JPH04310966A - Image forming device - Google Patents

Abstract

PURPOSE:To easily load or unload the unit of a photosensitive drum into/from the inside of a device case and to prevent the surface of the photosensitive drum from being damaged at the time of loading and unloading the unit at the same time. CONSTITUTION:The device case 1 is constituted of a lower part case 2 and an upper part case 4 which is fitted on the upper surface of the case 2 so that it can be opened and closed. Supporting bodies 5A and 5B are arranged on both sides in the inside of the case 2 and a guide groove 10 extending in an upper and lower direction is provided on the bodies 5A and 5B. Then, the photosensitive drum unit 12 provided with the photosensitive drum 14 is loaded between both supporting bodies 5A and 5B so that it can be loaded or unloaded along the groove 10 from the upper part.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention includes a photosensitive drum,
The present invention relates to an image forming apparatus embodied in a copying machine, a facsimile machine, and the like.

0002

2. Description of the Related Art In this type of image forming apparatus, the photosensitive drum is assembled into a frame together with other process parts to form a unit so that maintenance and inspection of the process unit including the photosensitive drum is easy. In this case, in conventional image forming apparatuses, the drum unit is inserted and removed from the side of the apparatus case by being moved along the axial direction of the photosensitive drum along guide means such as guide rails of the apparatus case. It was configured to be

0003

However, in conventional image forming apparatuses, it is not only troublesome to attach and detach the drum unit, but also there is a risk of damaging the surface of the photosensitive drum during attachment and detachment. In other words, a large number of various parts are arranged around the drum unit installation space in the device case, and inserting and removing the drum unit through the narrow space between the many parts along the axial direction of the photosensitive drum requires the distance the drum unit must move. Because of the long
Originally, it was time-consuming. In addition, especially when inserting a drum unit, since the drum unit is long in the axial direction of the photosensitive drum, when holding the drum unit, the insertion side end of the drum unit located in front of you, the unit mounting space, the guide rail, etc. It is difficult to visually confirm the positional relationship between the unit and the guide means because the unit itself gets in the way. Therefore, inserting the unit was particularly troublesome. Moreover, if the drum unit comes off the guide means or if the unit is tilted while being inserted or removed, there is a risk that the photosensitive drum will come into contact with the device case or other parts. This contact may damage the drum surface, resulting in fatal damage to the image forming function.

[0004] The present invention was made by focusing on the problems existing in the conventional technology, and the first
An object of the present invention is to provide an image forming apparatus in which the drum unit can be easily attached and detached, and the surface of the photosensitive drum can be reliably prevented from being damaged when the unit is attached and detached. A second object of the present invention is to provide an image forming apparatus in which a photosensitive drum unit can be reliably fixed and held at a predetermined mounting position within an apparatus case.

[0005]

[Means for Solving the Problems] In order to achieve the above first object, in the invention of claim 1, the device case includes a lower case having an open top surface and an open top portion that can be opened and closed. An upper case is supported by a lower case, and a drum unit including a photosensitive drum is removably installed in the lower case, and drum unit guide parts extending downward from the upper surface opening are provided on both sides of the interior of the lower case. The drum unit is configured to be attached and detached via the guide section.

In the second aspect of the invention, the upper case is provided with a pressing means for pressing and holding the installed drum unit from above when the lower case is closed.

[0007]

[Operation] In the image forming apparatus configured as described above, when the upper case is opened from above the lower case, the upper part of the guide portion faces the outside. In this state, by pulling the drum unit upward perpendicular to the axial direction of the photosensitive drum along the guide portion, the unit can be taken out from inside the lower case. Further, the drum unit can be installed into the apparatus by pushing the drum unit downward along the guide section with the upper case open. At this time, the guide section faces the top of the lower case, so
It is easy to confirm the position of the guide. Therefore, the drum unit can be easily attached and detached along the guide portion, and the photosensitive drum does not come into contact with other parts.

[0008] After the photosensitive drum unit is mounted between both supports, the upper case is placed in the closed position on the lower case, and the unit is pressed by the pressing means and fixedly held at a predetermined mounting position.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus embodying the present invention will be described below in detail with reference to the drawings. As shown in FIGS. 1 and 2, the device case 1 includes a substantially box-shaped lower case 2 with an open top surface, and a support shaft 3 on the lower case 2.
It consists of an upper case 4 which is attached so that it can be rotated to open and close through the upper case 4.

As shown in FIGS. 1, 3 to 6, a pair of left and right supports 5A and 5B are arranged on both sides of the interior of the lower case 2. As shown in FIGS. Both supports 5A and 5B are the lower case 2
A pair of metal side plates 6A and 6B are erected and fixed inside,
A pair of synthetic resin covers 7A covering both side plates 6A and 6B
, 7B. A pair of front and rear support grooves 8,
9 is formed toward the upper ends of the side plates 6A, 6B. In addition, in this specification, the left side of FIG. 2 is referred to as the front part. A pair of guide grooves 10 at the front and rear as a drum unit guide section
, 11 are both covers 7A, so as to correspond to the support grooves 8, 9.
Through holes 10a and 11a are formed in the guide grooves 7B downward from the upper surface thereof, and are formed in the inner bottom thereof to expose the inner peripheral edges of the support grooves 8 and 9 into the guide grooves 10 and 11. The front guide groove 10 extends in a direction that is slightly inclined toward the upper front with respect to the perpendicular line, and the rear guide groove 11 extends substantially along the perpendicular direction, and the guide grooves 10 and 11 are formed so as to widen on the upper side. has been done. Furthermore, of the two support grooves 8 on the front side, the amount of protrusion of one (left side in FIG. 6) of the support groove 8 from the through hole 10a is larger than that of the other support groove.

As shown in FIGS. 3 to 6, a fixed shaft 13 is fixed through the frame 18 of the photosensitive drum unit 12, and both ends 13a of the fixed shaft 13 protrude to the outside. Then, by engaging both ends 13a with the front support grooves 8 of the side plates 6A, 6B along the front guide grooves 10 of the covers 7A, 7B, the photosensitive drum unit 12 is attached to the lower case 2.
It is removably installed inside. This photosensitive drum unit 12 is positioned at a predetermined position in the front-rear direction by joining the outer circumferential surfaces of both ends 13a and the front support groove 8, and also has a small diameter portion 13b formed on the left end 13a and a protruding amount. It is positioned at a predetermined position in the left-right direction by engagement with the front support groove 8 on the left side, which has a large number of holes. A pair of handles 12a are fixed to both sides of the upper surface of the frame 18.

The photosensitive drum 14 is rotatably supported within a frame 18 on the fixed shaft 13 of the photosensitive drum unit 12, and has a photoconductive layer made of selenium, zinc oxide, etc. formed on its outer peripheral surface. The driven gear 15 is fixed to the right end of the photosensitive drum 14, and when the photosensitive drum unit 12 is installed between the side plates 6A and 6B, the driven gear 15 is fixed to the drive gear train 16 provided on the side plate 6B in FIG. It meshes with one drive gear 16a.

As shown in FIG. 2, a charger 17 is supported by a frame 18 above the photosensitive drum 14, and the charger 17 uniformly charges the photosensitive drum 14 to a predetermined potential (-700V in the embodiment). be done. The cleaner 19 is supported by the frame 18 in front of the photosensitive drum 14, and the outer peripheral surface of the photosensitive drum 14 is cleaned by the cleaner 19.

As shown in FIGS. 1 and 3, the exposure aperture 2
1 is formed on the rear side of the upper surface of the frame 18, and a pair of engaging recesses 22 are provided on the upper surface of the frame 18 on both sides thereof. The exposure unit 23 is attached to the inner cover 4a of the upper case 4, and has a lower surface that exposes the photosensitive drum 14 through the exposure opening 21 when the upper case 4 is rotated to the closed position on the lower case 2. An exposure device 24 facing the outer peripheral surface is supported. And this exposure device 24
As a result, the photosensitive drum 14 is exposed to light, the potential of the exposed area is changed (-100V in this example), and an electrostatic latent image is formed in this exposed area. A pair of engagement pins 25 constituting the pressing means are supported on both sides of the lower surface of the exposure unit 23, and are biased downward by a spring 26. When the upper case 4 is rotated to the closed position with the photosensitive drum unit 12 attached, the engagement pin 25 engages with the engagement recess 22, and the photosensitive drum unit 12 is pressed and held in the attached state. Along with this, the exposure device 24
is positioned at a predetermined position with respect to the photosensitive drum unit 12.

As shown in FIGS. 1 to 5, the developing unit 27 has engaging pins 28 protruding from both ends of the cover 7.
By engaging with the rear support grooves 9 of the side plates 6A, 6B along the rear guide grooves 11 of the side plates A, 7B, it is removably installed between the side plates 6A, 6B from above. The developing unit 27 is positioned at a predetermined position in the front-rear direction facing the photosensitive drum unit 12 by joining the outer circumferential surfaces of both engaging pins 28 and the rear support groove 9. Further, the developing unit 27 includes a toner case 29, and toner 30 is accommodated inside the toner case 29. The developing roller 31 is provided at the lower end opening of the toner case 29 so as to face the photosensitive drum 14 . And the photosensitive drum 14
A predetermined potential (-450V in this embodiment) is applied to the toner by the developing roller 31 which rotates at the same time, and the toner 30 adheres to the electrostatic latent image based on the potential difference between the toner and the electrostatic latent image. The latent image is visualized.

As shown in FIGS. 1, 3 and 8, the pair of pressing bodies 32 are attached to the inner cover 4a of the upper case 4 by a spring 3
3 and is biased downward. When the upper case 4 is rotated to the closed position with the developing unit 27 attached, both the pressing bodies 32 push the developing unit 27 and the covers 7A and 7A of the supports 5A and 5B, respectively.
The developing unit 27 is held in the attached state by pressing the abutted portion with the developing unit 7B.

A paper feed tray 34 is attached to the rear part of the lower case 2, and a large number of papers 35 are stacked and stored on this tray 34. Paper feed roller 36 and pair of feed rollers 38
is provided in the rear part of the lower case 2, and the paper 35 on the tray 34 is fed one by one into the lower case 2 by the rotation of the paper feed roller 36, and the paper 35 is fed into the lower case 2 one by one via the paper guide 37 and the feed roller 38. and transferred to the lower part of the photosensitive drum 14.

The transfer device 39 and the transfer roller 40 are arranged in the lower case 2 so as to face the lower outer periphery of the photosensitive drum 14. Then, the paper 35 is brought into close contact with the photosensitive drum 14 by the transfer roller 40, and a predetermined potential (+ in this embodiment) is applied to the contact portion by the transfer device 39.
100 V) is applied, and the toner image is transferred to the surface of the paper 35 based on the potential difference between the toner and the contact portion. The heating fixing device 41 is disposed inside the lower case 2, and the heating roller 4
2 and a pressure roller 43. Then, the paper 35 is fed between the heating roller 42 and the pressure roller 43 via a paper guide 44, and the image on the paper 35 is heated and fixed. The stacker 46 is disposed at the front upper part of the upper case 4, and the paper 35 on which the image has been heat-fixed passes through the paper guides 47, 48 and the guide roller 49.
It is discharged onto this stacker 46.

In the image forming apparatus configured as described above, the photosensitive drum 14 of the photosensitive drum unit 12 is rotated clockwise in FIG. 2 via the driving gear train 16 and the driven gear 15 by the rotation of a motor (not shown). Ru. After the outer peripheral surface of the photosensitive drum 14 is uniformly charged by the charger 17, an electrostatic latent image is formed on the outer peripheral surface by the exposure device 24. Thereafter, toner 30 is attached to the electrostatic latent image by the developing roller 31 of the developing unit 27, and the electrostatic latent image is visualized. Then, the toner image on the photosensitive drum 14 is transferred onto the surface of the paper 35 by the actions of the transfer device 39 and the transfer roller 40 . Thereafter, this paper 35 is sent to a heat fixing device 41 via a paper guide 44, and the image on the paper 35 is heat-fixed. Then, the paper 35 on which image formation has been completed is discharged onto the stacker 46 via paper guides 47, 48 and guide rollers 49.

On the other hand, in this image forming apparatus, when the upper case 4 is rotated upward as shown in FIG. 1, the upper surface of the lower case 2 is opened and the exposure unit 2 is opened.
The engagement pins 25 on both sides of the lower surface of the photosensitive drum unit 12
The photosensitive drum unit 1 is disengaged from the upper engagement recess 22.
The pressure on 2 is released. When the photosensitive drum unit 12 is pulled up by the handle 12a in this state, both ends 13a of the fixed shaft 13 are inserted into the front support grooves of the side plates 6A and 6B.
The photosensitive drum unit 12 can be taken out from inside the lower case 2 by being removed upward along the front guide grooves 10 of the covers 7A and 7B.

Furthermore, when the photosensitive drum unit 12 is installed in the lower case 2 when the lower case 2 is open, when the photosensitive drum unit 12 is held by the handle 12a and pushed downward, both ends of the fixed shaft 13 of the unit 12 are removed. The portion 13a is guided by the front guide groove 10 of the covers 7A, 7B and engaged in the front support groove 8 of the side plates 6A, 6B,
As shown in FIGS. 4 to 6, both ends 13a and the front support groove 8
Due to the engagement with the lower case 2, the photosensitive drum unit 12 is positioned at a predetermined position in the front-rear direction and the left-right direction.
installed inside. At this time, the driven gear 15 at the right end of the photosensitive drum 14 is connected to the driving gear train 1 provided on the right side plate 6B.
It is meshed with one of the drive gears 16a among the gears 16a.

After that, as shown in FIG. 2, the upper case 4
When the is rotated to the closed position on the lower case 2, the engagement pins 25 on both sides of the lower surface of the exposure unit 23 engage with the engagement recesses 22 on the photosensitive drum unit 12, and the photosensitive drum unit 12 is pressed into the attached state. At the same time, the exposure device 24 is positioned at a predetermined position with respect to the photosensitive drum unit 12 .

As described above, in this image forming apparatus, when the photosensitive drum unit 12 is to be taken out from the apparatus case 1, it is only necessary to open the upper case 4 and pull up the photosensitive drum unit 12. Furthermore, when installing the photosensitive drum unit 12 in the device case 1, the upper surface of the lower case 2 is opened so that the guide groove 10 that constitutes the guide section of the unit 12 is located in a position where it can be easily checked with the naked eye. be exposed. Then, since it is only necessary to fit both ends 13a of the fixed shaft 13 protruding from both ends of the frame 18 of the drum unit 12 into the guide groove 10, it is possible to align the guide groove 10 and both ends 13a close to hand. By the way, it can be done. After positioning, the photosensitive drum unit 12 can be simply pushed downward. Furthermore, the amount of movement of the photosensitive drum unit 12 when it is attached or removed is only approximately the height of the unit 12, so the amount of movement is extremely small. As described above, in this image forming apparatus, it is extremely easy to attach and detach the photosensitive drum unit 12.

Further, when the photosensitive drum 14 is attached or detached, the upper surface of the lower case 2 is opened, and a wide space is formed around the attachment/detachment section. In addition, as mentioned above, the photosensitive drum unit 12 is easy to attach and detach, and the amount of movement required for attachment and detachment is extremely small.
In addition, since the movement is guided by the guide groove 10, there is no risk that the surface of the photosensitive drum 14 will come into contact with the device case 1 or its internal components and be damaged.

In this embodiment, since the front guide groove 10 is inclined upwardly at the front, as the photosensitive drum unit 12 moves away from the mounting position, the photosensitive drum 1
4 leaves the developing roller 31. Therefore, when the photosensitive drum unit 12 is attached or detached, the photosensitive drum 14 is attached to the developing roller 3.
There is no conflict with 1. Therefore, damage to the photosensitive drum 14 can be more reliably prevented.

Furthermore, in this image forming apparatus, when the upper case 4 is in the closed state, the photosensitive drum unit 12 is always pressed and held in the installed position, so that there is no misalignment between the driven gear 15 and the driving gear 16a at the start of operation. Even if this happens, there is no risk that the photosensitive drum unit 12 will lift up. On the other hand, the toner case 2 of the developing unit 27
When replenishing the toner 30 into the inside of the developing unit 27, when the upper case 4 is opened from above the lower case 2 in the same manner as described above, the pressing bodies 32 on both sides of the lower surface of the upper case 4 are released from the upper surface of the developing unit 27. When the developing unit 27 is separated, the pressure on the developing unit 27 is released, and a wide space is formed above the lower case 2. When the developing unit 27 is lifted in this state, the engaging pins 28 on both sides of the developing unit 27 are inserted into the rear guide grooves 11 of the covers 7A, 7B from within the rear support grooves 9 of the side plates 6A, 6B.
The developing unit 27 can be removed from the lower case 2 by being separated upward along the .

Furthermore, the toner 30 into the toner case 29
After replenishing, etc., remove the developing unit 27 from the lower case 2.
When the upper case 4 is in an open state, the engaging pins 28 on both sides of the developing unit 27 are inserted into the side plates 6A, 6B along the rear guide grooves 11 of the covers 7A, 7B.
When the developing unit 27 is engaged in the rear support groove 9 of the photosensitive drum unit 12, as shown in FIGS. positioned in position.

After that, as shown in FIG. 2, the upper case 4
When it is rotated to the closed position on the lower case 2, the pressing members 32 on the lower surface of the upper case 4 engage with both sides of the upper surface of the developing unit 27, and the developing unit 27 is pressed and held in the installed state. Therefore, the operation of attaching and detaching the developing unit 27 can be easily performed by simply moving the developing unit 27 up and down slightly in a direction perpendicular to the longitudinal direction of the developing unit 27.

Note that the present invention is not limited to the configuration of the above-mentioned embodiment, and for example, the photosensitive drum unit 12
The internal configuration of the photosensitive drum unit 12, the pressing configuration for the mounting position of the photosensitive drum unit 12, or the integration of the photosensitive drum unit 12 and the developing unit 27 may be modified without departing from the spirit of the present invention. It is also possible to change the configuration arbitrarily and implement it.

[0030]

[Effects of the Invention] Since the present invention is constructed as described above, it achieves the following excellent effects. According to the first aspect of the invention, it is possible to easily attach and detach the photosensitive drum unit to and from the device case, and it is also possible to reliably prevent the surface of the photosensitive drum from being damaged when the unit is attached and detached.

Further, according to the second aspect of the invention, the photosensitive drum unit can be securely fixed and held at a predetermined mounting position within the device case.

[Brief explanation of the drawing]

FIG. 1 is a sectional view schematically showing an embodiment of an image forming apparatus embodying the present invention.

FIG. 2 is a sectional view showing details of the image forming apparatus.

FIG. 3 is an exploded perspective view showing a photosensitive drum unit, a developing unit, and their support.

FIG. 4 is an enlarged partial internal side view showing a state in which the fixed shafts of both units are engaged with the left support.

FIG. 5 is an enlarged partial internal side view showing a state in which the fixing shafts of both units are engaged with the right support body.

FIG. 6 is an enlarged partial sectional view showing a state in which a photosensitive drum unit is mounted between both supports.

FIG. 7 is a partial cross-sectional view showing a pressing configuration for the photosensitive drum unit.

FIG. 8 is a partial cross-sectional view showing a pressing configuration for the developing unit.

[Explanation of symbols]

1 Equipment case, 2 Lower case, 4 Upper case, 5A, 5B Support, 6A, 6B Side plate, 7A
, 7B cover, 8 front support groove, 10 front guide groove as a drum unit guide section, 12 photosensitive drum unit, 14 photosensitive drum, 25 engagement pin as pressing means, 26 spring.

Claims (2)

[Claims] Claim 1: The device case is composed of a lower case with an open top surface and an upper case supported by the lower case so that the open top surface can be opened and closed, and a drum unit including a photosensitive drum is attached to the lower case. The drum unit is detachably mounted inside the lower case, and a drum unit guide section is provided on both sides of the interior of the lower case and extends downward from the upper surface open section, and the drum unit is attached and detached via the guide section. Image forming device. 2. Claim 1, wherein the upper case is provided with a pressing means for pressing and holding the installed drum unit from above when the lower case is in the closed state.
The image forming apparatus described in .