JP2005300738A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of solving a problem that toner is left in a waste toner carrier path when toner amount to be disused is generated more than that of normal image formation, and toner is clogged into the waste toner carrier path when disused toner is allowed to flow into the toner carrier path again or a problem that toner in the waste toner carrier path is cohered in accordance with temperature or humidity in the apparatus and capable of starting image formation without waiting a user after the completion of warming-up. <P>SOLUTION: When toner to be disused is generated more than that of normal image formation, a control means (10) allows a driving means to continue drive for a shorter period out of the lapse of prescribed time and a period up to the start of image formation in addition to normal drive by the driving means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine having these functions.

  2. Description of the Related Art Conventionally, in an image forming apparatus, there is a method in which toner is placed on a photosensitive drum and the photosensitive drum is polished (cleaned) for the purpose of removing condensation on the photosensitive drum during warm-up immediately after power-on. On the other hand, when printing at a low density continues, there is a method of discharging toner onto the photosensitive drum and supplying new toner from a container for storing the toner in order to prevent deterioration of the toner in the developing device.

  The toner discharged onto the photosensitive drum as described above is not transferred to the paper, but is completely removed by a toner cleaning mechanism made of a rubber plate or the like. The toner scraped off by the toner cleaning mechanism is discarded toner. The toner is sent to the waste toner collection tank through the conveyance path (herein, the toner discarded without being transferred onto the paper in this way is referred to as waste toner).

On the other hand, in the technique described in Patent Document 1, in order to prevent toner aggregation around the conveying screw in the conveying pipe that conveys the toner collected from the cleaner to the foreign matter separating device, the outer periphery of the conveying screw hits the inner wall surface of the conveying pipe. A structural idea of disposing a contact member is shown. On the other hand, in the technique described in Patent Document 2, in order to reliably and efficiently clean the transfer residual toner on the image carrier, a predetermined image in the continuous image forming mode or at the end of the image forming mode in which the image is formed is used. It is described that a toner collection mode for collecting the toner removed from the image carrier by the cleaning device during image formation by the developing device is executed every time the image is formed, and then a standby state for executing the image formation mode is set. ing.
Japanese Patent Laid-Open No. 9-244506 Japanese Patent Laid-Open No. 8-21801

  If the motor that drives the transport mechanism of the waste toner transport path is stopped before the waste toner is completely collected in the waste toner recovery tank as in the prior art, the toner remains in the waste toner transport path and is again discarded. When the toner flows in, there is a problem that the toner is clogged there. There is also a problem that toner in the waste toner conveyance path aggregates depending on the temperature and humidity in the apparatus.

  Further, the technique described in Patent Document 1 requires a structural change. The technique described in Patent Document 2 is intended to reliably and efficiently perform recovery by a developing unit in normal image forming processing, such as condensation removal on a photosensitive drum during warm-up immediately after power-on. In order to prevent the toner in the developing unit from deteriorating when the toner is deposited on the photosensitive drum for the purpose or when low density image formation continues, the toner is discharged from the developing unit and deposited on the photosensitive drum. This does not take into consideration the problem of toner clogging or aggregation in the toner transport path when a large amount of waste toner is generated, and image formation cannot be started during execution of the toner recovery mode, thus causing the user to wait. .

  The present invention has been made in view of the above points. When a large amount of toner to be discarded is generated in comparison with normal image formation, when the toner remains in the waste toner conveyance path and the waste toner flows again, Providing an image forming device that can solve the problem of toner clogging and the aggregation of toner in the waste toner transport path due to the temperature and humidity in the machine, and can start image formation without waiting for the user after the warm-up is completed. To do.

  In order to solve the above-mentioned problems, the invention described in claim 1 includes an image carrier, a developing device that attaches toner to the image carrier, toner removal means that removes toner attached to the image carrier, In an image forming apparatus including a toner conveying unit that conveys the removed toner and a driving unit that drives the toner conveying unit, if a larger amount of toner is discarded than during normal image formation, the driving unit In addition to the above-described driving, there is provided control means for continuously driving by the driving means until a predetermined time elapses or until image formation is started.

  According to a second aspect of the present invention, there is provided an image carrier, a developing device for attaching toner to the image carrier, a toner removing means for removing the toner attached to the image carrier, and the removed toner. In an image forming apparatus comprising a toner conveying means for conveying and a driving means for driving the toner conveying means, a detecting means for detecting the remaining amount of toner in the toner conveying means is further provided, and the toner to be discarded is used for normal image formation. If it occurs in a larger amount than the time, until the remaining amount of toner in the toner conveying means detected by the detecting means becomes a predetermined value or less or until image formation is started, Control means for continuously driving by the drive means is provided.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect of the present invention, the driving unit rotates so that toner is attached to the surface of the image carrier by the developing unit. A developing motor for driving the developing sleeve, a conveying motor for driving a paper feeding roller for feeding printing paper, or a drum motor for driving the image carrier.

  Here, a large amount of toner to be discarded means that the toner adheres to the photosensitive drum for the purpose of removing condensation on the photosensitive drum during warm-up immediately after the power is turned on, or low-density image formation. In this case, a case where a large amount of toner to be discarded occurs, such as when the toner is discharged from the developing device onto the photosensitive drum and adhered to prevent the toner in the developing device from deteriorating.

  According to the present invention, when a large amount of waste toner is generated than in normal image formation, when the toner remains in the waste toner conveyance path and the waste toner flows again, the toner is clogged there, The problem that the toner in the waste toner conveyance path aggregates due to humidity can be solved. Also, because of this control, the user does not wait when starting the image formation.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention.
The basic configuration of the image forming apparatus 1 of the present embodiment is the same as that of a conventional image forming apparatus, and includes a control unit 10, a storage unit 20, a scanner unit 30, an image forming unit 40, an operation unit 50, and a display unit 60. The notification unit 70 is schematically configured.

The control unit 10 controls each unit of the image forming apparatus 1 and performs control for collecting waste toner, which will be described later.
The storage unit 20 stores a control program executed by the control unit 10 and various data.
The scanner unit 30 is a portion that reads a document set on a document table, and is equipped with an automatic document feeder (not shown) that sequentially conveys a plurality of documents to the document table.

  The image forming unit 40 includes a sheet feeding unit that feeds a sheet material that is printing paper, a transfer unit that performs a transfer process of a toner image to the sheet material, and a fixing unit that performs a fixing process of a toner image transferred to the sheet material. , And a sheet discharge unit (none of which is shown in FIG. 1) for discharging the sheet material after fixing, and performs a series of processes related to the image forming process. For example, at the time of copying, the scanner unit 30 reads a document set on a document table, the control unit 10 supplies the image data to the image forming unit 40, and the image forming unit 40 performs image processing according to the image data. A forming process is performed. The paper feed unit includes a paper feed stage for setting cut paper, and the sheet material of the selected paper feed stage is fed.

The operation unit 50 includes various keys, a touch panel, and the like for the user to input operation commands and settings to the image forming apparatus 1. The user performs various settings from the operation unit 50.
The display unit 60 is a display unit that displays a processing status in the image forming apparatus 1 and setting information input from the operation unit 50. A touch panel that constitutes the operation unit 50 is provided on the surface of the display unit 60. .
The notification unit 70 emits a notification sound (buzzer sound, melody, etc.) for abnormality notification or the like.

The control unit 10 includes a memory, a CPU (central processing unit), and the like, and loads a program (not shown) for realizing each function of the control unit 10 into the memory and executes the program. Functions shall be realized.
The storage unit 20 is configured by a nonvolatile recording device such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) or a hard disk, and the display unit 60 is configured by a CRT (Cathode Ray Tube) or a liquid crystal display device.
The image forming apparatus 1 is also provided with various sensors such as a sensor for detecting the remaining amount of toner in the waste toner conveyance path, a temperature sensor for detecting the temperature of the fixing unit, and a humidity sensor for detecting the humidity inside the apparatus. ing.

  Next, the configuration (outline) of the transfer unit included in the image forming unit 40 will be described with reference to FIG.

  The photosensitive drum 40a shown in FIG. 3 is charged by the charger 40b. A laser scanning unit (not shown), which is an exposure unit, irradiates the photosensitive drum 40a with a laser beam based on image data supplied from the control unit 10, thereby forming an electrostatic latent image on the photosensitive drum 40a. Let it form. The electrostatic latent image is developed by the developing device 40c to form a toner image (at this time, toner discharged from the developing device 40c adheres to the photosensitive drum 40a). On the other hand, the sheet material 40d is conveyed from the sheet feeding stage between the photosensitive drum 40a and the transfer roller 40e by a sheet feeding roller and a registration roller (both not shown in the figure).

  While the sheet material 40d passes between the photosensitive drum 40a and the transfer roller 40e, the toner image formed on the photosensitive drum 40a is transferred. The sheet material 40d to which the toner image has been transferred is further conveyed to a fixing unit, where the toner image transferred to the sheet material 40d is fixed. After the series of processes described above, the toner remaining on the photosensitive drum 40a is all removed by the toner cleaning mechanism 40f, and the toner scraped off from the photosensitive drum 40a is sent to the waste toner collection tank 40h through the waste toner conveyance path 40g. .

  The waste toner conveyance path 40g is formed in a pipe shape, and a spiral screw for conveying the waste toner is provided therein, and the waste toner is conveyed to the waste toner collection tank 40h by rotating the screw. . Further, as a driving source for driving the spiral screw, a developing motor that drives a developing sleeve that rotates so as to cause toner to adhere to the surface of the photosensitive drum 40a by a developing device 40c or a paper feeding roller that feeds printing paper is used. A driving motor for driving or a drum motor for driving the photosensitive drum 40a can be used.

  The above is an outline of the normal operation in the transfer unit. In the case where toner is adhered on the photosensitive drum 40a during the warming-up immediately after the power is turned on for the purpose of removing condensation on the photosensitive drum 40a (case 1), A large amount of waste toner is used when the toner is discharged from the developing device 40c onto the photosensitive drum 40a in order to prevent the toner in the developing device 40c from deteriorating when low density image formation continues (case 2). In this case, the toner scraped off from the photosensitive drum 40a by the toner cleaning mechanism 40f is controlled to be sent to the waste toner collection tank 40h through the waste toner transport path 40g.

  Conventionally, this control is performed by the image forming unit 40 until the warm-up is completed in the case of the case 1 or until the toner is completely removed from the photosensitive drum 40a in the case of the case 2, for example. While the waste toner conveyance path 40g is driven until the ready state (printable state) is reached, in the present embodiment, when a large amount of waste toner is generated, the predetermined amount is maintained after the ready state is entered. By controlling the waste toner conveyance path 40g to be driven so that almost no waste toner remains in the waste toner conveyance path 40g for a period of time (however, until the start of printing is instructed) Resolve clogging and aggregation problems.

Next, control related to the collection of waste toner in the image forming apparatus 1 of the present embodiment configured as described above will be described with further reference to the flowcharts of FIGS.
The example described here is an example in which a developing motor is used as a driving source for the waste toner transport path 40g, and the drive control of the waste toner transport path 40g is performed by controlling the developing motor.

First, when the power is turned on, the image forming apparatus 1 starts a warm-up operation (step S01). Here, heating is performed so that the fixing temperature of the fixing unit becomes a predetermined temperature.
Next, the developing motor is driven (step S02). At this time, the waste toner transport path 40g is driven by driving the developing motor. At this stage, toner does not adhere from the developing device 40c to the photosensitive drum 40a.
Next, it is determined whether or not the environmental humidity detected by the humidity sensor is 60% or more (step S03).

Here, if the environmental humidity is 60% or more, the determination in step S03 is YES, and the process proceeds to step S04, where drum polishing with toner is started. That is, for the purpose of removing condensation on the photosensitive drum 40a during warming up, the developing device 40c attaches toner onto the photosensitive drum 40a and polishes it by the toner cleaning mechanism 40f. The drum polishing by the toner loading is finished when all the toner adhering to the photosensitive drum 40a is removed.
Then, a waste toner remaining flag is set (step S05).

At this time, since the waste toner conveyance path 40g is already driven in the step S02, the polished and removed waste toner is immediately sent to the waste toner collection tank 40h through the waste toner conveyance path 40g.
On the other hand, if the environmental humidity is less than 60%, NO is determined in the determination in step S03, and the waste toner remaining flag is cleared in step S06. As described above, the waste toner remaining flag indicates that control is performed in which waste toner is generated in a larger amount than during normal image formation. That is, there is a possibility that the waste toner may remain in the waste toner conveyance path.

Next, it is determined whether or not the fixing temperature is stable at a predetermined temperature by a temperature sensor that detects the temperature of the fixing unit, and this determination is repeated until the fixing temperature is stabilized at the predetermined temperature (step S07). .
Here, it is assumed that the fixing temperature is stable at a predetermined temperature. That is, assume that the warm-up is completed and the camera is ready.

When the ready state is entered, it is determined whether or not the waste toner remaining flag is set (step S08).
Here, if the waste toner remaining flag is cleared, it is determined as NO in the determination in step S08, and at this time, the control unit 10 stops the driving of the developing motor (step S10), and proceeds to step S09. Here, the driving of the waste toner conveyance path 40g is also stopped by the driving stop of the developing motor.
On the other hand, if the waste toner remaining flag is set, YES is determined in the determination in step S08, the process proceeds to step S09, and a ready display is displayed on the display unit 60 to indicate to the user that the ready state is set. After this stage, the image forming apparatus 1 can print (images can be formed) at any time. Thus, since the warm-up time is not extended, there is no harmful effect such as waiting for the user.

Next, it is further determined whether or not the waste toner remaining flag is set (step S11).
Here, if the waste toner remaining flag is cleared, it is determined as NO in the determination in step S11, and the series of control processing ends.

On the other hand, if the waste toner remaining flag is set, it is determined as YES in the determination in step S11, and the process proceeds to step S12, whether or not a predetermined time has elapsed since the ready state is reached, until the predetermined time elapses. Repeat judgment. During this time, the waste toner conveyance path 40g is driven, and the conveyance of the waste toner to the waste toner collection tank 40h is continued.
As described above, since the driving is continued even after the ready state (standby state), the problem that the waste toner is clogged or aggregated in the waste toner conveyance path 40g can be avoided.

Thereafter, when a predetermined time elapses from the ready state, it is determined YES in step S12, and the driving of the developing motor is stopped (step S13). In other words, the drive of the waste toner conveyance path 40g is stopped, and a series of control ends.
The operation flow described above is an example and is not limited to the above processing flow.

  Although not shown in the flowchart for the sake of simplicity, if an operation for instructing image formation such as copying is performed by the user while the developing motor is being driven to drive the waste toner conveyance path 40g, normal image formation is immediately performed. Move to the operation. In this case, as described above, after the series of image forming processes, the toner remaining on the photosensitive drum 40a is completely removed by the toner cleaning mechanism 40f at a predetermined timing. The toner scraped off from the photosensitive drum 40a is sent to the waste toner collection tank 40h through the waste toner conveyance path 40g. At this time, if a part of the large amount of waste toner generated in step S04 remains in the waste toner conveyance path 40g, it is also discarded together.

Further, the operation related to the collection of the waste toner at the time of starting the image forming apparatus 1 has been described above. However, in order to prevent the toner in the developing device from deteriorating when low density printing continues, the photosensitive drum When the toner is to be discharged upward, a waste toner remaining flag is set, and in step S07 in FIG. 3, instead of determining whether the fixing temperature is stable, a determination is made as to whether or not printing is completed. In step S07, YES is determined; it is assumed that the developing motor is still driven at this stage), and the processing after step S08 is subsequently executed.
As described above, in the present embodiment, the toner in the waste toner transport path 40g is only controlled by the control unit 10, that is, the drive time management of the waste toner transport path 40g, without adding new hardware. The problem of clogging or agglomeration can be solved.

  As another form, a sensor for detecting the remaining amount of waste toner in the waste toner transport path 40g is provided, and the residual amount of waste toner in the waste toner transport path 40g is equal to or less than a predetermined remaining amount. In place of the determination in step S12, it may be determined whether or not this detection has been made in step S12, and drive control of the waste toner conveyance path 40g may be performed.

As a configuration for detecting the remaining amount or the presence or absence of the waste toner in the waste toner conveyance path 40g, the following configuration can be exemplified.
(1) A toner sensor composed of a magnetic permeability sensor, a piezoelectric sensor, and the like is disposed in the waste toner conveyance path 40g, and the presence or absence of waste toner in the waste toner conveyance path 40g is directly detected.
(2) A transparent window is provided in the waste toner conveyance path 40g, the light emitting element and the light receiving element are disposed facing each other, and based on whether or not the light receiving element can receive the light emitted from the light emitting element, The presence / absence of waste toner in the waste toner conveyance path 40g is detected.

  In the above configurations (1) and (2), a plurality of sets of toner sensors or light emitting elements and light receiving elements are arranged, and the remaining amount of waste toner can be detected based on the number of detected waste toners (for example, toner sensor If the number of toner sensors that detect waste toner is less than one, it is determined that the amount is less than a predetermined amount, and if no waste toner is detected at all positions, it can be determined that the waste toner conveyance path 40g is empty. ).

(3) A sensor for detecting the weight of the waste toner transport path 40g is installed, the weight of the waste toner transport path 40g is measured, and the waste is determined from the difference from the weight when the waste toner transport path 40g is empty. The presence / absence of toner is detected (in this configuration, the waste toner transport path 40g is movable in accordance with its weight, with flexible pipes before and after the waste toner transport path 40g).

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes a configuration and the like that do not depart from the gist of the present invention. Needless to say.
As described above, the control unit 10 realizes the function by loading a program for realizing each function of the control unit 10 into a memory and executing the program. In the control program, “If a larger amount of toner to be discarded is generated than in normal image formation, in addition to the normal driving by the driving means, a predetermined time elapses or until image formation is started, whichever is shorter. "Procedure for continuing driving by the driving means for a period of time" or "If a larger amount of toner to be discarded is generated than during normal image formation, the toner in the toner conveying means detected by the detecting means Procedure for continuously driving by the driving means until the remaining amount becomes a predetermined value or less or until image formation is started, whichever is shorter It can also be realized by combining. That is, the present invention can also be provided as a difference program (difference file) comprising any one of the above procedures.

1 is a block diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is a figure which shows schematic structure of the transfer part of the embodiment. 6 is a flowchart illustrating an operation related to waste toner collection according to the embodiment. FIG. 6 is a flowchart (continuation of FIG. 3) illustrating an operation related to waste toner collection according to the embodiment. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 10 ... Control part (control means)
DESCRIPTION OF SYMBOLS 20 ... Memory | storage part 30 ... Scanner part 40 ... Image formation part 40a ... Photoconductor drum (image carrier)
40b ... Charger 40c ... Developer 40d ... Sheet material (printing paper)
40e ... transfer roller 40f ... toner cleaning mechanism 40g ... waste toner transport path 40h ... waste toner collection tank 50 ... operation unit 60 ... display unit 70 ... notification unit

Claims (3)

Image carrier, developer for attaching toner to image carrier, toner removing means for removing toner attached to image carrier, toner carrying means for carrying removed toner, and toner carrying means In an image forming apparatus including a driving unit for driving
When a larger amount of toner is discarded than during normal image formation, in addition to normal driving by the driving means, a predetermined time elapses, or until the image formation starts, whichever is shorter. An image forming apparatus comprising control means for continuously driving by the drive means. Image carrier, developer for attaching toner to image carrier, toner removing means for removing toner attached to image carrier, toner carrying means for carrying removed toner, and toner carrying means In an image forming apparatus including a driving unit for driving
A detecting means for detecting a remaining amount of toner in the toner conveying means;
When a larger amount of toner is discarded than during normal image formation, until the remaining amount of toner in the toner transport unit detected by the detection unit becomes a predetermined value or less or until image formation is started. An image forming apparatus comprising: a control unit that continuously performs driving by the driving unit for any one of the short periods. The driving means includes: a developing motor that drives a developing sleeve that rotates to attach toner to the surface of the image carrier in the developing unit; or a conveyance motor that drives a paper feeding roller that feeds printing paper. The image forming apparatus according to claim 1, wherein the image forming apparatus is a drum motor that drives a carrier.

Images