JP2615448B2 - Laser printer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switch, etc., when a device is in an open state for maintenance and inspection, a laser beam leaks into the device, and an operator or serviceman The present invention relates to a laser printer having a safety device provided to prevent harm to a laser printer.

2. Description of the Related Art In general, in a device using a laser beam, in particular, in a laser printer, there is a case where the device is opened and the device is opened at the time of clearing a jam or performing maintenance and inspection. At that time, the generation of the laser beam is originally stopped by an interlock switch, etc., but if the interlock switch does not operate normally and the laser beam is irradiated, the operator or serviceman will expose the laser beam. And may be particularly harmful, such as eye damage. In order to prevent this, even if a laser beam is erroneously generated when the apparatus is opened, a mechanism is provided to block the beam so that an operator or a service person does not expose the beam.

An example of such a safety device will be described with reference to FIG. In the figure, reference numeral 22 denotes a frame on which a laser optical unit (omitted in the figure) is attached, and the frame 22 is provided with a beam irradiation slit 22a. Reference numeral 21 denotes a frame that is slidably attached to the frame 22 in the direction indicated by the arrow A. The shutter closes the beam irradiation slit 22a, 23 denotes a spring that presses the shutter 21 in the closing direction, and 20 denotes a photosensitive drum (not shown in the figure). ) And the like, and the process unit 20 can be attached to the frame 22 by sliding in the direction indicated by the arrow B. When the process unit 20 is mounted on the frame 22, the shutter 21 is opened by being pushed by the process unit 20, and when the process unit 20 is removed, the shutter 21 is closed by the force of the spring 23 to prevent beam leakage. The beam exposure of the operator and the serviceman when the process unit 20 is removed by removing the side plate (omitted in the drawing) and the like is prevented.

Problems to be Solved by the Invention However, in the above conventional example, the process unit 20 is detached after the side plate or the like is detached.However, if the process unit 20 is not detached with the side plate or the like detached, the shutter 21 is opened. If the beam is irradiated in this state, there is a good possibility that the beam reflected by the surface of the peripheral member is exposed to the operator or the service person. Further, in this conventional configuration, if the process unit 20 is not completely mounted, the shutter 21 is also half-open, and there is a danger of directly exposing the beam.

Means for Solving the Problems The present invention provides a base frame, an upper frame mounted on the base frame so as to be freely openable and closable with a laser beam generating means, and a lock means for maintaining a closed state between the base frame and the upper frame. The optical path of the laser beam from the laser beam generating means when the locking means moves to the state where the locking means is unlocked by being engaged with the locking means provided on the upper frame and moving in conjunction with the movement of the locking means and unlocking the locking means. It has a shutter to block.

According to the above configuration, the shutter engaged with the locking means allows the laser beam to move in conjunction with this movement when the locking means moves to the unlocked state in which the base frame and the upper frame are kept closed. Move in the direction that blocks the light path of

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of a laser printer, 1 is a laser generator (omitted in the figure), a laser driving circuit (omitted in the figure), and a lens group for shaping the laser beam (in the figure). A scanning unit for deflecting a beam generated from the laser unit 1, and a lens for forming an image of the deflected beam on the photosensitive member 19 shown in FIG. , 4
Is an optical path changing mirror for changing the optical path of the beam, 5 is an optical unit incorporating the laser unit 1, the scanning mirror 2, the lens 3, and the optical path changing mirror 4, and 11 is a developing unit for holding toner (not shown in the figure). , 12 is a photoreceptor unit, 7 is an upper frame for holding the optical unit 5, the developing unit 11, and the photoreceptor unit 12. As shown in more detail in FIG. 8, the frame 7 has a slit 7a through which a beam passes. Is provided. Reference numeral 6 denotes a shutter slidably mounted on the upper frame 7,
The shutter 6 has a rack gear 6b. 14 and 15 are arms rotatably attached to the upper frame 7,
Reference numeral 9 denotes a fixing device unit that melts the toner by heat, and 8 denotes a base frame that holds the fixing device unit 9 and the like. An upper frame 7 is attached to the base frame 8 so as to be rotatable about a shaft 10. 13 is a spring provided between the upper frame 7 and the base frame 8, and 16 is a projection provided on the base frame 8. FIG. 2 is a perspective view showing a state where the upper frame 7 is raised. As shown in the drawing, the laser printer according to the present embodiment has a so-called clamshell frame structure in which the fixing unit 9, the developing unit 11, and the photoreceptor unit 12 can be removed while the upper frame 7 is raised to perform work. ing. 3, 4, 5 and 6 are side views showing the shutter opening / closing mechanism, 6 a and 7 a are slits through which a beam passes, 14 a is a gear that meshes with the rack gear 6 b, and 14 b is a heart-shaped groove. , 17 is an actuator that enters the heart cam 14b, 15a is a pressing piece that presses the arm 14, 16a is a hole, and 15b is a latch that enters the hole. The arm 14 is constantly pressed in a clockwise direction, that is, in a direction to open the shutter 6, by a spring (omitted in the figure). FIG. 7 is an enlarged view showing the structure of the heart cam 14b, and the actuator 17 moves as indicated by an arrow C along the groove of the heart cam 14b. FIG. 8 is a plan view showing the optical path of the laser beam. The laser beam generated from the laser unit 1 is deflected by the scanning mirror 2 after beam shaping, and is deflected by the lens 3 onto the photoconductor 19 of the photoconductor unit 12. After being adjusted so as to form an image with a target beam diameter, the optical path is changed by the mirror 4 and reaches the photosensitive member 19.

In the laser printer configured as described above, during normal operation, the latch 15b of the arm 15 attached to the upper frame 7 is connected to the base frame 8 as shown in FIG.
It is hung on the hole 16a of the projection 16 on the side. At this time, the slit 6a of the shutter 6 and the slit 7a of the upper frame 7 coincide with each other, so that the beam can reach the photosensitive member 19.

Next, a case where the upper frame 7 is opened due to the occurrence of a jam in the laser printer or the need for maintenance and inspection will be described. First, when the arm 15 on the upper frame 7 side is rotated, the latch 15b is disengaged from the hole 16a on the base frame 8 side.
Is lifted. In this operation, when the arm 15 rotates as shown in FIG. 4, the arm 14 rotates in conjunction therewith, the rack gear 6b moves by the gear 14a, and the shutter 6 connected to the rack gear 6b moves in the same manner, and the slit 6a is moved to the upper frame. It is shifted from the slit 7a on the 7 side. That is, the bead exit slit is closed. At this time, the actuator 17 similarly moves along the groove of the heart cam 14b. Then, when the slits 6a and 7a are completely displaced, the actuator 17 enters the concave portion of the heart cam 14b as shown in FIG. At this time, even if the arm 15 is released, the shutter 6 does not return, and the beam exit slit is kept closed. In this state, even if a malfunction occurs in the interlock switch (not shown in the figure) that is activated by opening the upper frame 7 and the beam continues to be oscillated from the laser unit 1, 6 prevents the laser beam from leaking out of the optical unit 5 and eliminates the danger that the ore-repeater and serviceman will be exposed to the beam during the operation.

Next, after the work such as clearing jams and performing maintenance and inspection,
A case where the upper frame 7 is closed will be described. In this case, the arm 15 of the upper frame 7 is hooked into the hole 16a of the base frame 8 while the upper frame 7 is being pushed down. At this time, when the upper frame 7 is pushed down as shown in FIG. 8
Slightly rotating just before being caught by the side projection 16. As a result, the actuator 17 comes off from the concave portion of the heart cam 18. Accordingly, the arm 14 rotates in the opposite direction to the case where the frame is opened, and the gear 14a
b moves and the shutter 6 connected to it moves, and the position of the slit 6a coincides with the position of the slit 7a on the upper frame 7 side. That is, the beam exit slit is opened. This upper frame 7 and base frame 8
When the is closed, a beam optical path for the beam oscillated from the laser unit 1 to reach the photosensitive surface 19 is also secured. That is, the state is again as shown in FIG.

As described above, by using the shutter mechanism linked to the opening / closing operation of the upper frame 7, even when a laser beam is erroneously generated in a state where the apparatus is opened at the time of jam clearing or maintenance of the apparatus, The shutter mechanism prevents the laser beam from leaking out of the optical unit 5 and eliminates the risk that the operator or serviceman will be exposed to the beam during the operation.

In this embodiment, even after the upper frame 7 is opened, there is a risk that the operator touches the arm 15 and unlocks the shutter 6 by mistake.
In this case, it is more secure to provide a cover near the latch 15b and cover the arm 15.

The present invention provides a base frame, an upper frame mounted on the base frame so as to be openable and closable, and equipped with a laser beam generating means, a locking means for maintaining the base frame and the upper frame in a closed state, and provided on the upper frame. The lock means is engaged and moves in conjunction with the movement of the lock means, and moves to a state in which the lock means moves to a state where the lock means is unlocked and the optical path of the laser beam from the laser beam generating means is interrupted when the lock means moves. With the shutter, the shutter engaged with the lock means keeps the base frame and the upper frame closed, and the laser beam moves in conjunction with this movement when the lock means moves to the unlocked state where the lock is released. It moves in the direction that blocks the optical path of the shutter, so a separate member to move the shutter There is no need to attach or form, and simply by engaging the shutter with the locking means, it is possible to reliably prevent the operator or serviceman from being exposed to the laser beam without increasing the number of parts and materials, and It is possible to obtain a laser printer having a higher safety with less risk of leakage.

[Brief description of the drawings]

1 is a perspective view of a laser printer according to an embodiment of the present invention, FIG. 2 is a perspective view of the same, FIGS. 3 to 6 are side views of the same,
FIG. 7 is an enlarged view of the essential part, FIG. 8 is a plan view showing an optical path of a laser beam, and FIG. 9 is a perspective view of a conventional laser printer. 5 Optical unit, 6 Shutter, 7 Upper frame, 8 Base frame, 14 Arm, 14b Heart cam, 15 Arm, 15b Latch, 16 Projection, 16a … Hole, 17 …… actuator

Claims (2)

(57) [Claims] 1. A base frame, an upper frame mounted on the base frame so as to be openable and closable and equipped with a laser beam generating means, and a locking means for keeping the base frame and the upper frame closed.
The laser from the laser beam generating means when the locking means moves to a state in which the locking means is unlocked by being engaged with the locking means provided on the upper frame and moving in conjunction with the movement of the locking means. A laser printer comprising a shutter that moves in a direction that blocks an optical path of a beam. 2. A base frame, an upper frame mounted on the base frame so as to be openable and closable and equipped with a laser beam generating means, and an upper frame engaged with the base frame and maintaining a closed state of the upper frame. A first engagement means rotatably mounted on the upper frame, and a first engagement means rotatably mounted on the upper frame and urged by a spring to engage with the first engagement member and interlock with the first engagement member; And the first engagement means is engaged with the arm attached to the upper frame, moves in conjunction with the movement of the arm, and moves to a state in which the engagement state of the first engagement means is released. A shutter that moves in a direction that interrupts the optical path of the laser beam from the laser beam generating means when the first arm moves; The engagement state is released when the engagement state is released, and the return of the arm is prevented. When the engagement state of the first engagement means is reset, the engagement state is released and the arm can be returned. A laser printer comprising: a second engaging means for performing the operation.