JP2024171389A - Image forming device - Google Patents

Abstract

An image forming apparatus capable of accurately detecting when a waste toner container is full of waste toner is provided.
SOLUTION: A waste toner full detection unit 51 judges whether a waste toner container 12 is full of waste toner based on whether an output signal from an optical sensor 21 satisfies a predetermined detection condition, and detects that the waste toner container 12 is full of waste toner. Then, when the staying toner in the developing device discharged by the staying toner discharging operation is stored in the waste toner container 12 as waste toner, the waste toner full detection unit 51 sets the above-mentioned detection condition corresponding to the toner color of the toner discharged by the staying toner discharging operation.
[Selected figure] Figure 4

Description

The present invention relates to an image forming device.

One image forming device is equipped with a waste toner bottle that contains residual toner (waste toner) collected from an image carrier, and an optical sensor attached to the top end of the waste toner bottle detects when the waste toner bottle is full of waste toner. Furthermore, because the light transmittance of the toner of the multiple toner colors used for printing is different, such an image forming device specifies the amount of waste toner for each of the multiple toner colors used for printing, and adjusts the threshold value for detecting when the waste toner bottle is full of waste toner based on the ratio of the waste toner amounts of those toner colors (see, for example, Patent Document 1).

JP 2019-56794 A

In the case of a color image forming device, waste toners of multiple toner colors are stored in one waste toner container, and waste toners of multiple toner colors are mixed in the waste toner container. Therefore, in the above-mentioned image forming device, the threshold value is adjusted based on the ratio of the toner amount of each toner color used in printing. However, when the retained toner discharged by the retained toner discharge operation (the operation of discharging retained toner that has been retained in the developing device for a predetermined time or more and has deteriorated, and collecting it as waste toner without using it for printing) is stored in the waste toner container as waste toner, there is a relatively large amount of waste toner of a specific toner color near the optical sensor. In such a case, if the waste toner bottle is detected to be full of waste toner using a threshold value based on the ratio of the toner amount of each toner color used in printing, a false detection may occur.

The present invention was made in consideration of the above problems, and aims to provide an image forming device that can accurately detect when the waste toner container is full of waste toner.

The image forming apparatus according to the present invention includes a photosensitive drum, a developing device that contains toner and develops a toner image by adhering the toner to the photosensitive drum, an optical sensor that detects light passing through a predetermined portion of a waste toner container that contains residual toner after transfer of the toner image as waste toner, and a waste toner full detection unit that determines whether the waste toner container is full of waste toner based on whether an output signal from the optical sensor satisfies a predetermined detection condition and detects that the waste toner container is full of waste toner. The waste toner full detection unit sets the detection condition corresponding to the toner color of the toner discharged by the discharged toner operation, which discharges the discharged toner that has remained in the developing device for a predetermined time or more from the developing device, and stores the discharged toner in the waste toner container as waste toner.

The present invention provides an image forming device that can accurately detect when a waste toner container is full of waste toner.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a side view showing the configuration of a print engine in an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a side view showing an example of the waste toner container 12 and the optical sensor 21 shown in FIG. FIG. 4 is a block diagram showing the electrical configuration of the image forming apparatus 1 according to the embodiment of the present invention. FIG. 5 is a flowchart illustrating the operation of the image forming apparatus 1 shown in FIG.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is a side view showing the configuration of a print engine in an image forming apparatus according to an embodiment of the present invention. This image forming apparatus is a color image forming apparatus with an electrophotographic printing function, such as a printer, facsimile machine, copier, or multifunction machine.

The print engine 10 shown in FIG. 1 is a tandem type print engine and includes multiple photoconductor drums 1a-1d, exposure devices 2a-2d, and multiple development devices 3a-3d. The photoconductor drums 1a-1d are photoconductors for the four colors cyan, magenta, yellow, and black.

The exposure devices 2a to 2d are devices that irradiate and scan the photosensitive drums 1a to 1d with laser light to form electrostatic latent images. The laser light is scanned in a direction (main scanning direction) perpendicular to the direction of rotation (sub-scanning direction) of the photosensitive drums 1a to 1d. The exposure devices 2a to 2d have a laser scanning unit that includes a laser diode, which is the light source of the laser light, and optical elements (lenses, mirrors, polygon mirrors, etc.) that guide the laser light to the photosensitive drums 1a to 1d.

In addition, around the photoconductor drums 1a to 1d, there are arranged chargers such as scorotrons, cleaning devices, and static eliminators. The cleaning devices remove residual toner from the photoconductor drums 1a to 1d after the primary transfer, and the static eliminators eliminate static electricity from the photoconductor drums 1a to 1d after the primary transfer.

The developing devices 3a to 3d each have a toner cartridge filled with toner of one of the four colors, cyan, magenta, yellow, and black, and a developing unit that stores the toner transported from a toner hopper in the toner cartridge and adheres the toner to the photoconductor drums 1a to 1d. The toner is then adhered to the electrostatic latent images on the photoconductor drums 1a to 1d to form a toner image.

Magenta development is performed by photoconductor drum 1a and developing device 3a, cyan development is performed by photoconductor drum 1b and developing device 3b, yellow development is performed by photoconductor drum 1c and developing device 3c, and black development is performed by photoconductor drum 1d and developing device 3d.

The intermediate transfer belt 4 is a circular image carrier (intermediate transfer body) that comes into contact with the photoreceptor drums 1a to 1d and onto which the toner images on the photoreceptor drums 1a to 1d are primarily transferred. The intermediate transfer belt 4 is stretched around a drive roller 5, and is driven by the driving force of the drive roller 5 to rotate from the contact position with the photoreceptor drum 1d to the contact position with the photoreceptor drum 1a.

The transfer roller 6 brings the conveyed print paper into contact with the intermediate transfer belt 4, and performs a second transfer of the toner image on the intermediate transfer belt 4 onto the print paper. The print paper onto which the toner image has been transferred is then conveyed to the fixing device 9, where the toner image is fixed onto the print paper.

The roller 7 has a cleaning brush that comes into contact with the intermediate transfer belt 4 to remove any toner remaining on the intermediate transfer belt 4 after the toner image is transferred to the print paper.

The density sensor 8 is an optical sensor that irradiates the intermediate transfer belt 4 with a light beam and detects the reflected light from the surface of the intermediate transfer belt 4 or the toner pattern on that surface. For example, when adjusting the toner density, the density sensor 8 irradiates a light beam onto a specific area of the intermediate transfer belt 4, detects the reflected light of the light beam, and outputs an electrical signal according to the amount of light.

Figure 2 is a perspective view showing an image forming apparatus according to an embodiment of the present invention. As described above, toner remaining on an image carrier such as intermediate transfer belt 4 (on photoconductor drums 1a-1d in the case of a direct transfer method) is collected by a cleaning device including the cleaning brush described above. The image forming apparatus 1 shown in Figure 2 has a detachable waste toner container 12 inside the housing 11, and collected toner is transported to and stored in the waste toner container 12. In the image forming apparatus 1 shown in Figure 2, the waste toner container 12 is attached inside an opening/closing panel 11a on the side panel of the housing 11.

The image forming device 1 further includes an operation panel 13. The operation panel 13 is installed on the top surface (or front surface) of the housing 11, and includes a display device (display device 13a in FIG. 4) that displays various information to the user, and an input device (input device 13b in FIG. 4) that accepts user operations.

Figure 3 is a side view showing an example of the waste toner container 12 and the optical sensor 21 in Figure 2. Furthermore, as shown in Figure 2, the image forming device 1 includes a pair of support parts 31 that support the waste toner container 12 (at a predetermined portion) at a predetermined position, a waste toner discharge port 32, and an optical sensor 21 disposed within the support parts 31.

The waste toner container 12 is a member molded from a transparent or translucent resin or glass, and contains waste toner (such as residual toner after transfer of a toner image) inside. The waste toner falls from the waste toner discharge outlet 32, passes through a specified part, and accumulates inside the waste toner container 12. The light-emitting unit 31 uses electricity to emit light that passes through a specified part of the waste toner container 12 (for example, the cylindrical neck part 12a that protrudes upward).

The optical sensor 21 detects light passing through a predetermined portion of the waste toner container 12. Here, the optical sensor 21 is a PI sensor, and includes a light-emitting portion 21a, such as a light-emitting diode, and a light-receiving portion 21b, such as a photodiode or phototransistor. The light-receiving portion 21b receives the light that has passed through a predetermined portion of the waste toner container 12, and outputs an electrical signal according to the amount of light received. The electrical signal (output signal) output from the light-receiving portion 21b is supplied to the controller 42 (via an amplifier or AD converter as necessary).

When waste toner has not accumulated up to the specified area, the light emitted from the light-emitting unit 21a enters the light-receiving unit 21b, and the amount of light received by the light-receiving unit 21b becomes relatively large. When waste toner has accumulated up to the specified area, the amount of light emitted from the light-emitting unit 21a that corresponds to the light transmittance of the waste toner accumulated in the specified area enters the light-receiving unit 21b.

Here, four colors of toner, CMYK, are used in the developing devices 3a to 3d, with the light transmittance decreasing in the order of Y (yellow), M (magenta), C (cyan), and K (black).

Figure 4 is a block diagram showing the electrical configuration of the image forming device 1 according to an embodiment of the present invention. As shown in Figure 4, the image forming device 1 further includes a drive circuit 41 and a controller 42.

The drive circuit 41 is an electronic circuit that drives the light-emitting unit 31. The controller 42 is a microcomputer, an ASIC (Application Specific Integrated Circuit), or the like, and executes various processes.

Here, the controller 42 controls the print engine 10 to cause the print engine 10 to perform a printing operation, a retained toner discharge operation, and the like. The controller 42 also operates as a waste toner full detection unit 51.

The waste toner full detection unit 51 determines whether the waste toner container 12 is full of waste toner based on whether the output signal of the optical sensor 21 (light receiving unit 21b) satisfies a predetermined detection condition, and detects that the waste toner container 12 is full of waste toner. Here, the level of the output signal becomes lower as the amount of light received by the light receiving unit 21b increases.

Furthermore, when the retained toner discharged by the retained toner discharge operation is stored in the waste toner container 12 as waste toner, the waste toner full detection unit 51 sets the above-mentioned detection conditions corresponding to the toner color of the toner discharged by the retained toner discharge operation.

The retained toner discharge operation is an operation in which retained toner that has been retained in the developing devices 3a-3d for a predetermined time or more and has deteriorated is discharged from the developing devices 3a-3d and collected as waste toner without being used for printing. Here, the retained toner is attached to the photoconductor drums 1a-1d, and (in the case of the indirect transfer method) is transferred from the photoconductor drums 1a-1d to the intermediate transfer belt 4, and then collected from the intermediate transfer belt 4 and stored in the waste toner container 12. In the case of the direct transfer method, the retained toner is collected from the photoconductor drums 1a-1d and stored in the waste toner container 12.

Specifically, the waste toner full detection unit 51 sets the above detection conditions so that the higher the light transmittance of the retained toner contained therein, the easier it is to detect that the waste toner container 12 is full of waste toner.

In other words, since the retained toner discharge operation causes single-color toner to be stored in the waste toner container 12 as waste toner, when the waste toner container 12 becomes full with the toner stored in the retained toner discharge operation, the waste toner in the above-mentioned specified area contains a relatively large amount of that single-color toner. Therefore, the detection conditions are adjusted according to the toner color (light transmittance) of that single-color toner.

In addition, the waste toner full detection unit 51 (a) sets the above-mentioned detection conditions as standard conditions (for example, conditions set based on the ratio of the amount of residual toner of each toner color in the toner color used in the most recent print) during a print operation, (b) changes the above-mentioned detection conditions to correspond to the toner color of the toner discharged by the stayed toner discharge operation during a stayed toner discharge operation, and (c) returns the above-mentioned detection conditions to the standard conditions after determining whether the toner discharged by the stayed toner discharge operation is contained in the waste toner container 12 and whether the waste toner container 12 is full of waste toner.

Here, the above-mentioned detection condition is a threshold value to be compared with the output signal of the optical sensor 21. Specifically, here, if the level of the output signal of the optical sensor 21 is equal to or higher than the threshold value, it is determined that the waste toner container 12 is full of waste toner, and if not, it is determined that the waste toner container 12 is not full of waste toner. And, since the light transmittance of the retained toner collected as waste toner is high, this threshold value is set low.

Next, the operation of the image forming device 1 will be described. FIG. 5 is a flowchart illustrating the operation of the image forming device 1 shown in FIG. 3.

The controller 42 controls the print engine 10 in response to a user request to print an image specified by the user. At that time, the toner remaining on the intermediate transfer belt 4 and the like is collected and stored in the waste toner container 12 as waste toner. The residual toner at the time of printing is a mixture of toner of one or more toner colors used in printing. If the residual toner at the time of printing is finally stored in the waste toner container 12 and the waste toner container 12 becomes full, waste toner containing a mixture of toner of one or more toner colors used in the most recent printing is accumulated in the above-mentioned specified portion. Therefore, at the time of printing, the waste toner full detection unit 51 sets the threshold value as the above-mentioned reference condition to a reference value based on the light transmittance of toner of one or more toner colors according to the proportion of toner of one or more toner colors in the waste toner. At this time, the waste toner full detection unit 51 determines whether the level of the output signal from the optical sensor 21 is equal to or greater than this reference value. If the level of the output signal from the optical sensor 21 is equal to or greater than this reference value, it determines that the waste toner container 12 is full of waste toner. If not, it determines that the waste toner container 12 is not full of waste toner. If it is determined that the waste toner container 12 is full of waste toner, the controller 42 executes error processing (such as canceling any ongoing prints or displaying an error message on the operation panel 13).

The controller 42 also monitors whether or not a retained toner discharge operation is required for each toner color (step S1). Specifically, the controller 42 monitors the retention time of the toner in the developing devices 3a to 3d (the time elapsed since the toner was supplied from the toner cartridge) for each toner color, and if the retention time of any toner color exceeds a predetermined value, it determines that a retained toner discharge operation is required for that toner color.

When it is determined that a retained toner discharge operation is required for a certain toner color, the controller 42 controls the photoconductor drum, exposure device, developing device, etc. for that toner color to execute the retained toner discharge operation for that toner color. At this time, the retained toner is not transferred to the print paper, but is collected by the cleaning device and stored in the waste toner container 12.

Then, the waste toner full detection unit 51 waits (for a predetermined time) until the accumulated toner is contained in the waste toner container 12 (step S3), and the waste toner full detection unit 51 identifies the toner color of the accumulated toner for the accumulated toner discharge operation and sets a threshold value corresponding to the identified toner color as described above (step S4), and then determines whether the output signal level (detection level) of the optical sensor 21 is equal to or greater than the threshold value (step S5).

If the output signal level (detection level) of the optical sensor 21 at this time is not equal to or greater than the threshold value, the waste toner full detection unit 51 determines that the waste toner container 12 is full and executes error processing (step S6).

On the other hand, if the output signal level (detection level) of the optical sensor 21 at this time is not equal to or greater than the threshold, the waste toner full detection unit 51 returns the threshold to the above-mentioned reference value (step S7), returns to step S1, and resumes monitoring for each toner color as to whether or not the retained toner discharge operation is necessary.

As described above, according to the above embodiment, the optical sensor 21 detects light passing through a predetermined portion of the waste toner container 12. The waste toner full detection unit 51 determines whether the waste toner container 12 is full of waste toner based on whether the output signal of the optical sensor 21 satisfies a predetermined detection condition, and detects that the waste toner container 12 is full of waste toner. Then, when the retained toner discharged by the retained toner discharge operation is stored in the waste toner container 12 as waste toner, the waste toner full detection unit 51 sets the above detection condition corresponding to the toner color of the toner discharged by the retained toner discharge operation.

As a result, the detection conditions (threshold values mentioned above) are set according to the toner color of the remaining toner that is concentrated in the specified area that is detected by the optical sensor 21 during the remaining toner discharge operation, thereby suppressing false detections caused by differences in the light transmittance of the toner colors used and accurately detecting when the waste toner container 12 is full of waste toner.

It should be noted that various changes and modifications to the above-described embodiments will be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and scope of the subject matter and without diminishing its intended advantages. In other words, such changes and modifications are intended to be included within the scope of the claims.

For example, in the above embodiment, the reference value is set based on the ratio of the residual toner amount of each toner color to the most recent predetermined residual toner amount for all toner colors, but it may instead be a constant fixed value.

The present invention can be applied, for example, to electrophotographic image forming apparatuses.

1 Image forming apparatus 1a to 1d Photoconductor drum 3a to 3d Developing device 12 Waste toner container 21 Optical sensor 51 Waste toner full detection unit

Claims (4)

A photoconductor drum;
a developing device that contains toner and adheres the toner to the photosensitive drum to develop a toner image;
an optical sensor that detects light passing through a predetermined portion of a waste toner container that contains residual toner after the transfer of the toner image as waste toner;
a waste toner full detection unit that detects whether the waste toner container is full with waste toner by determining whether the output signal of the optical sensor satisfies a predetermined detection condition,
the waste toner full detection unit sets the detection condition corresponding to a toner color of the toner discharged by a stayed toner discharge operation for discharging the stayed toner that has stayed in the developing device for a predetermined time or more from the developing device and storing the stayed toner in the waste toner container as waste toner;
An image forming apparatus comprising: The image forming device according to claim 1, characterized in that the waste toner full detector sets the detection conditions so that the higher the light transmittance of the retained toner contained therein, the easier it is to detect that the waste toner container is full of waste toner. the waste toner full detection unit (a) uses the detection conditions as standard conditions during a printing operation, (b) changes the detection conditions during the staying toner discharging operation in accordance with the toner color of the toner discharged by the staying toner discharging operation, and (c) returns the detection conditions to the standard conditions after determining whether the toner discharged by the staying toner discharging operation is contained in the waste toner container and the waste toner container is full with waste toner;

2. The image forming apparatus according to claim 1, An image forming apparatus according to any one of claims 1 to 3, characterized in that the detection condition is a threshold value to be compared with the output signal of the optical sensor.

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