JP3518248B2 - Image recording device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for positioning and transmitting drive of a process unit used in an electrophotographic image recording apparatus, and more particularly to a mounting unit of an apparatus main body by combining a developing unit and a photoconductor unit. The present invention relates to a device capable of favorably performing drive transmission to two units and positioning of the units by utilizing the drive transmission action to the developing device unit when pressing and holding.

[0002]

2. Description of the Related Art Conventionally, in an image recording apparatus using an electrophotographic system, a process unit in which a photosensitive drum, a charger, a developing device and the like are integrally formed is used. Detachable. When the integrated process unit is configured as a unit capable of copying 10,000 sheets, for example, the life of the unit is estimated by using the count value of the counter provided in the image forming apparatus. , And information such as a command to replace the unit is output. Therefore, when using the unit as described above, it is not necessary to pay attention to the life of the photoconductor drum and the developing device individually, and when the unit replacement command is output to the display unit of the apparatus main body, The image recording apparatus can be used only by replacing the process unit.

The photoconductor drum and the developing unit arranged in the process unit are consumable items, and when each of these members reaches the end of its life, it is replaced with a new unit, but the life of the photoconductor drum and the developing unit is changed. There is a big difference. Therefore,
If these members having different lifespans are replaced in a lump, some of the members will be wasted. On the other hand, there is also used a device in which the photosensitive drum unit and the developing device unit are separately configured and are replaced for each individual unit according to the life of each of those units. There is. When the two units are separately replaceable, it is possible to fully utilize the capabilities of each unit.

[0004]

However, as described above, in a device in which the developing device unit and the photoconductor unit are individually replaceable, when a paper jam or the like occurs in the paper transport path, It is necessary to remove the two units from the apparatus main body to perform the jam processing, which causes a new problem that the attachment / detachment work of the units is troublesome. Also, in an image recording device of the type in which the developing device unit is mounted from the upper side of the main body of the device, the developing device unit is mounted in the image forming section and the top cover is closed, and the developing device unit is pressed from above to position There is a need to. Therefore, in the conventional apparatus, the 4
Four pressing springs are arranged on the top cover at positions corresponding to the four corners, and means for pressing and fixing the developing device unit is provided. However, when the means for pressing and fixing and holding the four springs provided on the top cover with respect to the developing device unit is used, it is necessary to accurately position the pressing spring provided on the top cover, and the number of parts is also increased. There is also the problem of increasing the number.

The present invention solves the above-mentioned problems of the conventional apparatus, and improves the drive transmission mechanism for the developing unit when the apparatus is formed by combining the photosensitive drum unit and the developing unit. By
An object of the present invention is to provide a device capable of reducing the number of pressing springs provided on the top cover.

[0006]

SUMMARY OF THE INVENTION The present invention is a combination of a photoconductor unit having a photoconductor drum, a developing unit having a toner container portion and a developing roller, and the photoconductor unit and the developing unit. The present invention relates to an image recording apparatus in which a process unit having a fixed holding unit that holds the apparatus in a fixed state is detachably attached to the apparatus main body. According to a first aspect of the invention, the fixing and holding means inserts the photosensitive drum shaft and the pin arranged above the drum shaft into the concave grooves of the pair of support plates arranged on both sides of the developing device unit. While the drum shaft is positioned at the bottom of the groove, the pin is pressed downward by a hook member provided in the groove to fix and hold the photoconductor unit and the developing device unit, In order to mount the developing unit on the main assembly of the apparatus, positioning means projecting on both sides of the developing unit is provided, and the positioning means is positioned on the main body of the apparatus, so that the developing unit is disposed on the outer surface of one end of the developing unit. At the position where the transmission gear meshes with the main body output gear, the gear is provided so as to rotate downward at the meshing part, and the drum bearing groove provided in the main body of the device and the support Characterized in that as a state in which the concave grooves of the plate overlap.

According to a second aspect of the present invention, the process unit in which the developing unit and the photoconductor unit are combined is positioned in the apparatus main body through positioning means provided so as to project on both sides of the developing unit, The developing unit is pressed and held by an elastic body arranged on a top cover that is openably and closably provided on the upper part of the main body of the apparatus, and the developing unit rotates around a support pin inserted into a pin receiving groove as a positioning means provided on the main body of the apparatus. The elastic body, which is provided so as to be possible on the top cover, excludes a portion from the main body output gear arranged on the apparatus main body side, which is drive-transmitted by the transmission gear arranged on the outer surface of the one side end portion of the developing unit. It is characterized in that the three corners are arranged so as to be pressed respectively.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, an image recording apparatus to which the apparatus of the present invention can be applied will be described with reference to FIG.
The image recording apparatus 1 shown in FIG. 1 is configured as a small-sized image forming apparatus. A main body 2 of the apparatus is equipped with a paper feed cassette accommodating paper of an arbitrary size, and conveys the paper. Means for sending out toward the path 3 are provided. The sheet conveying path 3 is formed between the upper frame 4 of the main body 2 and the upper guide plate 5, and the sheet is conveyed toward the image transfer portion by the conveying roller device 6 which functions as a registration roller device. Then, the toner image formed on the photoconductor drum 65 is transferred to a sheet by the potential difference between the toner image and the transfer roller 71, and is sent to the fixing device. In the present embodiment, the image forming unit 8 of the image recording apparatus is
Two units, that is, the developing unit 30 and the photoconductor unit 60, are provided in combination, and the two units are attached to the positioning means provided in the image forming portion of the apparatus main body, as described later.

The two units are detachably provided via a portion of a top cover 10 which is openably and closably provided on an upper portion of the apparatus main body. One end of the top cover 10 is supported by using a hinge portion 11 provided on an upper frame of the apparatus body as a fulcrum, and a lock member 12 is provided on the other end of the top cover 10. The lock member 12 is composed of a lever 14 supported by a support shaft 13 and an engagement claw 15, and the engagement claw 15 is locked to the engagement shaft 16 of the main body of the apparatus to fix the top cover 10 to the top cover 10. Secure in closed position. Further, on the lower surface of the top cover 10, a pressing spring 17 is provided at a position corresponding to a corner of the upper surface of the developing device unit.
By holding the top cover in the closed position, the developing unit is pressed and held via the pressing springs 17 ...

2 arranged in the image forming section 8 of the apparatus main body
The developing unit 30 of the two units has an appearance as shown in the plan view of FIG. 2 and the front view of FIG. 3, and the pressing springs 17 and 1 provided on the top cover are provided at the corners of the upper surface.
7a ... Are engaged with each other. As shown in FIGS. 2 and 3, a plurality of ribs are provided on the upper side of the main body frame of the developing device unit 30 so as to project in parallel on the side faces in the upstream and downstream directions of the sheet conveyance direction to reinforce the container portion. A handle member 31 for improving the handleability of the unit,
31a. Support pins 38, 38a are provided on the side frames 37, 37a arranged on the side portions of the frame member so as to project outward, and are used as mounting and positioning means for the image recording apparatus main body via the support pins. Further, the developing device unit 30 includes
A pair of support plates 40 and 40a are provided integrally with the frame so as to be positioned on the downstream side in the sheet conveying direction when mounted on the image recording apparatus. The supporting plates 40 are arranged in a state of being extended from the side frame 37 of the developing device unit, and are used for locking and holding the recessed groove for accommodating the drum shaft of the photoconductor unit 60 described later and the mounted shaft. And a hook member.

The developing unit 3 shown in FIGS.
0, as shown in FIG. 1, a stirring member (paddle member) 33 for supplying the toner to the supply roller 34 while stirring the toner is provided inside the container portion 32. Further, a supply roller 34, a developing roller 35 in contact with the photosensitive drum 65, and a layer thickness regulating member 36 in contact with the developing roller 35 are provided on the toner discharge side from the container portion 32. The supply roller 34 can be configured as an elastic roller having a sponge-like elastic body having electroconductivity or a flocked body having electroconductive fibers with a predetermined thickness provided on the shaft. A bias voltage of -600 to -700V, preferably about -650V, is applied to the supply roller 34 from a power supply member (not shown) via a shaft.

The developing roller 35 comprises a roller shaft made of metal such as stainless steel and coated with conductive rubber (silicon rubber, urethane rubber, NBR) to a predetermined thickness, and the roller surface is Make it smooth. A bias voltage having a value of about −300 to −400V, preferably about −350V is applied to the developing roller 35. Further, the layer thickness regulating member 36 arranged with respect to the developing roller 35 is for uniformly setting a thin layer of toner formed on the surface of the developing roller 35, and is made of an elastic material such as a urethane resin sheet or stainless steel. It is composed of a plate member. And, for the layer thickness regulating member 36, -600V to-
A bias voltage in the range of 700V, preferably about -650V, is applied.

The distance between the axes of the supply roller 34 and the developing roller 35 is set to be slightly smaller than the sum of the radii of the two rollers, and both rollers are rotated in the same direction (the arrow X direction). The roller contact portion is pressed and slid in the opposite direction. That is,
At the contact portion between the supply roller 34 and the developing roller 35,
Since both rollers slide in a pressure contact state, there is a large resistance in the sliding portion of the rollers, so the driving force for both rollers is large compared to the case where the two rollers are simply rotated without pressure contact. It has the feature that it must be set to a value. In the developing device unit, due to the frictional action of both rollers and the voltage difference applied to both rollers, the toner is charged between both rollers, and the toner is attached to the surface of the developing roller 35. Then, the toner attached to the surface of the developing roller 35 is formed into a thin layer having a uniform thickness by the layer thickness regulating member 36, and is exposed toward the photosensitive drum to expose the electrostatic drum formed on the photosensitive drum. Toner is transferred to the latent image to form a toner image.

The photoconductor unit 60 arranged in combination with the developing unit 30 includes a photoconductor drum 65 and
A charging roller 67 such as a brush roller whose surface is formed of a flocked member is arranged. Then, an image is written by the writing unit 70 arranged on the photoconductor drum 65, and the toner image formed on the photoconductor drum is transferred onto the sheet by the discharge of the transfer roller 71. Further, the writing unit 70 is composed of an LED head array, and causes the LED to emit light based on the information from the image information output device to irradiate the photoconductor drum with light. The surface of the photoconductor drum 65 is made of a grounded photoconductor, and is -750 V by a charging roller 67.
Is charged, and the potential of the portion irradiated with light from the writing unit 70, that is, the portion of the image information with respect to black becomes approximately −50V. Then, a potential difference occurs between the light-irradiated portion and the non-irradiated portion (the portion corresponding to white in the image information),
It is formed as an electrostatic latent image corresponding to image information.

When the toner adhering to the surface of the developing roller 35 comes into contact with the electrostatic latent image formed on the photoconductor drum in a state of being charged to about -650V, the toner is transferred to the photoconductor drum. 65 is sucked onto the light irradiation site on the surface,
A toner image is formed on the surface of the photosensitive drum (reverse development). At this toner image transfer position, a bias voltage of 500 V to 2 kV is applied by the transfer roller 71 located on the back surface of the paper, and the toner image is transferred to the paper. The sheet on which the toner image has been transferred is sent toward the fixing device by the rotation of the photoconductor drum, and the fixing device is heated and pressed to fix the sheet to complete a copy. Further, after the toner image is transferred onto the paper, the toner remaining on the surface of the photoconductor drum is disturbed by the charging roller 67 and dispersed on the surface of the photoconductor drum, and at the same time, the toner remains on the surface of the photoconductor drum. It is charged to the same potential. Then, at the position where the photosensitive drum is in contact with the developing roller 35, the residual toner is transferred to the developing roller 35 side due to the potential difference between the two, and is mixed with the toner newly supplied from the container portion and reused.

In combination with the developing device unit 30,
The photoconductor unit 60 mounted on the image forming unit of the image recording apparatus is a body frame 6 made of a plastic material.
1, a side frame is integrally provided, a metal drum shaft 66 is supported via a bearing member, and a photosensitive drum 65 is provided on the drum shaft. In addition to projecting the end of the drum shaft 66 outside the side frame,
The pin member 63 is provided on the upper part of the pin member 63 so as to project at a predetermined interval, and serves as a positioning means for the image recording device and the developing device unit. Further, a handle member 62 is provided above the main body frame 61 of the unit 60 so that it can be used as a handling member when attaching and detaching the photoconductor unit.

[0017]

EXAMPLE As described above, the sheet metal frame 20 shown in FIG. 4 is mounted on the image forming portion of the apparatus main body in order to mount the two units on the image recording apparatus and to position the units relative to each other. It is placed on the inner surface of the body frame. The sheet metal frame 20 is made of a conductive metal plate, and includes a pin receiving groove 21 and a drum bearing groove 22.
Two concave grooves that open toward the upper part are provided, and a main body output gear 23 used for driving transmission to the developing device unit 30 is arranged so as to project from the unit mounting portion. FIG. 5 shows a case where two units are arranged in combination with the sheet metal frame 20. First, the support pins 38 of the developing unit 30 are mounted in the pin receiving grooves 21 of the sheet metal frame 20. By doing so, the developing device unit 30 is positioned with respect to the image forming portion. In this state, the support plate 40 of the developing device unit 30
The recessed groove 41 provided in the sheet metal frame 20 and the drum bearing groove 22 of the sheet metal frame 20 overlap each other.

When the photoconductor unit 60 is attached to the developing device unit 30, the concave groove 4 of the support plate 40 is used.
The end portion of the drum shaft 66, which is arranged so as to project on the side portion of the photoconductor unit 60, is inserted in 1, and the drum shaft 66 is positioned at the bottom portions of the two concave grooves 41 and 22. In this state, since the upper pin 63 arranged on the upper part of the drum shaft 66 is located on the upper part of the concave groove 41, the upper pin 63 is pressed diagonally downward by the hook member 42. Becomes Then, the two protruding members 6 of the photoconductor unit
3, 66 are immovably fixedly held in the concave groove 41 of the supporting plate 40, so that the photoconductor unit 60 is detachably combined with the developing device unit 30 and mounted on the image recording apparatus main body. Will be.

As described above, by positioning the developing unit in the image forming portion of the image recording apparatus, the main body output gear 23 arranged on the sheet metal frame 20 is
The transmission gear 51 provided in the drive transmission portion of the developing device unit is engaged. Then, the agitating member 33, the supply roller 34, and the developing roller 35 provided in the developing unit are driven via the transmission gear 51 that meshes with the main body output gear 23. The example shown in FIG.
2 shows the structure of the drive transmission portion 50 of the developing device unit as seen from the rear side of the supply roller gear 52 and the development roller gear 5 via the transmission gear 51 meshing with the main body output gear 23.
3 is transmitted to the idler gear 54. Also, the idler gear 54 is coaxial with the paddle drive gear 5
5 are arranged, and the stirring member 3 is arranged via the paddle gear 56.
Rotate 3 at low speed. In the drive transmission portion 50 provided in the developing device unit, as described above, at the contact portion between the supply roller 34 and the developing roller 35, since both rollers slide in a pressure contact state, the rollers slide. Since there is a large resistance in the section, it is necessary to set the driving force for both rollers to a large value. Therefore, a large resistance acts on the meshing portion between the transmission gear 51 of the drive transmission portion 50 and the main body output gear 23.

In response to the above-mentioned problems, in the example of driving the drive transmission portion shown in FIG. 6, the main body output gear 2
The meshing portion of 3 and the transmission gear 51 sets the rotation direction of both gears in the direction in which a downward force acts on the frame of the developing device unit 30. As shown in FIG. 5, the downward force at the meshing portion between the transmission gear 51 provided in the developing unit and the main body output gear 23 causes the unit 30 to rotate clockwise with the support pin 38 as the center. It becomes a state that acts as a force to rotate. Therefore, a force F that presses the frame downward is applied to the rear portion of the frame of the developing device unit (portion on the upstream side in the paper transport direction).

As described above, if the reaction force due to the engagement between the main body output gear 23 of the apparatus main body and the transmission gear 51 of the drive transmission portion provided in the developing device unit is utilized, the developing device unit 30 of the present invention can be used. As a result, even if the pressing spring is not arranged at the position indicated by reference numeral 17c in FIG. Further, in the present embodiment, in the pressing spring arranged on the lower surface of the top cover 10, the pressing spring (the portion corresponding to the pressing spring 17c) where the pressing force acts due to the engagement of the drive gears is omitted. Will be possible. Therefore, the other three
By arranging the pressing springs 17 ... 17a and 17b respectively at the corners of the upper surface of one developing device unit, the developing device unit can be fixedly held in the apparatus. It is possible to simplify the configuration of the top cover by reducing the number of.
Further, as the pressing spring provided on the top cover, a plate spring bent into a predetermined shape is used, but in addition, if the developing unit can be pressed and held,
It is also possible to use any other elastic body.

In the embodiment of the present invention, the combination of the structure of the developing unit and the gear arranged in the drive transmission portion can be set arbitrarily. At the position where the transmission gear of the drive transmission unit meshes with the output gear of the device body,
It is possible to set the direction in which the transmission gear rotates downward at the meshing portion of both gears. Then, by setting the state in which the upward reaction force acts on the frame of the developing device unit,
The number of pressing springs that press the developing device unit can be reduced. Further, the downward force F generated in the developing device unit also acts on the position of the pressing spring 17b in FIG. 2, but when the developing device unit is relatively long, the pressing spring 17b is pressed. At the position corresponding to, a large reaction force (downward force) may not be expected. Therefore, in order to stably support the developing device unit on the apparatus main body, as shown in FIG.
Two pressing springs should be placed on the top cover. In addition,
In the above embodiment, the case where the image recording apparatus is configured has been described, but the apparatus of the present invention can also be applied to the case where the facsimile apparatus is configured by combining the image reading unit and the image information transmitting unit.

[0023]

With the above-described structure, in the image recording apparatus, the direction of rotation of the transmission gear is set so that the outer surface of one end of the developing device unit faces downward due to gear engagement. Is applied, the drive transmission to the developing unit can be favorably performed. Further, it is not necessary to dispose a pressing spring on the top cover for one corner of the developing device unit to which a downward force due to gear engagement is applied, and the structure of the pressing and holding mechanism for the unit can be simplified. . Further, in the developing device unit, a pair of supporting plates that are arranged so as to project in parallel to the photoconductor unit side are provided, and the photoconductor unit is detachably held via the support plates. Can be easily positioned with respect to. Further, it is possible to dispose the two units in combination in the image forming portion of the image recording apparatus, and to attach / detach the photoconductor unit together with the developing device unit, so that the operation at the time of processing such as paper jam can be easily performed. it can.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of an image forming unit in which a developing unit and a photoconductor unit are combined.

FIG. 2 is a plan view of a developing device unit used in the present invention.

FIG. 3 is a front view of the developing device unit shown in FIG.

FIG. 4 is an explanatory diagram of a sheet metal frame arranged in the apparatus main body.

FIG. 5 is an explanatory diagram showing a state in which two units are combined via a sheet metal frame.

FIG. 6 is an explanatory diagram of a drive transmission portion arranged in the developing device unit.

[Explanation of symbols]

1 image recording device, 10 top cover, 12
Lock member, 17 pressing spring, 20 sheet metal frame, 21 pin receiving groove, 22 drum bearing groove, 23 main body output gear, 30 developing device unit, 34 supply roller, 35 developing roller, 3
8 support pins, 40 support plates, 41 recessed grooves,
42 hook member, 50 drive transmission part, 51
Conduction gear, 52 supply roller gear, 53 developing roller gear, 54 idler gear, 55 paddle drive gear, 56 paddle gear, 60 photoconductor unit, 61 main body frame, 63 upper pin, 6
5 photoconductor drum, 66 drum shaft, 67
Charging roller, 70 writing unit, 71 transfer roller.

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 15/08

Claims (2)

(57) [Claims] 1. A photoconductor unit having a photoconductor drum, a developing device unit having a toner container portion and a developing roller, and a fixed holding device which holds the photoconductor unit and the developing device unit in combination. In the image recording apparatus, the process holding unit including a process unit and the process unit including the process unit is detachably attached to the apparatus main body, and the fixed holding unit includes the photosensitive unit in a concave groove of a pair of support plates arranged on both sides of the developing unit. Insert the body drum shaft and the pin arranged on the upper part of the drum shaft, press the pin downward by the hook member provided in the concave groove with the drum shaft positioned in the concave groove bottom part, The photoconductor unit and the developing device unit are fixedly held, and in order to mount the developing device unit on the main body of the apparatus, positioning means protruding to both sides of the developing device unit is provided. By arranging the positioning means in the main assembly of the apparatus, at the position where the transmission gear arranged on the outer surface of the one end of the developing device unit meshes with the output gear of the main body, the meshing portion rotates downward. An image recording apparatus, wherein a drum bearing groove provided in the apparatus body and a concave groove of the support plate overlap each other. 2. The process unit, which is a combination of the developing unit and the photoconductor unit, is positioned above the apparatus main body in a state of being positioned in the apparatus main body by positioning means provided so as to project on both sides of the developing unit. The developing unit is pressed and held by an elastic body arranged on an openable and closable top cover, and the developing unit is rotatably provided with a support pin inserted into a pin receiving groove as a positioning means provided on the apparatus main body as a fulcrum. The elastic body provided on the top cover has three corners excluding a portion which is drive-transmitted from a main body output gear arranged on the apparatus main body side by a transmission gear arranged on an outer surface of one side end portion of the developing unit. The image recording apparatus according to claim 1, wherein the image recording apparatuses are arranged so as to press each.