JPH04268576A - Image forming device - Google Patents

Abstract

PURPOSE:To obtain an image forming device in which a photosensitive unit and a developing unit which can be attached/detached are surely positioned. CONSTITUTION:In the developing unit 6, a developing sleeve driving gear 13 is set as a planet gear so that the gear 13 may abut on a gear 8 to be driven by the developing sleeve after inserting a supporting point 15 in a guide 11, and in the photosensitive unit 3, a guide 105 is such formed that a rotational center shaft 14 moves in a direction where it separates from the developing unit 6 as the shaft 14 is inserted in the guide 105. The supporting point 15 and the shaft 14 are made to easily get in the deep parts of the guides 11 and 105, respectively, so that they are positioned in the deepest parts of the guides 11 and 105.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus.

0002

2. Description of the Related Art Printers using electrophotography have made remarkable progress in recent years. An image forming apparatus using this electrophotographic method will be described below with reference to the drawings.

FIG. 5 is a schematic configuration diagram of a conventional image forming apparatus in which the upper body is in an open state and a photoreceptor unit and a developing unit are installed, and FIG. 6 is a schematic diagram of a conventional image forming apparatus in which the upper body is in a closed state and a photoreceptor FIG. 7 is a schematic diagram of the main parts of the conventional image forming apparatus shown in FIG. 6. FIG. 8 is a schematic diagram showing the engagement of the driven gear and drive gear of the photoreceptor unit. FIG. 9 is a schematic diagram for explaining the engagement between the driven gear and the driving gear of the developing unit.

Reference numeral 1 denotes a lower body, and an upper body 2 is rotatably attached to the lower body 1. Reference numeral 3 denotes a photoreceptor unit, which includes a photoreceptor 4, a photoreceptor driven gear 5 (hereinafter referred to as a driven gear), a charger 19, a cleaning device 20, and the like. A developing unit 6 includes a developing sleeve 7, a developing sleeve driven gear 8 (hereinafter referred to as driven gear), a developing sleeve 9, and the like.

[0005] The photoreceptor unit 3 and the developing unit 6 are maintenance units, and are to be replaced by the user etc. when each reaches a certain set lifespan.
, 6 are removable in the direction of the arrow in the figure along guides 10, 11 provided on the lower body 1, and the respective units 3, 6 are detachable in the direction of the arrow in the figure.
6 is attached and removed with the upper body 2 open to the lower body 1.

A driven gear 5 provided on the photoreceptor unit 3 meshes with a photoreceptor drive gear 12 (hereinafter referred to as a drive gear) of the lower body 1 when the photoreceptor unit 3 is attached to the lower body 1. The drive gear 12 drives the drive gear 12 to rotate the drive gear 12 . Similarly, when the developing unit 6 is attached to the lower body 1, the driven gear 8 provided in the developing unit 6 is connected to the developing sleeve drive gear 13 (hereinafter referred to as the drive gear) of the lower body 1. ) and is driven to rotate.

[0007] The positional relationship between the driven gear 5 and the driving gear 12, and between the driven gear 8 and the driving gear 13 are at their respective centers O1 and O2.
, O3 and O4 are arranged at an angle θ which is larger than the meshing pressure angle α of the gears, so the driven gears 5 and 8 are subjected to forces F and P perpendicular to the tooth surfaces. Become. For this reason, a downward force acts on the photoconductor unit side due to the vertical component F1 of the force F, and the rotation center axis 1 of the photoconductor unit 3
4 is pressed against the bottom of the guide 10 and engaged, the position of the photoreceptor 4 is determined, and the driven gear 5 and the driving gear 12
Drive is transmitted while the distance between the shafts is always kept constant.

The developing unit 6 receives a vertical component P1 of the force P.
As a result, a downward force is exerted, and the fulcrum 15 of the developing unit 6 is pressed against the bottom of the guide 11, and the mating position is determined. Further, in the developing unit 6, since the center of the driven gear 8 and the fulcrum 15 are located at different positions, the force P causes a rotational moment M in the direction of the photoreceptor unit 3 to be applied around the fulcrum 15.

Using this rotational moment M, the photoreceptor 4
The developing sleeve 7 is abutted against the developing sleeve 7 through a spacer 16, thereby controlling the gap G between the photoreceptor 4 and the developing sleeve 7, which is important during image formation. Note that the distance between the shafts of the driven gear 8 and the driving gear 13 is determined by the fulcrum 15 and the abutting position of the photoreceptor 4 and the developing sleeve 7.

With the above configuration, when the unit is installed,
It is possible that the tips of the teeth of the driven gear and the driving gear are touching each other and are not meshing properly. When driving starts with the tips of the teeth touching each other, each unit 3, 6 is pushed up by upward resistance from the tips of the drive gear teeth. For this reason, each unit has a spring member 17 provided on the upper body 2.
, 18 is configured to press downward. Therefore, as soon as the driving gear is rotated, it can mesh with the driven gear.

[0011]

[Problems to be Solved by the Invention] However, in the conventional configuration described above, when the tips of the teeth of the driven gear and the driving gear are in contact with each other, there is a phenomenon that the position of the unit cannot be determined until after driving has started. As a result, there were the following problems. FIGS. 10 and 11 are schematic configuration diagrams for explaining the problems of the conventional image forming apparatus, and the explanation will be given below based on the figures.

The first problem is that the driven gear 8 of the developing unit 6 is fully engaged with the drive gear 13 when the unit is installed, but the driven gear 5 on the photoreceptor unit side has its tooth tips aligned with the drive gear 12. It occurs when the teeth are touching but not meshing. In other words, when the driving of both units starts in this state, the position of the fulcrum 15 of the developing unit 6 is first determined, and the developing sleeve 7 moves toward the photoconductor unit in an attempt to contact the photoconductor 4, but the object it comes into contact with is Since the position of the photoreceptor 4 is not determined, the photoconductor 4 ends up going beyond the normal abutting position.

Thereafter, the photoreceptor unit 3 attempts to determine its position and descends downward so as to be pressed against the bottom of the guide 10. At this time, the photoreceptor 4 of the photoreceptor unit 3 attempts to push the developing unit 6 back toward the anti-photoreceptor unit side via the spacer 16 and the developing sleeve 7. However, since the developing unit 6 has already started to be driven and cannot be returned in the direction opposite to the photoreceptor unit, there is a risk that the photoreceptor 4 may stop at a halfway position (see Fig. 10).
reference).

Next, the second problem is that the driven gear 5 of the photosensitive unit 3 has completed meshing with the driving gear 12 when the unit is installed, but the driven gear 8 on the developing unit 6 side has teeth that are aligned with the driving gear 13. This occurs when the teeth are touching but not meshing. That is, when driving of both units begins in this state, first the position of the rotation center axis 14 of the photoreceptor unit 3 is determined. Thereafter, the position of the fulcrum 15 of the developing unit 6 is about to be determined, and the developing sleeve 7 moves toward the photoreceptor unit so as to abut against the photoreceptor 4. Here, the position of the photoreceptor 4 is determined, and the position of the drive gear 13 is determined with respect to the lower main body 1, so the developing sleeve 7 (
The spacer 16 and the developing sleeve gear 9 (coaxial) cannot be set in the correct position unless they are inserted straight between them together with the driven gear 8. However, since the developing unit 6 is subjected to a rotational moment M around the fulcrum 15, it cannot be inserted between the two, and as a result, the developing sleeve 7 is
There was a fear that it would climb onto the photoreceptor 4 as shown in 1. When the above-mentioned problems occur, the mutual positional relationship of the image forming processes becomes disjointed, and there is a possibility that normal image forming operations cannot be performed.

Therefore, it is an object of the present invention to provide an image forming apparatus that can solve the conventional problems as described above.

[0016]

[Means for Solving the Problems] To this end, the present invention provides a system that responds to the opening and closing operations of a lower body having a drive system and an upper body configured to be able to open and close with respect to the lower body, and when the upper body is brought into an open state. When the developing sleeve drive gear provided on the lower main body is retracted from the position of the developing sleeve driven gear provided on the developing unit that is removably attached to the lower main body with which it is engaged, and the developing sleeve driven gear is placed in a closed state, the developing sleeve driven gear returns to the engaged position. The photoreceptor drive gear provided on the lower body is connected to the photoreceptor driven gear provided on the photoreceptor unit so that the guiding direction of the first guide means, which has a gear moving means and guides the attachment of the photoreceptor unit to the lower body, is determined by the photoreceptor driving gear provided on the lower body. The image forming apparatus is configured such that the direction of the force applied to the tooth surface of the photoconductor driven gear is approximately the same as the direction of the force that is applied when the photoconductor driven gear is rotationally driven.

[0017]

[Operation] With the above structure, the fulcrum positioning of the developing unit is completed when it is attached to the lower main body. Further, since the developing sleeve driven gear and the developing sleeve driving gear of the developing unit are not in contact with each other, the developing unit can freely rotate about the fulcrum. On the other hand, the direction of the guide of the photoreceptor unit in the lower body is approximately the same direction as the direction of the positioning force of the photoreceptor unit to the lower body, and the positioning operation of the photoreceptor unit is such that the developing unit that is in contact with the photoreceptor through the spacer Accordingly, the direction is such that it will not be pushed back toward the anti-photoreceptor unit.

When the photoreceptor unit is mounted there and the tooth tips of the photoreceptor driven gear and the photoreceptor driven gear mesh without touching each other, if the center of gravity of the developing unit is on the opposite side of the photoreceptor unit from the fulcrum, the development will be completed. Since the sleeve is tilted past the final abutment position with the photoreceptor toward the photoreceptor unit, the two are positioned at the time of mounting the photoreceptor unit.

On the other hand, if the center of gravity of the developing unit is closer to the photoreceptor unit than the fulcrum, the upper body is closed and the developing sleeve driven gear and the developing sleeve driving gear come into contact and start driving, thereby positioning them. . If the teeth of the photoconductor driven gear and the photoconductor drive gear do not come into contact with each other, when the upper body is closed and the developing sleeve driven gear and the developing sleeve drive gear come into contact and start driving, the guide direction of the photoconductor unit will change. Since it is in the direction mentioned above,
The developing unit is not pushed back by the action that determines the position of the photoreceptor unit. In other words, since the photoreceptor and the developing sleeve are positioned in the same direction, both units can be positioned reliably. Due to the above operations, normal image forming operation is performed.

[0020]

Embodiments Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of an embodiment of the present invention in which the upper body is in an open state, a photoreceptor unit and a developing unit are attached, and a driven gear and a driving gear are engaged.
is a schematic configuration diagram of an embodiment of the present invention in which the upper body is in an open state, a photoreceptor unit and a developing unit are attached, and the driven gear and the driving gear do not mesh and their tooth tips touch each other;
FIG. 3 is a schematic configuration diagram of an embodiment of the present invention in which the upper body is in a closed state and a photoreceptor unit and a developing unit are attached and driven, and FIG. 4 is a state in which the upper body of an embodiment of the present invention is in an open state. FIG. 2 is a schematic configuration diagram of a state in which only a developing unit is attached. Components that are the same as those of the conventional device shown in FIGS. 5 to 11 are given the same reference numerals, redundant explanations will be omitted, and points different from the conventional device will be described below.

When the upper body 2 is open with the developing unit 6 attached to the lower body 1, as shown in FIG. The plate 102 is fixed to the lower body 1 with a fulcrum 107 as the center of rotation, and is pushed counterclockwise in the figure by a cam 101 that is biased downward by a coil spring 100, and the supporting drive gear 13 is driven. It is forcibly separated from gear 8.

When the upper body 2 is closed, the cam 101 is pushed by the protrusion 103 of the upper body 2 and separates from the gear support plate 102, as shown in FIG. The gear support plate 102 from which the cam 101 is separated is biased clockwise in the figure by the coil spring 104 so that the driving gear 13 meshes with the driven gear 8, and the meshing is officially completed when driving starts.

[0023] Photosensitive unit 3 provided in the lower main body 1
The guide 105 first moves between the position where the tooth tips of the driven gear 5 and the driving gear 12 touch each other to the final meshing position (
2 and 1) is approximately the same direction as the direction of the positioning force (F) applied to the photoconductor unit 3, and the rotation center axis 14 of the photoconductor unit 3 is positioned between the positions shown in FIGS. The developing unit 6 that is abutting against the photoreceptor unit 4 is oriented in such a way that it is not pushed back toward the side opposite to the photoreceptor unit when the photoreceptor unit 3 is positioned.

As a result, from the unit mounting entrance of the guide 105 to the position where the tooth tips of the driven gear 5 and the driving gear 12 touch each other, the final positioning center O1 of the rotation center shaft 14 of the photoreceptor unit 3 (the final positioning center of the driven gear 5 (same position as the center of the meshing position), it will pass closer to the developing unit 6 (
If the position where the tooth tips of the driven gear 5 and the drive gear 12 contact each other is on the side of the developing unit 6 from the final positioning center O1 of the rotation center shaft 14 of the photoreceptor unit 3, the unit installation entrance does not have to be on the side of the developing unit 6. good).

The operation of the image forming apparatus of the present invention having the above configuration will be explained below. First, when the upper main body 2 is opened and the developing unit 6 is installed, the fulcrum 15 of the developing unit 6 is positioned at the bottom of the guide 11 provided on the lower main body 1. Furthermore, since the center of gravity of the developing unit 6 is on the anti-photoreceptor unit side with respect to the fulcrum 15, and the driven gear 8 and the driving gear 13 are not in contact with each other, the center of gravity of the developing unit 6 is centered on the fulcrum 15 on the photoreceptor unit side (clockwise in the figure). As a result of the rotational moment, the final abutment position with the photoreceptor 4 is moved beyond the photoreceptor unit side to a developing unit stopper (not shown) (see FIG. 4).

When the photoreceptor unit 3 is installed along the guide 105 of the lower main body, the guide 105 passes from the entrance to the tip of the drive gear 5 toward the developing unit 6 from the final positioning center O1, and As mentioned above, since the developing unit 6 has passed the final contact position with the photoconductor 4 toward the photoconductor unit side, the photoconductor 4 of the photoconductor unit 3
The developing unit 6 is rotatable around the fulcrum 15.
The developing sleeve 7 is easily inserted while being pushed back toward the anti-photoreceptor unit via the spacer 16.

However, from there, that is, from the position where the tips of the driven gear 5 and the driving gear 12 touch each other to the final meshing position, when the driven gear 5 and the driving gear 12 smoothly mesh according to the unit mounting operation, the tips of the teeth do not meet each other. Two states occur when they touch but do not mesh, resulting in the following two operations.

First, the former case (FIG. 1) will be explained. In this case, since the driven gear 5 and the driving gear 12 mesh smoothly according to the unit mounting operation, the photoconductor 4 of the photoconductor unit 3 and the developing sleeve 7 of the developing unit 6 both move toward the final positioning center O1 of the rotation center shaft 14. Go in and complete positioning. After that, when the upper body 2 is closed, the driven gear 8 and the driving gear 13 come into contact with each other due to the above-described mechanism, and both units 3 and 6 are moved by the spring members 17 and 18.
When the unit is pressed downward and driving starts, the positions of both units have been determined, and the image forming operation starts normally.

Next, the latter case (FIG. 2) will be explained. In this case, the tooth tips of the driven gear 5 and the driving gear 12 touch and do not mesh, so the photoconductor 4 of the photoconductor unit 3 and the sleeve 7 of the developing unit 6 both move toward the final positioning center O1 of the rotation center shaft 14. He tries to move in, but he stops where the tip of his teeth hits him. After that, when the upper body 2 is closed, the driven gear 8 is activated by the mechanism described above.
and the drive gear 13 come into contact with each other, and both units 3 and 6 are pressed downward by spring members 17 and 18.

When driving starts, the developing unit 6 moves to the fulcrum 1.
5 and tries to move toward the photoreceptor unit by receiving a rotational moment M due to a force P. On the other hand, the photoreceptor unit 3 also attempts to move toward the final positioning center O1 due to the force F. Here, since the guide 105 is oriented in the direction described above, the development unit 6 is not pushed back by the operation of the photoreceptor unit 3. Further, the direction of the abutting force of the developing sleeve 7 against the photoconductor 4 due to the rotational moment M and the direction of action of the force F are almost the same, and the direction of the positioning operation of the photoconductor unit 3 due to the force F and the direction of the guide 105 are approximately the same. Almost identical.

As described above, since the direction of movement and the direction of the force applied to both units 3 and 6 are almost the same, they are reliably positioned without interfering with each other's movements, and normal image formation is possible. The operation begins.

[0032]

As explained above, the present invention responds to the opening/closing operation of the lower body having a drive system and the upper body configured to be able to open and close with respect to the lower body, and when the upper body is opened, the lower body opens and closes. The developing sleeve drive gear installed in the main body is
The developing sleeve driven gear retracts from the position of the developing sleeve driven gear provided in the developing unit that is removably attached to the lower body that is engaged with the lower body, and returns to the engaged position when the developing sleeve is in a closed state, and the photosensitive unit is moved to the lower body. When the photoconductor driving gear provided on the lower body rotationally drives the photoconductor driven gear provided on the photoconductor unit, the guiding direction of the first guide means for guiding the mounting is determined by the tooth surface of the photoconductor driven gear. Since the image forming apparatus is configured in approximately the same direction as the direction of the force applied to the photoconductor unit, the positioning of the photoreceptor unit and the developing unit can be performed accurately under any circumstances, eliminating the problem of poor positioning of both units. This has the effect of reliably resolving problems such as inability to perform normal image forming operations.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention in which the upper body is in an open state, a photoreceptor unit and a developing unit are attached, and a driven gear and a driving gear are engaged;

FIG. 2 is a schematic configuration diagram of the embodiment of the present invention in which the upper body is in an open state, a photoreceptor unit and a developing unit are attached, and the driven gear and driving gear do not mesh and their tooth tips touch each other.

FIG. 3 is a schematic configuration diagram of the embodiment of the present invention in which the upper body is in a closed state and a photoreceptor unit and a developing unit are attached and driven.

FIG. 4 is a schematic configuration diagram of the embodiment of the present invention in which the upper main body is in an open state and only the developing unit is attached.

FIG. 5 is a schematic configuration diagram of a conventional image forming apparatus in which the upper body is in an open state and a photoreceptor unit and a developing unit are attached.

FIG. 6 is a schematic configuration diagram of a conventional image forming apparatus in which the upper body is in a closed state and a photoreceptor unit and a developing unit are attached.

FIG. 7 is a schematic configuration diagram of the main parts of the conventional image forming apparatus shown in FIG. 6;

[Fig. 8] A schematic configuration diagram for explaining the engagement between the driven gear and the driving gear of the photoconductor unit.

FIG. 9 is a schematic configuration diagram for explaining the engagement between the driven gear and the driving gear of the developing unit.

FIG. 10 is a schematic configuration diagram for explaining the problems of conventional image forming apparatuses.

FIG. 11 is a schematic configuration diagram for explaining the problems of conventional image forming apparatuses.

[Explanation of symbols]

1 Lower body 2 Upper body 3 Photoconductor unit 4 Photoreceptor 5 Photoconductor driven gear 6 Developing unit 7 Developing sleeve 8 Developing sleeve driven gear 11 Guide 12 Photoconductor drive gear 13 Developing sleeve drive gear 16 Spacer 107 Fulcrum

Claims (1)

[Claims] 1. A lower body comprising: a lower body having a drive system; an upper body configured to be openable and closable with respect to the lower body; a photoconductor; and a photoconductor driven gear transmitting driving force to the photoconductor; The rotational driving force of the photoreceptor is removable from the main body as guided by the first guide means, and the rotational driving force of the photoreceptor is caused by coupling and driving the photoreceptor driving gear and the photoreceptor driven gear of the lower main body.
and a photoreceptor unit that obtains a positioning force to the lower body, a developing sleeve and a developing sleeve driven gear that transmits a driving force to the developing sleeve, and is detachable from the lower body using a second guide means as a guide. At the same time, the connection and driving of the developing sleeve driving gear and the developing sleeve driven gear of the lower body generates rotational driving force of the developing sleeve, positioning force to the lower body, and abutting of the photoreceptor and the developing sleeve. and a developing unit that obtains a force, and the image forming apparatus is configured such that the photoreceptor unit and the developing unit are attached to and detached from the lower main body when the upper main body is in an open state with respect to the lower main body, When the upper main body is brought into an open state in response to the opening/closing operation of the upper main body and the lower main body, the developing sleeve driving gear retreats from the position of the developing sleeve driven gear in which it is engaged, and when the upper main body is brought into a closed state, the developing sleeve driven gear is moved to the engaged position. and a developing sleeve drive gear moving means, wherein the tooth surface of the photoreceptor driven gear receives the guiding direction of the first guide means when the photoreceptor driving gear rotationally drives the photoreceptor driven gear. An image forming apparatus characterized in that the image forming apparatus is set in substantially the same direction as the direction of force.