JPH0749483Y2 - Drive force transmission device for photosensitive drum in image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Technical Field] The present invention relates to a driving force transmission device for a photosensitive drum in an image forming apparatus.

[Prior Art] In a conventional image forming apparatus, as a method of driving a photosensitive drum, a method of directly transmitting from a motor to a rotary shaft of the photosensitive drum through a speed reducing means such as a speed reduction gear is generally adopted. .

On the other hand, the driving force of the rotating body such as the charging brush, the developing brush, the cleaning brush, and the charge eliminating brush arranged around the photosensitive drum is set to a gear or a belt from the middle of the driving force transmission system from the motor to the photosensitive drum. Generally, the driving force is transmitted via a motor or another motor.

In such a conventional driving force transmission device, it is necessary to dispose the motor and the speed reducing member thereof near the axis of the rotary shaft of the photosensitive drum. This is disadvantageous in that various design restrictions are imposed on the downsizing of the image forming apparatus.

Further, in an image forming apparatus in which a rotating body such as the static elimination brush or the charging brush is arranged around the photosensitive drum, when the photosensitive drum is directly driven from a motor via a reduction gear, the rotation speed of the static elimination brush or the charging brush is Since it is much higher than the number of rotations of the drum, it is not preferable to rotate the static elimination brush or the charging brush from the photosensitive drum side, and it is necessary to provide a separate drive system for driving the static elimination brush, which makes the device larger and the cost higher. The following defects occur.

[Problems to be Solved] According to the present invention, it is possible to alleviate the design restrictions on the installation location of the motor and to omit the reduction gear for driving the photosensitive drum, which facilitates the miniaturization of the image forming apparatus. The present invention intends to provide the driving force transmission device described above.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the apparatus of the present invention is an image forming apparatus having at least a discharging unit, a developing unit, and a cleaning unit arranged around a photosensitive drum. It is characterized in that the means or the cleaning means is constituted by a rotating body, and the driving force of the power unit is transmitted to the photosensitive drum via the rotation shaft of any one of the rotating bodies.

[Operation and Effect] Regarding the rotational relationship between the rotating body around the photosensitive drum, for example, the static elimination brush and the photosensitive drum, the rotation speed of the static elimination brush is usually much higher than the rotation speed of the photosensitive drum, and the rotation diameter of the static elimination brush is Since the rotation diameter of the photosensitive drum is smaller than that of the photosensitive drum, the driving force transmission device according to the present invention, which directly connects the static elimination brush and the photosensitive drum with a gear, transmits the decelerated driving force from the static elimination brush side to the photosensitive drum side. The torque can be transmitted smoothly without overwhelming the system.

Further, since the motor drives the photosensitive drum by decelerating it through the static elimination brush, a reduction gear for directly driving the photosensitive drum from the motor in the conventional apparatus can be omitted, and the restriction on the installation location of the motor is eased. Therefore, it has a great effect on downsizing of the device and cost reduction.

Further, in the present invention, since the transmission of the driving force from the motor to the static elimination brush may be carried out by either a gear or a belt, the position of the motor can be separated from the vicinity of the rotary shaft of the photosensitive drum, and the gap or concave portion Since the motor can be arranged at a place, the design constraint for downsizing the device is greatly relaxed and the practical effect is great.

Similarly, in the rotating body of the charging brush and the cleaning brush disposed around the photosensitive drum, if the rotation speed is higher than that of the photosensitive drum, the rotating force can be smoothly and preferably transmitted from the rotating body to the photosensitive drum. You can

More preferably, as in the charge removal brush, it is preferable to use a combination of the rotating body that saturates its effect at a certain number of rotations or more and the photosensitive drum, because the setting condition of the reduction ratio can be relaxed. From this point of view, the static elimination brush and the cleaning brush are particularly recommended as the drive transmission system for the photosensitive drum of the present invention.

However, in the rotating body of the developing brush, the load of the toner conveying member varies depending on the amount of toner, and uneven rotation occurs. For this reason, when the photosensitive drum is rotated via the rotating body of the developing brush, a deviation occurs on the image on the photosensitive drum, so the developing brush is excluded from the rotating body of the present invention.

[Embodiment of the Invention] Next, an embodiment of the invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of an image forming apparatus.

Explaining the configuration and the image forming process, the photosensitive drum 1 is charged by a charging unit 2 such as a scorotron, and an electrostatic latent image is formed on the surface by an exposing unit 3 such as a laser light source. Next, the electrostatic latent image is made into a powder image by the developing means 4 using a magnetic brush carrying a developer, and transferred onto the transfer sheet 6 by the transfer means 5 using a corotron or the like. The transferred powder image on the transfer sheet is fixed on the transfer sheet 6 by the fixing means 7 such as a pressure roll.

On the other hand, the photosensitive drum 1 after transfer is cleaned by a cleaning means 8 such as a blade (hereinafter, an example of this cleaning means is referred to as a blade cleaning member 8).
The residual toner on the drum is cleaned, and then the residual charge on the photosensitive drum 1 is removed by a charge removing unit 9 (hereinafter, an example of this charge removing unit will be referred to as a charge removing brush 9) using a conductive brush or the like. Used for image formation.

The present invention relates to a driving force transmission device for a photosensitive drum of such an image forming apparatus. However, the device according to the present invention includes all the image forming means 1 to 9 arranged around the photosensitive drum. The image forming means arranged around the photosensitive drum is surrounded by a dotted line as shown in FIG. Dividing into a developing unit A, a photoconductor unit B surrounded by a one-dot chain line, and a toner cartridge C surrounded by a two-dot chain line, combining these units, and detachably replacing the main body D of the apparatus for use. It can be applied to any photosensitive drum of a combination type process unit system.

FIG. 2 is a schematic diagram of the image forming apparatus shown in FIG. 1, which is surrounded by an alternate long and short dash line. The charging device 2 is a scorotron provided around the photosensitive drum 1, the blade cleaning member 8 and the conductive material of the rotating body. Integrates with the static elimination brush 9,
1 shows an example of a drive system for transmitting a drive force from a charge eliminating brush 9 to a photosensitive drum 1 in a photosensitive body unit B of a split combination type process unit that can be attached to and detached from an apparatus main body D.

In the figure, the drive transmission system on the main unit side is a motor
It has 15, gears 16 and 18, and a timing belt 17. Motor 1
Reference numeral 5 is arranged in an appropriate gap or recess in the apparatus main body D apart from the photosensitive drum 1 and the static elimination brush 9, and drives the gear 18 from the gear 16 provided on the motor rotation shaft via the timing belt 17. The gear 18 has, at the other end, a coupling 19 ₁ provided on the apparatus main body side.

On the other hand, on the side of the photoconductor unit B, the charge removal brush 9 and the photoconductor drum 1 are provided with a gear 20 provided on each rotation shaft.
Directly connected at 21, the charge eliminating brush 9 and the photosensitive drum 1 are rotated in opposite directions. The tip of the rotation shaft of the discharging brush 9 is provided with a coupling 19 _2, the photosensitive member unit B
The device is fitted with a coupling 19 ₁ motor side of the apparatus main body when attached to the body D.

In this way, by mounting the photoconductor unit B on the apparatus main body D, the motor 15 → gear 16 → timing belt
17 → Gear 18 → Coupling 19 ₁ → Coupling 19 ₂ → Eliminating brush gear 20 → Photosensitive drum gear 21 The drive system is connected in this order, and the rotational force of the motor 15 causes the removing brush 9 to be removed from the motor in the above connecting order. It is transmitted to the photosensitive drum 1 via.

In the present embodiment, a DC servomotor is used as the motor 15, the rotation speed is 900 rpm, and the gear 16 provided on the motor rotation shaft has a spur gear having an XL tooth shape with 14 teeth and a coupling 19 ₁ . The gear 18 is an XL tooth-shaped spur gear having 40 teeth and is connected by a timing belt 17. Gear 20 for static elimination brush has 1 tooth
7. The module 1 is a helical gear, and the photosensitive drum gear 21 is the module 1, a helical gear. With this combination, the photosensitive drum 1 of 120φ can obtain smooth rotation at a rotation speed of 47.8 rpm. At this time, the rotation speed of the static elimination brush 9 is 312.1 rpm, and the residual charge on the photosensitive drum 1 can be eliminated effectively.

As described above, the driving force transmission device of the photosensitive drum according to the present invention transmits the driving force of the power unit to the driving force of the power unit through the rotary shaft of one rotating member selected from the charge removing unit or the cleaning unit. Since it is transmitted to the photosensitive drum, as described above, the reduction gear for directly driving the photosensitive drum from the conventional motor can be omitted, and a separate system for the static elimination brush 9 when the photosensitive drum 1 is directly driven. Since the drive system is unnecessary and the motor 15 can be arranged in the gap or the recess of the main body of the apparatus, it is significantly effective in downsizing the apparatus and reducing the cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an image forming apparatus, and FIG. 2 shows an embodiment of the present invention, and is a diagram showing a driving force transmission system of a photosensitive drum in a photosensitive unit B of FIG. A ... Developing unit, B ... Photosensitive unit, C ... Toner cartridge, D ... Device body, 1 ... Photosensitive drum, 2 ... Charging means, 3 ... Exposure means, 4 ... Developing means, 5 ...... Transfer means, 6 ...... Transfer sheet, 7 ...... Fixing means, 8 ...... Cleaning means, 9 ...... Electrifying means, 15 ......
Motor, 16,18 …… Gear, 17 …… Timing belt, 1
9 ₁ , 19 ₂ …… Coupling, 20 …… Gear, 21 …… Gear.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Nishina 1014 Miyahara-cho, Kofu-shi, Yamanashi Yamanashi Electronics Industrial Co., Ltd. (72) Inventor Gomi 1014 Miyahara-cho, Kofu-shi, Yamanashi Yamanashi Electronics Industrial Co., Ltd. (72) Inventor Kaomi Sakamoto 1014 Miyahara-cho, Kofu-shi, Yamanashi Yamanashi Electronics Industrial Co., Ltd. (56) References JP 63-27860 (JP, A) JP 57-76575 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A static eliminator arranged around a photosensitive drum,
In an image forming apparatus having at least a developing unit and a cleaning unit, the charge removing unit or the cleaning unit is composed of a rotating body, and a driving force of a power unit is transmitted via a rotating shaft of any one of the rotating bodies. A drive force transmission device for a photosensitive drum in an image forming apparatus, characterized in that the drive force is transmitted to the photosensitive drum.