JPH073413Y2 - Paper guide for electrophotographic device - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a paper guide of an electrophotographic apparatus such as a page printer or a copying machine, and particularly to guide a paper conveyed between a transfer device and a photosensitive drum. For a paper guide for an electrophotographic device.

[Conventional technology]

FIG. 6 shows a page printer as an example of a conventional electrophotographic apparatus. A box-shaped printer body 1 has one end portion to which paper feed cassettes 2 and 2 for accommodating sheets of different sizes can be freely attached and detached. Is attached to the other end of the printer main body 1, and is provided with a paper ejection tray 3 for ejecting paper after printing.
Is installed. An upper cover 4 is attached to the upper surface of the printer body 1 so as to be openable and closable, and a release lever for locking and unlocking the upper cover 4 is attached to an end surface of the upper cover 4 on the side of the paper feed cassette 2. 5 are provided. An operation panel 6 for operating the printer is arranged above the front surface of the printer body 1.

Further, as shown in FIG. 7, inside the printer main body 1 and in the vicinity of the upper part of each of the paper feed cassettes 2, hopping rollers 7 for taking out the papers in the paper feed cassette 2 one by one are arranged. It is set up. Further, a cylindrical photosensitive member (hereinafter, referred to as a photosensitive drum) 8 is arranged inside the printer main body 1, and between the paper feeding cassettes 2 and the photosensitive drum 8, the photosensitive member 8 is provided. A transport roller 9 that transports the paper taken out by each hopping roller 7 and a paper feed roller 10 that transports the paper transported by each of these transport rollers 9 to the transfer portion of the photosensitive drum 8 are provided. On the outer periphery of the photosensitive drum 8, a corona charger 11 as a state control mechanism for uniformly charging the photosensitive drum 8 to bring the photosensitive drum 8 into a writable state, and an electrostatic latent image on the photosensitive drum 8. An LED head 12 as an optical writing means to be formed, a developing device 13 which attracts toner to the electrostatic latent image formed on the photosensitive drum 8 to make it visible, and a transfer device 1 which transfers the toner to a sheet.
4, a peeling device 15 for peeling the sheet on which the toner is transferred from the photosensitive drum 8, a static eliminator 16 for removing the residual potential on the photosensitive drum 8, a cleaner 17 for removing the residual toner on the photosensitive drum 8, etc. are sequentially arranged. It is set up. Further, as shown in FIG. 8, a fixed paper guide 18 for guiding the paper conveyed between the photosensitive drum 8 and the transfer device 14 is provided on the lower surface side of the peeling device 15 and the photosensitive drum 8 in a predetermined manner. The fixed paper guide 18 is mounted so as to have a gap and the transfer device 14
The side end portion extends toward the transfer device 14 side and is inclined slightly upward so that the paper can be properly conveyed between the fixed paper guide 18 and the photosensitive drum 8.

Further, on the downstream side of the photosensitive drum 8 in the sheet conveying direction,
A conveyance device 19 is provided inside the upper cover 4 for adsorbing and conveying the sheet after transfer by means such as air suction. Further, on the downstream side of the transfer device 19,
A fixing device 21 having a pair of fixing rollers 20 and 20 that are heated to a high temperature is provided, and a sheet after fixing is ejected outside the printer body 1 on the downstream side of the fixing device 21. A paper discharge roller 22 for discharging to the tray 3 is provided.

Further, a motor 23 that drives the photosensitive drum 8 and the like is disposed below the inside of the printer body 1, and a fan 24 that radiates heat inside the printer body 1 is provided above the printer body 1. Is provided.

In the conventional page printer, by driving the motor 23, the hopping roller 7, the photosensitive drum 8, the conveying device 19, each roller 20 of the fixing device 21, the conveying roller 9, the paper feeding roller 10, and the paper discharging roller 22. Etc. As a result, the paper stored in the paper feed cassette 2 is taken out one by one by the hopping roller 7, and is conveyed between the photosensitive drum 8 and the transfer device 14 by the conveying roller 9 and the paper feeding roller 10. Next, the photosensitive drum 8 is charged by the corona charger 11.
Is set to a writable state, the LED head 12 is caused to emit light at a predetermined timing based on a predetermined print signal to form an electrostatic latent image on the photosensitive drum 8. Then, the developing device 13 causes toner to be attracted to the electrostatic latent image formed on the photosensitive drum 8, and the transfer device 14 transfers the toner onto the paper while guiding the paper along the fixed paper guide 18. .
After that, the paper after transfer is separated from the photosensitive drum 8 by the peeling device 15, and the paper after transfer is sent between the fixing rollers 20 of the fixing device 21 by the conveying device 19. Then, the sheet is heated while being pressed by each fixing roller 20 to melt the toner transferred to the sheet to fix the sheet. After the fixing, the sheet is ejected from the printer body 1 by the ejection roller 22. It is ejected to the paper tray 3. On the other hand, the residual potential on the photosensitive drum 8 is removed by the static eliminator 16,
By removing and collecting the above residual toner by the cleaner 17, the photosensitive drum 8 can be charged again.

[Problems to be solved by the device]

In the conventional page printer, as shown in FIG. 9 (a), the paper 25 conveyed by the paper feed roller 10 is used.
Is brought into contact with the fixed paper guide 18 and then guided along the fixed paper guide 18, as shown in FIG. 9 (b). However, in this case, since a fixed gap is formed between the fixed paper guide 18 and the photosensitive drum 8, a paper sheet passing between the fixed paper guide 18 and the photosensitive drum 8 is formed.
When the stiffness of 25 is strong, there is no problem, but when the stiffness of the paper 25 is weak, the paper 25 shakes in the vertical direction and unstablely passes, and the transfer of the photosensitive drum 8 is not performed uniformly. I have a problem. Also, FIG. 9 (c)
As shown in (d) and FIG.
When passing through the portion, the rear end of the sheet 25 is not properly held and is free, so that the sheet 25 flutters and a transfer failure occurs.

The present invention has been made in view of these points, and an electronic device capable of stably guiding a sheet, properly transferring a toner image, and capable of performing beautiful and high-quality printing. It is intended to provide a paper guide for a photographic device.

[Means for Solving the Problems]

In order to achieve the above object, the paper guide of the electrophotographic apparatus according to the present invention is disposed between a photosensitive drum and a transfer device and a peeling device which are disposed in parallel above the photosensitive drum. In a paper guide of an electrophotographic apparatus that guides a sheet conveyed between a transfer device and a transfer device, the paper guide includes a guide portion located below the peeling device and a holding portion extended to the transfer device side. Each of these paper guides is formed, and in the normal state, the guide portion is held at a position lowered by its own weight, and while the paper is being conveyed, the guide portion is raised to cause the pressing portion to hold the paper. It is arranged so as to be swingable so as to be pressed against the photosensitive drum side.

[Action]

According to the present invention, when the front end of the paper is inserted between the paper guide and the photosensitive drum and the front end of the paper comes into contact with the lower surface side of the paper guide, the paper guide swings to guide the paper. And the pressing section descends, and the sheet is pressed against the photosensitive drum by the pressing section of the paper guide. In this state, while the sheet is being conveyed, the toner image on the photosensitive drum is transferred onto the sheet by the transfer device, so that the sheet can be stably guided, and uniform transfer can be performed. Also,
Even when the trailing edge of the sheet passes, the sheet is conveyed while being held by the holding portion of the paper guide, so that it is possible to prevent the sheet from fluttering and to reliably prevent transfer defects and the like. It is possible.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

1 and 2 show an embodiment of the present invention.
Above the photosensitive drum 8, a transfer device 14 for transferring the toner image adhering to the surface of the photosensitive drum 8 onto the paper 25 conveyed from the paper feed cassette, and the paper on which the toner is transferred.
The peeling device 15 for peeling 25 from the photosensitive drum 8 is integrally provided, and the transfer device 14 and the peeling device 15 are
A partition plate 26 is provided below the opening, that is, on the side of the photosensitive drum 8 and between the transfer device 14 and the peeling device 15. A plurality of (four in this embodiment) notches 27 are formed at the lower end edge of the partition plate 26, and the notch 27 has a support shaft extending along the lower end edge of the partition plate 26. 28 are formed. As shown in FIG. 3, the support shafts 28 may be formed so that two left and right sides are symmetrically oriented in the same direction, respectively, and as shown in FIG. You may make it direct so that it may face each other.

A paper guide 29 is attached to the support shaft 28 so as to be swingable about the support shaft 28.
The reference numeral 29 has a guide portion 30 located below the peeling device 15 and a holding portion 31 extending and formed on the transfer device 14 side. Further, a connecting bar 32 is connected to the guide portion 30 of each of the paper guides 29, and each paper guide 29 can be integrally swung by the connecting bar 32. In the paper guide 29, in the normal state, due to the weight of the guide portion 30, the guide portion 30 is held in the lowered position,
When the paper 25 is conveyed, the paper 25 comes into contact with the guide portion 30 to swing the paper guide 29 around the support shaft 28,
The pressing unit 31 presses the paper 25 against the photosensitive drum 8 side.

Next, the operation of this embodiment will be described with reference to FIG.

In the present embodiment, first, when the front end of the paper 25 conveyed from the paper feed cassette 2 is inserted between the transfer device 14 and the photosensitive drum 8, as shown in FIG. Paper 25
The leading end of the sheet 25 is inserted between the paper guide 29 and the photosensitive drum 8 so that the leading end of the sheet 25 contacts the lower surface side of the sheet guide 29. Then, when the paper 25 is further conveyed, the fifth
As shown in FIG. 2B, the paper guide 29 swings around the support shaft 28, the guide portion 30 rises, and the pressing portion 31 descends. The pressing portion 31 of the paper guide 29 causes the paper 25 to move.
Is pressed onto the photosensitive drum 8. In this state, while the sheet 25 is being conveyed, the toner image on the photosensitive drum 8 is transferred onto the sheet 25 by the transfer device 14. Then, as shown in FIGS. 5C and 5D, even when the rear end of the sheet 25 passes, the sheet 25 is conveyed while being held by the holding portion 31 of the paper guide 29. 25 flapping can be prevented. When the paper 25 passes through the paper guide 29, the paper guide 29 descends and swings due to its own weight of the guide portion 30, and returns to the original normal position.

Therefore, in the present embodiment, the conveyed paper 25 is guided by the paper guide 29 that can be swung, and
The pressing portion 31 of the paper guide 29 causes the paper 25 to move the paper 25 to the photosensitive drum 8.
Since the transfer is performed while being pressed to the side, the paper 25 can be stably guided regardless of the strength of the waist, and proper transfer can be performed. Also, the paper
Even when the rear edge of the 25
Since it is possible to prevent the fluttering of the paper 25, it is possible to reliably prevent the toner image transfer failure due to the fluttering of the paper 25.

The present invention is not limited to the above embodiment,
Various changes can be made as necessary.

[Effect of device]

As described above, the paper guide of the electrophotographic apparatus according to the present invention guides the conveyed paper by the rockable paper guide, and presses the paper to the photosensitive drum side by the holding portion of the paper guide. Since the transfer is performed in the closed state, the paper can be stably guided regardless of the strength of the waist, and proper transfer can be performed. Further, even when the trailing edge of the paper passes, the paper can be pressed by the pressing portion, so it is possible to reliably prevent the paper from fluttering, and to reliably prevent toner image transfer failure due to paper fluttering. The effect is that it can be prevented and consistently beautiful and high-quality printing can be performed.

[Brief description of drawings]

1 to 5 show one embodiment of the paper guide of the electrophotographic apparatus of the present invention. FIG. 1 is a perspective view of a photosensitive drum portion, and FIG. 2 is one of a transfer device and a peeling device portion. An enlarged perspective view with a part cut away, FIGS. 3 and 4 are partial perspective views showing the shape of the support shaft, and FIGS. 5 (a), (b),
FIGS. 6 (c) and 6 (d) are vertical sectional views showing the guide state of the paper by the paper guide, FIG. 6 is a perspective view showing a conventional electrophotographic apparatus, and FIG. 7 is a vertical sectional view of the conventional electrophotographic apparatus, 8th
FIG. 9 is a vertical sectional view showing a conventional fixed paper guide, and FIGS. 9 (a), (b), (c), and (d) are vertical sectional views showing a guide state of paper by the conventional fixed paper guide. . 8 ... Photosensitive drum, 14 ... Transfer device, 15 ... Peeling device, 26 ... Partition plate, 27 ... Notch, 28 ... Support shaft, 29 ... Paper guide, 30 ... Guide part, 31 ... Holding part.

Claims (1)

[Scope of utility model registration request] 1. A photosensitive drum and a transfer device and a peeling device, which are arranged in parallel above the photosensitive drum, are provided.
In a paper guide of an electrophotographic apparatus for guiding a sheet conveyed between the photosensitive drum and the transfer device, a guide portion located below the peeling device and a presser extending to the transfer device side in the paper guide. And the guide part is held at a position where the guide part is lowered by its own weight in a normal state, and the guide part is raised while the paper is being conveyed and the pressing part is A paper guide for an electrophotographic apparatus, wherein the paper is arranged so as to be swingable so as to be pressed against the photosensitive drum side.