JP4244536B2 - In-casing airflow measuring device and airflow optimization processing method in image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an in-casing airflow measuring device and an airflow optimization process in an image forming apparatus for observing and measuring the behavior of scattered toner generated in the nip region of a photoconductor of an electrophotographic image forming apparatus and determining the optimization of the airflow. Regarding the method.
[0002]
[Prior art]
In an electrophotographic image forming apparatus, as one of the techniques for suppressing the removal of scattered toner once generated before contamination, in order to optimize the air flow path through which the scattered toner passes, particularly in the vicinity of the nip region. Conventionally, an image forming apparatus provided with an apparatus for performing the airflow design has been disclosed. For example, JP-A-10-247042 and JP-A-10-48948 can be mentioned. Japanese Patent Laid-Open No. 10-247042 discloses an “image forming apparatus” which includes an image carrier (photosensitive member), a charging device that charges the image carrier, and a sheet-like member for preventing toner scattering. An image forming apparatus having a developing device provided upstream in the direction, wherein a means for removing contaminants on the surface of the image carrier is provided between the charging device and the developing device. It consists of what has an air outlet directed to the contact portion between the sheet-like member and the image carrier, and generates this air flow over the entire axial width of the image carrier to remove contaminants. . On the other hand, the “developing device for image forming apparatus” disclosed in Japanese Patent Application Laid-Open No. 10-48948 prevents the scattered toner generated in the nip area from being dissipated inside and outside the casing by adjusting the static pressure in the developing unit case. .
[0003]
[Problems to be solved by the invention]
Each of the above-described known techniques has characteristics, but has the following problems. Since the toner scattering phenomenon is difficult to measure the attributes of the toner particles, the characteristics are not yet sufficiently grasped. In addition, since the mass is very small, it is a phenomenon that is very difficult to control because it depends very much on the external force, such as the electrostatic force of the surrounding units, humidity and temperature, in addition to the force received from the airflow. Therefore, when it is attempted to suppress the scattered toner by measures such as airflow design, whether the intended flow field is really generated, and whether the scattered toner stays within the target area by the flow field, or A method for measuring and evaluating whether or not it is suppressed is necessary, but has not existed in the past.
In particular, the behavior of the scattered toner due to the air current is strongly non-stationary, and if the measurement of the air current and the scattered toner is separately analyzed, it is difficult to evaluate whether the air flow design is essentially reflected.
[0004]
The present invention has been invented in view of the above circumstances, and uses a tracer to observe the flow state of scattered toner in the vicinity of the nip region, and the flow state between the tracer and the scattered toner is simultaneously and independently determined. It is an object of the present invention to provide an in-casing airflow measuring device and an airflow optimization processing method in an image forming apparatus, which are designed to optimize airflow design by measuring.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an in-casing airflow measuring device in an image forming apparatus that supplies toner from a developing roller disposed in the housing of the image forming apparatus to a photoconductor. An apparatus for measuring the state of airflow of scattered toner generated near a supply point (hereinafter referred to as a nip area), which generates a fumed tracer having a density substantially the same as that of air. Light emission that illuminates the generator and the tracer that is scattered from the photoconductor side by the airflow generated in the nip area and the tracer that is ejected from the tracer generator and behaves almost the same as the airflow An apparatus (light source), an imaging apparatus for imaging the nip area, and image information of the scattered toner and the tracer obtained by the imaging apparatus are stored. And recording device, for an arithmetic unit for Kaiori the recorded image information, characterized by comprising a an output device for outputting the operation result. As a result, the flow state of the scattered toner and the tracer in the vicinity of the nip area is photographed, a recording calculation process is performed based on the photographed image information, and the result can be output. You can get a design.
[0006]
In the image forming apparatus according to a second aspect of the present invention, the in-casing airflow measuring device is characterized in that the tracer generating device is configured to generate the tracer by incompletely burning refined kerosene. As a result, the contents of the tracer generator can be realized and the tracer can be easily formed.
[0007]
According to a third aspect of the present invention, there is provided the in-casing airflow measuring device in the image forming apparatus, wherein the photographing device is composed of a digital video camera and includes a solid-state imaging device and a lens capable of photographing the nip area. It is characterized by that. Thereby, the specific structure of the said imaging device is clarified.
[0008]
According to a fourth aspect of the present invention, the in-casing airflow measuring device in the image forming apparatus is characterized in that the solid-state imaging element bit depth is 8 bits or more. By using the solid-state imaging device of 8 bits or more, a gray scale image of 256 gradations can be recorded, and the image can be clarified.
[0009]
According to a fifth aspect of the present invention, there is provided the in-casing airflow measuring device in the image forming apparatus, wherein the photographing device has a function of photographing a moving image. As a result, an unsteadiness that cannot be obtained with a still image becomes a problem and an accurate observation is performed.
[0010]
According to a sixth aspect of the present invention, there is provided the in-casing airflow measuring device in the image forming apparatus, wherein the photographing device performs photographing in synchronization with irradiation by the light emitting device. Thereby, when the phenomenon is particularly fast, a lot of information can be put in the image, and effective measurement can be performed.
[0011]
According to a seventh aspect of the present invention, the in-casing airflow measuring device in the image forming apparatus is such that the tracer generating device calibrates the brightness value of the tracer. The tracer emitted in a state where an image forming operation is not performed is illuminated with the light source, image information of a nip area is stored, and calibration is performed based on the stored information. Thereby, average brightness information of the tracer can be obtained, and the airflow independent behavior separated from the scattered toner is measured.
[0012]
According to an eighth aspect of the present invention, there is provided an in-casing airflow measurement device, wherein the arithmetic device reads a plurality of still image information obtained by moving image shooting and permuted in time series, and performs an averaging operation. And recording the result in a recording device, and performing a process of subtracting the result from a plurality of the still image information obtained by moving image shooting and divided in time series (hereinafter referred to as background removal process) And By performing the background subtraction process, the background portion that becomes noise is removed, and only the airflow or the scattered toner information can be obtained with high accuracy.
[0013]
In the image forming apparatus according to claim 9 of the present invention, the in-casing airflow measuring device is a tracer calibrated from the still image obtained by the background removal process and permuted in time series. A process of subtracting the luminance value (hereinafter referred to as scattered toner particle extraction process) is performed. The information on the airflow can be sensed from an image in which the airflow and the scattered toner are reflected at the same time, and only the information on the scattered toner can be extracted with high accuracy.
[0014]
Further, in the image forming apparatus according to claim 10 of the present invention, the airflow measurement device in the casing is a particle tracking algorithm based on a still image obtained by the scattered toner particle extraction process and permuted in time series. The particle mobility is calculated by the following. Thereby, the behavior of the scattered toner can be measured quantitatively.
[0015]
According to an eleventh aspect of the present invention, the airflow optimization processing method by the in-casing airflow measuring device in the image forming apparatus includes a first procedure for performing an airflow design review, and a first procedure for separating the behavior of the airflow and the toner. The third procedure for separately performing the procedure of 2 and the measurement of the separated airflow and the behavior of the toner, and whether or not the intended airflow and the intended toner behavior can be obtained from the measurement result. If the intended result is obtained, the airflow design is completed. If not, return to the airflow design review of the first procedure and repeat each of the above steps. A process for optimizing the arrangement of a duct or the like for regulating the airflow in the housing is performed. Thereby, optimal airflow design can be performed.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, a one-component magnetic toner that acquires a charge by frictional charging with the developing sleeve or charge injection is used as a developer, and a thin toner layer is formed on the developing sleeve. It is intended to simultaneously measure scattered toner and airflow in an image forming apparatus that uses a developing method in which an electrostatic latent image is formed close to the surface of the photoconductor and the toner is allowed to fly to the surface of the photoconductor and adhere to the surface of the photoconductor. Is.
FIG. 1 shows an example of the intended development mechanism 100. The toner 1 is transferred to the photosensitive member 101 by the rotation of the developing roller 102 from the developing unit. The toner 1 is generally attached by Coulomb force according to the charge of the electrostatic latent image formed on the photoconductor 101. However, some of the toner is peeled off from the surface of the photoconductor 101 due to mechanical action due to contact with the photoconductor 101, etc., and becomes scattered toner 2 (FIG. 2). There is a case to become. The toner 1 that normally adheres on the photoreceptor 101 is further biased and transferred to the intermediate transfer belt 103 by the intermediate transfer charger 104. Thereafter, the image is fixed on a transfer paper such as paper and an image is formed.
[0017]
FIG. 2 shows the configuration of an apparatus corresponding to claims 1 and 3 of the present invention. The scattered toner 2 generated in the nip region 105 performs a specific behavior by a surrounding external force, particularly an air flow. In order to measure the interaction with the airflow, the tracer generator 50 that visualizes the behavior of the airflow generates the tracer 3 having the same density as the air and easily discernible to the eyes, and floats in the nip area 105. Let The tracer 3 is operated by the rotational motion of the photoconductor 101 or the like and the forced airflow by the airflow design. However, since the behavior is the same as the airflow, if the behavior of the tracer 3 is grasped, the behavior of the airflow in the nip region 105 can be known. it can. Further, in order to clarify the behavior of the scattered toner 2 and the tracer 3, the entire nip region 105 is illuminated in a planar shape by a light source 51 (light emitting device) for visualization. The light source 51 is preferably halogen light or laser sheet light. In this way, the behavior of the tracer 3 and the scattered toner 2 in the nip region 105 is photographed by the photographing device 52 including the solid-state imaging device 60 (FIG. 4) and the lens 59 (FIG. 4), and the photographed image is recorded. Recorded by device 53. The photographing device 52 is preferably a digital video camera or the like. The recording device 53 is preferably a digital recording device such as a hard disk, but can also be used for analog video or the like. Based on the image information recorded by the recording device 53, the image is analyzed by the arithmetic device 54, and necessary information is extracted. The extracted information is output by the output device 55. The output device 55 can be changed according to the usage status of the user, such as a monitor or a printer.
[0018]
FIG. 3 shows an embodiment corresponding to claim 2. When heating is applied to the refined kerosene by wrapping the nichrome wire around the cotton 57 impregnated with refined kerosene and connecting the energizing device 58 that allows an arbitrary current to flow through the nichrome wire, the refined kerosene burns incompletely. And smoke-like tracer 3 is generated. The tracer 3 is injected out of the tracer generator 50 by a fan 56 at an appropriate injection speed. Appropriate injection speed refers to the speed at which the average fan flow speed is 1/10 or less of the main flow speed of the airflow. This is to avoid unnecessarily disturbing the airflow.
[0019]
FIG. 4 shows an embodiment corresponding to the fourth aspect. It is desirable that the solid-state imaging device 60 of the imaging device 52 has the capability of recording 8-bit information, that is, a so-called 256 gray scale image. If this is less than 7 bits, the image will change discontinuously depending on the threshold value when an image is taken of a small-scale contrast, such as the smoke-like tracer 3 used to visualize the current airflow. This is because such an image can be obtained. For example, when used for PIV (image tracking speed measurement method) or the like, an abnormal flow velocity is detected at this discontinuous portion.
[0020]
FIG. 5 shows an embodiment corresponding to the fifth aspect. An image photographed by the photographing device 52 is recorded as a moving image by the digital video 61 of the recording device 53. The recording is preferably recorded as a set of still image images that are permuted at regular time intervals in time series. This is because the phenomenon is unsteady, so that a single still image that does not include temporal information is inappropriate for analysis.
[0021]
FIG. 6 shows an embodiment corresponding to the sixth aspect. The synchronization generator 62 allows the light source 51 and the imaging device 52 to be synchronized. By illuminating the light source 51 with an arbitrary pulse and photographing with the photographing device 52 at an appropriate time exposure, the image of the scattered toner 2 forms a blinking locus. Since the blinking interval expresses the time interval of the pulse, it becomes possible to insert time information into one image and further increase the image information.
[0022]
FIG. 7 shows an embodiment corresponding to the seventh aspect. In a situation where no image is formed, that is, in a situation where the scattered toner 2 is not completely generated, the tracer 3 is generated from the tracer generator 50, illuminated by the light source 51, and photographed by the photographing device 52. The moving image is recorded by the recording device 53. The recorded image is subjected to appropriate processing by the arithmetic device 54, and the processed image is recorded as a standard image of the tracer 3 in the recording device 53. This standard image is preferably used as a calibrated tracer image.
[0023]
FIG. 8 shows an embodiment corresponding to the eighth aspect. The process of the arithmetic unit 54 is shown. First, the n still image groups 63 having the same pixel size, which are captured by the imaging device 52 and are permuted in time series, are averaged. Here, averaging is the summation of luminance information at the same coordinates and dividing by n. A new still image having this value at its coordinates is created. If a sufficiently large n is employed, the scattered toner 2 and the tracer 3 that move from the averaged image disappear. That is, if the area is limited to the nip area 105 within a sufficiently long time, the scattered toner 2 and the tracer 3 are generated randomly. Subtraction processing is performed from each of the still image group 63 based on the new image obtained by the averaging. Here, the subtraction processing refers to subtracting the luminance information of the same coordinates from each image of the still image group 63, and the luminance information of a new image obtained by averaging. By calculating in this way, it is possible to obtain a still image group 64 in which noise information that is not necessary for analysis, for example, effects such as background are appropriately removed from the group 63.
[0024]
FIG. 9 shows an embodiment corresponding to the ninth aspect. The process of the arithmetic unit 54 is shown. By performing level division processing on the still image group 64 from which the influence of background noise has been removed by the background removal process, the still image group 65 in which only the tracer is reflected and only the scattered toner image are reflected. A still image group 66 is divided. Here, the level division process refers to the following process. In general, the image of the scattered toner 2 directly reflects the light from the light source 51 and therefore has a higher luminance than the image of the tracer 3. Take advantage of this property. The threshold value representative of the brightness of the tracer 3 is obtained using the information of the calibrated tracer 3 obtained in advance by the invention of claim 6. As the threshold value, an average value of an image area in which the tracer 3 is captured may be adopted. By this threshold value, the brightness of the still image in which the tracer 3 and the scattered toner 2 are simultaneously reflected is divided to obtain two images. This operation is performed on the entire still image group 64.
[0025]
FIG. 10 shows an embodiment corresponding to the tenth aspect. The process of the arithmetic unit 54 is shown. The particle mobility is quantitatively measured by the particle tracking algorithm using the still image group 66 in which only the scattered toner obtained by the level division processing is shown. Here, the particle tracking algorithm means the following algorithm.
Let F0 be the particle image at an arbitrary time t0. Let F1 be the particle image when a certain time interval dt has elapsed. Search for corresponding particles in both images. The search is generally performed using the least square method of luminance information difference. Dividing the vector connecting the corresponding particles by the time interval dt indicates the mobility of the particles at that point.
[0026]
FIG. 11 is a flowchart showing the airflow design processing procedure corresponding to claim 11. First, an airflow design review is performed (step 100). Next, the airflow and the toner behavior are separated (step 101). Separated airflow and toner behavior are measured separately (steps 102 and 103). Here, it is determined whether or not the intended airflow is obtained (step 104), and in the case of OK, the airflow design is completed (step 105). In the case of NO, the flow returns to step 100 through the airflow design improving process (step 105) and the same steps are repeated. On the other hand, it is determined whether or not the intended toner behavior is obtained (step 106). If OK, the airflow design is completed (step 108). In the case of NO, the flow returns to step 100 through the airflow design improvement process (step 107) and the same steps are repeated. An optimized airflow design can be performed by proceeding according to the above procedure.
[0027]
【The invention's effect】
1) According to the first and third aspects of the invention, in particular, in an image forming apparatus using an electrophotographic system, an apparatus for determining whether or not an airflow design is optimally performed for evaluation when toner scattering becomes a problem. Can be provided.
2) According to the invention described in claim 2, in addition to the effect of claim 1, it is possible to provide a visualization device capable of more clearly grasping the behavior of the airflow.
3) According to the invention described in claim 4, in addition to the effect of claim 1, when an image analysis calculation of airflow and scattered toner is to be performed, the minimum necessary for the calculation is required in the image acquisition which is the premise thereof. It is possible to provide a device that defines limited information.
4) According to the invention described in claim 5, in addition to the effect of claim 1, it is possible to provide an apparatus capable of measuring the scattering phenomenon in which unsteadiness is a problem.
5) According to the invention described in claim 6, in addition to the effect of claim 1, when the phenomenon is particularly fast, the effect can be obtained by inserting more information into one still image. A device capable of performing measurement automatically can be provided.
6) According to the invention described in claim 7, in addition to the effect of claim 1, it is possible to provide an apparatus capable of calibrating an air flow when performing measurement.
7) According to the invention described in claim 8, in addition to the effect of claim 1, it is possible to provide an apparatus capable of performing measurement with further reduced noise.
8) According to the invention described in claim 9, in addition to the effects of claims 1 and 7, it is possible to provide an apparatus capable of separating and measuring airflow and scattered toner while suppressing noise more.
9) According to the invention of the tenth aspect, in addition to the effect of the first aspect, an apparatus for obtaining a measurement result quantitatively can be provided.
10) According to the invention of claim 11, in addition to the effect of claim 1, a more precise airflow design process can be defined.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a toner scattering state and the like around a nip area of a phenomenon mechanism to which the present invention is applied.
FIG. 2 is a configuration diagram showing a schematic configuration of an in-casing airflow measurement device in the image forming apparatus of the present invention.
FIG. 3 is a schematic configuration diagram showing one embodiment of a tracer generator of the present invention.
FIG. 4 is a schematic configuration diagram showing one embodiment of a photographing apparatus of the present invention.
FIG. 5 is a schematic configuration diagram showing an embodiment of a recording apparatus of the present invention.
FIG. 6 is a schematic configuration diagram for explaining generation of synchronization between the tracer generator of the present invention and a light source.
FIG. 7 is a schematic configuration diagram for explaining tracer photographing, recording calculation, and the like by the tracer generating device before the operation of the image forming apparatus of the present invention.
FIG. 8 is a schematic explanatory view for explaining one embodiment of processing means of the arithmetic unit of the present invention.
FIG. 9 is a schematic explanatory view for explaining an embodiment of processing means of the arithmetic unit of the present invention.
FIG. 10 is a schematic explanatory diagram for explaining an embodiment of processing means of the arithmetic unit of the present invention.
FIG. 11 is a flowchart for explaining one of the processing methods of the optimized airflow design according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Toner 2 Scatter toner 3 Tracer 50 Tracer generating device 51 Light source 52 Image pickup device 53 Recording device 54 Calculation device 55 Output device 56 Fan 57 Cotton 58 containing refined kerosene Application device 59 Lens 60 Solid-state image sensor 61 Digital video 62 Synchronous generation Device 63 Still image group 64 Still image group 65 from which influence of noise has been removed Still image group 66 including only tracer Still image group including only scattered toner image 100 Developing mechanism 101 Photoconductor 102 Developing Roller 103 Intermediate transfer belt 104 Intermediate transfer charger 105 Nip area

Claims (11)

An apparatus for measuring an air current state of scattered toner generated near a supply point (hereinafter referred to as a nip area) for supplying toner from a developing roller disposed in a housing of an image forming apparatus to a photoconductor, The apparatus includes: a tracer generator that generates a smoke-like tracer having a density substantially the same as that of air; and the scattered toner scattered from the photoconductor side by the air current generated in the nip area, and the tracer generator. A light emitting device (light source) that illuminates the tracer that has been ejected and behaves substantially the same as the airflow, a photographing device that photographs the nip region, the scattered toner obtained by the photographing device, and the tracer A recording device for storing the image information, an arithmetic device for breaking the recorded image information, and an output device for outputting the calculation result Housing airflow measuring device in an image forming apparatus according to claim and. The in-casing airflow measuring device in an image forming apparatus according to claim 1, wherein the tracer generating device is configured to generate the tracer by incompletely burning refined kerosene. The apparatus for measuring an airflow in a housing of an image forming apparatus according to claim 1, wherein the photographing device is composed of a digital video camera and includes a solid-state imaging device and a lens capable of photographing the nip area. The in-casing airflow measuring device in the image forming apparatus according to claim 3, wherein the solid-state imaging device has a bit depth of 8 bits or more. The in-casing airflow measuring device in the image forming apparatus according to claim 1, wherein the photographing device has a function of photographing a moving image. The in-casing airflow measuring device in an image forming apparatus according to claim 1, wherein the photographing device performs photographing in synchronization with irradiation by the light emitting device. The tracer generating device calibrates the brightness value of the tracer, and the calibration method includes illuminating the tracer emitted when the image forming device is not performing an image forming operation with the light source, The in-casing airflow measuring device in the image forming apparatus according to claim 1, wherein the image information of the partial area is stored and calibration is performed based on the stored information. The arithmetic device reads a plurality of still image information obtained by moving image shooting and permuted in time series, performs an averaging operation, records the result in a recording device, and obtains the result by moving image shooting. The in-casing airflow measuring device in the image forming apparatus according to claim 5, wherein a process of subtracting the plurality of still image information divided into series (hereinafter referred to as background removal process) is performed. The arithmetic unit performs a process of subtracting the calibrated luminance value of the tracer from the still image obtained by the background removal process and permuted in time series (hereinafter referred to as scattered toner particle extraction process). The in-casing airflow measuring device in the image forming apparatus according to claim 8. 10. The image forming apparatus according to claim 9, wherein the computing device computes particle mobility by a particle tracking algorithm from still image images obtained by the scattered toner particle extraction process and permuted in time series. Airflow measurement device in the housing. Measurement by the airflow measuring device in the housing for measuring the airflow state of the toner generated near the supply point (hereinafter referred to as the nip portion region) for supplying the toner from the developing roller arranged in the housing of the image forming apparatus to the photosensitive member. A processing method for optimizing the airflow state based on the first method, wherein the processing method is separated from a first procedure for performing an airflow design review and a second procedure for separating the behavior of the airflow and the toner. A third procedure for separately measuring the airflow and the toner behavior, and a fourth procedure for checking whether the intended airflow and the intended toner behavior can be obtained from the measurement result. If the intended result is obtained, the airflow design is completed. If not, the flow returns to the airflow design review of the first procedure and the above steps are repeated to restrict the airflow in the housing. Daku Housing airflow measuring device the method according to the airflow optimization process in the image forming apparatus characterized by performing a process for optimizing the placement and the like.

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