JP2002072656A - Developing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a developing device and an image forming device constituted so that the occurrence of a defective image due to the insufficient density is prevented by accurately detecting the remaining quantity of developer at a low cost. SOLUTION: This developing device is provided with a developing cartridge 7 incorporating a developing member 5 for supplying the developer to a latent image carrier 2 and a developer supply part 5A for supplying the developer to the developing member 5, a discoloring member 14 which is arranged on the outer surface of the developing cartridge 7 and discoloring in accordance with a time during the member 14 is exposed in air, an optical detecting means 5 arranged facing the discoloring member 4, and a control part 16 whose input side is connected to the optical detecting means 15 and whose output side is connected to an alarm means 18, and in the case of discriminating that the presence or absence of the developing cartridge 7 and the arrangement of the cartridge 7 based on the discoloring state of the discoloring member 14 by receiving a signal from the optical detecting means 15 regarding the discoloring member 14 as an object, an operation of counting the number of image forming times is started by the control part 16 from this point of time, and the remaining quantity of the developer is discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developing device and an image forming apparatus, and more particularly, to a structure for detecting a remaining amount of a developer.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic process, such as a printer, a copying machine, or a facsimile machine, a charging step and an image writing step are performed on a photosensitive member serving as an image bearing member, so that the photosensitive member is formed on the photosensitive member. The electrostatic latent image is formed in the developing process, and the electrostatic latent image is subjected to visible image processing in a developing process. The visible image is electrostatically transferred to a recording medium such as transfer paper in a transfer step, and the transferred visible image is fixed in a fixing step and discharged as a copy.

In an image forming apparatus, a developer used for visible image processing is reduced by consumption. For this reason, if the user has overlooked the decrease, a predetermined image density cannot be obtained. Therefore, the remaining amount of the developer is monitored and the replenishment is controlled. As a method of detecting the remaining amount, for example, a two-component developer or a toner in which a magnetic carrier and a toner are mixed is used. When a one-component developer containing a magnetic component is used, a change in magnetic flux density according to the amount of toner may be detected by a magnetic sensor.

[0004]

In the conventional developer remaining amount detecting method, the cost of the developing device is increased because the magnetic sensor used for detecting the remaining amount is relatively expensive. When a magnetic sensor is used, there is a problem that erroneous detection occurs in addition to an increase in cost. That is, depending on the arrangement position of the magnetic sensor, it is not possible to determine that the developer is biased, so that the remaining amount detection at a position corresponding to the magnetic sensor, that is, only the remaining amount of toner may be detected. As described above, in the remaining amount detection structure using the conventional magnetic sensor,
At present, it is difficult to accurately detect the remaining amount of the developer at low cost.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the conventional developing apparatus and the image forming apparatus using the same, an object of the present invention is to produce a defective image in which the remaining amount of the developer is accurately detected at low cost and the density becomes insufficient. An object of the present invention is to provide a developing device and an image forming apparatus having a configuration capable of preventing the occurrence of the image.

[0006]

According to the first aspect of the present invention,
A developing device used to process a latent image on a latent image carrier into a visible image, comprising: a developing member that supplies a developer to at least the latent image carrier; and a developer that supplies a developer to the developing member. A developing cartridge having a built-in developer supply unit, a color changing member disposed on the outer surface of the developing cartridge, the color changing member changing its color according to the time of contact with air, and optical detecting means provided opposite to the color changing member And a control unit in which the optical detection unit is connected to the input side and an alarm unit is connected to the output side, and the control unit is configured to change the color of the color changing member by a signal from the optical detection unit intended for the color changing member. If it is determined based on the discoloration state that the developing cartridge is present and the developing cartridge is disposed, counting of the number of times of image formation from that time is started to determine the remaining amount of the developer. It is a symptom.

According to a second aspect of the present invention, in the developing device according to the first aspect, the count value of the number of times of image formation that is started when the control unit determines that the developing cartridge is disposed is a predetermined number of times. Is reached, the determination is made as a near-end state in which the remaining amount of the developer is small.

[0008] The invention described in claim 3 is claim 1 or 2.
In the developing device described above, the developer runs out when the count value of the number of image formations started after the control unit determines that the developing cartridge is disposed is greater than the number of image formations corresponding to the near-end state. It is characterized in that it is determined as an end state which means that the end state has occurred.

According to a fourth aspect of the present invention, in the developing device according to the first aspect, the control unit includes:
A predetermined range is set for the degree of color change of the color changing member, and among the degrees of color change within the predetermined range, counting of the number of times of image formation is performed with reference to a point in time when a signal corresponding to the degree of color change of the maximum output is output from the optical detection means. It is characterized by starting.

According to a fifth aspect of the present invention, in the developing device according to the fourth aspect, the maximum output color change degree among the color change degrees within the predetermined range is obtained from the newest color change member.

According to a sixth aspect of the present invention, in the developing device according to any one of the second to fifth aspects, the control unit detects the near-end state or the end state from the optical detection means after determining the near-end state or the end state. When the detection signal of the maximum value is obtained according to the degree of color change of the color changing member, it is determined that a new developing cartridge has been re-installed, and counting of the number of image formations is started. When an output corresponding to a low degree of discoloration is obtained, it is determined that there is no developing cartridge.

According to a seventh aspect of the present invention, there is provided the developing device according to the first aspect.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing an example of an image forming apparatus using a developing device according to an embodiment of the present invention. The image forming apparatus shown in FIG. 1 has functions as a copier and a printer. This is a multifunction device that has both functions. In the present invention, the image forming apparatus is not limited to the above-described copying machine or printer, but includes a facsimile machine.

Referring to FIG. 1, an image forming apparatus 1 includes a drum-shaped photosensitive member 2 as a latent image carrier disposed in a housing 1A. The device 4, the developing device 5, and the cleaning device 6 are collectively arranged in a developing cartridge 7 which forms a unit. A transfer device 8 composed of a roller is provided at a position facing the photoconductor 2, and a fixing device 9 and a discharge device are provided downstream of the photoconductor 2 and the transfer device 8 with respect to the recording paper conveyance direction indicated by an arrow. Paper ejection device 1 with paper tray 10A
0 is arranged.

In the image forming apparatus 1 shown in FIG. 1, a paper feeder 11 is disposed below the developing cartridge 7 and a document reading device 12 is disposed above the developer cartridge 7. In the image forming apparatus 1, after the photosensitive member 2 is uniformly charged, when the writing device 4 forms an electrostatic latent image, the developing device 5 performs visible image processing of the electrostatic latent image, and the sheet feeding device. The visible image is transferred via the transfer device 8 to the recording paper fed at a transfer timing from the paper feed tray 11A via the registration roller 11B via the registration roller 11B, and the recording paper passes through the fixing device 9. The image is fixed in the process, and the recording paper is discharged onto the paper discharge tray 10A by the paper discharge device 1 to obtain a copy.

Photoconductor 2, tank 5A forming developer supply unit
The developing device 5 and the cleaning device 6 provided with the image forming apparatus are collectively provided in the developing cartridge 7, and the developing cartridge 7 is configured to be detachable from the image forming apparatus 1. For this reason, when the developer runs out, as shown in FIG. 2, it can be replaced with a new developing cartridge 7 by being attached to and detached from the image forming apparatus 1.

The developing cartridge 7 is housed in a polyethylene bag 13 as shown in FIG. 3 before it is mounted on the image forming apparatus 1. At the time of replacement, it is taken out from the polyethylene bag 13 and the developing cartridge 7 shown in FIG. As shown, the image forming apparatus 1
Attached to. A color changing member 14 (see FIG. 3) that changes color when exposed to air is attached to a part of the wall surface of the developing cartridge 7, and the bag 13 is attached to the surface of the developing cartridge 7 until it is taken out of the polyethylene bag 13. It is in a state where it is attached so that it does not come into contact with air.

The color changing member 14 is one of the components used for detecting the remaining amount of the developer contained in the developing cartridge 7, and the other one is, as shown in FIG. An optical detection sensor 15 that is provided at a position facing the color changing member 14 and that can detect the degree of color changing of the color changing member 14 is used. As the optical detection sensor 15, a reflection type sensor including a light source and a light receiving unit is used, and the color changing member 1 is used.
The degree of discoloration according to the time when the element 4 touches the air, that is, the reflection density is detected. Discoloration member 14
Has a characteristic that the density increases as the time of contact with air increases and the reflection density decreases. Note that this characteristic can be reversed from the state described above.

The remaining amount of the developer in the developing cartridge 7 is
This is determined by the control unit 16 shown in FIG. In FIG. 4, a main part of the control unit 16 is constituted by a microcomputer, and an optical detection sensor 14 and a counter 17 for counting the number of times of image formation are provided on the input side via an I / O interface (not shown), and on the output side. The alarm display units 18 are respectively connected.

When the control section 16 determines the presence or absence of the developing cartridge 7 and the presence of the developing cartridge 7 based on the color change state of the color changing member 14, the control section 16 starts counting the number of times of image formation from that time. The remaining amount of the developer is determined. This will be described below.
In the control unit 16, as shown in FIG. 5, the correlation between the reflection density (D) of the color changing member 14 and the sensor output (P) from the optical detection sensor 15 is stored in advance, and the correlation between the reflection density and the sensor output is stored. A predetermined range is set, and if a sensor output within the range is obtained, it is determined that the developing cartridge 7 is disposed. If a sensor output lower than the range is obtained, the developing cartridge 7 is determined. Is determined not to be located. The timing of detecting the reflection density of the optical detection sensor 15 with respect to the color changing member 14 is the time when the image forming apparatus 1 is started. The start time in this case includes the time when the power is turned on, the time when the image formation is started, and the time when the operation is started again after the inside of the image forming apparatus is opened due to the occurrence of a paper jam or the like.

When the control section 16 determines that the developing cartridge 7 is arranged, counting of the number of times of image formation from that time is started, and when the number of times reaches a preset number, the counting is started. It is determined that the image is in the near-end state, which means a state in which the image density is reduced, and when the number of times is exceeded, the developer runs out and the amount of the developer required for visible image processing of the image is not present. Each is judged to be in the end state and an alarm is issued.

Since the present embodiment has the above configuration,
The operation of the control unit 16 will be described with reference to the flowchart of FIG. 6, when the image forming apparatus is started (ST1), an output signal from the optical detection sensor 15 is fetched, and the output is compared with a predetermined range shown in FIG. 4 (ST2). If it is out of the predetermined range in step ST2, it is determined whether or not the sensor output is a value lower than the predetermined range (ST2).
3) If it is low, it is determined that the developing cartridge 7 is not arranged, and a message for arranging the developing cartridge is warned (ST4). If an output within the predetermined range and higher than the predetermined range is obtained in step ST2, the counter 15 is reset (ST5), and counting of the number of image formation is started (ST6).

It is determined whether or not the number of times of image formation has reached the number (N1) corresponding to the near end state (ST).
7) If the number of times has been reached, a warning that the vehicle is in the near-end state is issued (ST8). The near-end state of the developer is a state in which the image formation itself is possible although the image density is reduced, and depending on the operator, the image formation may be continued depending on the operator. Therefore, in the present embodiment, counting of the number of times of image formation is performed until the developer, which corresponds to a state in which image formation is almost impossible, is almost exhausted, and an alarm is issued again. That is, the counting of the number of times of image formation is continued even after the warning of the near-end state is issued in step ST8, and the number of times of image formation has reached the number of times (N2) corresponding to the end state meaning that there is little developer. (ST9), and if reached, a warning that image formation is impossible is issued (ST1).
0). In this case, the operation of the image forming apparatus may be forcibly stopped in addition to the alarm.

According to this embodiment, the remaining amount of the developer can be determined only by counting the number of image formations performed after determining the presence or absence of the developing cartridge by detecting the density of the color changing member. There is no need to use it.

Next, another embodiment of the present invention will be described. The optical detection sensor 15 controls the sensor output while the color changing member 14 changes color with time.
6 is output. For this reason, in the course of the change in the reflection density from the color changing member 14, the control unit 16 determines that a new developing cartridge 7 has been loaded throughout the process of the color change, and a sensor output corresponding to the reflection density is obtained. During this time, the counting of the number of times of image formation is repeated. Therefore, as in the case where a new developing cartridge 7 is actually loaded, the count value clearing process is also performed in the process in which the color of the color changing member 14 is progressing after the loading of the developing cartridge. Accordingly, if the number of times of image formation is cleared a plurality of times while the density detection of the color changing member 14 is performed again after the new developing cartridge 7 is loaded, the state where the remaining amount of the developer is insufficient is determined based on the reference. Even if the total value of a certain number of image formations is the same, the start value that reaches the total value is shifted. As a result, the timing when the total value is reached is later than the original timing, and there is a possibility that a determination is made that the developer cartridge is in a state where the developer is insufficient but has not yet reached that state. is there.

In this embodiment, the controller 16 uses only the sensor output obtained when the developing cartridge is replaced as a condition for starting the clearing of the count value, based on the result of determination of the remaining amount of the developer at the present stage. In other cases, the process of clearing the count value based on the sensor output is not performed. Sensor output obtained when the developer cartridge is replaced, in Figure 5, the maximum output as shown at P _0, the reflection density (D ₀₎ corresponding to the output is maximum. Sensor output obtained after the developing cartridge 7 has been replaced, as indicated at P ₁ in FIG. 5, which is lower than immediately after replacement, the reflection density (D ₁₎ of the color change member 14 corresponding thereto is low Has become.

Since the present embodiment has the above configuration,
The operation will be described with reference to a flowchart illustrating the operation of the control unit 16, as shown in FIG. In FIG.
After the start determination (ST1), the detection result of the remaining amount of the developer in the developing cartridge 7 at that time is determined (ST1).
11). The determination of the remaining amount detection result is to determine the result of the remaining amount detection performed before the start, and when in the near end state or the end state, the optical detection sensor 1 is used.
When the sensor output is determined to be smaller than the predetermined range (ST12), it is determined that there is no developing cartridge as in the case shown in FIG. An alarm is issued (ST13).

If it is determined in step ST12 that the sensor output is not less than the predetermined range, the magnitude of the sensor output is determined (ST14). In this determination, when the maximum output is obtained, the count value of the number of times of image counting is reset and counting is newly started (ST15, ST16). Since the processing after step ST16 is the same as the processing shown in FIG. 5, only the reference numerals are shown and the description is omitted.

If it is determined in step ST11 that the developer remaining amount detection result is not in the near end state or the end state, the sensor output is determined (ST17). If the sensor output is less than the predetermined range, the developing cartridge 7 is detected. When the sensor output is not below the predetermined range, it is determined that a new developing cartridge 7 does not need to be replaced, and the process proceeds to step ST7.

According to the present embodiment, the counting of the number of image formations can be started only when the developing cartridge is replaced with a new one. Since the start timing is set for the state in which the amount of the filled developer is the largest, it is possible to match the set remaining amount warning of the developer with the actual remaining amount of the developer. As a result, there is no erroneous determination that there is no shortage in the actual state of a shortage, as determined from the count value.

[0031]

According to the first aspect of the present invention, the presence or absence of the developing cartridge is determined by monitoring the degree of color change of the color changing member provided in the developing cartridge, and the developing cartridge is installed based on the degree of color change. If it is determined at that time k that time, the number of image formations is counted and the consumption of the developer used for image formation can be determined to determine the remaining amount. Therefore, the developer can be determined without using a magnetic sensor or the like. Can be determined. Therefore, unlike the case where a special sensor such as a magnetic sensor is used, the cost required for the configuration used for detecting the remaining amount of the developer does not increase. In particular, since the remaining amount is determined not for the developer in the developing cartridge but for the consumption amount of the developer, it is possible to eliminate erroneous detection due to the bias of the developer in the developing cartridge.

According to the second and third aspects of the present invention, it is possible to determine the near end state when the number of image formations reaches a predetermined number, and the end state when the number of image formations exceeds the predetermined number. Therefore, the remaining amount can be accurately determined only by referring to the number of times of image formation, which is a parameter that affects the amount of developer actually consumed.

According to the fourth aspect of the present invention, a predetermined range of the color change is set, and the detection of the remaining amount of the developer is started based on the time when the maximum output color change is obtained within the predetermined range. Therefore, it is possible to prevent the start of counting the number of times of image formation from being repeated many times when a color changing member that changes according to the time of contact with air is used. For this reason, it is possible to prevent the timing when the remaining amount of the developer is exhausted from being shifted, and to accurately detect the remaining amount.

According to the fifth aspect of the present invention, the color change degree obtained from the newest color change member is the color change degree at which the maximum output can be obtained within the predetermined range set for the color change degree. Since the disposed developing cartridge is a developing cartridge containing a developer in an unconsumed state, the remaining amount can be detected for a so-called developer that is changed from an unused state to a used state. This allows
By setting the start of use as the remaining amount detection start time instead of the middle of use, unlike the case of using the middle of use as the count start time,
The actual remaining amount of the developer in the developing cartridge can be accurately determined.

According to the sixth and seventh aspects of the present invention, after the near-end state or the end state is determined, whether or not a new developing cartridge has been re-installed can be determined based on a detection signal from the optical detecting means, and the new state can be determined. Only when a new developing cartridge is re-installed, the number of times of image formation for determining the remaining amount can be started, so that the time when the developer becomes insufficient can be accurately determined. It is possible to prevent the occurrence of defective images such as development.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus to which a developing device used in an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a state in which a developing cartridge to be replaced is mounted on the image forming apparatus shown in FIG.

FIG. 3 is a diagram illustrating a packed state of the developing cartridge illustrated in FIG. 2;

FIG. 4 is a block diagram for explaining a control structure for detecting a remaining amount of a developer in the developing device shown in FIG. 1;

FIG. 5 is a diagram for explaining a relationship between a reflection density of a color changing member and a sensor output stored in a control unit shown in FIG. 4;

FIG. 6 is a flowchart for explaining the operation of the control unit shown in FIG. 4;

FIG. 7 is a flowchart illustrating another operation of the control unit illustrated in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Photoreceptor which is an image carrier 5 Developing device 7 Developing cartridge 14 Color changing member 15 Optical detection sensor 16 Control unit 17 Counter 18 Alarm display unit

Claims (7)

[Claims] 1. A developing device for processing a latent image on a latent image carrier into a visible image, comprising: a developing member for supplying at least a developer to the latent image carrier; A developing cartridge having a built-in developer supply unit for supplying a developer, a discoloring member disposed on the outer surface of the developing cartridge, and discoloring in accordance with time of contact with air; Optical detection means, and the optical detection means on the input side, the output side comprises a control unit connected to the alarm means, the control unit, the signal from the optical detection means for the color changing member Accordingly, based on the color change state of the color changing member, the presence / absence of the developing cartridge and when it is determined that the developing cartridge is arranged, counting of the number of times of image formation from that time is started and the remaining amount of the developer is Developing apparatus is characterized in that to determine. 2. The developing device according to claim 1, wherein the control unit starts developing when the count value of the number of image formations started when it is determined that the developing cartridge is disposed reaches a predetermined number. A developing device for determining a near-end state in which the remaining amount of the developer is small. 3. The image forming apparatus according to claim 1, wherein the control unit determines that the count of the number of image forming operations started after determining that the developing cartridge is disposed corresponds to the near-end state. A developing device that determines that the developer has run out when the amount of developer has increased. 4. The developing device according to claim 1, wherein the control section sets a predetermined range for the degree of color change of the color change member,
A developing device which starts counting the number of times of image formation based on a point in time when a signal corresponding to the maximum output color change degree among the color change degrees within the predetermined range is output from the optical detection means. 5. The developing device according to claim 4, wherein the maximum output color change degree among the color change degrees within the predetermined range is:
A developing device characterized by being obtained from the newest discoloration member. 6. The developing device according to claim 2, wherein the control section determines the near-end state or the end state and then changes the detection signal from the optical detection means to the color change. When the maximum output is obtained according to the degree of discoloration of the member, it is determined that a new developing cartridge has been re-installed, and counting of the number of image formations is started. A developing device characterized in that when an output is obtained, it is determined that there is no developing cartridge. 7. An image forming apparatus using the developing device according to claim 1.