JP2006113483A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus, having a first drive motor for rotationally driving an image carrier and a second drive motor for rotationally driving a developing roller, in which the nonconformity of overruning of the first drive motor due to the heat generation of the first drive motor is prevented. <P>SOLUTION: A fan 33 having vanes 35 is fixed to the rotary shaft 23 of the second drive motor 19Y, the fan 33 is rotated by the actuation of the second drive motor 19Y, and the first drive motor 18Y is cooled by an air current produced by the rotation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus having a first drive motor that drives an image forming element and a second drive motor that drives another image forming element.

  In an image forming apparatus of the above type configured as an electronic copying machine, various printers, a facsimile machine, a printing machine, or a combination machine thereof, the temperature of the drive motor rises due to self-heating generated from the drive motor itself. The drive motor may run away due to heat. Therefore, conventionally, a fan is provided in the main body of the image forming apparatus, and an air flow generated by the fan is blown to the drive motor to suppress the temperature increase of the drive motor. However, according to this method, the number of drive motors As the number of fans increases, the number of fans also increases, so the disadvantage of increasing the cost of the image forming apparatus is inevitable.

  In addition, an image forming apparatus has been proposed in which fins are provided on a flywheel that is coaxial with the motor, and heat generated by the motor due to rotation of the fins is exhausted (see Patent Document 1). This configuration cannot be adopted unless a flywheel is arranged.

JP 2002-268456 A

  An object of the present invention is to provide an image forming apparatus capable of efficiently cooling a drive motor while suppressing an increase in cost.

  In order to achieve the above object, according to the present invention, in the image forming apparatus of the type described at the beginning, at least one of the first drive motor and the second drive motor is rotationally driven by the operation of the drive motor, The present invention proposes an image forming apparatus provided with a fan for generating an air flow for cooling the drive motor.

  The image forming apparatus according to claim 1, wherein the rotation speed of the second drive motor is set higher than the rotation speed of the first drive motor, and the fan is provided at least in the second drive motor. It is advantageous if it is provided (Claim 2).

  Furthermore, in the image forming apparatus according to claim 1 or 2, it is advantageous that the rotation directions of the first drive motor and the second drive motor are opposite to each other (claim 3).

  Further, in the image forming apparatus according to claim 2 or 3, it is advantageous that a rectifying means for guiding air is provided so that an airflow flows around the first drive motor. 4).

  Furthermore, in the image forming apparatus according to any one of claims 1 to 4, the image forming element driven by the first drive motor is an image carrier on which a toner image is formed, and the second The image forming element driven by the drive motor is a developing roller of a developing device that forms a toner image on the image carrier, or a cleaning member that removes transfer residual toner adhering to the image carrier after the toner image is transferred It is advantageous if it is (Claim 5).

  Further, in the image forming apparatus according to claim 5, it is advantageous that the rotation of the first drive motor is directly transmitted to the image carrier without passing through the transmission member. (Claim 6).

  According to the present invention, the drive motor can be efficiently cooled while suppressing an increase in cost.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view showing an example of an image forming apparatus, and FIG. 2 is a diagram showing a part of the image forming apparatus shown in FIG. 1 with some elements omitted, mainly of a drive system not shown in FIG. It is the perspective view which clarified the structure. The image forming apparatus shown here includes a plurality of image carriers 2Y, 2C, 2M, 2BK made of a drum-shaped photosensitive member, and an intermediate transfer belt 3 made of an endless belt in contact with the peripheral surface of these image carriers. have. The intermediate transfer belt 3 is wound around the support rollers 4, 5 and 6, guided by the guide roller 8, and rotationally driven in the direction of arrow A by the belt motor 12 shown in FIG. 2. On the other hand, the image carriers 2Y to 2BK are also driven to rotate counterclockwise in FIG.

  In each of the image carriers 2Y to 2BK, toner images of different colors are formed. In the illustrated example, a yellow toner image, a cyan toner image, a magenta toner image, and a black toner image are formed on the image carriers 2Y to 2BK. It is formed. The toner image formed on the surface of each image carrier is transferred to the surface of the intermediate transfer belt 3.

  The configuration for forming a toner image on each of the image carriers 2Y, 2C, 2M, and 2BK and transferring the toner image to the intermediate transfer belt 3 is substantially the same except that the color of the toner image is different. Therefore, only a configuration in which a toner image is formed on one of the image carriers 2Y and the toner image is transferred to the intermediate transfer belt 3 will be described. As shown in FIG. 1, when the image carrier 2Y is rotated counterclockwise in FIG. 1, the image carrier 2Y is charged to a predetermined polarity by a charging device comprising a charging roller 7Y to which a charging voltage is applied. The The charged image carrier 2Y is irradiated with a light-modulated laser beam L emitted from an optical writing device (not shown), whereby an electrostatic latent image is formed on the image carrier 2Y. This electrostatic latent image is visualized as a yellow toner image by the developing device 9Y.

  The developing device 9Y shown here has a developing case 13Y containing a dry developer DY, and a developing roller 14Y that is rotated clockwise in FIG. 1 by a driving motor (to be described later) while carrying the developer DY. The electrostatic latent image formed on the image carrier 2Y is visualized as a toner image by the developer carried and conveyed by the developing roller 14Y.

  A primary transfer device composed of a transfer roller 10Y is disposed on the opposite side of the intermediate transfer belt 3 from the image carrier 2Y, and a transfer voltage is applied to the transfer roller 10Y to form the image carrier 2Y. The toner image is transferred onto the intermediate transfer belt 3 that rotates in the arrow A direction. The transfer residual toner adhering to the image carrier 2Y after the toner image transfer is removed by the cleaning device 11Y. The cleaning device 11Y shown here has a cleaning brush 20Y which is an example of a cleaning member, and this cleaning brush 20Y is rotationally driven while being in contact with the surface of the image carrier 2Y, and the transfer residual on the image carrier 2Y. Remove toner.

  In the same manner as described above, a cyan toner image, a magenta toner image, and a black toner image are respectively formed on the image carriers 2C, 2M, and 2BK shown in FIG. 1, and these toner images are transferred to the yellow toner image. Then, the toner images are sequentially transferred onto the intermediate transfer belt 3, and a composite toner image is formed on the intermediate transfer belt 3. The transfer residual toner on each of the image carriers 2C, 2M, 2BK after the toner image transfer is removed by the cleaning device is the same as in the case of the first image carrier 2Y. In FIG. 1, for each image forming element provided around each image carrier 2M, 2C, 2BK, instead of Y attached to each symbol of each image element provided around image carrier 2Y. In addition, symbols with C, M, and BK are added.

  On the other hand, a support roller 6 positioned at the lowermost of the support rollers around which the intermediate transfer belt 3 is wound is provided with a transfer roller 16 as an example of a secondary transfer device with the intermediate transfer belt 3 interposed therebetween. A recording medium P made of, for example, paper or a resin sheet is fed between the transfer roller 16 and the intermediate transfer belt portion wound around the support roller 6 as indicated by an arrow B. At this time, a predetermined transfer voltage is applied to the transfer roller 16, whereby the composite toner image on the intermediate transfer belt 3 is transferred onto the recording medium P. The transfer residual toner adhering to the intermediate transfer belt 3 after the toner image is transferred to the recording medium P is removed by the belt cleaning device 15. Further, the recording medium P to which the toner image has been transferred is further conveyed leftward in FIG. 1, and the toner image is fixed on the recording medium P when passing through the fixing device 17. The recording medium that has passed through the fixing device 17 is discharged onto a paper discharge tray (not shown).

  The image forming apparatus described above is also referred to as a tandem color image forming apparatus because a plurality of image carriers 2Y, 2C, 2M, and 2BK are juxtaposed.

  As shown in FIG. 2, each of the image carriers 2Y to 2BK, which is one of the image forming elements, is rotationally driven by a separate drive motor 18Y, 18C, 18M, 18BK, and each developing device that is another drive element. The developing rollers 14Y, 14C, 4M, and 14BK are also rotationally driven by separate drive motors 19Y, 19C, 19M, and 19BK, respectively. The drive motors 18Y to 18BK that drive the image carriers 2Y to 2BK, the drive motors 19Y to 19BK that drive the development rollers 14Y to 14BK, and the related components are all substantially the same. Only the drive motor 18Y for driving the image carrier 2Y and the drive motor 19Y for driving the developing roller 14Y will be described here.

  FIG. 3 is a side view of the drive motors 18Y and 19Y arranged vertically, and FIG. 4 is a view of the drive motors 18Y and 19Y viewed from the right side of FIG. Here, the drive motor that drives the image carrier 2Y that is an example of the image forming element is referred to as a first drive motor 18Y, and the drive motor that drives the developing roller 14Y that is an example of another image forming element is the second drive motor. It will be called a drive motor. As shown in FIGS. 3 and 4, the first drive motor 18Y and the second drive motor 19Y include rotating shafts 22 and 23 and rotors 24 and 25 fixed to the rotating shafts 22 and 23, respectively. The bases 26 and 27 are fixedly supported on a frame (not shown) of the image forming apparatus main body via a common bracket 21.

  As shown in FIG. 2, the image carrier 2Y is detachably fixedly connected to the rotary shaft 22 of the first drive motor 18Y, and the first drive motor 18Y is operated to connect the rotor 24 and the rotary shaft 22 to each other. By rotating in the clockwise direction in FIG. 4, the image carrier 2Y is driven to rotate in the counterclockwise direction in FIGS. Further, as shown in FIG. 3, teeth 28 are formed on the rotation shaft 23 of the second drive motor 19Y, and the rotation shaft 23 is configured as a gear. The first intermediate gear 29 is engaged with the first intermediate gear 29. The first intermediate gear 29 is fixed to a second intermediate gear 31 concentric with the first intermediate gear 29 via a connecting shaft 30, and the second intermediate gear 31 is connected to the shaft of the developing roller 14Y. Is engaged with a roller gear 32 fixed to the roller. When the second drive motor 19Y is actuated and the rotor 25 and the rotary shaft 23 are rotated counterclockwise in FIG. 4, the rotation is the first intermediate gear 29, the connecting shaft 30, the second intermediate gear 31 and This is transmitted to the developing roller 14Y via the roller gear 32, and the developing roller 14Y is rotationally driven in the clockwise direction in FIGS.

  As described above, the other first drive motors 18C, 18M, 18BK and the other second drive motors 19C, 19M, 19BK are the same as the first drive motor 18Y and the second drive motor 19Y described above. The image bearing members 2Y to 2BK and the developing rollers 14Y to 14BK are rotationally driven by these drive motors, respectively. Thus, the image carriers 2Y to 2BK are driven to rotate by the dedicated first drive motors 18Y to 18BK, respectively, so that each image carrier is not affected by uneven rotation from other elements. Thus, a high-quality toner image without banding can be formed on each image carrier. In the image forming apparatus of this example, the rotation of each of the first drive motors 18Y to 18BK is directly transmitted to each of the image carriers 2Y to 2BK without passing through a transmission member such as a gear. It is possible to prevent vibrations from being generated on the image carriers, and thereby it is possible to form a high-quality image without banding on each image carrier.

  As described above, since the first drive motors 18Y to 18BK are connected to the image carriers 2Y to 2BK without using a transmission member such as a gear, the rotation of each first drive motor is decelerated. Without being transmitted to each image carrier. On the other hand, the second driving motors 19Y to 19BK are connected to the developing rollers 14Y to 14BK via gears, and the rotations of the second driving motors are decelerated, and the developing rollers 14Y to 14BK are connected. Is transmitted to. Accordingly, the rotation speeds of the second drive motors 19Y to 19BK are set higher than the rotation speeds of the first drive motors 18Y to 18BK. The first drive motor rotates at a lower speed than the second drive motor.

  As described above, the image forming apparatus of this example includes the first drive motor that drives an image carrier that is an example of an image forming element and the second drive that drives a developing roller that is an example of another image forming element. However, if the temperature of the drive motor exceeds the rated motor temperature due to the self-heating generated by the drive motor or the heat received from other devices, the drive motor will run away and cause abnormal operation. There is a risk. In particular, in the image forming apparatus of this example, the four first drive motors 18Y to 18BK and the four second drive motors 19Y to 19BK are arranged close to each other, so that it is difficult for air to circulate. The temperature of each drive motor is likely to rise.

  Therefore, in the image forming apparatus of this example, as shown in FIGS. 3 and 4, the second drive motor 19 </ b> Y positioned adjacent to and above the first drive motor 18 </ b> Y has a second rotation shaft 23. There is provided a fan 33 that is rotationally driven by the operation of the drive motor 19Y. The fan 33 shown as an example in the figure includes a ring 34 arranged concentrically with the rotation shaft 23 of the second drive motor 19Y, and a plurality of blades each end of which is fixed to the ring 34 and the rotation shaft 23. 35. When the second drive motor 19Y is operated and the rotor 25 and the rotating shaft 23 rotate counterclockwise in FIG. 4, the fan 33 also rotates in the same direction. At this time, by the action of the blades 35, an air flow indicated by an arrow C in FIG. 3 and indicated by arrows C1, C2, and C3 in FIG. 4 is generated. This airflow flows from the fan 33 toward the rotation shaft 23 and along the rotation direction of the second drive motor 19Y, and also flows around the first drive motor 18Y. For this reason, the first drive motor 18Y is efficiently cooled by the airflow. In this manner, the drive motor can be cooled without providing an independent fan for the drive motor, the cost increase of the image forming apparatus can be suppressed, and the enlargement of the image forming apparatus main body can be prevented.

  Also, the first drive motor 18Y can be provided with a fan that rotates by the operation of the drive motor 18Y, and the second drive motor 19Y can be cooled by the fan. Only the motor 18Y may be provided with a fan that is rotationally driven by the operation of the drive motor, thereby cooling the second drive motor 19Y. In this manner, at least one of the first drive motor and the second drive motor is provided with a fan that generates airflow that is rotationally driven by the operation of the drive motor and cools the other drive motor.

  As described above, a fan can be provided in both the first and second drive motors. However, in the illustrated example, the fan 33 is provided only in the second drive motor 19Y. The reason is as follows.

  As described above, the rotation speed of the second drive motor 19Y is set higher than the rotation speed of the first drive motor 18Y. Here, in general, when a motor rotates at a relatively high speed, the efficiency of the motor is improved. When the motor rotates at a low speed, the efficiency decreases and the amount of self-heating increases. Therefore, the amount of self-heating of the first drive motor 18Y shown in FIGS. 3 and 4 is larger than the amount of self-heating of the second drive motor 19Y. For this reason, in the illustrated example, the fan 33 is provided in the second drive motor 19Y, and the first drive motor 18Y is cooled by the airflow generated thereby. Thus, when the rotational speed of the second drive motor 19Y is set higher than the rotational speed of the first drive motor 18Y, it is desirable to provide the fan 33 at least in the second drive motor 19Y. .

  Here, as described above, the first drive motor 18Y rotates in the clockwise direction in FIG. 4, and the second drive motor 19Y rotates in the counterclockwise direction in FIG. Although the rotation directions of the first drive motor 18Y and the second drive motor 19Y are opposite to each other, the following effects can be obtained.

  When the first drive motor 18Y rotates, an air flow indicated by arrows E1, E2, and E3 in FIG. 4 is generated around the drive motor 18Y. At this time, if the rotation direction of the first drive motor 18Y is the same as the rotation direction of the second drive motor 19Y, that is, the counterclockwise direction in FIG. 4, the rotation of the first drive motor 18Y The generated airflow flows in the direction indicated by the two-dot chain line arrow F. The air flow indicated by the arrow F is opposite to the direction of the air flow indicated by the arrow C2 generated by the fan 33. For this reason, these airflows collide with each other, the airflow indicated by the arrow C2 is disturbed, and the airflow hardly flows around the first drive motor 18Y, and the cooling effect on the motor 18Y is reduced. On the other hand, in the image forming apparatus of this example, since the airflow flows in the directions indicated by the arrows E1, E2, and E3 due to the rotation of the first drive motor 18Y, the airflow indicated by the arrow C2 is disturbed. The first drive motor 18Y can be efficiently cooled.

  Further, as shown by a two-dot chain line in FIG. 3 and by a solid line in FIG. 4, a pair of rectifying plates disposed on the bracket 21 so as to sandwich the first drive motor 18Y and the second drive motor 19Y. A rectifying means 36 is provided. This rectifying means serves to guide air so that an airflow flows around at least the first drive motor 18Y of the first and second drive motors 18Y, 19Y. By providing such a rectifying means, air can surely flow around the first drive motor 18Y, and the cooling effect on the first drive motor 18Y can be further enhanced.

  The other first and second drive motors 18C, 18M, and 18BK; 19C, 19M, and 19BK shown in FIG. 2 and related fans are configured in the same manner as described above.

  As described above, the image forming element driven by the first drive motor is an image carrier on which a toner image is formed, and the image forming element driven by the second drive motor places a toner image on the image carrier. Although the example in the case of the developing roller of the developing device to be formed has been described, each of the above-described configurations can also be adopted when these drive motors drive other image forming elements. For example, even when the image forming element driven by the second drive motor is a cleaning member that removes transfer residual toner adhering to the image carrier after the toner image is transferred, the above-described configuration can be employed without any problem.

  The present invention also provides an image forming apparatus of a type in which toner images of different colors are formed on a plurality of image carriers, and the toner images are directly superimposed on a recording medium, and a single color toner image is transferred. The present invention can be widely applied to various types of image forming apparatuses such as an image forming apparatus to be formed.

It is a schematic sectional drawing which shows an example of an image forming apparatus. FIG. 2 is a perspective view in which some of the elements of the image forming apparatus shown in FIG. 1 are omitted and the drive system for the image carrier and the developing roller is mainly clarified. It is a side view of the 1st and 2nd drive motor. It is the figure which looked at the 1st and 2nd drive motor from the right side of FIG.

Explanation of symbols

2Y, 2C, 2M, 2BK Image carrier 14Y, 14C, 14M, 14BK Developing roller 18Y, 18C, 18M, 18BK First motor 19Y, 19C, 19M, 19BK Second motor 33 Fan

Claims (6)

In an image forming apparatus having a first drive motor for driving an image forming element and a second drive motor for driving another image forming element, at least one of the first drive motor and the second drive motor is provided. An image forming apparatus comprising: a fan that is rotationally driven by the operation of the drive motor and generates an airflow that cools the other drive motor. The image forming apparatus according to claim 1, wherein the rotation speed of the second drive motor is set higher than the rotation speed of the first drive motor, and at least the second drive motor includes the fan. The image forming apparatus according to claim 1, wherein rotation directions of the first drive motor and the second drive motor are opposite directions. 4. The image forming apparatus according to claim 2, wherein a rectifying unit that guides air is provided so that an airflow flows around the first drive motor. 5. The image forming element driven by the first drive motor is an image carrier on which a toner image is formed, and the image forming element driven by the second drive motor generates a toner image on the image carrier. 5. The image forming apparatus according to claim 1, wherein the image forming apparatus is a developing roller of a developing apparatus to be formed or a cleaning member that removes transfer residual toner attached to an image carrier after the toner image is transferred. The image forming apparatus according to claim 5, wherein the rotation of the first drive motor is directly transmitted to the image carrier without passing through a transmission member.

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