JPH01185669A - Image recorder - Google Patents

Abstract

PURPOSE:To prevent toner from scattering from a cleaning unit and to improve reliability by providing a transfer part and a photosensitive drum, both of which comprise a recorder, in the way that they can be directed toward the upper part of the recorder and that they can be moved, opened and closed and blocking the opening part of the cleaning unit with a cover together with opening, closing and moving. CONSTITUTION:The part 30 of the upper cover of the recorder main body is turnable, centered about a shaft 31 provided on the recorder, and can be lifted upwardly, opened and closed. A transfer charger 4, and the upper roller 11 of a resist roller pair are moved integrally together with the part 30 of the cover. On the other hand, the photosensitive drum 1 and the lower roller 12 of the resist roller pair remain on the side of the main body when the part 30 opens. Consequently, the transfer part and a pair of rollers 11 and 12 can open the charger and the upper roller 11 by attaching them to the part 30 in case transfer paper is jammed. A transfer paper conveying path is fully opened, and the opening part 53 of the cleaning unit 5 can be blocked with the cover 54.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an image forming apparatus, and particularly to an image forming apparatus in which optical writing is performed on a photoreceptor drum via an optical writing unit with a light beam according to an image information signal. Regarding equipment.

(Prior art) In various image forming apparatuses such as laser printers and facsimile machines, the emission of a laser beam is controlled or modulated according to an image information signal, and the image information beam is applied to a photoreceptor as a latent image carrier through an optical writing unit. Optical writing is performed on the drum, thereby forming an electrostatic latent image on the photosensitive drum. This electrostatic latent image is developed into a toner image by a developing unit, and this toner image is further transferred to transfer paper fed from a paper feeding unit under the action of a transfer charger, and then transferred to a fixing unit. Fixation is performed by. After the toner image is transferred, the toner remaining on the photoreceptor drum is removed by a cleaning unit, and the photoreceptor drum is initialized.

Incidentally, in conventional forming apparatuses of this type, the optical writing unit is provided above the photoreceptor drum, and the optical writing operation is generally performed on the upper side of the photoreceptor drum. Roughly speaking, the developing unit is provided on the side of the photoreceptor drum, and the transfer charger is placed below the photoreceptor drum. Normally, the transfer paper is fed with the transfer surface facing upward.

The paper feeding section is arranged so as to protrude further to the side of the developing unit, or is arranged further below the transfer charger. If the paper feed section is arranged to protrude to the side of the developing unit, the entire device must be constructed in a long shape, and if the paper feed section is arranged below the transfer charger, However, there is a problem in that the height of the entire apparatus becomes large because sufficient space is required to make a U-turn of the transfer paper without difficulty.

Furthermore, in the conventional device described above, when the transfer paper becomes jammed in the transfer section or the paper feed path, in order to remove the jammed paper, not only the optical writing unit but also the optical writing unit is used.
It is necessary to open the entire unit housing the developing unit and the photoreceptor drum upward, which poses a problem in operability.

In order to solve this problem, the inventors of the present invention arranged the optical writing unit below the photoreceptor drum and the developing unit, and arranged the transfer charger above the photoreceptor drum. An image forming apparatus has already been proposed which is provided so as to be openable toward the upper side outside the machine. The cleaning unit in this proposed device is arranged above the optical writing unit and below the transfer section. The cleaning unit is provided with an opening of a predetermined size to receive a part of the photoreceptor drum, and
A cleaning blade is attached to the opening to be pressed against the surface of the photoreceptor drum.

However, in such a device, when the photoreceptor drum is moved to open, the opening where the cleaning blade is installed is opened to the outside.
There is a problem in that toner tends to scatter from the opening. For example, when replacing the cleaning unit, if the cleaning unit is moved with the photoconductor drum open, toner often scatters from the opening formed as the photoconductor drum opens and moves, resulting in contamination inside the machine. become the cause. In particular, the scattered toner tends to flow into the optical writing unit disposed on the lower side, and if the optical writing unit becomes contaminated with toner, image formation will be greatly affected.

(Purpose) Therefore, the present invention provides an image forming apparatus that is capable of reducing the size of the apparatus, improving operability, and simultaneously preventing toner scattering from the cleaning unit and improving the reliability of the apparatus. The purpose is to provide.

(Structure) In order to achieve the above object, the present invention forms an electrostatic latent image by optically writing on a photoreceptor drum via an optical writing unit with a light beam corresponding to an image information signal, and forms an electrostatic latent image. In an image forming apparatus in which a toner image is obtained by developing a toner image with a developing unit, and a cleaning unit removes toner remaining on the photoreceptor drum after the toner image is transferred, the optical writing unit is connected to the photoreceptor drum and the developing unit. The cleaning unit is disposed below the optical writing unit, and the cleaning unit is disposed above the optical writing unit, and the photosensitive drum is provided so as to be openable upward, and the cleaning unit includes:
A cleaning cover is provided so as to close an opening opened to the outside as the photoreceptor drum is moved to open.

In an apparatus having such a configuration, first, the cleaning unit can be easily exposed by opening the photoreceptor drum toward the upper side outside the machine, which facilitates the operation of the cleaning unit. The opening of the cleaning unit, which is opened to the outside as the photoreceptor drum is moved to open, is closed by a cleaning cover that is provided in conjunction with the opening movement of the photoreceptor drum.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a laser printer. A charger 2, a developing unit 3, a transfer charger 4, a cleaning unit 5, etc. are arranged around the photoreceptor drum 1 in this apparatus along the direction of rotation indicated by an arrow. An optical writing unit 7 is provided so that a writing beam is incident on the photosensitive drum 1 at a position 6 between the photosensitive drum 1 and the optical writing unit 3, and the optical writing unit 7 is exposed.

In this embodiment, the charger 2 and the light beam writing position 6 are
is arranged below the photoreceptor drum 1 , and the optical writing unit 7 is arranged below the photoreceptor drum 1 , the developing unit 3 and the cleaning unit 5 . Further, the transfer charger 4 is disposed above the photoreceptor drum 1, and a paper feed cassette that feeds transfer paper to a transfer portion formed between the transfer charger 4 and the photoreceptor drum 1. 8 is provided further below the optical writing unit 7. Then, the double feed of the transfer paper is separated by the feed roller 9 and the friction bat 10 that is pressed against the feed roller 9, and the transfer paper is sent out one by one.The transfer paper is then made a large U-turn on the side of the developing unit 3, and is placed above the developing unit 3. Registration roller pair 11.1
2, the paper is fed to the transfer section at a timing such that the image formed on the photosensitive drum 1 is aligned with the position. A fixing unit 13 is arranged on the transfer paper path after the transfer, and a paper discharge tray 14 is further provided on the discharge side of the fixing unit 13.

As shown in FIG. 1, FIG. 2, and FIG.
2, the light is incident on a polarizing mirror 24 that is integrally attached to the shaft of a scanner motor 23, and is repeatedly deflected over a certain angular range.

The deflected light is imaged on a straight line by the fθ lens 25 at the incident position 6 on the photoreceptor drum 1, and corrected so that the projection point is moved at a constant speed. The light enters the photoreceptor drum 1 via the second mirror 26 and the cylindrical lens 27, and main scanning is performed by the polarization of this incident light, and sub-scanning is performed by the rotation of the photoreceptor drum 1, resulting in an image information signal. An image corresponding to the image is written to form an electrostatic latent image. The components of the optical writing unit 7 are mounted directly on the base cover 28 of the device. Note that the reference numeral 29 indicates a synchronization detection sensor.

The electrostatic latent image formed on the photosensitive drum 1 is developed and visualized by a developing unit 3, thereby obtaining a toner image.

On the other hand, the transfer paper is fed to a transfer section by a pair of registration rollers 11 and 12, where the toner image is transferred by the action of the transfer charger 4. After the transfer, the transfer paper separated from the photoreceptor drum 1 is fixed by the fixing unit 13 and discharged to the paper discharge tray 14.

After the transfer, the toner remaining on the photoreceptor drum 1 is cleaned by the cleaning unit 5 and prepared for the next image formation.

In this device, as described above, the optical writing unit 7 is provided below the photosensitive drum 1 and the developing unit 3, the automatic paper feeding unit 8 is further arranged below the optical writing unit 7, the transfer section 4 and the registration roller pair 11. 12 is provided above the photoreceptor drum 1, the transfer paper fed from the paper feed unit 8 can be turned around the outside of the developing unit 3 and transferred to the pair of registration rollers 11 and 12 without taking up a large space. The device can be made smaller.

A part 30 of the upper cover of the apparatus main body is rotatably installed around a shaft 31 provided at the right end of the apparatus in FIG. 1, and can be opened by flipping upward. It looks like this. Further, the transfer charger 4 and the upper roller 11 of the registration roller pair are also provided so as to move integrally with the portion 30 of the upper cover. On the other hand, the photosensitive drum 1 and the lower roller 12 of the registration roller pair can be left on the main body of the apparatus when the upper cover part 30 is opened, or can be lifted up integrally with the upper cover. It is supported in such a way that it can be selected. Therefore, the transfer portion or registration roller pair 11.
When the transfer paper jams in step 12, as shown in FIG. The paper transport path is completely open,
Jam paper can be easily removed. If the part 3o of the upper cover is configured to be automatically opened by removing a latching member using a spring (not shown), for example, the operability can be improved.

Further, as shown in FIG. 5, if the photosensitive drum 1 and the lower opening 512 of the registration roller pair are also made movable together with the part 30 of the upper cover, the cleaning unit 5 and the developing This facilitates operations when replacing the unit 3 and the like.

Next, the cleaning unit 5 has a box-shaped cleaning body frame 51, and this cleaning body frame 51
An opening opening toward the photoreceptor drum 1 side is provided inside. And on the lower edge of this opening,
The base side of the cleaning blade 52 made of an elastic plate member is fixed. This cleaning blade 52
The leading edge of the cleaning blade 52 is pressed against the surface of the photosensitive drum 1, and a part of the photosensitive drum 1 is placed between the pressed leading edge of the cleaning blade 52 and the upper edge of the opening. A gap 53 is formed to accommodate the receiver.

A cleaning cover 54 for opening and closing the gap 53 is attached to the gap 53. The cleaning cover 54 is formed from an elongated plate-like member, and both ends of the cleaning cover 54 in the longitudinal direction are connected to the cleaning body frame 5.
It is rotatably attached to the swinging tip of a swinging arm 55 pivotally mounted on the first side. The swinging arm 55 is provided so as to be swingable in the vertical direction in FIG. The cleaning blade 52 is moved to a certain closed position and opens the gap 53.
It is adapted to be reciprocated between an open position, which is a lower position in which it is in contact with the base side portion of the holder. Roughly speaking, the swinging arm 55 is given a swing biasing force toward an upper position, that is, a position where the gap 53 is opened, by a spring (not shown), and is interlocked with the part 30 of the upper cover. It is designed to be swayed. Specifically, when the part 30 of the upper cover is closed as shown in FIG. When the cleaning cover 54 is maintained in the open position and the upper cover part 30 and the photosensitive drum 1 are flipped upward as shown in FIG. is moved to the upper position where the gap 53 is closed. When the cleaning cover 54 is in the position where the gap 53 is closed, the toner inside the cleaning body frame 51 is prevented from flowing out from the gap 53.

In this embodiment, when the part 30 of the upper cover is closed as shown in FIG. 1, the cleaning cover 54 resists the urging force of the spring to open the gap 53 in the lower position. Therefore, the gap 53 of the cleaning body frame 51 is kept in an open state. A part of the photoreceptor drum 1 is received in this gap 53. On the other hand, when replacing the cleaning unit, for example, if the part 30 of the upper cover and the photosensitive drum 1 are flipped upward from the state shown in FIG. 1 as shown in FIG. 5, the cleaning unit can be replaced. 5 is exposed to the outside, so that the cleaning unit 5 can be easily operated.

At this time, the cleaning cover 54 is moved to the upper position, which is the closing position of the gap 53, by the biasing force of the spring in conjunction with the upward flip-up operation of the part 30 of the upper cover and the photoreceptor drum 1. , the gap 53 of the cleaning body frame 51 is closed by the cleaning cover 54. When the gap 53 is closed by the cleaning cover 54 in this way, the toner inside the cleaning body frame 51 will not flow out from the gap 53, and as a result, toner scattering from the cleaning unit 5 is prevented. .

(Effects) As described above, in the present invention, a cleaning cover is attached to the cleaning unit, and the cleaning cover closes the gap in the cleaning unit that is opened to the outside as the photoreceptor drum is moved to open. This makes it possible to prevent toner from scattering from the cleaning unit when the photoreceptor drum is opened, avoid toner contamination inside the machine, and maintain good reliability of the image forming apparatus.

[Brief explanation of the drawing]

FIG. 1 is a schematic side sectional view showing the entire laser printer according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line II-II in FIG. 1, and FIG. 3 is an optical writing unit. Exterior perspective views showing the configuration, Figures 4 and 5 are
FIG. 3 is a schematic side sectional view showing the operation of the device shown in the figure. 1... Photosensitive drum, 3... Developing unit, 5...
-Cleaning unit, 51...Cleaning body frame, 52...Cleaning blade, 53...Gap portion, 54...Cleaning cover, 55...Swing arm.

Claims (1)

[Claims] An optical writing unit that forms an electrostatic latent image by optically writing on a photoreceptor drum with a light beam according to an image information signal.
A transfer section for transferring a toner image obtained by developing the electrostatic latent image onto a transfer paper is disposed below the photoconductor drum, and furthermore, after the toner image is transferred, a transfer section is disposed above the photoconductor drum. In an image forming apparatus in which a cleaning unit for removing toner remaining on the photoreceptor drum is disposed above the optical writing unit and below the transfer section, the transfer section and the photoreceptor drum are arranged on the upper side outside the machine. A cleaning cover is attached to the cleaning unit so as to be movable in an open direction towards the cleaning unit, and a cleaning cover is attached to the cleaning unit so as to close an opening formed in the cleaning unit as the transfer section and the photoreceptor drum are moved in the open direction. An image recording device characterized by: