JP2018153948A - Drive mechanism and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive mechanism in which such a malfunction that the tooth tip of a unit-side gear collides with the tooth tip of a body-side gear hardly occurs when a detachable unit is attached to an image formation apparatus body, and provide an image formation apparatus.SOLUTION: There is provided a unit-side gear 40 which is engaged with a body-side gear 50 following the operation of attaching a process cartridge 10 (detachable unit) to an image formation apparatus body 100. The body-side gear 50 and the unit-side gear 40 are formed so as to satisfy such a relation that the tooth tip width A becomes A≤0.75×m/cosβ when a module is defined as m, and a torsion angle is defined as β.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a driving mechanism in which a main body side gear and a unit side gear are installed, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine or a printing machine including the driving mechanism. is there.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a technique is known in which a detachable unit such as a process cartridge or a fixing unit (fixing apparatus) is detachably attached to an image forming apparatus main body (for example, (See Patent Documents 1 and 2.)

Specifically, in Patent Documents 1 and 2, a detachable unit such as a process cartridge or a fixing unit (fixing device) is taken out from the image forming apparatus main body when a predetermined replacement cycle is reached or maintenance is performed. It is replaced with a new one (or one that has undergone maintenance). The detachable unit is provided with a unit side gear (gear) for rotating the roller member installed therein.
On the other hand, the image forming apparatus main body is provided with a main body side gear (gear) that rotates by receiving a drive from a driving source. As the detachable unit is attached to the image forming apparatus main body, the unit side gear meshes with the main body side gear. As a result, it is possible to drive the detachable unit mounted on the image forming apparatus main body.

  On the other hand, Patent Documents 1 and 2 disclose a main body side gear train (a drive system including a main body side gear) installed in the main body of the image forming apparatus for the purpose of improving the detachability of the detachable unit with respect to the main body of the image forming apparatus. )) Has been disclosed.

In the conventional image forming apparatus described above, since play is provided in the main body side gear train installed in the main body of the image forming apparatus, an effect of improving the detachability of the detachable unit with respect to the main body of the image forming apparatus can be expected.
However, in the conventional image forming apparatus, when the detachable unit is attached to the main body of the image forming apparatus, the tooth tip of the unit side gear may collide with the tooth tip of the main body side gear. For this reason, there is a possibility that a setting failure of the detachable unit with respect to the image forming apparatus body may occur.

  The present invention has been made to solve the above-described problems. When the detachable unit is mounted on the image forming apparatus main body, the tooth tip of the unit side gear and the tooth tip of the main body side gear collide with each other. It is an object of the present invention to provide a drive mechanism and an image forming apparatus that are less likely to cause such a problem.

  The drive mechanism according to the present invention is installed in the apparatus main body, and is installed in a main body side gear that rotates by receiving a drive from a drive source, and an attachment / detachment unit that is detachably installed on the apparatus main body. And a unit side gear that meshes with the main body side gear in accordance with the operation of mounting on the apparatus main body, and the main body side gear and the unit side gear both have a module as m and a twist angle β , The tip width A is formed so as to satisfy the relationship of A ≦ 0.75 × m / cos β.

  According to the present invention, when the detachable unit is attached to the main body of the image forming apparatus, the drive mechanism and the image forming are less likely to cause a problem that the tooth tip of the unit side gear and the tooth tip of the main body side gear collide with each other. An apparatus can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention from the side. FIG. FIG. 4A is a perspective view illustrating the image forming apparatus, and FIG. 4B is a perspective view illustrating the image forming apparatus in a state where the opening / closing cover is opened. FIG. 6 is a schematic diagram illustrating a state in which a unit side gear meshes with a main body side gear in accordance with the mounting operation of the process cartridge to the image forming apparatus main body. It is the schematic which shows the state in which the unit side gear and the main body side gear meshed normally, and (B) the schematic which shows the state in which the tooth tips of the unit side gear and the main body side gear collided. It is an enlarged view which shows the tooth profile of a gearwheel. It is a graph which shows the relationship between the dislocation coefficient of a gearwheel, and a tooth tip width. It is a graph which shows the relationship between the phase angle of a gearwheel, and the force produced at the time of mounting of a process cartridge.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the overall configuration and operation of the image forming apparatus 100 will be described with reference to FIG.
In FIG. 1, 100 is a printer as an image forming apparatus, 1 is a photosensitive drum on which a toner image is formed, 7 is a photosensitive drum that emits exposure light L based on image information input from an input device such as a personal computer. 1 shows an exposure part (writing part) to be irradiated on the top.
Reference numeral 9 denotes a transfer roller for transferring the toner image carried on the surface of the photosensitive drum 1 to the sheet P conveyed to the transfer nip portion (transfer position), and reference numeral 10 denotes the photosensitive drum 1, the charging roller 4, and the developing device 5. And a cleaning cartridge 2 are integrated into a process cartridge (detachable unit), and 12 is a paper feeding device (paper feeding cassette) in which a sheet P such as paper is stored.
Reference numeral 16 denotes a registration roller (timing roller) that conveys the sheet P toward the transfer nip where the photosensitive drum 1 and the transfer roller 9 abut, and 20 denotes a fixing device that fixes an unfixed image on the sheet P. 21 Denotes a fixing roller installed in the fixing device 20, 22 denotes a pressure roller installed in the fixing device 20, and 30 denotes a toner container containing toner.

Here, around the photosensitive drum 1, a charging roller 4, a developing device 5, a cleaning device 2, and the like are disposed. These members (the photosensitive drum 1, the charging roller 4, the developing device 5, and the cleaning device 2) are integrated as a process cartridge 10 (detachable unit), and are attached to the image forming apparatus main body 100. And is detachable (replaceable). The process cartridge 10 as a detachable unit is taken out from the image forming apparatus main body 100 (apparatus main body) when a predetermined replacement cycle is reached or maintenance is performed, and a new one (or maintenance is performed). The toner container 30 is detachably (replaceable) with respect to the image forming apparatus main body 100 above the process cartridge 10 (developing device 5). The toner container 30 contains toner (one-component developer). Then, toner is supplied from the toner container 30 toward the inside of the developing device 5. The toner container 30 is replaced with a new one when the toner accommodated therein becomes empty (or when the toner accommodated inside the developing device 5 becomes empty).

With reference to FIG. 1, an operation during normal image formation in the image forming apparatus 100 will be described.
First, when image information is transmitted from an input device such as a personal computer to the exposure unit 7 of the image forming apparatus 100, exposure light L (laser light) based on the image information is transmitted from the exposure unit 7 to the surface of the photosensitive drum 1. It is emitted toward.
On the other hand, the photosensitive drum 1 is driven by a drive motor 110 (drive source) installed in the image forming apparatus main body 100 and rotates in the arrow direction (clockwise). First, the surface of the photosensitive drum 1 is uniformly charged at the portion facing the charging roller 4 (this is a charging process). Thus, a charged potential (about −900 V) is formed on the photosensitive drum 1. Thereafter, the surface of the charged photosensitive drum 1 reaches the irradiation position of the exposure light L. Then, the potential of the portion irradiated with the exposure light L becomes a latent image potential (about 0 to −100 V), and an electrostatic latent image is formed on the surface of the photosensitive drum 1 (exposure process). .)

Thereafter, the surface of the photosensitive drum 1 on which the electrostatic latent image is formed reaches a position facing the developing device 5. Then, toner is supplied from the developing device 5 onto the photosensitive drum 1, and the latent image on the photosensitive drum 1 is developed to form a toner image (this is a developing step).
Thereafter, the surface of the photosensitive drum 1 after the development process reaches a transfer nip portion (transfer position) with the transfer roller 9. Then, a transfer bias (a bias having a polarity different from the polarity of the toner) is applied from the power supply unit to the transfer roller 9 at the transfer nip portion with the transfer roller 9, whereby the sheet conveyed by the registration roller 16. A toner image formed on the photosensitive drum 1 is transferred onto P (transfer process).

Then, the surface of the photosensitive drum 1 after the transfer process reaches a position facing the cleaning device 2. At this position, the untransferred toner remaining on the photosensitive drum 1 is mechanically removed by the cleaning blade and collected in the cleaning device 2 (this is a cleaning process).
Thus, a series of image forming processes on the photosensitive drum 1 is completed.

On the other hand, the sheet P conveyed to the transfer nip portion (transfer position) between the photosensitive drum 1 and the transfer roller 9 operates as follows.
First, the uppermost sheet P stored in the sheet feeding device 12 is fed by the sheet feeding roller 15 toward the conveyance path.
Thereafter, the sheet P reaches the position of the registration roller 16. Then, the sheet P that has reached the position of the registration roller 16 is aligned with the image formed on the photosensitive drum 1 at the same timing, and the transfer nip portion (the transfer roller 9 and the photosensitive drum 1 are aligned with each other). It is conveyed toward the contact position.

The sheet P after the transfer process passes through the position of the transfer nip portion (transfer roller 9), and then reaches the fixing device 20 through the conveyance path. The sheet P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. . The sheet P on which the image has been fixed is delivered from between the fixing roller 21 and the pressure roller 22 (a fixing nip portion), then discharged from the image forming apparatus main body 100, and placed on a paper discharge tray. Placed.
Thus, a series of image forming processes is completed.

Here, the image forming apparatus 100 according to the present embodiment is covered with a plurality of exterior covers as shown in FIG. As shown in FIG. 2B, a part of the front exterior cover is configured as an opening / closing cover 90 formed to be openable and closable.
Specifically, the opening / closing cover 90 is held by the image forming apparatus main body 100 so as to be rotatable about a support shaft 90a (rotation center axis). Then, the open / close cover 90 is turned in the counterclockwise direction of FIG. 1 about the support shaft 90a to be in a closed state (the state shown in FIGS. 1 and 2A), or the support shaft 90a is moved. By rotating in the clockwise direction in FIG. 1 to the center, it becomes an open state (the state of FIG. 2B).

In this embodiment, as shown in FIG. 2B, the process cartridge 10 (detachable unit) and the toner container 30 are attached to and detached from the image forming apparatus main body 100 when the open / close cover 90 is open. It is configured to be exposed as possible. Then, with the open / close cover 90 opened, one of the process cartridge 10 and the toner container 30 is replaced with a new one, or the process cartridge 10 and the toner container 30 are simultaneously replaced with a new one. It will be. The direction in which the process cartridge 10 and the toner container 30 are attached / detached is the direction indicated by the broken-line double arrow in FIG.
As shown in FIGS. 1 and 2A, the image forming process (printing operation) described above with reference to FIG. 1 is performed with the open / close cover 90 closed.

Hereinafter, the configuration and operation of the image forming apparatus 100 (drive mechanism 80) characteristic of the present embodiment will be described in detail.
As described above with reference to FIGS. 1 and 2, in the present embodiment, the process cartridge 10 as an attachment / detachment unit is detachably installed on the image forming apparatus main body 100.

Here, referring to FIG. 3, the image forming apparatus main body 100 is provided with a main body side gear 50 that rotates by receiving a drive from a drive motor 110 as a drive source.
Although not shown, the image forming apparatus main body 100 is provided with a main body side gear train (main body side drive train) for transmitting driving from the drive motor 110 (drive source) to the main body side gear 50. ing. That is, the main body side gear train including the main body side gear 50 is installed in the image forming apparatus main body 100.

On the other hand, as shown in FIG. 3, the process cartridge 10 serving as the detachable unit has a unit side gear 40 that meshes with the main body side gear 50 when the process cartridge 10 (detachable unit) is attached to the image forming apparatus main body 100. Is installed.
Although not shown in the figure, the process cartridge 10 includes the unit side gear 40 to the roller members in the unit (the photosensitive drum 1, the charging roller 4, the developing roller and the conveying roller installed in the developing device 5). ) Is provided with a unit side gear train (unit side drive train).

As described above, the image forming apparatus 100 according to the present embodiment includes the drive mechanism 80 that is configured by the main body side gear 50 and the unit side gear 40 and that drives the process cartridge 10.
When the process cartridge 10 is attached to the image forming apparatus main body 100, as shown in the left side of FIG. 3, when the process cartridge 10 is moved in the direction of the black arrow, as shown in the right side of FIG. The ten unit side gears 40 are engaged with the main body side gear 50, and the mounting of the process cartridge 10 is completed. As a result, drive can be transmitted from the drive motor 110 of the apparatus main body 100 to the unit side gear 40 via the main body side gear 50. Then, the image forming process described above with reference to FIG. 1 is performed while driving the process cartridge 10.

  Here, when the process cartridge 10 is mounted in the image forming apparatus main body 100 as described above, the tooth surfaces of the main body side gear 50 and the unit side gear 40 first contact each other as shown in FIG. In this case, even if the gear is engaged and then the process cartridge 10 is pushed in the mounting direction, the smaller one of the unit side gear train and the main body side gear train will rotate. A great force is not required until the mounting of the process cartridge 10 is completed.

On the other hand, when the process cartridge 10 is mounted on the image forming apparatus main body 100, the tooth tips of the main body side gear 50 and the unit side gear 40 first contact each other as shown in FIG. As a result, the gears are not engaged, and even if the process cartridge 10 is subsequently pushed in the mounting direction, the unit side gear train and the main body side gear train do not rotate. Even if it can, it will require a lot of power. That is, the process cartridge 10 is not set correctly with respect to the image forming apparatus main body 100 (gear connection failure), or the process cartridge 10 is set poorly.
In the present embodiment, in order to reduce such a problem when the process cartridge 10 is mounted (a problem in which the tooth tips of the main body side gear 50 and the unit side gear 40 collide with each other), the drive mechanism 80 is configured as follows. It is configured as follows.

Referring to FIG. 5, in drive mechanism 80 in the present embodiment, body side gear 50 and unit side gear 40 both have a tooth tip width when the module is m and the twist angle is β. A (top width) is
A ≦ 0.75 (mm) × m / cos β
It is formed to satisfy the relationship.
Specifically, in the present embodiment, the main body side gear 50 and the unit side gear 40 are both spur gears in which the module m is 1 and the torsion angle β is 0 degrees, and the tooth tip width thereof. A is
A ≦ 0.75 (mm)
It is formed to satisfy the relationship.

  By configuring the main body side gear 50 and the unit side gear 40 in this manner, the tooth tip width A can be reduced without impairing the function as a gear, and therefore the main body side gear when the process cartridge 10 is mounted. The problem that the tooth tips of the gear 50 and the unit side gear 40 collide with each other (the problem shown in FIG. 4B) is less likely to occur.

Here, in the present embodiment, the main body side gear 50 and the unit side gear 40 are gears that are positively shifted so that the shift coefficient is in the range of 0.3 to 0.6.
FIG. 6 is a graph showing the relationship between the dislocation coefficient and the tooth tip width A (the tooth tip width of the tooth tip formed using the corrected tooth tip circle). In FIG. 6, the gear 1 is a spur gear with a tooth number Z of 27, a module m of 1 and a torsion angle β of 0 degree, and the gear 2 has a tooth number Z of 35, a module m of 1 and a torsion angle β. Is a 0 degree spur gear. It can be seen that the tooth tip width A can be made considerably small by shifting the gears 1 and 2 positively so that the dislocation coefficient is in the range of 0.3 to 0.6. Therefore, the problem that the tooth tips of the main body side gear 50 and the unit side gear 40 collide with each other when the process cartridge 10 is mounted is further reduced. Further, by performing the positive dislocation, the tooth tip width A can be reduced without making the tooth tip into a special shape.

  In addition, when the tooth tip is formed so that it becomes a standard tooth tip circle without using the corrected tooth tip circle, the tooth is shifted by plus dislocation so that the dislocation coefficient is in the range of 0.3 to 0.6. Since the tip width A can be further reduced, the problem that the tooth tips of the main body side gear 50 and the unit side gear 40 collide with each other when the process cartridge 10 is mounted is further reduced. Both the main body side gear 50 and the unit side gear 40 are positively displaced so that the dislocation coefficient is in the range of 0.3 to 0.6, and are formed so as to be a standard tip circle. It is preferable to use a gear.

FIG. 7 is a graph showing the relationship between the phase angle of the gear (the posture in the rotational direction of the gear) and the force generated when the process cartridge is mounted.
In FIG. 7, a graph S <b> 1 is a simulation result when the gears 1 and 2 described in FIG. 3 are connected (the dislocation coefficient is 0 and the tooth tip width A is 0.78 mm). is there. Further, in the graph S2, the gears 1 and 2 described in FIG. 3 (both are set to a dislocation coefficient of +0.5 and the tooth tip width A is set to 0.75 mm by a corrected tooth tip circle) are connected. It is a simulation result. In addition, the graph S3 connects the gears 1 and 2 described in FIG. 3 (in which both the dislocation coefficient is +0.5 and the tooth tip width A is 0.65 mm by a standard tooth tip circle). It is a simulation result.
From the results of FIG. 7, it can be seen that the use of the positively shifted gear reduces the collision between the tooth tips and significantly reduces the force generated when the process cartridge is mounted. Furthermore, it can be seen that by using a gear formed so as to be shifted positively to become a standard addendum circle, the collision between addendums is further reduced, and the force generated when the process cartridge is mounted is further reduced.

In the present embodiment, each of the main body side gear 50 and the unit side gear 40 has a higher tooth depth than a parallel tooth (a toothpaste is about 2.25 times the module m). It can also be a high-tooth gear.
Even when a high-tooth gear is used as the main body side gear 50 and the unit side gear 40 as described above, the tooth tip width A can be reduced, so that the main body side gear 50 and the unit side gear 40 are attached when the process cartridge 10 is mounted. The problem that the tooth tips collide with each other will be reduced.

In the present embodiment, the main body side gear 50 and the unit side gear 40 are both spur gears.
On the other hand, both the main body side gear 50 and the unit side gear 40 can be helical gears. Also in that case, each tooth tip width A (top width) of the main body side gear 50 and the unit side gear 40 is as described above.
A ≦ 0.75 (mm) × m / cos β
By forming so as to satisfy this relationship, substantially the same effect as that of the present embodiment can be obtained. Furthermore, by making the main body side gear 50 and the unit side gear 40 be helical gears, the meshing ratio between the gears is increased, and the quietness at the time of driving is enhanced, and high-precision driving is possible. Become.

Here, in the present embodiment, a main body side gear train including the main body side gear 50 installed in the image forming apparatus main body 100 or a unit side including the unit side gear 40 installed in the process cartridge 10 (detachable unit). A play is formed in the gear train.
Thereby, when the process cartridge 10 is mounted on the image forming apparatus main body 100, even if the main body side gear 50 and the unit side gear 40 come into contact with each other, a play is formed between the unit side gear train and the main body side gear train. Therefore, it will not rotate so much. Therefore, the setability of the process cartridge 10 is further improved.

As described above, the drive mechanism 80 (image forming apparatus 100) according to the present embodiment meshes with the main body side gear 50 as the process cartridge 10 (detachable unit) is mounted on the image forming apparatus main body 100. A unit side gear 40 is provided. The main body side gear 50 and the unit side gear 40 both have a relationship in which the tooth tip width A is A ≦ 0.75 × m / cos β when the module is m and the torsion angle is β. It is formed to satisfy.
Thereby, when the process cartridge 10 is mounted on the image forming apparatus main body 100, it is possible to make it difficult to cause a problem that the tooth tip of the unit side gear 40 and the tooth tip of the main body side gear 50 collide with each other.

In the present embodiment, the present invention is applied to the monochrome image forming apparatus 100. However, the present invention can also be applied to a color image forming apparatus.
In this embodiment, the present invention is applied to the electrophotographic image forming apparatus 100. However, the application of the present invention is not limited to this, and other types of image forming apparatuses (for example, inkjet) Of course, the present invention can also be applied to an image forming apparatus of a system, an offset printing machine, etc.) as long as a detachable unit is detachably installed on the apparatus main body.
Even in these cases, the same effects as those of the present embodiment can be obtained.

In the present embodiment, the present invention is applied to the drive mechanism related to the process cartridge 10 as the detachable unit. However, the application of the present invention is not limited to this, and the present invention can naturally be applied to a drive mechanism related to other detachable units (for example, the fixing device 20).
In the present exemplary embodiment, the present invention is applied to the drive mechanism installed in the image forming apparatus 100. However, the drive mechanism installed in an apparatus other than the image forming apparatus can be applied to the apparatus main body. Of course, the present invention can be applied if the detachable unit is detachably installed.
Even in these cases, the same effects as those of the present embodiment can be obtained.

  It should be noted that the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

10 Process cartridge (detachable unit),
40 unit side gear,
50 Body side gear,
80 drive mechanism,
100 Image forming apparatus (apparatus body),
110 Drive motor (drive source).

Japanese Patent No. 4980762 Japanese Patent No. 4647351

Claims (8)

A main body side gear that is installed in the apparatus main body and rotates by receiving a drive from a drive source;
A unit-side gear that is installed in a detachable unit that is detachably installed with respect to the apparatus main body, and meshes with the main body-side gear as the detachable unit is mounted on the apparatus main body;
With
The body side gear and the unit side gear both have a tooth tip width A when the module is m and the torsion angle is β.
A ≦ 0.75 (mm) × m / cos β
A drive mechanism formed to satisfy the following relationship. Each of the main body side gear and the unit side gear is a spur gear in which the module m is 1 and the twist angle β is 0 degrees, and the tooth tip width A is
A ≦ 0.75 (mm)
The drive mechanism according to claim 1, wherein the drive mechanism is formed to satisfy the following relationship.   The drive mechanism according to claim 1, wherein each of the main body side gear and the unit side gear is a helical gear.   The main body side gear and the unit side gear are gears that are positively shifted so that the shift coefficient is in the range of 0.3 to 0.6. The driving mechanism according to any one of the above.   5. The drive mechanism according to claim 4, wherein each of the main body side gear and the unit side gear is a gear formed to be a standard addendum circle.   The drive mechanism according to any one of claims 1 to 3, wherein each of the main body side gear and the unit side gear is a high-tooth gear having a tooth depth higher than that of a parallel tooth.   The main body side gear train including the main body side gear installed in the apparatus main body or the unit side gear train including the unit side gear installed in the detachable unit is formed with play. The drive mechanism according to any one of claims 1 to 6.   An image forming apparatus comprising the drive mechanism according to claim 1.

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