide 12 and the paper guide member disposed below it. 13 and comes into contact with the surface of the photosensitive drum 10. Here, the reason why the paper is brought into contact with the paper guide 12 is that by bringing the paper into contact with the surface of the photosensitive drum 10 along the tangential line of the photosensitive drum 1, image disturbance at the leading edge of the paper 2 dirt on the back of the paper 9 This is to prevent toner from scattering inside the machine.

The paper 14 fed into the transfer section is pressed against the surface of the photosensitive drum 1 by the transfer charger 7, and the toner attached to the photosensitive drum 1 is transferred onto the paper. Thereafter, the paper 14 is separated from the photosensitive drum 1 by a charger 8 for paper separation, and is conveyed by a conveyor belt 15 to a fixing section (not shown) consisting of a heating/pressure roller, thereby becoming a copy.

After the transfer, the surface of the photosensitive drum 1 is cleaned by a cleaner 17 including a cleaning blade 16.
used repeatedly.

FIG. 2 shows that the leading end of the paper 14 sent out by the timing rollers 5a and 5b is connected to the paper guide 12 and the paper guide member 13.
The paper 14 is shown in contact with the surface of the photosensitive drum 1 through the gap, and the paper 14 contacts the photosensitive drum 1 along the paper guide 12 and along the tangential line of the photosensitive drum 1.

FIG. 3 shows the rear end of the paper 14 just before it leaves the paper guide member 13. Here, the tip of the paper guide member 13 is spaced apart from the surface of the photosensitive drum 1 by a gap d. If the gap d is too small, the paper 14 will be prevented from entering, and if it is too large, the rear end of the paper 14 will not be lifted up, resulting in defective toner image transfer in that area. Therefore, the gap d is determined from the viewpoints of making it easy for the paper to enter the transfer section and preventing insufficient transfer of the image at the trailing edge of the paper.

By the way, since electrostatic transfer type copying machines can copy on plain paper, the range of paper that can be used is expanding. Generally, what is called copy paper is Bs.

Most of them are A4 size, and the thickness is around 80μ. On the other hand, the size is 10100x1
48 and a thickness of 230μ, it is necessary to increase the gap d, but this would cause insufficient transfer of the trailing edge with ordinary copy paper, and
If the gap d was made smaller in order to eliminate such inconveniences, there was a contradictory problem in that official postcards would no longer be able to pass through.

The present invention solves the above-mentioned contradictory problems with a simple structure, and does not cause insufficient transfer in parts of paper, whether it is ordinary copy paper or paper such as official postcards.

That is, it is an object of the present invention to provide a paper feed guide device capable of uniformly copying over the entire surface of paper. The embodiment will be described below with reference to FIGS. 4 and 6.

FIG. 4 is a perspective view of an example of the paper guide member 13a used in the present invention, and FIG. 6 is a side view of the main part showing its attached state. In those drawings, the paper guide member 13' is made by bending a metal strip having a required thickness so that the cross section is L-shaped or F-shaped. Elastic thin plate-like members 18a, 18, such as plastic films, are disposed on both sides when viewed from F).
b are installed at a predetermined interval W. Here, the above-mentioned interval W allows the government postcard 20 to pass through, but
Do not pass B6 size copy paper 21 (in this case,
For copy paper of 66 size and above, thin plate members 18a and 18b are used.
10).
0 Cabinet <W (182mm is not a practical problem.

On the other hand, the tip ends of the thin plate-like members 1sa and 1sb are made to protrude further in the paper guiding direction than the tip end 13a of the metal body of the paper guide member 13'. That is, when the paper guide member 13' is disposed near the paper entrance side of the transfer section as shown in FIG.
The configuration is such that d2<dl, where d4 is the gap between the thin plate members 18a and 18b, and d2 is the gap between the photosensitive drum 1 and the tips of the thin plate members 18a and 18b.

With this structure, when ordinary copy paper such as B6 or A4 size is used, the copy paper rests on the thin plate members 18a and 18b, so the rear end of the copy paper is lifted. As a result, a full-page copy without insufficient transfer at the trailing edge can be obtained. On the other hand, it is as thick as a government postcard.

Moreover, if you want to make copies on small-sized paper, use monshi.
It enters the transfer section through the upper surface of the central part of the main body fitting of the paper guide member 13' located between them without riding on the thin plate members 18a and 18b. In this case, the paper guide member 13'
Gap d1 between the tip 13a of the main body metal fitting and the photosensitive drum 1
Since d2 is larger than d2, the light enters the transfer section smoothly and a good copy can be obtained.

As described above, the paper feed guide device of the present invention makes the gap between the tip of the paper guide member and the photosensitive drum different between the central part and both side parts of the paper guide member, so that the paper feed guide device according to the present invention can produce paper feeds such as official postcards. Even thick, small-sized paper can be sent to the transfer unit without any problems, and when using regular copy paper, full-page copies can be obtained without causing insufficient transfer at the trailing edge of the paper. It is something.

Further, the present invention can be realized with a very simple configuration such as pasting a thin plate-like member such as a plastic film, and is extremely advantageous in terms of cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional side view of a main part showing an example of an electrostatic transfer type copying machine to which the present invention can be applied, FIGS. 2 and 3 are side sectional views of a main part of a conventional paper feed guide device, and FIG. 6 is a perspective view of an example of a paper guide member used in the present invention, and FIG. 6 is a side view of essential parts of an embodiment of the present invention. 1...Photosensitive drum, 4...Paper feed cassette, 7...Charger for transfer, 13'...
・Paper guide member, 13a... Tip part of main body metal fitting of paper guide member, 18a, 18b... Thin plate member,
dl, d2...Gap.

Claims (1)

[Claims] In order to receive the paper sent from the paper feed section and guide it to the transfer section,
A paper guide member is provided in the vicinity of the paper entrance side of the transfer section, with its tip facing the surface of the photosensitive drum with a required gap of dl, and on both sides of the paper guide member when viewed from the paper guide direction. , a copying machine comprising elastic thin plate-like members spaced apart from each other at required intervals such that the gap between their tips and the surface of the photosensitive drum is d2 (however, d2 minus dl). Paper feed guide device.