JPH0419548Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention uses a transfer paper guide mechanism of a copying device, that is, a lower part of the developing device, to move the transfer paper sent from the paper feed cassette between the photoreceptor drum and the transfer device. Concerning the guide plate.

Prior Art In an electrostatic copying apparatus, a charging device irradiates the surface of a photosensitive drum with an original image to form an electrostatic latent image, and then a developing device electrostatically attracts toner to the electrostatic latent image. Then, a transfer device transfers the toner image onto a transfer paper.

A guide plate is disposed below the developing device to guide the transfer paper from the paper feed cassette to the transfer device.

Problems that the invention aims to solve As mentioned above, since the guide plate is located at the bottom of the developing device, toner scattered from the developing device tends to fall and adhere to the upper surface of this guide plate, that is, the transfer paper guide surface. . As a result, in a copying device that positions the original using the center of the contact glass as a reference, when transfer paper smaller than the maximum copy width passes continuously over the guide plate, scattered toner accumulates on the left and right upper surfaces of the guide plate. After that, when a large size transfer paper is passed through, the accumulated scattered toner adheres to the back surface of the transfer paper, resulting in so-called back staining.

Furthermore, in a copying apparatus in which the document is positioned at one side edge of a contact glass, the back stain occurs on one side of the transfer paper in the width direction.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a transfer paper guide mechanism for a copying device that can prevent stains on the back side of the transfer paper from occurring at the ends in the width direction.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention is designed to transfer the transfer paper fed from the paper feed section between the photoreceptor drum and the transfer device under the developing device around the photoreceptor drum. There is a guide plate that guides you, and near the end of this guide plate,
A plurality of slits for toner falling are formed along the direction of movement of the transfer paper, and the guide plate is supported on the main body of the apparatus so as to be movable in the left and right directions, and the guide plate is biased to one side in the left and right direction. It is characterized by comprising a fixing spring and a knob for moving the guide plate against the spring.

Function: During the process in which transfer paper having a width smaller than the maximum copying width passes continuously over the guide plate, most of the toner that has been scattered on the edge of the guide plate falls into the toner falling slit.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 5 is a simplified sectional view of a copying apparatus according to an embodiment of the present invention.

First, the general configuration and operation of a copying apparatus will be explained, and then the transfer paper guide mechanism, which is the main part of the present invention, will be explained.

The transfer sheets 4 in the paper feed cassettes 2 and 3 mounted on the side of the apparatus main body 1 are selectively transferred one by one from the cassettes 2 and 3 to the transport rollers 7 and 8 by the respective paper feed rollers 5 and 6. and is sent out.

Note that the transfer paper 4 is fed from the cassettes 2 and 3, but there are also types that feed the transfer paper from the cassettes 2 and 3, but there are also types that are fed from a rolled-up state on a roller, or types that are fed manually, and therefore the structure of the paper feeding section is also different. It is not limited to what is illustrated.

A document 10 is pressed by a document presser cover 11 onto a contact glass 9 serving as a horizontal transparent plate provided at the top of the main body 1 of the apparatus. The light from the exposure lamp 12 is irradiated onto the original 10 through the contact glass 9, and the original image is formed on the first mirror 13, the second mirror 14, and the third mirror 1 of the optical device.
5, the image is formed on the photosensitive drum 18 via the lens 16 and the fourth mirror 17. Exposure lamp 12
A reflecting plate 19 is provided on the back of the document 10 to efficiently irradiate the original 10 with future light.

The exposure lamp 12, the first mirror 13, and the reflection plate 19 move back and forth in the directions of arrows A ₁ and A ₂ , and the exposure lamp 12 is turned on during the outward movement, so that the original 1
0 optical scanning is performed. Further, the second mirror 14 and the third mirror 15 reciprocate in the directions indicated by arrows A ₁ and A ₂ by a movement amount that is 1/2 of the movement amount of the exposure lamp 12 .

On the other hand, the document image is formed on the surface of the photoreceptor drum 18 charged by the charging device 20, so that an electrostatic image is formed on the surface of the photoreceptor drum 18. This electrostatic image is developed into a toner image by a developing device 21, which will be described later, and this toner image is transferred by a transfer device 22 onto the transfer paper 4 conveyed from the conveyance roller 8. The transfer paper 4 on which the toner image has been transferred is peeled off from the photoreceptor drum 18 by a peeling device 23 and conveyed to a thermal fixing device 25 by a conveying device 24. Further, the transfer paper 4 having completed fixing is passed through a paper ejection roller 26. After that, the device body 1
The liquid is discharged into a tray 27 provided on the side of the container.

A two-component developer 28 consisting of toner and carrier is stored in the developer storage section 21a of the developing device 21. Developer 28 in developer storage section 21a
The developing roller 21c is supplied by the stirring supply means 21b.
is supplied to the outer peripheral surface of the The developer supplied to the developing roller 21c forms a magnetic brush, and as the magnetic brush slides on the circumferential surface of the photosensitive drum 18, the electrostatic image on the drum surface is visualized as described above. .

Of the two-component developer, toner is consumed according to the development process, and the toner is replenished from the toner replenishing device 29 to the developer storage section 21a according to the amount of toner consumed.

At the bottom of the developing device 21, there is a pair of upper and lower guides that guide the transfer paper 4 sent from the paper feed cassette 2 or 3 via the conveyance roller 8 between the photoreceptor drum 18 and the transfer device 22. Plate 30,
31 are arranged.

Note that 32 is a cleaning device for cleaning the surface of the photosensitive drum 18 after the transfer, and 33 is a cooling fan that cools the exposure lamp 12 and various parts heated by the light from the exposure lamp 12.

FIG. 1 shows a lower guide plate 31, which is the main part of the present invention. This guide plate 31 is made of metal, and the direction 3 is perpendicular to the transfer paper traveling direction 34.
A plurality of toner falling slits 31 are provided at both ends 31a, 31a of the transfer paper 5 along the transfer paper traveling direction 34.
b is formed. Slit 31 for toner fall
The reason why b is placed along the transfer paper advancing direction 34 is to avoid interfering with the smooth progress of the transfer paper 4.

As shown in the cross-sectional view of FIG. 2, the slit bottom 3
1c is formed into a tapered surface facing forward like the upper transfer paper guide surface 31d.

Further, as shown in FIG. 3, the left end bracket 31f of the guide plate 31 is attached to the protrusion 36a of the holder 36 fixed to the side plate 1a of the device main body 1, and the guide plate 3
Pin 37 fixed to the right end bracket 31g of 1
A direction 3 perpendicular to the transfer paper traveling direction 34 is attached to the holder 38 provided on the side plate 1b on the opposite side of the apparatus main body 1.
5, each of which is movably supported. That is, the guide plate 31 is movable in the left-right direction.
A knob 39 is attached to a portion of the pin 37 that protrudes outside the side plate 1b. Right end bracket 31
A compression spring 40 that is fitted onto and supported by the pin 37 is interposed between g and the holder 38, and the repulsive force of the compression spring 40 biases the guide plate 31 to one side in the left-right direction, that is, Guide plate 31 on holder 36
The left end surface of is pressed and fixed.

Next, the function of the guide plate 31 will be described. Fifth
In the copying apparatus shown in the figure, the positioning of the original 10 is performed using the center of the contact glass 9 as a reference. Therefore, when the transfer paper 4 having a width smaller than the maximum copying width passes over the guide plate 31, the left and right ends (FIG. 1) 31a, 31a of the guide plate 31 are connected to the developing device 21.
This will open up the area where the toner will fall from. However, both left and right ends 31 of the guide plate 31
Most of the toner scattered on the surfaces 31a and 31a falls into the toner falling slit 31b, slides on the slit bottom 31c, and falls onto the bottom plate of the main body 1 of the apparatus. Therefore, even if a transfer paper 4 of a larger size passes over the guide plate 31 after the transfer paper 4 having a width smaller than the maximum copying width passes continuously on the guide plate 31, both ends of the back side of the transfer paper 4 in the width direction There is no back-stain development, where the area is smeared with toner.

As the period of use becomes longer, toner adheres to and accumulates on the slit bottoms 31c and the side surfaces of the slit spacing walls 31e. In such a case, in FIG. 3, if the knob 39 protruding outside the main body 1 of the apparatus is pulled out to the right, that is, in the direction of the arrow 35a, and released, the guide plate 31 is instantly moved to the left by the return force of the compression spring 40. It returns and collides with the holder 36, and due to the collision, the toner adhering to each slit spacer wall 31e, slit bottom 31c, etc. can fall downward.

The reason why the toner falling slits 31b are provided only near both ends of the guide plate as shown in FIG. 1 is as follows.

That is, when the toner falling slit 31b is provided over the entire length of the guide plate 31, when the transfer paper 4 is transferred to the transfer device 22 in close contact with the surface of the photoreceptor drum 18 in FIG. Transfer paper 4
This is because the waves wave over the entire width.

Although the toner falling slit 31b in the above embodiment has a bottom portion 31c, the present invention is not limited to this. For example, as shown in FIG. The slit 31b is bottomless.

In addition, in a copying apparatus in which the document is positioned at one side edge of the contact glass, the toner falling slit 31b of the guide plate 31 shown in FIG. 1 or 4 is formed only on the side opposite to the side edge. Ru.

Effects of the Invention As explained above, according to the transfer paper guide mechanism of the copying device of the present invention, a plurality of strips are provided near the end of the transfer paper guide plate disposed at the bottom of the developing device along the transfer paper traveling direction. Since the slit for toner falling is provided, most of the toner scattered on the edge of the guide plate is absorbed by the slit for falling toner when the transfer paper having a width smaller than the maximum copying width passes continuously over the guide plate. It can be dropped inside. As a result, even if a large-sized transfer paper passes over the guide plate thereafter, it is possible to avoid the phenomenon of back staining in which the widthwise end of the back side of the transfer paper becomes stained with toner.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a transfer paper guide mechanism and a photosensitive drum portion of a copying apparatus according to an embodiment of the present invention;
Fig. 2 is a sectional view of Fig. 1, Fig. 3 is a front view of the transfer paper guide mechanism, Fig. 4 is a perspective view showing another embodiment of the guide plate, and Fig. 5 is a simplified version of the copying device. FIG. 1... Apparatus main body, 2, 3... Paper feed cassette, 4
. . . Transfer paper, 21 . . . Developing device, 22 .

Claims (1)

[Scope of utility model registration request] Below the developing device around the photoconductor drum, there is a guide plate that guides the transfer paper fed from the paper feed section between the photoconductor drum and the transfer device. A plurality of toner falling slits are formed along the traveling direction, and the guide plate is supported by the main body of the apparatus so as to be movable in the left and right directions, and the guide plate is biased to one side in the left and right direction to be fixed. A transfer paper guide mechanism for a copying apparatus, comprising a spring and a knob for moving a guide plate against the spring.