JP3046496B2 - Laser printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser printer.

[0002]

2. Description of the Related Art Conventionally, in the process of rotating a photoconductor drum, an outer peripheral surface of the photoconductor drum is charged by a charging unit, and an optical signal corresponding to a print signal is irradiated from an optical unit to the charged portion, thereby forming an electrostatic latent image. An image is formed, the electrostatic latent image is developed as a toner image by a developing unit, the toner image on the photosensitive drum is transferred to a sheet by a transfer unit, and the transferred image on the sheet is fixed by a fixing unit. There is a laser printer.

In such a conventional laser printer, a photosensitive drum is provided above a substantially horizontal paper transport path, and a charging unit and a developing unit are provided on the outer periphery of the photosensitive drum. A flat optical unit is arranged above the charging unit and the developing unit, and a transfer unit facing the lower periphery of the photosensitive drum is arranged below the paper transport path, and paper is loaded into both ends of the paper transport path. And a fixing unit are provided. This is the case of a cleaner-less type laser printer. However, in the case of a laser printer that requires cleaning of the photosensitive drum, a cleaning unit is provided above the paper transport path.

[0004]

In recent years, office space has been limited due to rising rents and the like, and many offices require various office automation equipment. Since the flat optical unit is mounted in a nearly horizontal state, and the power supply unit including the substrate is also flat and arranged in the horizontal direction, it can be reduced in thickness but requires a large installation space. A thin laser printer uses a rack or other
There is a way to set up the device A in a vertical relationship,
When prioritizing the computer keyboard layout for operation,
The operability deteriorates because the laser printer cannot be placed at the optimum position. In addition, thin laser printers generally have front and back sides longer than the sides, so if you place the front side on a desk with the front facing you in consideration of operability, there will be a lot of space in the depth direction. However, since the frontage is widened, space is likely to be insufficient when a plurality of OA devices are arranged adjacent to each other toward the front.

[0005]

According to the present invention, there is provided a photosensitive drum rotatably driven above an intermediate portion of a sheet conveying path provided substantially horizontally below a main body case, and a charging drum which is brought close to the photosensitive drum. A transfer unit facing the outer periphery of a lower portion of the photosensitive drum with the paper transport path therebetween, and a transport roller disposed at one end of the paper transport path and the paper transport thereof. A fixing unit is disposed at the other end of the path, and a vertically long power supply unit whose width in the direction along the sheet conveying direction is set to a small value is vertically moved through the center of the photosensitive drum at the upper part of the sheet conveying path. An optical unit and a developing unit, which are disposed on one side of the surface and emit light signals corresponding to print signals, each having a narrow width dimension corresponding to the paper transport direction, are vertically opposed to each other. An optical path for irradiating the photosensitive drum with an optical signal emitted from the optical unit is provided between the power supply unit and the optical unit, with the vertical plane being interposed therebetween. It is a laser printer provided.

[0006]

According to the present invention, a narrow optical unit and a developing unit are arranged close to each other in the vertical direction so as to be opposed to a narrow vertical power unit. By providing an optical path, it is possible to shorten the overall length of the paper transport path and use a vertically long main body case with a narrow frontage.

[0007]

An embodiment of the present invention will be described with reference to the drawings. In FIG. 2, reference numeral 1 denotes a main body case. When viewed from the front 2, the main body case 1 has a narrow frontage and a vertically long shape, but the side surface 3 has a long depth dimension. A power switch 5 is provided on the front surface 2 side of the upper surface 4 of the main body case 1, and an exhaust hole 7 is formed on the rear surface 6 side of the upper surface 4.
A plurality of display elements 8 such as LEDs for displaying various operation states or displaying a toner empty state of a developing unit described later are provided on the front surface 2 of the main body case 1.
Are arranged. Further, on both side surfaces 3 of the main body case 1, a paper feed tray 9 and a paper discharge tray 10 are rotatably supported by a support structure described later. A sliding guide plate 11 is provided on the inner surfaces of the paper feed tray 9 and the paper discharge tray 10 so as to be freely drawn out. These sliding guide plates 11
The center of the edge is provided with a non-slip 12 for improving the gripping property, and an arc-shaped concave portion 13 for exposing the non-slip 12 is formed in the center of the edge of the sheet feeding tray 9 and the sheet discharging tray 10. ing.

As shown in FIG. 1, below the main body case 1, there is provided a substantially horizontal and short paper transport path 14 for transporting the paper along the width direction of the frontage 2 thereof. A photosensitive drum 15 and a charging unit (charging brush) 16 proximate to the photosensitive drum 15 are rotatably provided above an intermediate portion of the sheet transporting path 14, and the photosensitive drum 15 is interposed between the photosensitive drum 15 and the photosensitive drum 15. A transfer unit (transfer roller) 17 facing the lower periphery of the photosensitive drum 15 is rotatably provided. A pair of transport rollers 18 is rotatably provided at the right end of the paper transport path 14, and a fixing unit 21 including a heating roller 19 and a pressure roller 20 is provided at the left end.

Further, a vertically long power supply unit 22 having a narrow width in a direction along the sheet conveying direction is disposed above the sheet conveying path 14 on the side of the fixing unit 21. An optical unit 23 and a developing unit 24, each of which has a narrow width dimension corresponding to the paper transport direction and emits an optical signal corresponding to a print signal, are disposed in the upper portion of the upper side of the transport roller 18 side of They are arranged facing each other. Then, the power supply unit 22
Between the optical unit 23 and the optical unit 23
There is provided an optical path 27 for irradiating the photosensitive drum 15 with an optical signal emitted from the mirror and reflected by the mirrors 25 and 26. The optical path 27 is located on a vertical plane passing through the center of the photosensitive drum 15, and the optical unit 23 and the developing unit 24 are close to the power supply unit 22 with the optical path 27 as a boundary. Further, an opening 28 for replacing the developing unit 24 and a paper feed port 29 facing the right end of the sheet transport path 14 are formed on the right side of the main body case 1.
On the left side of the paper discharge path 30 facing the left end of the paper transport path 14.
Are formed.

The photosensitive drum 15, the charging unit 16, the transfer unit 17, and the transport roller 1
8, a motor (not shown) for driving the heating roller 19, the developing roller 24a of the developing unit 24, an agitator (not shown), and the like, and an exhaust fan (not shown) for releasing heat in the main body case 1. Is provided on the back surface 6 side of the main body case 1 (near the lower part of the exhaust hole 7 in FIG. 2). The optical unit 23 has a laser diode (not shown) that modulates a print signal and emits an optical signal, and a polygon mirror driven by a polygon motor to scan the optical signal from the laser diode. Further, the developing unit 24 is compatible with no cleaning. Therefore, a cleaning unit for cleaning the residual toner on the photosensitive drum 15 is unnecessary.

Next, referring to FIG.
The support structure of No. 0 will be described. Sliding rods 32 urged inward by springs 31 are provided at both ends in the front-rear direction of the main body case 1 so as to be freely drawn out. It is rotatably supported by 33. In addition, the discharge tray 10
A protrusion 34 having a triangular cross section is formed on both lower ends of the
An engagement recess 35 that engages with these projections 34 is formed in the main body case 1. The support structure of the paper feed tray 9 is exactly the same as the support structure of the paper discharge tray 10, and a description thereof will be omitted.

In such a configuration, when printing, the paper feed tray 9 and the paper discharge tray 10 are opened outward with the support shaft 33 as a fulcrum. In the initial stage of the opening operation, as shown in FIG. 3B, the projection 34 is engaged with the engagement recess 35, so that the paper discharge tray 10 and the paper supply tray 9 are maintained in a half-open state. When fully opened, as shown in FIG. 3 (c), the sheet ejection tray 10 and the sheet supply tray 9 are pivoted around the support shaft 33 while pulling the sliding rod 32 outward against the urging force of the spring 31. Is rotated outward. Further, as shown by the imaginary line in FIG.
Can be pulled out.

Then, the power switch 5 is turned on, and the leading edge of the sheet is brought into contact with the nip of the transport roller 18, and in this state, printing is started according to an instruction from an external host computer or personal computer. That is, the photosensitive drum 15 is driven clockwise in FIG. A latent image is formed. This electrostatic latent image is developed by the developing unit 24. On the other hand, since the transport roller 18 is driven in synchronization with the rotational movement of the photosensitive drum 15, the paper that has been stopped at the nip portion of the transport roller 18 is supplied to the photosensitive drum 15, and the photosensitive drum 15 The upper developed image is transferred to the sheet by the transfer unit 17. The paper fed by the photosensitive drum 15 is sandwiched between a heating roller 19 and a pressure roller 20 and is discharged onto a paper discharge tray 10. In this discharging process, the transferred image on the paper is pressed by the heating roller 19 and the pressure roller. The toner is fixed by the roller 20.

As described above, the power supply unit 22 is formed in a vertically long shape having a small width along the sheet conveying direction, and the optical unit 23 and the developing unit 24 each having a narrow width are arranged close to the power supply unit 22. The provision of the optical path 27 between the power supply unit 22 and the optical unit 23 makes it possible to shorten the overall length of the paper transport path 14 and use the vertically long main body case 1 having a narrow frontage. This allows
The main body case 1 can be used in a narrow place without sacrificing operability with the front face of the main body case 1 facing forward. In particular, as shown in FIG. 1, since the sheet feed tray 9 and the sheet discharge tray 10 can be used in a state where they are slightly opened, the main body case 1 can be placed in a small space. Further, when not in use, the paper feed tray 9 and the paper discharge tray 10 can be closed on the side surface of the main body case 1, so that it is convenient to store in a narrow place and the portability is improved.

[0015]

According to the present invention, the power supply unit is formed in a vertically long shape having a small width along the paper transport direction, and the narrow optical unit and the developing unit are arranged close to the power supply unit, respectively. By providing an optical path between the power supply unit and the optical unit for irradiating the photoconductor drum with an optical signal emitted from the optical unit, the overall length of the paper transport path is shortened and a vertically long main body case with a narrow frontage is used. Accordingly, the main body case can be used in a narrow place without impairing the operability with the front face of the main body case facing forward.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention.

FIG. 2 is a perspective view.

FIG. 3 is a partial longitudinal front view showing a supporting structure of a discharge tray together with an opening / closing operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body case 14 Paper transport path 15 Photoconductor drum 16 Charging unit 17 Transfer unit 18 Transport roller 21 Fixing unit 22 Power supply unit 23 Optical unit 24 Developing unit 27 Optical path

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/16-21/18

Claims (1)

(57) [Claims] A photoconductor drum rotatably driven above an intermediate portion of a paper conveyance path provided substantially horizontally below a main body case, and a charging unit proximate to the photoconductor drum are provided. A transfer unit facing the outer periphery of the lower part of the photosensitive drum is provided with a paper transport path therebetween, a transport roller is provided at one end of the paper transport path, and a fixing unit is provided at the other end of the paper transport path. Is disposed, and a vertically long power supply unit in which a width dimension in a direction along the paper transport direction is set to a narrow value is located on one side of a vertical plane passing through the center of the photosensitive drum at an upper part of the paper transport path. Arrange,
An optical unit and a developing unit, each of which has a width dimension corresponding to the paper transport direction set to a small value and emits an optical signal corresponding to a print signal, are vertically opposed to each other, and the power supply unit is disposed with the vertical surface therebetween. A laser path provided between the power supply unit and the optical unit for irradiating the photosensitive drum with an optical signal emitted from the optical unit.