JP2008185926A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the periphery of a developing device from being contaminated by a developer when the developer is fed to the developing device by attaching and detaching a developer feeding member. <P>SOLUTION: An image-forming device is provided with a photosensitive drum 21, a developing device 221, a toner-feeding pipe 73, a toner-feeding pipe moving mechanism, a cooling fan, and a cooling air feeding-stopping means. The toner-feeding pipe 73 is a member for feeding a toner to the developing device 221. The toner-feeding pipe moving mechanism is a mechanism for moving the toner-feeding pipe 73 to a feeding position, at which the toner is fed into the developing device 221, and to a standby position at which the toner stands by at the outside of the developing device 221. The cooling fan is a device for feeding cooling air for cooling the developing device 221 to the developing device 221. The cooling air feeding-stopping means is a means for making the cooling fan stop the feeding of the cooling air to the developing device 221 at least when the toner-feeding pipe 73 is moved, by the toner-feeding pipe moving mechanism, from the feeding position to the standby position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus capable of supplying developer to the developing device from the outside of the developing device.

  An electrophotographic image forming apparatus such as a copying machine or a printer includes a developing device, forms an image on a sheet, a fixing unit that fixes the formed image on the sheet, and conveys the sheet to the image forming unit. In some cases, the printer includes a paper transport unit that discharges the paper, a paper discharge unit that discharges the paper on which the image is fixed, and a toner supply pipe that can be inserted into and removed from the developing device and can supply toner. In such an image forming apparatus, an image is formed on a sheet by an image forming unit, and the image is fixed on the sheet by a fixing unit. The sheet on which the image is fixed is discharged from the discharge unit. When the toner in the developing device decreases, the toner is supplied to the developing device by the toner supply pipe.

In addition, the image forming apparatus is provided with a cooling fan as disclosed in Japanese Patent Application Laid-Open No. H10-228707. In the apparatus disclosed in this document 1, after the image forming operation is completed, the motor that drives the cooling fan can be controlled to arbitrarily control the in-machine temperature according to the usage environment.
Japanese Patent Laid-Open No. 08-129331

  Here, in an image forming apparatus that replenishes toner to the developing device through a toner replenishing pipe, when toner is replenished, the toner leaks from the tip of the pipe or the replenishing port of the developing device with a minute amount. On the other hand, since the cooling air for cooling the developing device is supplied by the cooling fan, the toner leaked at the time of replenishing the toner flows into the cooling air and contaminates the inside of the apparatus. In particular, falling toner tends to be washed away by the wind and easily contaminates the inside of the machine.

  An object of the present invention is to prevent the surroundings of the developing device from being contaminated by the developer when the developer supply member is inserted and removed to supply the developer to the developing device.

  An image forming apparatus according to a first aspect includes an electrostatic latent image carrier, a developing device, a developer supply member, a moving mechanism, and an airflow stopping unit. The electrostatic latent image carrier is a member on which an electrostatic latent image is formed. The developing device is a device that develops the electrostatic latent image on the electrostatic latent image carrier. The developer supply member is a member that can supply the developer to the developing device. The moving mechanism is a mechanism that moves the developer supply member to a supply position where the developer supply member is inserted into the developing apparatus and a standby position where the developer supply member is made to wait outside the developing apparatus. The airflow stopping means is means for stopping the flow of gas in the vicinity of the developing device when the developer supply member is moved from the supply position to the standby position by at least the moving mechanism.

  In this image forming apparatus, an electrostatic latent image is formed on the electrostatic latent image carrier, and a developer is supplied from the developing device onto the electrostatic latent image carrier. When the developer in the developing device decreases, the developer supply member is moved from the standby position to the supply position by the moving mechanism, and the developer is supplied to the developing device. When the supply of the developer to the developing device is completed, the developer supply member is moved from the supply position to the standby position. At this time, the flow of gas in the vicinity of the developing device is stopped by the airflow stopping means.

  Here, at least when the developer supply member moves from the supply position to the standby position, the flow of gas in the vicinity of the developing device is stopped by the airflow stopping means, so that at least the developer supply member is moved from the supply position to the standby position. It is possible to make the periphery of the developing device less likely to be contaminated by the developer when moving to.

  An image forming apparatus according to a second aspect is the image forming apparatus according to the first aspect, wherein the airflow stopping unit further generates an airflow when the developer supply member is moved from the standby position to the supply position by the moving mechanism. Stop.

  Here, when the developer supply member is moved from the standby position to the supply position, the periphery of the developing device can be made less likely to be contaminated by the developer.

  An image forming apparatus according to claim 3 is the image forming apparatus according to claim 1 or 2, wherein the image forming apparatus is disposed in the vicinity of the developing device and is directed from the outside toward the developing device or from the vicinity of the developing device toward the outside. A fan for carrying air is further provided.

  Here, the temperature of the developing device can be prevented from rising.

  An image forming apparatus according to a fourth aspect is the image forming apparatus according to any one of the first to third aspects, wherein the developer supply member is a cylindrical member, and the developer supply member includes a developer supply member. A toner supply port that can be inserted and removed is provided.

  Here, when the developer is replenished in such a manner, the developer is particularly effective because the developer is easily scattered around the developing device when the developer is replenished.

  An image forming apparatus according to a fifth aspect is the image forming apparatus according to any one of the first to fourth aspects, wherein the image formed on the electrostatic latent image carrier is disposed in the vicinity of the developing device. The image forming apparatus further includes a fixing unit for fixing the image on the screen.

  In such a case, it is necessary to use a cooling air supply device because the developing device is easily affected by the heat of the fixing unit, and this is particularly effective because the cooling air is supplied to the developing device by the cooling air supply device. is there.

  In the present invention, when the developer supply member is inserted and removed to supply the developer to the developing device, the periphery of the developing device can be hardly contaminated by the developer.

1. Configuration FIG. 1 shows a color printer 1 as an image forming apparatus according to an embodiment of the present invention. FIG. 1 is a schematic diagram for illustrating the arrangement of each component, and details of each part are omitted.

  The color printer 1 is connected to a computer (not shown) or the like, and is a device that can print a color image on paper based on image information sent from an external computer or the like. The color printer 1 includes an image forming unit 2, a sheet conveyance path 3, a fixing unit 4, a sheet storage unit 5, a discharge unit 6, a toner supply device 7 (developer supply device), and a cooling fan 8 (cooling). It has a wind supply device (see FIG. 4) and a controller 9 (see FIG. 5). Here, the toner replenishing device 7, the cooling fan 8, and the control unit 9 will be described in detail later.

  The image forming unit 2 includes a photosensitive drum 21, a rotary developing device 22, a charging device 23, a laser unit 24, and a cleaning device 25. The rotary developing device 22 will be described in detail later.

  The photosensitive drum 21 is a member on which an electrostatic latent image is formed, and is disposed at the approximate center of the color printer 1. The photosensitive drum 21 is a drum-shaped member, and a rotation shaft is provided in a direction orthogonal to the paper surface of FIG. An intermediate transfer belt 211 for transferring a toner image on the photosensitive drum 21 to a sheet is disposed below the photosensitive drum 21 in the vicinity of the photosensitive drum 21. The charging device 23 is a device for charging the surface of the photosensitive drum 21, and is disposed on the upper side of the photosensitive drum 21.

  The laser unit 24 is a member arranged on the upper side of the rotary developing device 22 and is a portion for irradiating a laser beam to form an electrostatic latent image based on image data on the photosensitive drum 21. It is.

  The cleaning device 25 is a device for removing deposits such as residual toner remaining on the photosensitive drum 21. In the color printer 1, the cleaning is performed on the entire axial direction of the photosensitive drum 21 above the photosensitive drum 21. A blade is provided.

  The paper transport unit 3 has a transport path that continues from the paper storage unit 5 through the image forming unit 2 and the fixing unit 4 to the discharge unit 6.

  The fixing unit 4 is disposed below the rotary developing device 22 and has a heating roller 41 and a pressure roller 42. The heating roller 41 is a member for melting toner that forms an image formed on a sheet with heat, and is disposed on the upper side of the pressure roller 42.

  The paper storage unit 5 is a part disposed at the lower part of the color printer 1 and has a paper feed cassette 51.

  The discharge unit 6 is disposed on the upper surface of the color printer 1 and discharges a sheet on which an image is formed.

2. Rotating developing device, toner replenishing device, cooling fan, control unit The rotating developing device 22 is a member disposed adjacent to the photosensitive drum 21 and is a cylindrical device as a whole. The rotary developing device 22 includes four developing devices 221 (developing devices) and a frame 222 that supports the four developing devices 221.

  As shown in FIGS. 1 and 3, the developing device 221 includes a container body 223 and a developing roller 224. The container body 223 has a shape in which a cylinder is divided into four in the circumferential direction, and has an opening extending in the longitudinal direction. Further, a toner supply port 223a through which a toner supply pipe 73 described later can pass is formed on the surface of the container body 223, and the toner supply port 223a has a seal member 223b. The seal member 223b is a substantially square sheet-like elastic member, and has a single slit 223c formed in the approximate center. The four container main bodies 223 store yellow, cyan, magenta, and black toners, respectively. Here, FIG. 3 shows one developing unit 221.

  The developing roller 224 extends in the rotation axis direction of the rotary developing device 22 and is disposed in the opening of the container main body 223. The developing roller 224 is a member for supplying toner to the surface of the photosensitive drum 21. At both ends of the developing roller 224, distance regulating rollers 225 for maintaining a distance between the photosensitive drum 21 and the developing roller 224 are disposed. The distance regulating roller 225 is a disk-shaped member having a radius larger than that of the developing roller 224, and the distance between the photosensitive drum 21 and the developing roller 224 is set by contacting the outer peripheral surface with the photosensitive drum 21. Kept constant.

  As shown in FIGS. 1 and 2, the toner replenishing device 7 is for replenishing toner to the developing device 221, and includes a toner container 71, a toner transport pipe 72, and a toner supply pipe 73 (developer supply member). ) And a toner supply pipe moving mechanism 74 (moving mechanism). Here, FIG. 3 is a view showing a seal member 223b and the like provided in the developing device 221. Further, the toner container 71 is disposed at substantially the same height as the laser unit 24 above the photosensitive drum 21. The toner container 71 is a box-shaped member that stores toner therein. The toner transport pipe 72 is a flexible pipe so that it can move following the vertical movement of the toner supply pipe 73. A coil spring 721 is disposed inside and rotated by a driving mechanism (not shown), whereby the toner is conveyed to the toner supply pipe 73 side through the toner conveyance pipe 72. The toner supply pipe 73 is long in the vertical direction, and the upper end is inclined to the right side in FIG. 1 and the lower end is inclined to the left side in FIG. In addition, an opening for supplying toner is provided at the tip of the toner supply pipe 73. The toner supply pipe 73 has a tapered tip, and when it moves downward, the tip enters the interior through a slit 223c formed in a seal member 223b disposed on the surface of the developing unit 221. Is possible.

  As shown in FIG. 2, the toner supply pipe moving mechanism 74 has a standby position where the toner supply pipe 73 waits outside the developing device 221 for toner supply, and the tip of the toner supply pipe 73 is connected to the developing device 221. A mechanism for moving between a supply position where the toner can be supplied to the developing device 221 by being inserted therein, and a rack 741 provided along the axial direction on the outer periphery of the toner supply pipe 73; A pinion gear 742 that meshes with the rack 741 is provided. The pinion gear 742 is rotatably supported by the frame of the apparatus, and is driven by a motor, a worm, a worm wheel, and a reduction gear train (not shown). Then, the toner supply pipe moving mechanism 74 allows the four toner supply pipes 73 to take an upper standby position and a supply position where the tip portion enters the inside of the developing device 221 below. Here, FIG. 2 is a diagram showing the toner transport pipe 72, the toner supply pipe 73, and the like.

  As shown in FIG. 4, the cooling fan 8 (cooling air supply device) is provided in the vicinity of the developing device 221, and can supply cooling air around the developing device 221. The cooling fan 8 is attached to the frame of the color printer 1. Here, FIG. 4 is a view showing the vicinity of the developing device 221. 4 is a perspective view showing the inside of the color printer 1 from the back side of the sheet of FIG. 1. The four developing units 221 and the toner replenishing device 7 out of the three developing units 221 and the toner replenishing device 7 A part of the frame of the color printer 1 is omitted.

  The controller 9 is composed of a microcomputer including a CPU. As shown in FIG. 5, the cooling air supply stop means 91 (airflow stop means), the toner supply timing detection means 92, and the toner supply end timing detection means. 93. Here, FIG. 5 is a block diagram showing the control unit 9. The controller 9 also functions as a cooling air supply stop unit 91, a toner supply timing detection unit 92, and a toner supply end timing detection unit 93 by executing a program. Further, the control unit 9 performs various other controls, for example, temperature control of the fixing unit 4.

  The cooling air supply stopping means 91 is moved when the toner supply pipe 73 is moved, that is, when the toner supply pipe 73 is moved from the standby position to the supply position for toner supply, and when the toner supply is completed and moved from the supply position to the standby position. This is means for stopping the cooling fan 8 and stopping the supply of cooling air.

  The toner supply timing detection unit 92 is a unit that detects the toner supply timing from the toner amount inside the developing device 221. Here, as a method of detecting the toner amount inside the developing device 221, for example, the dot count of the image formed when the image is formed is calculated, and the dot count of the image formed after supplying the toner to the developing device 221 is calculated. The accumulated dot count obtained by accumulating is calculated. Then, the toner consumption amount is detected from the accumulated dot count, and can be calculated by subtracting the toner consumption amount from the toner amount in the developing device 221 after the toner supply. Note that the present invention is not limited to this method, and the toner amount in the developing device 221 may actually be measured.

  The toner supply end timing detection means 93 is a means for detecting the toner supply end timing, and can detect whether or not the toner amount in the developing device 221 has reached a predetermined amount (amount after toner replenishment). The toner detection end time is detected from a sensor (not shown) attached inside the developing device 221.

3. Operation An image forming operation will be described.

  When image information is transmitted from a computer connected to the outside, the surface of the photosensitive drum 21 is charged by the charging device 23, and laser light is emitted from the laser unit 24 based on the image information. When an electrostatic latent image is formed on the photosensitive drum 21, the frame 222 rotates and toner is supplied from each developing device 221 to the photosensitive drum 21. When an image is formed on the photosensitive drum 21 in this way, this image is transferred to a sheet via the intermediate transfer belt 211. The sheet onto which the image has been transferred is conveyed to the fixing unit 4 where the image is fixed. Thereafter, the paper is discharged from the discharge unit 6 to the outside of the color printer 1.

  Next, the operation of supplying toner when the toner in the developing device 221 is reduced will be described with reference to the flowchart shown in FIG.

  First, it is determined whether or not toner replenishment is performed (S1). When toner is not supplied (NO in S1), the process waits for the next toner supply. When the toner consumption reaches a predetermined amount or more, toner supply is performed (YES in S1). Here, the number of dots of the image formed by the image forming operation as described above is counted, and the amount of toner consumed after toner replenishment is calculated by accumulating the dot count of the image formed after toner replenishment. The

  When the toner is replenished, the cooling air supply from the cooling fan 8 is stopped (S2). The pinion gear 742 is rotated by the power of the motor while the cooling air supply from the cooling fan 8 is stopped, and the toner supply pipe 73 moves from the standby position to the supply position as the pinion gear 742 rotates. Then, it is determined whether the toner supply pipe 73 has reached the supply position (S3). If the toner supply pipe 73 has not reached the supply position (NO in S3), the toner supply pipe 73 is moved until it reaches the supply position. When the toner supply pipe 73 reaches the supply position (YES in S3), the supply of cooling air by the cooling fan 8 is resumed (S4). Thereafter, it is determined whether or not the toner supply is completed (S5). Specifically, it is determined whether or not the toner amount in the developing unit has reached a predetermined amount by a sensor (not shown). If the toner supply is not completed (NO in S5), that is, if the toner amount in the developing device 221 has not reached the predetermined amount, the toner supply is continued until the toner amount reaches the predetermined amount. When the toner amount in the developing device 221 reaches a predetermined amount (YES in S5), the cooling air supply of the cooling fan 8 is stopped (S6), and the toner supply pipe 73 is moved from the supply position to the standby position. Next, it is determined whether the toner supply pipe 73 is in the standby position (S7). If the toner supply pipe 73 has not reached the standby position, the movement of the toner supply pipe 73 is continued (NO in S7). If the toner supply pipe 73 has reached the standby position (YES in S7), cooling is performed. Supply of cooling air from the fan 8 is resumed (S8).

  Here, since the cooling fan 8 is stopped when the toner supply pipe 73 is inserted into and removed from the developing device 221, it is possible to prevent the toner leaked during the toner supply from scattering into the apparatus. Since the cooling air is supplied while the toner is supplied by the toner supply pipe 73, the cooling air is not stopped for a long time, and the abnormal heat generation of the developing device 221 can be prevented.

4). Other Embodiments (a) Although the color printer 1 has been described in the above embodiment, the present invention is not limited to this, and may be a copying machine, a multifunction machine, or the like.

  (B) In the above embodiment, the supply of the cooling air by the cooling fan 8 is stopped when the toner supply pipe 73 is inserted into the developing device 221 and when the toner supply pipe 73 is detached from the developing device 221. However, the supply of the cooling air by the cooling fan 8 may be stopped only when the toner supply pipe 73 is detached from the developing device 221. In this case, it is possible to prevent the temperature of the developing device 221 from rising because the cooling fan 8 is supplied with cooling air to the developing device 221 for a long time.

  (C) In the above embodiment, the cooling air is supplied by the cooling fan 8, but the present invention is not limited to this, and the air near the developing device 221 may be discharged by the cooling fan 8.

Schematic diagram of a color printer. The figure which shows a toner supply pipe, a toner conveyance pipe, etc. FIG. 3 is a diagram illustrating a toner supply port of a developing device. The figure which shows a cooling fan. The block diagram which shows a control part. The figure which shows a cooling fan.

Explanation of symbols

1 Color printer (image forming device)
7 Toner supply device 8 Cooling fan 21 Photosensitive drum (electrostatic latent image carrier)
71 Toner container 72 Toner transport pipe 73 Toner supply pipe (developer supply member)
74 Toner supply pipe moving mechanism (developer supply member moving mechanism)
75 Seal member support member 91 Cooling air supply stopping means (airflow stopping means)
92 Toner supply time detection means 93 Toner supply end time detection means (Developer supply end time detection means)
221 Developer (Developer)
223a Toner supply port 223b Seal member 223c Slit 224 Developing roller 744 Shutter mechanism

Claims (5)

An electrostatic latent image carrier on which an electrostatic latent image is formed;
A developing device for developing the electrostatic latent image on the electrostatic latent image carrier;
A developer supply member capable of supplying a developer to the developing device;
A moving mechanism for moving the developer supply member between a supply position for inserting the developer supply member into the developing device and a standby position for waiting the outside of the developing device;
An airflow stopping means for stopping the flow of gas in the vicinity of the developing device when the developer supply member is moved from the supply position to the standby position by at least the moving mechanism;
With
Image forming apparatus. The air flow stop means further stops the air flow when the developer supply member is moved from the standby position to the supply position by the moving mechanism;
The image forming apparatus according to claim 1. A fan that is disposed in the vicinity of the developing device and conveys air from the outside toward the developing device or from the vicinity of the developing device toward the outside;
The image forming apparatus according to claim 1. The developer supply member is a cylindrical member,
The developing device is provided with a toner supply port through which the developer supply member can be inserted and removed.
The image forming apparatus according to claim 1. The image forming apparatus further includes a fixing unit disposed in the vicinity of the developing device and configured to fix an image formed on the electrostatic latent image carrier on a sheet.
The image forming apparatus according to claim 1.

Images