JPS58137863A - Paper feed guiding device of copying machine - Google Patents

Abstract

PURPOSE:To obtain a whole-surface copy of a government postcard or ordinary copying paper, by making a notch at the center of the tip of a paper guide member that faces a photosensitive drum. CONSTITUTION:A paper guide member 13' is made by bending a metallic band to an L-shape and provided with a notch 18 of specified width W at the center of the tip 13a that faces a photosensitive drum. The width W is 100mm.<W< 182mm. that passes a government postcard but does not pass copying paper of B5 size. When ordinary copying paper of B5 size, A4 size etc. is used, the paper gets on the both sides 13b, 13c of the guide member 13' and the rear end of the copying paper is lifted up, and a whole-surface copy free from transfer deficiency is obtained. When thick small-sized paper such as government postcard is used, it goes smoothly into the transferring section through the notch 18, and a 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 feed cassette 4, and the leading end of the paper enters between the pair of timing rollers sa and 6b. 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 1. 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 1 along the tangential line of the photosensitive drum 1, the image is disturbed at the leading edge of the paper, and the back side of the paper becomes dirty. 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 sa and sb 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 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 papers 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 100X148
If you want to make a copy on an official postcard with a thickness of 230 μm and a thickness of 230 μm, it is necessary to increase the above-mentioned gap d, but this will cause insufficient transfer of the trailing edge with ordinary copy paper. If the gap d is made smaller to eliminate the inconvenience,
There was the contradictory problem of not being able to send official postcards.

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, and has a tip end 13a facing the photosensitive drum. Some have a notch 18 of a predetermined width W in the center.

Here, the above-mentioned width W is such that the official postcard 20 is passed through, but the Bs size copy paper 21 is not passed through (in this case, the copy paper of Bs size or larger is placed above the portions 13b and 13C located on both sides of the paper guide member 18. It is sufficient if the dimensions are such that it will be in a state where it rides on the board, and there is no problem in practical use if the dimensions are 100 mm, width, and 182 mm.

With this structure, when a general copy paper such as Bs or A4 size is used, the copy paper is placed on both sides 13b of the paper guide member 13'.

13c, the trailing edge of the copy paper is lifted, and as a result, a full-page copy without insufficient transfer at the trailing edge can be obtained. On the other hand, it is thick like a government postcard.
Moreover, when small-sized paper is used, the patterned paper enters the transfer section through the notch 18 located between them without riding on both side portions 13b and 13c of the paper guide member 13'. In this case, the gap between the notch 18 and the photosensitive drum 1 is
Since the gap is larger than the gap between the both side portions 13b and 13c and the photosensitive drum 1, entry into the transfer section is performed 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 structure such as cutting out the central portion of the leading end of the paper guide member facing the photosensitive drum, 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 of paper guide member, 13b, 13C...Both sides of paper guide member, 18...Notch.

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 disposed near the paper entrance side of the transfer section with a tip facing the surface of a photosensitive drum with a required gap, and a central portion of the tip of the paper guide member facing the photosensitive drum; A paper feed guide device for a copying machine, characterized in that a notch of a predetermined width is provided in the paper feed guide device.