JPH0732055Y2 - Laser printer device - Google Patents

Description

[Detailed Description of the Invention] "Industrial field of application" The present invention relates to a laser printer device, and more particularly to a laser printer device for reducing the time required for maintenance and extending the life of a motor using a dynamic pressure air bearing. .

“Prior Art” Recently, demands for printers to improve printing quality and speed up have become more severe. One means for responding to such a demand is a laser printer device, for example, there is one capable of high-speed printing of 50 sheets per minute with a resolution of 90,000 dots per square inch and Japanese Industrial Standard A4 size.

As such a high-quality laser printer with high printing quality, for example, using the principle of an electronic copying machine, the laser beam output from a gas laser tube is modulated with data, and then a motor scans a photoconductor while rotating a polygon mirror. There is a system in which an electrostatic latent image is formed by carrying out a developing process, and the electrostatic latent image is developed to transfer a toner image onto a sheet to print characters and figures.

By the way, as the gas laser tube, for example, a helium-neon tube is used, but as shown in FIG. 3, a warming-up time of about 1 to 10 minutes is required for the laser output to reach a specified value and stabilize.

Further, as the motor for driving the polygon mirror, for example, a dynamic pressure air bearing is used which forms an air layer between the fixed portion and the rotating portion during rotation and maintains the rotating state in a non-contact manner. As shown in FIG. 4, it takes several seconds to several minutes for the rotation speed of this motor to reach the specified rotation speed and stabilize.

Here, a motor using a dynamic pressure air bearing according to FIG.
Explain 100.

As shown in the figure, in the lower case 101, a stator 103 around which a coil 102 is wound is fixed. A large-diameter shaft 105 and a flange 106 are formed at the lower end of the fixed shaft 104, and the fixed shaft 104 is fixed in the lower case 101 via these.

A spiral groove 107 is formed on the outer peripheral surface of the fixed shaft 104. A tube shaft 108 is loosely fitted to the fixed shaft 104, and a pivot 109 fixed to an upper part of the tube shaft 108 is fixed while the tube shaft 108 is stationary.
The tube shaft 104 is held by abutting on the upper end of the fixed shaft 104. The tube shaft 108 is a rotor 1 made of a permanent magnet.
10 is fixed via a sleeve 111. A drive source 120 is composed of the rotor 110 and the stator 103.

A rotary polygon mirror 1 is attached to a flange formed at a proper position on the tube shaft 108.
12 is fixed. An optical glass 114 is fixed to the upper case 113 at a position corresponding to the rotary polygon mirror 112. The flange 106 and the like integrated with the optical glass 114 and the fixed shaft 104 are kept airtight.

In order to operate the motor 100 having such a configuration, the drive source 1
When 20 is energized to rotate the rotor 110, the rotor 110
Due to the rotation of the tube shaft 108 and the dynamic pressure of the fluid (for example, air) generated by the groove 107 of the fixed shaft 104, while being levitated from the fixed shaft 104, it is stably supported in both the radial direction and the thrust direction. ing.

[Problems to be solved by the invention] By the way, in order to always use the above-mentioned high-performance laser printer device in the best condition, system maintenance such as regular inspection is required. In this system maintenance, the power switch is frequently turned on and off.

However, as mentioned above, it takes a considerable warm-up time for the output of the gas laser tube to reach the specified value, and once the power is turned off during system maintenance work, it will be specified again even if the power switch is turned on. It takes 1 to 10 minutes to reach the value, which is a waste of time.

Further, since the motor 100 using the dynamic pressure air bearing has no mechanical contact during rotation, there is no loss due to rotational friction. However, when the rotation is stopped, the rotating portion (pivot 109 or the like) is placed on the upper end of the fixed shaft 104, and when the rotation is started, the fixed shaft 104 and the rotating portion cause friction. That is, the use of the dynamic pressure air bearing causes mechanical loss only when the rotation is stopped and started, and the life of the dynamic pressure air bearing largely depends on the number of times the power switch is turned on and off.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a laser printer apparatus which eliminates the warm-up time of a gas laser tube and extends the life of a motor using a dynamic pressure air bearing.

"Means for Solving the Problem" The present invention is directed to a main switch for turning on and off a power source for operating the entire apparatus, a gas laser tube for generating a laser beam, and a laser beam generated by the gas laser tube for deflection. The laser printer device includes a polygon mirror, a motor that rotatably supports the polygon mirror through a dynamic pressure air bearing, and a sub switch that can supply power to the gas laser tube and the motor regardless of whether the main switch is turned on or off. It was prepared for.

In this way, even if the main switch is turned off and the energization of the laser printer main body is stopped, the sub switch can be operated to energize only the gas laser tube and the motor continuously. The time is not lost and the life of the motor using the dynamic pressure air bearing is not shortened.

[Example] Hereinafter, the present invention will be described based on an illustrated example.

FIG. 1 is a block diagram showing a laser printer device of the present invention.

The commercial power source 11 is connected to a switch unit 12 including a pushing unit, a contact piece, a fixed contact, and the like. That is,
The commercial power supply 11 is connected to the first and second fixed contacts 12 ₁ and 12 ₂ and forms a third fixed contact 12 which makes a pair with the first fixed contact.
₃ is connected to an AC-DC converter (hereinafter referred to as A / D converter) 13. In addition, the fourth fixed pair of contacts 12 ₂ and the fourth
Stationary contact 12 ₄ is connected to a laser printer apparatus main body 14.

When the pusher 12a, which is the main switch, is pressed, the first contact piece 12b, which is the first sub-switch, and the second contact piece 12c, which is the second sub-switch, are pressed simultaneously, and the first contact piece 12b is pressed.
The contact pieces 12b simultaneously contact the fixed contacts 12 ₁ and 12 ₃ to electrically connect these contacts. Similarly, the second contact piece 12c
Simultaneously makes contact with the fixed contacts 12 ₂ and 12 ₄ to establish conduction between these contacts.

Further, for example, when performing system maintenance, a main body cover (not shown) of the laser printer device may be opened. The third contact piece 12d, which is the third sub-switch, is
When the main body cover is opened, it is automatically pushed down to simultaneously contact the first and third fixed contacts 12 ₁ and 12 ₃ to secure the conduction state.

The first output end of the A / D converter 13 is the motor drive unit 1
It is connected to the drive source 120 of the motor 100 via 5. The motor 100 rotatably supports the polygon mirror 112 via a dynamic pressure air bearing.

The second output end of the A / D converter 13 is connected to a laser high-voltage power supply 18, and the output side thereof is connected to a gas laser tube 19 composed of a helium-neon tube.

The laser beam emitted from the gas laser tube 19 is controlled to pass / block by the laser shutter 20, and the passed laser beam reaches the reflecting surface of the polygon mirror 17 via the lens 21, the acoustic / optical modulator 22 and the lens 23. .

The laser beam reflected by the polygon mirror 112 that is rotationally driven by the motor 100 scans the photoconductor 25 to form an electrostatic latent image according to the data. Further, a detector 26 for outputting a horizontal scanning synchronization signal that detects a laser beam is arranged near the starting point of scanning.

Next, the operation of the laser printer device configured as described above will be described with reference to the flow chart shown in FIG.

First, when the pushing portion 12a that is the main switch is turned on, the first contact piece 12b that is the first sub switch and the second contact piece 12b that is the second sub switch are turned on.
All the second contact pieces 12c, which are sub-switches, are turned on, and the AC of the commercial power supply 11 is supplied to the A / D converter 13 and the laser printer body 14 (step).

This causes the motor 100 to rotate. Polygon mirror 112
In the rotating part including, the pivot 109 is in mechanical contact with the fixed shaft 104 at the beginning of rotation, but the mechanical contact is separated from the fixed shaft 104 as the rotation increases, and eventually an air layer is formed to continue rotating without friction. (Step). Further, a high voltage is also supplied to the gas laser tube 19 to start lighting (step).

On the other hand, the commercial power source 11 is supplied to the laser printer apparatus main body 14 via the second contact piece 12c which is in the conductive state,
For example, an operation such as paper feeding is started (step).

In this state, it can be used as a normal printer device.

Eventually, it is time to perform system maintenance, and a serviceman removes the main body cover of the laser printer device (step).

Then, the third contact piece 12d, which is the third sub-switch, is activated, and commercial power is continuously supplied to the motor drive unit 13 (step).

Further, by removing the body cover, the pushing portion 12a is turned off, and at the same time, the first and second contact pieces 12b and 12c are turned off (step).

In this state, commercial power is supplied to the A / D converter 13 via the third contact piece 12d, and the motor 16 and the gas laser tube 19 are operated via the motor drive unit 15 and the laser high-voltage power supply 18, respectively. The voltage required to continue is supplied (step,). On the other hand, since commercial power is not supplied to the laser printer main body 14, the operation up to that point is stopped (step), and the maintenance work can be performed safely.

Then, if the body cover is attached (step;
Y), the main switch is turned on again (step), and normal use as a printer device is possible.

As described above, the motor 16 continues to rotate and the gas laser tube 19 continues to emit a laser beam even during system maintenance. Therefore, the fixed shaft of the motor 100 and the rotating part do not come into contact with each other, so that the service life is not shortened, and the gas laser tube 19 continuously emits a laser beam. Even if the main switch is turned on, no warm-up time is required.

If the polygon mirror 17, the gas laser tube 19 and the like are surrounded by the exposure prevention cover 30 as shown by the dotted line in FIG. 1, it is possible to prevent exposure by the laser beam.

Further, in this embodiment, when the main body cover is removed, the third contact piece 12d, which is a sub switch, is automatically brought into a conductive state. However, before opening the body cover,
Of course, the third contact piece 12d may be manually turned on.

"Effect of the device" According to the present invention, the motor continues to rotate even during system maintenance so that the service life will not be shortened, and the gas laser tube will continue to emit, so the main No unnecessary waiting time is required when the switch is turned on.

[Brief description of drawings]

The drawings are for explaining the laser printer apparatus of the present invention. FIG. 1 is a block diagram of the apparatus, FIG. 2 is a flow chart showing the operation of the apparatus, and FIG. 3 is an output prescribed by a gas laser tube. Fig. 4 is a characteristic diagram showing the warm-up time until it reaches the following, Fig. 4 is a characteristic diagram showing the time until the motor reaches the specified number of revolutions, and Fig. 5 is a sectional view of a motor using a conventional dynamic pressure air bearing. Is. 11 ... Commercial power supply, 12 ... Switch section, 12a ... Pushing section (main switch), 12d ... Third contact piece (sub switch), 19 ... Gas laser tube, 25 ... Photoconductor, 100 ... …
Motor with dynamic pressure air bearing, 112 ... Polygon mirror.

Claims (1)

[Scope of utility model registration request] 1. A main switch for turning on and off a power source for operating the entire apparatus, a gas laser tube for generating a laser beam, a polygon mirror for deflecting the laser beam generated by the gas laser tube, and this polygon mirror. And a sub-switch capable of supplying power to the gas laser tube and the motor regardless of whether the main switch is turned on or off. Laser printer device.