JPH032768A - Laser beam printer - Google Patents

Abstract

PURPOSE:To definitely maintain the position relation of a photosensitive body and an optical system unit by providing the photosensitive body and the optical system unit on a main body side. CONSTITUTION:The main body 1 is provided with a photosensitive drum 5 and the optical system unit 18. Therefore, the optical system unit 18 is hardly moved attending, with the opening/closing of a lid 2 with respect to the photosensitive drum 5 and the optical system unit 18 can be constantly fixed to the photosensitive drum 5. Thus by setting the position relation of the optical system unit 18 and the photosensitive drum 5 so that they are mounted in such a manner that laser beams outputted from the optical system unit 18 are made to image-form on prescribed image-forming points on the surface of the photosensitive drum 5, the position relation is definitely maintained.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to laser beam printers.

[Prior Art] Laser beam printers, which have recently been used in OA equipment, are devices that scan a photoreceptor with laser light to form an image on the photoreceptor, and then transfer this image onto recording paper for recording. .

Conventionally, this laser beam printer has adopted the configuration shown in FIG.

In the figure, 1 is a main body with an open upper part, and 2 is a lid that covers the upper open part of the main body 1. One end is pivotally connected to the main body 1 by a pivot 3 so that it can be opened and closed. The main body 1 and the lid 2 constitute a housing 4 that houses each component. The following components are provided inside the main body 1. That is, main body 1
A photosensitive drum 5, which is an example of a photosensitive member, is provided inside the photosensitive drum 5, and around the photosensitive drum 5 are a charging unit) 6, a developing unit h7, and a transfer NN unit 8 in the order of the recording process.
and a static elimination cleaner unit 9 are provided. The charging unit 6 charges the surface of the photosensitive drum 5. The developing unit 7 has a toner tank 10 that stores toner and a sleeve 11 that sends out the toner. The transfer charging unit 8 is of a corona charging type. The static eliminating cleaner unit 9 removes charges and toner remaining on the surface of the photosensitive drum 5. Further, a paper feed cassette 13 in which recording paper 12 is set is attached to one end of the main body 1, and between this paper feed cassette 13 and the photosensitive drum 5, the recording paper 1 set in the paper feed cassette 13 is inserted. A paper feed roller 14 is provided, and a pair of paper pressing rollers 15, 15 are provided that press and feed the fed recording paper 12 from above and below. A heat roller 16 and a press roller 17 are disposed vertically opposite to each other between the other end of the main body 1 and the static elimination cleaner unit 9. The heat roller 16 heats the recording paper 12 and fixes the transferred image.

On the other hand, an optical system unit 18 is disposed on the lid 2 and positioned above the photosensitive drum 5 . This optical system unit 18
In this method, a laser beam controlled by an information signal is reflected by a reflecting surface of a polygon mirror rotated by a motor, and is scanned onto the surface of the photosensitive drum 5 to form a latent image. In order to form a latent image by focusing laser light on a predetermined position on the surface of the photosensitive drum 5, the optical system unit 18 sets a certain positional relationship in advance with respect to the photosensitive drum 5, and attaches it to the lid 2. It is set up. Note that a paper ejection port 19 and an ejection selector 20 are provided at the other end of the main body 1, and a circuit board 21 is provided at the bottom.

A paper discharge port 22 and a discharge roller 23 are provided at the other end of the lid 2.

When recording with this laser beam printer, the photosensitive drum 5 is rotated by a rotating device (not shown), and recording is performed in the following process while the photosensitive drum 5 rotates. First, the surface of the photosensitive drum 5 is charged by the charging unit 6. Next, the optical system unit 18 scans the surface of the photosensitive drum 5 with a laser beam, thereby forming a latent image on the surface of the photosensitive drum 5. Next, in the developing unit 7, the toner stored in the toner tank 10 is transferred to the sleeve 11.
The toner image is attached to the surface of the photosensitive drum 5 to form a toner image corresponding to the latent image. Thereafter, as the photosensitive drum 5 rotates, the toner image moves to a position corresponding to the transfer charging unit 8. On the other hand, the recording paper 1 set in the paper feed cassette 13
2 is sent out one by one by the rotation of the paper feed roller 14,
The fed-out recording paper 12 is moved by paper press rollers 15, 15 toward 1.1 between the photosensitive drum 5 and the transfer charging unit 8. Here, the transfer charging unit 8 charges the recording paper 12 by corona discharge, thereby transferring the toner image on the surface of the photosensitive drum 8 onto the recording paper 12. Then, while the recording paper 12 further moves and passes between the heat roller 16 and the paper pressing roller 17, the toner image transferred to the recording paper 12 is fixed. For ejecting the recording paper 12, the paper ejection port 19 of the main body 1 or the paper ejection port 22 of the lid 2 is selected. Also,
After the transfer is completed, the charges and toner remaining on the photosensitive drum 5 are removed by the static eliminating cleaner unit 9.

However, in such a laser beam printer,
When performing maintenance and inspection of the unit installed inside the housing 4 as needed, the normally closed lid 2 is rotated upward about the pivot 3 to open the upper open portion of the main body 1. Then, the inside of the casing 4 is observed and maintenance and inspection work is performed as necessary.

[Problems to be Solved by the Invention] However, such conventional laser beam printers have the following problems.

That is, in the conventional laser beam printer, the main body 1 is provided with the photosensitive drum 5, and the lid 2 is provided with the optical system unit 18. Then, with the lid 2 closed, the optical system unit 18
The positional relationship between the photosensitive drum 5 and the photosensitive drum 5 is set. but,
When the lid 2 is opened, the optical system unit 18 moves together with the lid 2 and separates from the photosensitive drum 5. Therefore, when the lid 2 is closed, the position of the optical system unit 18 with respect to the photosensitive drum 5 may shift due to various dimensional errors such as backlash between the lid 2 and the pivot shaft 3. However, since the optical system unit 18 and the photosensitive drum 5 are set in advance in a certain positional relationship in order to accurately image the laser beam emitted from the optical system unit 18 on the photosensitive drum 5, If the relationship deviates from the preset positional relationship, the position where the laser beam from the optical system unit 18 forms an image on the photosensitive drum 5 will shift, which will affect the recording accuracy.

The present invention has been made based on the above circumstances, and it is an object of the present invention to provide a laser beam printer that can maintain a constant positional relationship between the photoreceptor and the optical system unit without being affected by opening and closing of the lid. .

[Means for Solving the Problems] In order to achieve the above-mentioned object, the laser beam printer of the present invention has a housing configured with a main body and a lid that is openable and closable at the opening of the device main body, and the interior of the housing is In the apparatus in which an optical system unit scans a laser beam onto a photoreceptor to form an image on the photoreceptor, and this image is transferred and recorded onto recording paper supplied inside a housing, the photoreceptor and the optical system It is characterized in that a uni-soto is provided on the main body side.

This laser beam printer includes a paper feed roller that feeds the recording paper from the paper feed cassette, a paper press roller that presses the fed recording paper from above, and a transfer charging unit that transfers the image on the photoreceptor onto the recording paper. Provided on the lid side,
A structure in which a recording paper passage is provided between the lid and the main body is good for maintenance and inspection work.

[Function] In a laser beam printer having such a configuration, the optical system unit and the photosensitive drum are fixed to the main body with a certain positional relationship, so that they can be set in advance to record accurately. Can be maintained in position.

In addition, since the optical system unit is provided on the main body side, a transfer charging unit is provided on the lid side, and a roller that presses the recording paper from above is provided on the lid side, so when the lid is opened, the transfer charging unit is provided on the lid side. By exposing the recording paper path, maintenance and inspection work such as paper jams can be easily performed.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 shows the entire laser beam printer of this embodiment, and the same components as in FIG. 4 will be explained using the same symbols.

A lid 2 is provided on the upper open part of the main body 1 and is pivotally mounted on a pivot 3 to form a housing 4. The main body 1 includes a photosensitive drum 5.
The following components are provided around the periphery except for the upper side. A developing unit 7 is provided between the photosensitive drum 5 and one end of the main body 1.
and an optical system unit 18 are disposed, and a charging unit 6 is disposed below the photosensitive drum 5, and a charging unit 6 is disposed below the photosensitive drum 5.
A static elimination cleaner unit 9 is disposed between the other end. Here, the optical system unit 18 and the photosensitive drum 5 are connected so that the laser beam output from the optical system unit 18 can be focused on a predetermined imaging point on the surface of the photosensitive drum 5, as will be described later. Set the positional relationship. Further, the developing unit 7 is arranged on the upper side, and the optical system unit 18 is arranged on the lower side. A heat roller 16 is provided between the static elimination cleaner unit and the other end of the main body 1.

On the other hand, a paper feed cassette 13 is provided at one end of the lid 2, and a paper feed roller 14 and a pair of paper press rollers 15, 15 are provided alongside the paper feed cassette 13. Further, the lid 2 is provided with a transfer charging unit 8 on the upper side thereof, facing the photosensitive drum 6 provided on the main body 1, and further has a paper pressing roller 17 on the upper side thereof, facing the heat roller 16 provided on the main body 1. It is provided.

Note that the main body 1 is provided with a paper outlet 19 and a circuit board 21. The lid 2 is provided with a paper discharge port 22 and a paper discharge roller 23.

The optical system unit 18 will be explained with reference to FIG. In the figure, 24 is a laser diode, 25 is a collimator lens, 26 is a silica lens, 27 is a plano-convex lens, 28 is a first mirror, 29 is a second mirror, 30 is a polygon mirror, 31 is a third mirror, 32 is a correction lens, and 33 is a photo The diode 34 is a detection mirror. Among these components, the diodes 24 and 33 are provided on the circuit board 38, and the other components are provided on the unit body (not shown). When the laser diode 24 emits a laser beam controlled by the information signal, the laser beam passes through each of the lenses 25 to 27, is reflected by the first mirror 28, and enters the reflective surface of the polygon mirror 30. The polygon mirror 30 has, for example, six reflective surfaces, and is rotated by a motor (not shown) to change the position of the reflective surfaces. The laser beam reflected by the polygon mirror 30 is reflected by the second mirror 29 and the third mirror 31, passes through the correction lens 32, and is focused at a predetermined position on the surface of the photosensitive drum 5 to form an image. In this manner, the laser beam is scanned onto the photosensitive drum 5, and the laser beam is repeatedly scanned by rotating the polygon mirror 30. Note that a portion of the laser beam reflected by the two second mirrors is reflected by the detection mirror 34 and is incident on the photodiode 33 to detect the starting position of scanning. A shutter 35 is provided in front of the laser diode 24 to mechanically block the laser light emitted from the laser diode 24. As shown in FIG. 3, this shutter 35 is formed of, for example, an iron plate, and is supported vertically by a guide 36 provided on the unit body. The shutter 35 is driven by an appropriate mechanism to block the laser beam when the lid 2 is open. That is,
The shutter 35 is normally located at a position where it is lowered by its own weight and does not block the optical path of the laser beam. A magnet 37 that interlocks with the lid 2 is provided above the guide 36 by a mechanism not shown. When the lid 2 is normally closed, this magnet 37 stands upright and is located away from the shutter 35, and when the lid 2 is opened, the magnet 37 moves downward and blocks the optical path of the laser beam. Therefore, when the lid 2 is closed, the laser beam is not blocked and the lid 2 is closed.
When opened, the laser light is blocked. Note that the area in the figure indicates laser light.

In the laser beam printer configured in this way,
Recording on the recording paper 12 is performed in the same manner as in a conventional laser beam printer. During this recording, the recording paper 12 moves as follows. That is, the recording paper 12 set in the paper feed cassette 13 provided on the lid 2 is fed out by the paper feed roller 14, and after passing between the paper pressing rollers 15, 15 provided on the lid 2, the transfer charging Unit 8 and main body 1
The photosensitive drum 5 is placed between the photosensitive drum 5 and the photosensitive drum 5, and an image is recorded at this time. Thereafter, the paper passes between the paper press roller 17 provided on the lid 2 and the heat roller 16 provided on the main body 1, and is ejected from the paper ejection port 22 of the lid 2 or the paper ejection port 19 of the main body 1. Note that the photosensitive drum 5 is rotated in a direction opposite to the conventional direction.

When it is necessary to perform maintenance or inspection on the inside of the housing 4, the lid 2 is opened and the upper opening of the main body 1 is opened to perform the work. When the lid 2 is rotated upward about the pivot 3 and released from the upper opening of the main body 1, the paper feed cassette 13, paper feed roller 14, paper press roller 15°15, transfer charging unit 8, and paper press roller 17 are removed. moves together with the lid 2 and separates from the main body 1.

As a result, the upper opening portion of the main body 1 is opened, and the developing unit 7, the photosensitive drum 5, the static eliminating cleaner unit 9, and the heat roller 16 provided in the main body 1 are exposed. By opening the lid 2 in this way, the elements forming the upper side of the recording paper path through which the recording paper 12 passes are separated from the recording paper path, and the elements forming the lower side of the recording paper path are exposed. That is, since the recording paper path is exposed, if the recording paper 12 becomes jammed in the recording paper path, the recording paper 12 can be removed with a simple operation. Further, since the photosensitive drum 5, which requires replacement, and the developing unit 7, which requires toner replenishment, are provided in the upper open portion of the main body 1, handling of these units is easy. Since the optical system unit 18 is provided close to the circuit board 21, noise is reduced, and the laser driver circuit can be incorporated into the main body and easily wired using lead wires. Further, when the lid is opened, the shutter 35 of the optical system unit 18 closes and blocks the laser beam, so there is no danger to the operator. Moreover, since the shutter 35 is reliably held in the blocking position by the magnet 37, there is no risk of it being removed from the blocking position due to external vibrations.

Therefore, the laser beam printer of this embodiment has a main body 1 provided with a photosensitive drum 5 and an optical system unit 18.
As the lid 2 is opened and closed, the optical system unit 18 is moved to the photosensitive drum 5.
The optical system unit 18 does not move relative to the
can be fixedly provided to the photosensitive drum 5.

Therefore, the laser beam output from the optical system unit 18 connects the optical system unit 18 and the photosensitive drum 5.
By setting and providing the positional relationship between the two so that the image can be formed at a predetermined imaging point on the surface of the lens, the positional relationship can be maintained constant.

It should be noted that the present invention is not limited to the above-described embodiments, but can be implemented with various modifications within the range that does not change the paper.

[Effects of the Invention] As explained above, according to the laser beam printer of the present invention, by providing the optical system unit and the photosensitive drum in the main body, it is possible to record both accurately in advance regardless of whether the lid is opened or closed. It can maintain the set positional relationship and has high reliability.

In addition, the transfer charging unit, paper feed roller, and paper press roller are installed on the lid side, so when the lid is opened, the recording paper path in the main body is exposed, making maintenance and inspection work such as paper jams easier. can be done.

FIG. 2 is a diagram showing a schematic structure of an optical system unit, FIG. 3 is a diagram showing a shutter of the optical system unit, and FIG. 4 is a sectional view showing a schematic structure of a conventional laser beam printer.

DESCRIPTION OF SYMBOLS 1... Main body, 2... Lid, 4... Housing, 5... Photosensitive drum, 8... Transfer charging unit, 14... Paper feed roller, 15... Paper pressing roller, 17 ...Paper presser roller.

Applicant's agent: Patent attorney Takehiko Suzue

Claims (2)

[Claims] (1) A housing is composed of a main body and a lid that is openable and closable on the opening of the main body, and inside the housing, an optical system unit scans a laser beam onto a photoreceptor to form an image on the photoreceptor. . A laser beam printer which records the image by transferring it onto recording paper supplied inside a housing, characterized in that the photoreceptor and the optical system unit are provided on the main body side. (2) A paper feed roller that feeds the recording paper from the paper feed cassette, a paper pressing roller that presses the fed recording paper from above, and a transfer charging unit that transfers the image on the photoreceptor onto the recording paper are provided on the lid side; 2. A laser beam printer according to claim 1, further comprising a recording paper path formed between the lid and the main body.