JP4294464B2 - Powder conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a powder conveyance device that conveys powder such as toner from a powder container through a conveyance tube toward a conveyance destination below the powder container, and an image forming apparatus including the same. Is.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers, facsimiles, and printers that use a toner conveying device are known. This toner conveying device connects the toner container with a toner discharging means for discharging toner from the toner container, and a developing device for developing a latent image carried on a latent image carrier such as a photosensitive member into a toner image. It is equipped with a transport pipe. The toner discharging means is operated as necessary to discharge the toner stored in the toner container into the transport pipe, and the toner is transported directly into the developer through the transport pipe. In an image forming apparatus using such a toner conveying device, it is assumed that the toner container is disposed at a position lower than the developing device. In this case, it is necessary to transport the toner, which is a powder passed from the toner container into the transport pipe, toward the developing device so as to lift it against gravity, so that the transport efficiency is deteriorated or the toner is clogged in the transport pipe. It becomes easy. Therefore, the toner container is generally disposed at a higher position than the developing device so that the toner is conveyed in the direction of gravity. As a toner conveyance device that performs such conveyance in the direction of gravity, for example, the one described in Patent Document 1 is known. In this toner conveying device, the toner discharged from the toner box, which is a toner container, into the conveying tube by the toner discharging means is dropped by its own weight and sent into the developing device.

JP-A-8-30097

  However, in this toner conveying device, there is a possibility that the toner discharged from the toner box into the conveying tube accumulates on the inner wall of the conveying tube and then flows into the developing device at a time when the amount becomes a certain amount. When the toner is allowed to flow in this manner, for example, in the two-component development method using the two-component developer containing the toner and the magnetic carrier, it becomes difficult to accurately control the toner concentration of the two-component developer. For example, in a one-component development method that uses only toner without using a magnetic carrier, the ratio of toner that is not sufficiently frictionally charged in the developing device is increased at a stretch, and the toner adheres to the non-image portion of the latent image carrier. It is easy to cause so-called soiling. If the toner box and the developing device are disposed close to each other so that the length of the transport pipe is as short as possible so as not to accumulate toner, the rapid flow of toner from the transport pipe into the developing device can be suppressed. However, the degree of freedom of layout in the image forming apparatus is deteriorated due to the restriction of proximity arrangement.

  On the other hand, the toner transported to the developing device is driven by the drive amount of the transport member provided in the transport pipe while the toner discharged from the toner container is retained in the transport pipe instead of dropping the toner passed through the transport pipe by its own weight. It is also possible to adjust this. However, even if such a configuration is adopted, if some impact is applied to the transport tube, the toner in the tube may flow into the developing device at once, even though the drive of the transport member is stopped. There is.

  Until now, the problem which arises in the toner conveyance device which conveys toner as powder has been explained. However, even in other powder conveying apparatuses that convey powder different from the toner, there is a possibility that some problem may occur if the powder rapidly flows from the inside of the conveying pipe to the conveying destination.

The present invention has been made in view of the above background, and an object of the present invention is to provide a powder conveying apparatus capable of realizing the following matters and an image forming apparatus including the same. .
(1) Eliminate problems caused by conveying powder against gravity.
(2) Suppressing problems caused by the powder flowing into the transport destination from the transport pipe at once without deteriorating the layout freedom between the powder container and the transport destination.

In order to achieve the above object, the invention of claim 1 includes a powder container for storing powder, and a transport pipe for guiding the powder from the powder container to a transport destination below the powder container. A coil that is disposed in the transfer tube and applies a moving force toward the transfer destination side from the powder storage unit side to the powder in the transfer tube by its own rotation, and in the powder storage unit In the powder conveyance device that conveys the powder to the conveyance destination through the conveyance tube, a portion extending downward from the powder container side toward the conveyance destination side in the conveyance tube, and more than the portion located in the transport destination side, provided a bent portion for bending the angle of inclination from the horizontal so as to be smaller than the site, the inner diameter of the bent portion, the non-bending, which is a site that is not bent in the conveying pipe larger than the inner diameter of the part, and, as the coil, naturally without bending and stretching one In a state where the linear posture is taken, a portion where the helical pitch is relatively short and a portion where the helical pitch is relatively long in the axial direction is provided, and the latter portion is positioned at the bent portion of the transport pipe. It is characterized by using what was made to be .
Further, the invention according to claim 2 is the powder conveying apparatus according to claim 1, wherein, as the conveying tube, an inclination angle from a horizontal of a portion adjacent to the bent portion on the conveying destination side is 30 [ °] is used .
Also, the invention of claim 3, the image forming comprising a toner image forming means for forming a toner image by using a powder toner which, a toner conveying device for conveying the toner from the toner accommodating portion to said toner image forming means In the apparatus, the powder conveyance device according to claim 1 or 2 is used as the toner conveyance device.
According to a fourth aspect of the present invention, in the image forming apparatus of the third aspect , as the toner image forming means, at least a latent image carrier that carries a latent image and a latent image on the latent image carrier are developed. A developing unit having an image forming unit configured to be detachable from the image forming apparatus main body as one unit is used, and the toner containing portion serving as a powder containing portion is provided separately from the unit. It is characterized by being configured to be attachable to and detachable from.

In these inventions, by transferring the powder from the powder container to the lower transfer destination, problems caused by transferring the powder against gravity can be eliminated.
In addition, even if the powder flows vigorously in the direction of gravity from the powder container side toward the transport destination side in the transport pipe, the gradient of the course is made gentle at the bent portion of the tube before reaching the transport destination. Therefore, the momentum of the powder flow can be weakened in front of the transport destination. And even if the length of a conveyance pipe is made comparatively large by this, the malfunction by flowing powder into a conveyance destination from the inside of a conveyance pipe at a stretch can be suppressed.
In addition, since it is possible to adopt a layout in which the length of the transfer pipe is relatively large and the powder container and the transfer destination are separated from each other, the degree of freedom in layout of both is not deteriorated.
Therefore, the above items (1) and (2) can both be realized.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of an electrophotographic printer (hereinafter simply referred to as a printer) will be described.
First, the basic configuration of the printer will be described. FIG. 1 is a schematic configuration diagram showing the printer. In FIG. 1, the printer 100 includes four process cartridges 6Y, 6M, 6C, and 6K for generating toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). ing. These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached. Taking a process cartridge 6Y for generating a Y toner image as an example, as shown in FIG. 2, a drum-shaped photoreceptor 1Y, a drum cleaning device 2Y, a charge eliminating device (not shown), a charging device 4Y, a developing device 5Y, and the like. It has. The process cartridge 6Y as an image forming unit can be attached to and detached from the main body of the printer 100 so that consumable parts can be replaced at a time.

  The charging device 4Y uniformly charges the surface of the photoreceptor 1Y that is rotated clockwise in the drawing by a driving unit (not shown). The uniformly charged surface of the photoreceptor 1 </ b> Y is exposed and scanned by the laser beam L to carry a Y electrostatic latent image. The electrostatic latent image of Y is developed into a Y toner image by a developing device 5Y using a Y developer containing Y toner and a magnetic carrier. Then, intermediate transfer is performed on the intermediate transfer belt 8. The drum cleaning device 2Y removes the toner remaining on the surface of the photoreceptor 1Y after the intermediate transfer process. The static eliminator neutralizes residual charges on the photoreceptor 1Y after cleaning. By this charge removal, the surface of the photoreceptor 1Y is initialized and prepared for the next image formation. In the other process cartridges 6M, 6C, and 6K, M, C, and K toner images are similarly formed on the photoreceptors 1M, 6C, and 6K, and are intermediately transferred onto the intermediate transfer belt 8.

  The developing device 5Y has a developing roll 51Y disposed so as to be partially exposed from the opening of the casing. Further, it also includes two conveying screws 55Y, a doctor blade 52Y, a toner density sensor (hereinafter referred to as T sensor) 56Y, and the like that are arranged in parallel to each other.

  In the casing of the developing device 5Y, Y developer containing a magnetic carrier and Y toner is accommodated. The Y developer is frictionally charged while being agitated and conveyed by the two conveying screws 55Y, and is then carried on the surface of the developing roll 51Y. Then, after the layer thickness is regulated by the doctor blade 52Y, the layer is transported to the developing region facing the Y photoreceptor 1Y, where Y toner is attached to the electrostatic latent image on the photoreceptor 1Y. This adhesion forms a Y toner image on the photoreceptor 1Y. In the developing unit 5Y, the Y developer that has consumed Y toner by the development is returned into the casing as the developing roll 51Y rotates.

  A partition wall is provided between the two transport screws 55Y. By this partition wall, the first supply unit 53Y that accommodates the developing roll 51Y, the right conveyance screw 55Y in the drawing, and the like, and the second supply unit 54Y that accommodates the left conveyance screw 55Y in the drawing are separated in the casing. . The right conveying screw 55Y in the drawing is driven to rotate by a driving means (not shown), and supplies the Y developer in the first supply unit 53Y to the developing roll 51Y while being conveyed from the near side to the far side in the drawing. The Y developer conveyed to the vicinity of the end of the first supply unit 53Y by the right conveyance screw 55Y in the drawing enters the second supply unit 54Y through an opening (not shown) provided in the partition wall. In the second supply unit 54Y, the left conveyance screw 55Y in the drawing is driven to rotate by a driving means (not shown), and the Y developer sent from the first supply unit 53Y is the right conveyance screw 55Y in the drawing. Transport in the reverse direction. The Y developer transported to the vicinity of the end of the second supply unit 54Y by the transport screw 55Y on the left side in the drawing passes through the other opening (not shown) provided in the partition wall, and the first supply unit. Return to 53Y.

  The above-described T sensor 56Y composed of a magnetic permeability sensor is provided on the bottom wall near the center of the second supply unit 54Y, and outputs a voltage having a value corresponding to the magnetic permeability of the Y developer passing therethrough. Since the magnetic permeability of the two-component developer containing toner and magnetic carrier shows a certain degree of correlation with the toner concentration, the T sensor 56Y outputs a voltage corresponding to the Y toner concentration. This output voltage value is sent to a control unit (not shown). This control unit includes a RAM that stores a Vtref for Y that is a target value of an output voltage from the T sensor 56Y. The RAM also stores M Vtref, C Vtref, and K Vtref data, which are target values of output voltages from a T sensor (not shown) mounted in another developing device. The Y Vtref is used for driving control of a Y toner conveying device to be described later. Specifically, the control unit drives and controls a Y toner conveying device (not shown) so that the value of the output voltage from the T sensor 56Y is close to the Y Vtref, and the Y toner in the second supply unit 54Y. To replenish. By this replenishment, the Y toner concentration in the Y developer in the developing device 5Y is maintained within a predetermined range. The same toner replenishment control using the M, C, and K toner conveying devices is performed for the developing units of the other process units.

  In FIG. 1 shown above, an exposure device 7 is disposed below the process cartridges 6Y, 6M, 6C, 6K in the drawing. The exposure device 7 serving as a latent image forming unit irradiates the respective photoconductors in the process cartridges 6Y, 6M, 6C, and 6K with a laser beam L emitted based on the image information. By this exposure, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 1Y, 1M, 1C, and 1K. The exposure device 7 irradiates the photoconductor with a laser beam (L) emitted from a light source through a plurality of optical lenses and mirrors while scanning with a polygon mirror rotated by a motor. The exposure device 7 constitutes toner image forming means for forming a toner image on a photosensitive member as a latent image carrier together with process process cartridges 6Y, 6M, 6C, 6K and the like.

  On the lower side of the exposure apparatus 7 in the figure, paper supply means including a paper storage cassette 26, a paper supply roller 27 incorporated therein, a registration roller pair 28, and the like are disposed. The paper storage cassette 26 stores a plurality of transfer papers P, which are recording media, and a paper feed roller 27 is brought into contact with each uppermost transfer paper P. When the paper feeding roller 27 is rotated counterclockwise in the drawing by a driving means (not shown), the uppermost transfer paper P is fed toward the rollers of the registration roller pair 28. The registration roller pair 28 rotationally drives both rollers to sandwich the transfer paper P, but temporarily stops rotating immediately after sandwiching. Then, the transfer paper P is sent out toward a later-described secondary transfer nip at an appropriate timing. In the sheet feeding unit having such a configuration, a recording medium conveying apparatus is configured by a combination of the sheet feeding roller 27 and the registration roller pair 28 corresponding to the timing roller. This recording material transport device transports transfer paper P from a paper storage cassette 26 serving as storage means to a secondary transfer nip described later.

  Above the process cartridges 6Y, 6M, 6C, and 6K in the drawing, an intermediate transfer unit 15 that moves the intermediate transfer belt 8 that is an intermediate transfer member endlessly while stretching is disposed. The intermediate transfer unit 15 includes a cleaning device 10 in addition to the intermediate transfer belt 8. Also provided are four primary transfer bias rollers 9Y, 9M, 9C, 9K, a secondary transfer backup roller 12, a cleaning backup roller 13, a tension roller 14, and the like. The intermediate transfer belt 8 is endlessly moved in the counterclockwise direction in the figure by the rotational drive of at least one of the rollers while being stretched around these seven rollers. The primary transfer bias rollers 9Y, M, C, and K sandwich the intermediate transfer belt 8 moved endlessly in this manner from the photoreceptors 1Y, M, C, and K to form primary transfer nips, respectively. Yes. In these methods, a transfer bias having a polarity opposite to that of toner (for example, plus) is applied to the back surface (loop inner peripheral surface) of the intermediate transfer belt 8. All of the rollers except the primary transfer bias rollers 9Y, 9M, 9C, and 9K are electrically grounded. The intermediate transfer belt 8 sequentially passes through the primary transfer nips for Y, M, C, and K along with the endless movement thereof, and Y, M, and C on the photoreceptors 1Y, M, C, and K are sequentially transferred. , K toner images are superimposed and primarily transferred. As a result, a four-color superimposed toner image (hereinafter referred to as a four-color toner image) is formed on the intermediate transfer belt 8.

  The secondary transfer backup roller 12 sandwiches the intermediate transfer belt 8 between the secondary transfer roller 19 and forms a secondary transfer nip. The visible four-color toner image formed on the intermediate transfer belt 8 is transferred to the transfer paper P at the secondary transfer nip. Then, combined with the white color of the transfer paper P, a full color toner image is obtained. Untransferred toner that has not been transferred onto the transfer paper P adheres to the intermediate transfer belt 8 after passing through the secondary transfer nip. This is cleaned by the cleaning device 10.

  In the secondary transfer nip, the transfer paper P is sandwiched between the intermediate transfer belt 8 and the secondary transfer roller 19 whose surfaces move in the forward direction, and conveyed in the opposite direction to the registration roller pair 28 side. The When the transfer paper P sent out from the secondary transfer nip passes between the rollers of the fixing device 20, the full-color toner image on the surface is fixed under the influence of heat and pressure. Thereafter, the transfer paper P is discharged out of the apparatus through a pair of paper discharge rollers 29. A stack portion 50a is formed on the upper surface of the printer body. The transfer paper P discharged to the outside by the discharge roller pair 29 is sequentially stacked on the stack portion 50a.

  A bottle support portion 31 is disposed between the intermediate transfer unit 15 and the stack portion 50a located above the intermediate transfer unit 15. The bottle support portion 31 has toner bottles 32Y, 32M, 32C, 32K serving as toner storage portions for storing Y, M, C, and K toners. The toner bottles 32Y, 32M, 32C, and 32K are arranged so as to be arranged at an angle slightly inclined from the horizontal, and the arrangement positions are higher in the order of Y, M, C, and K. The Y, M, C, and K toners in the toner bottles 32Y, 32M, 32C, and 32K are appropriately supplied to the developing units of the process cartridges 6Y, 6M, 6C, and 6K, respectively, by a toner transport device that will be described later. These toner bottles 32Y, 32M, 32C, and 32K are detachable from the main body of the printer 100 independently of the process cartridges 6Y, 6M, 6C, and 6K.

  As described above, the four process cartridges 6Y, 6M, 6C, and 6K each include a photoconductor, a drum cleaning device, a charge removal device, a charging device, and a developing device. These are integrated with the printer main body. In the old days, these photoconductors and the like have been provided as consumable parts that can be separately attached and detached, and are exchanged as necessary. However, it is difficult for the operator to understand each attachment / detachment operation. This caused poor maintainability.

  Accordingly, a process cartridge system has been introduced that improves the maintainability by exchanging these photoconductors as a single unit, and a system that makes the lifetime when the toner in the developing device runs out. However, in such a configuration, there is a problem in that when the toner runs out, it is necessary to replace even a part that still has a sufficient life span, which increases waste.

  On the other hand, an image forming apparatus is also known in which a toner container for storing toner to be supplied to a developing device of a process cartridge is configured to be detachable from the process cartridge (for example, Japanese Patent Laid-Open No. 10-239974). As described). However, in such an image forming apparatus, even when only the toner container is replaced, the process cartridge has to be removed from the main body of the image forming apparatus, and there is a problem that the replaceability of the toner container is poor.

  In the printer 100, the process cartridges 6Y, 6M, 6C, and 6K and the toner bottles 32Y, 32M, 32C, and 32K can be separately attached to and detached from the printer body, thereby eliminating these problems. is doing.

  FIG. 3 is a perspective view showing a toner bottle 32Y for Y. In the figure, a toner bottle 32Y for Y has a bottle portion 33Y and a cap portion 34Y fixed to the tip side thereof. The bottle portion 33Y formed in a columnar shape is embossed so that screw-like protrusions protruding from the outside toward the inside are along the circumferential surface. When the Y toner bottle 32Y is rotated by a Y toner conveying device, which will be described later, the Y toner in the bottle portion 33Y moves from the bottle bottom side toward the bottle front end side along the screw-like protrusion. And it enters the cap part 34Y from the bottle part 33Y. In such a configuration, since the toner can be moved in the bottle without providing the toner conveying means in the toner bottle 32Y, an increase in cost due to the provision of the toner conveying means can be avoided. Further, the bottle can be reduced in size.

  The cap part 34Y is formed in a cylindrical shape having a slightly smaller diameter than the bottle part 33Y, and has a handle 35Y, a shutter 36Y, and a gear part 37Y on its circumferential surface. The handle 35Y protrudes from the circumferential surface of the cap so as to extend in the cylinder axis direction. The shutter 36Y is slidable in the circumferential direction. In the illustrated state, the shutter 36Y covers and hides a toner discharge port (not shown) provided on the circumferential surface of the cap. The gear portion 37Y is provided in a region on the bottle portion 33Y side where the handle 35Y and the shutter 36Y are not provided in the axial direction of the cap portion 34Y, and a plurality of gears (not shown) are provided over the entire circumferential direction. Have. The Y toner bottle 32Y is rotated by meshing the gear of the gear portion 37Y with a drive gear of a toner conveying device described later. The toner bottles 32M, C, and K for other colors M, C, and K have the same configuration.

  FIG. 4 is a perspective view showing the bottle support portion 31 and the four toner bottles 32Y, 32M, 32C, 32K. The bottle support portion 31 has four bottle mounting portions 31Y, 31M, 31C, and 31K for individually mounting the four toner bottles 32Y, 32M, 32C, and 32K. This figure shows a state in the middle of attaching the toner bottle 32K for K among the four toner bottles 32Y, 32M, 32C, 32K. The operator places the toner bottle 32K on the K bottle mounting portion 31Y of the bottle support portion 31, and then grips the handle 35Y provided on the cap portion 34K of the toner bottle 32K to rotate the toner bottle 32K. Along with this rotation, the shutter (not shown) provided in the cap part 34K is opened, and the toner discharge port (not shown) of the cap part 34K is exposed and faces downward in the vertical direction. At the same time, the cap part 34K is engaged and fixed by an engaging part (not shown) of the bottle attaching part 31K. The other color toner bottles 32Y, 32M, 32C are also fixed on the bottle support 31 by the same operation and the toner discharge port is exposed.

FIG. 5 is a perspective view showing a part of the Y, M, C, and K toner replenishing devices 40Y, 40M, 40K, and 40K in the printer 100. These toner replenishing devices 40Y, 40M, 40C, and 40K have substantially the same configuration except that the colors of the handled toners are different from each other. Taking the Y toner supply device 40Y that handles Y toner as an example, the configuration is as follows. That is, the toner conveyance device 40Y includes a drive motor 41Y, a drive gear 42Y, a conveyance tube 43Y, and the like in addition to the toner bottle 32Y. In addition, although not shown in the drawings, the above-described bottle support portion for Y (31Y in FIG. 4) is also provided. The toner bottle 32Y correctly set on the Y bottle support portion meshes the gear portion 37Y of the cap portion 34Y with the drive gear 42Y. When the drive gear 42Y is rotated by the drive motor 41Y, the rotational driving force is transmitted to the entire toner bottle 32Y via the gear portion 37Y, and the toner bottle 32Y rotates. Then, Y toner is discharged from a toner discharge port (not shown) facing the lower side in the vertical direction of the cap portion 34Y, and falls to the transport tube 43Y. A resin coil (not shown) is provided in the transport pipe 43Y, and this is also rotationally driven by the drive motor 41Y. The resin coil functions as a moving force applying means for applying a moving force in the tube length direction to the Y toner received in the conveying tube 43Y from the toner discharge port. Then, the Y toner received in the transport pipe 43Y is transported by applying a moving force and supplied to the Y developing device (5Y). Note that the ON / OFF of the drive motor 41Y, that is, the ON / OFF of toner replenishment to the Y developing device (5Y), as described above, is a T sensor provided in the Y developing device. (56Y) based on the detection result.
Instead of toner density control based on the detection result by such a T sensor, toner density control based on another detection result may be performed. For example, for each process cartridge (6Y, M, C, K), the image density of the reference toner image formed in the non-image area of the photoreceptor is detected by an optical sensor, and the detection result is used for toner density control. May be.

  FIG. 6 is a perspective view showing the process cartridges (6Y, M, C, K) for each color and a part of the toner transport devices (40Y, M, C, K) for each color. In the same figure, the process cartridges (6Y, M, C, K) of the respective colors are arranged on the lower side in the gravity direction than the toner bottles (32Y, M, C, K) of the toner conveying devices facing each other. In such a configuration, the powder is conveyed from the toner bottle (32Y, M, C, K) serving as the powder container into the developing unit of the process cartridge (6Y, M, C, K) located below the toner bottle (32Y, M, C, K). Thus, it is possible to eliminate a problem caused by conveying the toner against gravity. Each of the toner bottles (32Y, M, C, K) and each of the process cartridges (6Y, M, C, K) are disposed at relatively distant positions, and an intermediate transfer unit 15 is disposed between them. Intervene.

Next, a characteristic configuration of the printer will be described.
FIG. 7 is an enlarged configuration diagram showing a part of the Y toner conveying device 40Y. Y toner discharged from a toner discharge port (not shown) provided in the cap portion 34Y of the toner bottle 32Y is received in the transport tube 43Y. The transport pipe 43Y has a receiving part A for receiving Y toner from the toner discharge port, a straight descending part B straight from the bottle side toward the developing unit (not shown), which is the transport destination, and an inclination angle from the horizontal. It has a bent portion C that bends so as to be smaller. Further, it also has a connecting portion D for connecting to a developing device (not shown). By forming the bent portion C, it can be seen that the inclination angle from the horizontal at the connecting portion D connected to the developing device on the downstream side of the bent portion C is significantly reduced as compared with the straight descending portion B. In the transport pipe 43Y, even if Y toner flows vigorously in the gravitational direction from the bottle side to the developing device side in the linear descending portion B, the course of the course is gentle at the bent portion C before reaching the developing device. become. For this reason, the momentum of the flow of Y toner is weakened in front of the developing device. In the toner transport device 40Y having such a configuration, even if the length of the transport pipe 43Y is increased as the intermediate transfer unit 15 is interposed between the toner bottle 32Y and the process cartridge 6Y as shown in FIG. The flow of Y toner can be weakened in front of the developing unit. As a result, it is possible to suppress problems caused by the Y toner flowing into the developing unit of the process cartridge 6Y from the inside of the transport pipe 43Y at a stroke. Further, since the length of the transport pipe 43Y is relatively large, it is possible to employ a layout in which the toner bottle 32Y and the process cartridge 6Y are separated from each other. As a result, it is possible to eliminate the deterioration of the degree of freedom in layout due to the toner bottle 32Y and the process cartridge 6Y being disposed close to each other. The other color toner conveying devices (40M, C, K) have the same configuration.

  In this printer, as shown in FIG. 8, the bent angle in the transport pipe 43 </ b> Y, that is, the inclination angle θ from the horizontal of the connecting portion D is set within 30 [°]. This is because the present inventors have found that a rapid flow of Y toner into the developing device can be reliably suppressed by setting the inclination angle θ to 30 [°] or less.

  FIG. 9 is a perspective view showing a coil 44 </ b> Y disposed in the transport pipe. When the coil 44Y is rotated in a transport pipe (not shown), a moving force toward the developing device is applied to Y toner (not shown) in the pipe. By disposing such a coil 44Y in the transport tube, the toner in the transport tube can be transported more reliably. In addition, the code | symbol A, B, C, D in a figure has shown the above-mentioned receiving part A, the linear descent | fall part B, the bending part C, and the connection part D, respectively.

  In the conveying tube, the moving force imparting ability of the moving force imparting means such as the coil 44Y is at least at the bent portion C and the straight tube portion (A, B, D) according to the retention property and wearability of the toner. Is desirable. For example, in the bent portion C, the toner is more likely to stagnate than the straight tube portion, so that a toner lump is easily formed. Therefore, when the generation of the toner lump in the bent portion C is remarkable, the moving force applying ability in the bent portion C may be higher than the moving force applying ability in the straight pipe portion. As a result, the generation of a toner lump in the bent portion C can be suppressed. Further, for example, in the bent portion C, the friction between the inner wall of the tube and the toner becomes larger than that in other tube portions, so that toner deterioration due to wear is likely to occur. In particular, when the coil 44Y is used as the moving force applying means as in the present printer, the friction between the coil 44Y and the inner wall of the tube also increases (especially inside the curve), and toner deterioration due to wear is likely to occur. Therefore, when the toner deterioration due to wear in the bent portion C is remarkable, contrary to the case where the generation of the toner lump is remarkable, the ability to impart the moving force in the bent portion C is set to be different at other pipe locations. It is better to make it lower than the ability to apply movement. Then, toner deterioration due to wear in the bent portion C can be suppressed. In this printer, the toner deterioration due to wear is more remarkable than the generation of the toner lump, so that the coil pitch in the bent portion C of the coil 44Y is made larger than the other pipe locations as shown in FIG. . And by this, the moving force provision capability in the bending part C is made smaller than another pipe location.

  Moreover, about the inside of a conveyance pipe, it is desirable to make the internal diameter of the said bending part C larger than the internal diameter of a linear pipe location (A, B, D). This is because by increasing the inner diameter of the bent portion C, the toner clogging can be suppressed. Further, when the coil 44Y is used as the moving force imparting means as in this printer, the friction between the coil 44Y and the inner wall of the tube is reduced by increasing the inner diameter of the bent portion C, and wear. It is also possible to suppress toner deterioration due to toner. Therefore, in this printer, as shown in FIG. 10, the inner diameter d2 of the bent portion C is made larger than the inner diameters (d1, d3) of the linear descending portion B and the connecting portion D.

  Next, specific structural examples that can be employed in each part of the printer according to the present invention will be described. FIG. 11 is a perspective view illustrating a specific structural example of an engaging portion between the toner transport pipe 43Y of the toner transport device 40Y and the toner supply port of the process cartridge 6Y. FIG. 12 is a perspective view of the engaging portion of FIG. 11 viewed from a different angle. FIG. 13 is a perspective view showing a toner conveying device 40Y that conveys yellow toner. FIG. 14 is a perspective view showing the toner conveying device 40Y in a state in which a spring provided near the tip of the conveying tube 43Y is contracted. FIG. 15 is a perspective view partially showing the process cartridge 6Y to which yellow toner is supplied by the toner conveying device 40Y in the vicinity of the supply port 62Y. FIG. 16 is a perspective view showing the process cartridge 6Y in a state where the supply port shutter 67 is opened.

  The end portion of the process cartridge 6Y shown in FIG. 11 is the end portion on the back side when mounted on the printer main body. A pair of side plates 61Y facing each other with a predetermined width are provided on the side surfaces of both ends in the longitudinal direction of the process cartridge 6Y so as to support a photoreceptor, a developing sleeve, two toner conveying screws, and the like (not shown) at the longitudinal ends. ing. The side plate 61Y supports shafts such as a photosensitive member, a developing sleeve, and two toner conveying screws that are components of the process cartridge 6Y. A toner replenishing port 62 </ b> Y positioned above the first supply unit (53 </ b> Y in FIG. 2) in the above-described developing device is provided at a developing device casing corresponding to the inner region of the pair of side plates 61. Thus, by providing the toner replenishing port 62Y within a predetermined width inside the side plate 61Y, the opposing width of the side plate 61Y does not have to be wider than the predetermined width in order to provide the toner replenishing port 62Y. Further, it is not necessary to newly provide a toner supply area outside the side plate 61Y. Therefore, an increase in the size of the process cartridge can be prevented. In this specific structural example, the front surfaces of the pair of side plates are provided in parallel with a certain width, but the shape is not limited to this. For example, this structural example can also be applied to a case where the side plates are partially provided with different widths in order to support each component of the process cartridge at the end. To support each component of the process cartridge, a toner replenishing port may be provided within the predetermined width without changing a predetermined width between the side plates.

  The height of the toner replenishing port 62Y is positioned below the upper end of a developing sleeve (51Y in FIG. 2) (not shown). The tip of the toner transport pipe 43Y is located above the toner supply port 62Y, and an opening 45Y that faces the toner supply port 62Y is formed below the toner transport pipe 43Y. The tip of the toner transport pipe 43Y is a pipe-like engaging portion, that is, a tubular engaging portion, of the toner transport pipe 43Y with respect to the process cartridge 6Y. The tip of the toner transport pipe 43Y is slidable in a direction parallel to the direction of movement of the process cartridge 6Y when the process cartridge 6Y is attached to and detached from the printer body. When the process cartridge 6Y is attached to the printer, the cartridge is inserted in the direction of the arrow b, and the process cartridge 6Y stops at a position where the opening 45Y of the toner transport pipe 43Y faces the toner supply port 62Y, and the attachment is completed.

  A support ring 63Y, which is a ring-shaped support portion that is large enough to receive the tip of the toner transport pipe 43Y, may be provided above the process cartridge 6Y. When the toner transport pipe 43Y is attached to the process cartridge 6Y, the tip of the toner transport pipe 43Y enters the support ring 63Y. When the process cartridge 6Y is detached from the printer, if the cartridge is pulled out in the direction of the arrow a, the toner transport pipe 43Y comes out of the support ring 63Y and leaves the process cartridge 6Y. When the process cartridge 6Y is mounted on the printer again, the cartridge is inserted in the direction of the arrow b, the toner transport pipe 43Y enters the support ring 63Y, and the toner transport pipe 43Y is mounted on the process cartridge 6Y.

  The toner transport pipe 43Y has an opening shutter 47Y at the opening 45Y. On the other hand, the process cartridge 6Y has a supply port shutter 67Y at the supply port 62Y. The two shutters open and close in conjunction with the attachment and detachment of the process cartridge 6Y with respect to the printer body.

  First, the process cartridge 6 is attached to and detached from the printer main body as follows. That is, first, when the process cartridge 6Y in the set position as shown in FIG. 1 is extracted, the front cover 101 on the front surface of the apparatus is opened as shown in FIG. Then, the process cartridge 6 is pulled out to the front. A guide member (not shown) is provided inside the printer body so that the process cartridge can be slid out and inserted. When the process cartridge 6 is started to be extracted, the guide member guides the front end of the photosensitive member shaft and moves the photosensitive member to the retracted position along with the extraction operation. When further extracted, the engagement of each photosensitive member shaft tip with the guide member is released. As a result, the process cartridge 6 is extracted from the opening 45Y on the front surface of the apparatus as shown in FIG. Conversely, when the process cartridge 6 is inserted in the back and stopped at a position where it cannot be pushed any further, the front cover 101 is closed.

Next, a specific example of the opening / closing operation of the shutter in the engaging portion between the transport pipe 43Y and the process cartridge 6Y of FIG. 11 will be described.
When the process cartridge 6Y is not attached, the toner conveying device 43Y is in a state as shown in FIG. Further, the process cartridge 6Y is in a state as shown in FIG. The conveying pipe 43Y closes the opening 45Y by an opening shutter 47Y biased by a spring 46Y. The process cartridge 6Y closes the replenishing port 62Y by an opening shutter 67Y biased by a spring 66Y.

  When mounting the process cartridge 6Y, the process cartridge 6Y is slid and the toner transport pipe 43Y is inserted into the support ring 63Y. Since the shutter 47Y cannot pass through the inside of the support ring 63Y, it is caught by the support ring, the spring 66Y is contracted, and the shutter 47Y is slid as shown in FIG. 14 so that the opening 45Y appears. Simultaneously with this operation, the tip of the toner transport pipe 43Y that has passed through the support ring 63Y pushes the supply port shutter 67Y by further sliding of the process cartridge. As a result, the spring 66Y contracts, and the supply port shutter 67Y slides to cause the supply port 62Y to appear as shown in FIG. When the process cartridge 6Y is installed at a predetermined position, the engaged state as shown in FIG. 11 is obtained. In this engaged state, the opening 45Y and the replenishing port 62Y communicate with each other so that toner can be delivered. At a position where the opening 45Y and the replenishing port 62Y face each other, a sealing material that suppresses toner leakage from the gap is provided.

  When removing the process cartridge 6Y from the printer body, the process cartridge 6Y is pulled out from the state shown in FIG. 11 in the direction of arrow a in the figure. At this time, the following changes occur on the process cartridge 6Y side. That is, the replenishment port shutter 67Y is urged toward the back of the printer body by the restoring force of the spring 66Y of the process cartridge 6Y that has been contracted by the toner transport pipe 43Y. As a result, the supply port shutter 67 moves in the direction of the arrow a to close the supply port 62Y, and the process cartridge 6Y returns to the state shown in FIG. On the other hand, the following changes occur on the toner transport pipe 43Y side. That is, the opening shutter 47Y is moved to the end of the toner transport pipe 43Y by the restoring force of the spring 46Y of the toner transport pipe 43Y that has been shrunk by the support ring 63Y from the support ring 63Y of the process cartridge 6Y. Biased in the direction. As a result, the opening shutter 47Y moves in the direction of arrow b, closes the opening 45Y, and the toner transport pipe 43Y returns to the state shown in FIG.

  The example in which the present invention is applied to an electrophotographic printer has been described so far, but the present invention can also be applied to an image forming apparatus that forms a toner image by other methods such as a direct recording method. This direct recording method is not related to the latent image carrier, but forms a pixel image by directly adhering a toner group that has been ejected in a dot shape from a toner flying device to a recording medium or an intermediate recording medium. In this method, a toner image is directly formed on an intermediate recording medium. Also, a printer using a toner transport device that transports toner as powder has been described, but the present invention can also be applied to a powder transport device that uses powder different from toner.

As described above, in the printer according to the embodiment, as the transport pipe (for example, 43Y) of each toner transport apparatus, the one having the bent inclination angle θ within 30 [°] is used. A sudden flow of toner into the developing device can be more reliably suppressed.
In addition, since a coil (for example, 44Y) is provided as a moving force applying means for applying a moving force from the bottle side to the developing device side to the toner in the conveying tube, the toner in the conveying tube can be more reliably conveyed. it can. Furthermore, since the moving force imparting ability at the bent portion C and the moving force imparting ability at other pipe locations (A, B, D) are different for this coil, the generation of toner mass in the bent portion C is prevented. It is possible to suppress toner deterioration due to wear.
In addition, since the inner diameter of the bent portion C of the transport pipe is made larger than the inner diameter of other tube locations, this also suppresses the generation of toner masses in the bent portion C and suppresses toner deterioration due to wear. can do.
Further, as the toner image forming means, a process cartridge (6Y, M, C, K) in which the photosensitive member and the developing device are detachably attached to the printer main body as one unit is used, and the toner serving as the toner storage unit is used. The bottles (32Y, M, C, K) are configured to be detachable from the printer main body separately from the cartridge. With this configuration, it is possible to eliminate the trouble of having to remove the process cartridge when replacing the toner bottle.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 3 is an enlarged configuration diagram showing a process cartridge for Y of the printer and its surroundings. FIG. 3 is a perspective view showing a toner bottle for Y of the printer. FIG. 3 is a perspective view showing a bottle support portion and four toner bottles in the printer. FIG. 3 is a perspective view illustrating a part of a toner supply device for Y, M, C, and K in the printer. FIG. 3 is a perspective view showing a process cartridge for each color and a part of a toner transport device for each color. FIG. 3 is an enlarged configuration diagram illustrating a part of a Y toner conveyance device. FIG. 3 is an enlarged view showing a part of a conveyance tube of the toner conveyance device. The perspective view which shows the coil arrange | positioned in the conveyance pipe. The side view which shows a part of the conveyance pipe. FIG. 3 is a perspective view illustrating a specific structure example of an engaging portion between a toner conveyance pipe of the toner conveyance device and a toner supply port of a Y process cartridge. The perspective view which looked at the same engaging part from the angle different from FIG. FIG. 3 is a perspective view showing the toner conveying device. FIG. 3 is a perspective view showing the toner conveying device in a state where a spring provided near the tip of the conveying tube is compressed. FIG. 3 is a perspective view partially showing the process cartridge, in which yellow toner is supplied by the toner conveying device, in the vicinity of a supply port. The partial perspective view which shows the process cartridge of the state which opened the supply port shutter. FIG. 2 is a partial perspective view showing the printer.

Explanation of symbols

1Y, M, C, K photoconductor (latent image carrier)
5Y Developer (Destination)
6Y, M, C, K process cartridge (part of toner image forming means, image forming unit)
7 Exposure device (part of toner image forming means)
32Y, M, C, K Toner bottle (toner container)
40Y, M, C, K Toner conveying device (powder conveying device)
43Y Conveying tube 44Y Coil (moving force applying means)
θ Inclination angle

Claims (4)

A powder container for storing powder, a transport pipe for guiding the powder from the powder container to a transport destination below the powder container, and a container disposed in the transport pipe so as to be rotated by its own rotation. And a coil for applying a moving force from the powder container side to the transport destination side of the powder, and transports the powder in the powder container part to the transport destination through the transport pipe In the powder conveying device,
A portion that extends downward from the powder container side toward the transport destination side on the transport pipe, and is positioned closer to the transport destination side than the portion, so that the inclination angle from the horizontal is smaller than the portion. And a bent portion that bends ,
The inner diameter of the bent portion, and larger than the inner diameter of the non-bending portion located at a site which is not bent in the conveying pipe,
In addition, the coil is provided with a portion where the helical pitch is relatively short and a portion where the helical pitch is relatively long in the axial direction in a state in which the coil naturally takes a straight posture without being bent or stretched. A powder conveying apparatus using the latter portion, which is located at the bent portion of the conveying tube . In the powder conveying apparatus according to claim 1,
A powder conveying apparatus characterized in that the conveying tube has an angle of inclination of 30 [°] or less from the horizontal of a portion adjacent to the bent portion on the conveying destination side. An image forming apparatus comprising: a toner image forming unit that forms a toner image using toner that is powder; and a toner conveying device that conveys the toner from a toner container to the toner image forming unit.
An image forming apparatus using the powder conveying device according to claim 1 or 2 as the toner conveying device. The image forming apparatus according to claim 3 .
As the toner image forming means, at least a latent image carrier that carries a latent image and a developer that develops the latent image on the latent image carrier can be attached to and detached from the image forming apparatus main body as one unit. An image forming apparatus comprising: an image forming apparatus having a configured image forming unit; and the toner container serving as a powder container being detachable from the image forming apparatus main body separately from the unit.

Images