JP2011027786A - Image forming apparatus and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce detection errors in a test image caused by deformation of a test image conveying medium, while considering also other than detection accuracy. <P>SOLUTION: In a method for image quality adjustment using a test image, a test image detection method is selected in consideration of short detection time priority and low toner consumption priority, in addition to accuracy of detecting test image information. In this case, if priority is given to the short detection time, a selection is made to increase the size of a test image or to use a color ground image as a ground for a K color test image. If priority is given to a low consumption of toner, a selection is made to form a test image and its comparison image on the same part of the surface of a transfer belt. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a program.

  Patent Document 1 describes a configuration in which each of a plurality of patch densities is corrected based on the background density at the same position. Patent Document 2 describes a configuration in which density correction is performed based on a comparison between a density correction pattern and a belt surface portion (background) detected in advance. In Patent Document 3, the average and dispersion of each patch formed on the belt is obtained and compared with a reference value, and the uniformity of each position is calculated by statistical analysis and compared with the reference value. If lower than that, a configuration is described in which the operator is notified of belt replacement.

Japanese Patent No. 3272768 JP 2008-185914 A Japanese Patent Laid-Open No. 11-288198

  It is an object of the present invention to provide a technique that can take into account factors other than detection accuracy while suppressing detection errors of a test image caused by deformation of a test image carrying medium.

  According to the first aspect of the present invention, there is provided a test image forming unit that forms a test image on a test image transport medium that transports a test image, a deformation determination unit that determines deformation of the test image transport medium, An image forming apparatus comprising: a test image changing unit that performs change.

  According to a second aspect of the present invention, in the first aspect of the present invention, in addition to the determination result of the deformation determination means, the amount of image forming material required for forming the test image and / or the formation of the test image Selection means for selecting one or more of the plurality of formation methods of the test image based on a comparison with values possessing a plurality of types of request modes for the time required for the test.

  The invention according to claim 3 further comprises temperature / humidity detection means for detecting temperature and humidity during the stop period of the test image carrying medium in the invention according to claim 1 or 2, wherein the deformation determination means comprises: The deformation of the test image carrying medium is determined based on the output of the temperature / humidity detecting means.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, further comprising image detection means for optically detecting the test image carrying medium, wherein the deformation determination means is It is characterized in that the deformation of the test image carrying medium is determined based on the output of the image detecting means.

  According to a fifth aspect of the present invention, in the second aspect of the present invention, the plurality of forming methods include a standard first method and a detected portion of the test image that is more than the first method. A second method having a large size; a third method in which a reference image to be compared with the test image is formed by changing a formation position of the test image in the first method; and a plurality of types of the test images. And a fourth method of forming a base of a specific test image contained therein using the colors of the other test images, and the selection means includes image formation consumed in the formation of the test image. One of the second method to the fourth method is selected based on the amount of material consumption and / or the time required for forming the test image.

  According to a sixth aspect of the present invention, there is provided a computer, a test image forming function for forming a test image on a test image transport medium for transporting a test image, a deformation determination function for determining deformation of the test image transport medium, Or a test image changing function for changing the test image based on a consumption amount of an image forming material and / or a time required for forming the test image based on or in addition to the deformation determination function. It is a program.

  According to the first aspect of the present invention, there is provided an image forming apparatus capable of taking into consideration factors other than the detection accuracy while suppressing the detection error of the test image generated due to the deformation of the test image carrying medium. .

  According to the second aspect of the present invention, the detection error of the test image can be suppressed while taking into consideration the consumption of the image forming material required for forming the test image and / or the time required for forming the test image.

  According to the third aspect of the present invention, it is possible to improve the efficiency of processing required for determining the deformation of the test image carrying medium.

  According to the fourth aspect of the present invention, the deformation of the test image carrying medium can be detected more precisely.

  According to the invention described in claim 5, by selecting the second method, the consumption of the image forming material is increased as compared with the first method, but the detection accuracy of the test image can be increased, By selecting the third method, the time required for processing increases as compared with the first method, but the detection accuracy of the test image can be increased, and by selecting the fourth method, the first method can be achieved. Compared with this method, the consumption of the image forming material is increased, but the detection accuracy of the test image can be increased.

  According to the sixth aspect of the present invention, there is provided a program that can take into account elements other than the detection accuracy while suppressing the detection error of the test image generated due to the deformation of the intermediate transfer member.

1 is a conceptual diagram of an image forming apparatus according to an embodiment. FIG. 2 is a block diagram illustrating a configuration of a control system of the image forming apparatus in FIG. 1. 3 is a flowchart illustrating an example of an operation procedure of the image forming apparatus in FIG. 1. It is a pattern figure which shows an example of the formation pattern of a test image. It is a graph which shows the relationship between the detection output of a test image, and the length of a test image. It is a graph which shows the relationship between the detection output of a test image, and the length of a test image.

(Constitution)
FIG. 1 is a conceptual diagram of an image forming apparatus according to an embodiment. FIG. 1 shows an image forming apparatus 100. The image forming apparatus 100 includes a recording paper storage device 101. The recording paper storage device 101 stores a plurality of recording papers 102 as recording sheets. The recording sheet is not limited to paper, and may be made of resin such as OHP paper.

  The recording paper is sent out from the recording paper storage device 101 to the transport path 103 by a paper feeding mechanism (not shown). Conveying roll mechanisms 104 and 105 are arranged on the conveying path 103, and convey the recording paper toward the secondary transfer unit 106.

  The secondary transfer unit 106 includes a transfer roll and a counter roll, and nips the recording paper and the transfer belt 107 between them to transfer the toner image formed on the transfer belt 107 onto the recording paper.

  The transfer belt 107 is an example of an intermediate transfer member that also functions as a test image carrying medium, and is a closed belt-like belt member made of polyimide amide. The transfer belt 107 is guided by guide rolls 108 and 109 and is driven by the guide roll 109 to rotate counterclockwise in the drawing. A toner image is primarily transferred from the photosensitive drums 110, 111, 112, and 113 to the transfer belt 107. On each of the photosensitive drums 110 to 113, toner images of basic colors of Y (yellow), M (magenta), C (cyan), and K (black) are formed, and this is primarily transferred to the transfer belt 107. Is done.

  Each of the photosensitive drums 110 to 113 includes a cleaning device, a charging device, an exposure device, and a developing device that supplies toner, which are not shown, along the counterclockwise direction of the drawing. Each of the photosensitive drums 110 to 113 rotates counterclockwise in the figure, and at that time, the surface is cleaned by a cleaning device, the cleaned portion is charged, and the charged portion is exposed. Is performed to form an electrostatic latent image, and toner (powder of image forming material) is supplied from the developing device to the electrostatic latent image to form a toner image.

  The YMCK toner images formed on the photosensitive drums 110 to 113 are superimposed on the transfer belt 107 and primarily transferred. As a result, a color toner image is formed on the transfer belt 107. The toner image is transported toward the secondary transfer unit 106 by the rotation of the transfer belt 107, and is transferred to the recording paper transported from the left direction in the drawing by the secondary transfer unit 106.

  The recording paper onto which the toner image has been transferred in the secondary transfer unit 106 is sent to the image fixing unit 114, where toner image fixing processing is performed. The image fixing unit 114 includes a heating roll and a counter roll, applies heat and pressure to the recording paper, and fixes the toner image on the recording paper as an image. The recording paper that has passed through the image fixing unit 114 is sent from the transport roll mechanism 115 to the discharge mechanism 116 and discharged onto the recording paper discharge surface 117.

  When images are formed on both sides of the recording paper, the recording paper is sent from the transport roll mechanism 115 to the reversing device 118, where the recording paper is switched back and transported through the back surface image forming transport path 119. The recording sheet conveyed through the back surface image forming conveyance path 119 is supplied to the conveyance path 103 and reaches the secondary transfer unit 106 again.

  An image detection sensor 120 is arranged in the vicinity of the transfer belt 107. The image detection sensor 120 optically detects a test image formed on the transfer belt 107. The image detection sensor 120 includes a regular reflection sensor or a regular reflection sensor and a diffusion sensor. The regular reflection sensor is an optical sensor that detects reflected light that is irradiated from a light source (not shown) onto a surface to be irradiated and is regularly reflected (incident angle = reflection angle). The diffuse reflection sensor is an optical sensor that detects only diffused light, not regular reflection.

  The test image is an image used for a test for determining the quality (mainly density) of each YMCK toner image, and is called a patch or a patch image. This test image is formed on the transfer belt 107 at a predetermined timing and is detected by the image detection sensor 120. Based on this test image, the conditions for forming the image formed on the recording paper are adjusted.

  The image forming apparatus 100 includes a controller 200. The controller 200 has a function as a computer and includes a CPU, a memory, an interface circuit, and a clock function, and executes a process for changing a test image forming method (a process for changing a test image), which will be described later.

  FIG. 2 is a block diagram illustrating a configuration of a control system of the image forming apparatus 100 of FIG. FIG. 2 shows the controller 200 also shown in FIG. In the controller 200, functional units to be described later are configured in software by a program stored in a memory (not shown). The controller 200 executes control of image formation processing, control of processing for acquiring image quality information of a toner image using a test image, and control of processing for changing a test image formation method (detection method). A specific example of the control of the process of changing the test image formation method (detection method) will be described later.

  The output of the image detection sensor 120 is input to the controller 200. The image detection sensor 120 detects a test image formed on the transfer belt 107 and outputs the image data to the controller 200.

  The output of the temperature / humidity sensor 210 is input to the controller 200. The temperature / humidity sensor 210 includes a temperature sensor, a humidity sensor, and a memory that stores humidity data detected by these sensors and a change profile of the temperature data. The temperature / humidity sensor 210 includes a battery, operates even when the image forming apparatus 100 is turned off or in a standby state, continues to acquire temperature / humidity information during that time, and stores the measurement result.

  The controller 200 includes an image formation processing control unit 201, a curl prediction prediction unit 202, a curl / surface roughness determination unit 203, and a detection method selection unit 204. The image forming process control unit 201 controls the image forming process in the image forming apparatus 100. This image formation processing includes formation of a test image on the transfer belt 107 in addition to formation of an image on recording paper. Specifically, recording paper conveyance control by the conveyance roll mechanism 104, control of density of toner images formed on the photosensitive drums 110 to 113, control of formation timing, control of the secondary transfer unit 106 and the image fixing unit 114, and the like. Is performed in the image forming process control unit 201.

  The curl prediction determining unit 202 is based on the period when the image forming apparatus 100 is not forming an image (the transfer belt 107 is not rotating) and the output of the temperature / humidity sensor 210, and the curl attached to the transfer belt 103. Predictive judgment.

  The curl / surface roughness determination unit 203 determines the curl and surface flatness disorder (surface roughness) of the transfer belt 107 based on the output of the image detection sensor 120. Curling and surface roughness are mainly caused by deformation of the transfer belt due to moisture absorption.

  The detection method selection unit 204 selects a method for detecting a test image (a method for forming a test image). In this example, as a method for detecting a test image (hereinafter referred to as a patch), four types of methods (four types of test images) shown in Table 1 below are prepared, and any one of them can be selected. Has been. FIG. 4 is a pattern diagram showing an example of a patch formation pattern in each of the detection methods in Table 1 above. FIG. 4 shows an example in which three types of density patterns are formed for each color.

  “Initial patch detection” in Table 1 above is a standard detection method, and is a reference for evaluating other methods. “Initial patch detection” is set so as to be balanced in consideration of various factors.

  “Increasing the patch length” is a detection method when the pattern of each density in the moving direction of the transfer belt 107 is lengthened (doubled in FIG. 4). In this method, the time for detecting a patch becomes longer, and the probability that area information without a curled part is obtained is increased, so that the detection accuracy can be improved. On the other hand, the toner consumption increases.

  “Vcln and Vpatch are formed at the same position” means a detection method of forming a patch to be detected at a position where a clean surface detection value “Vcln” (which is a reference value) on the transfer belt 107 is acquired. It is. In this method, after detecting Vcln, a patch is formed at the same location, and Vpatch is obtained by detecting it. In this method, since the reference value and the detection value are acquired at the same portion, the influence of the deformation of the transfer belt 107 hardly appears in the detection result, and the detection accuracy is improved. On the other hand, since a patch is formed at the same location after detecting Vcln and Vpatch is obtained by detecting the patch, the time required for detection becomes longer. Further, since the contact time between the transfer belt and the photosensitive drum becomes long, the wear of the photosensitive member becomes large.

  “Overlaying a K color patch on a color patch” is a method of forming a background toner image of any color (or two or more colors) in YMC on the background when forming a K color patch. It is. When this method is adopted, the K color patch can be detected based on the difference in the degree of diffusion of the diffused light from the color other than the K color around the K color patch, so that sensing can be performed by detecting the diffused light. . Since the diffused light is hardly affected by the deformation of the patch forming surface (in this case, the transfer belt 107), the detection accuracy can be increased. Since a toner image of a color other than K is formed as the background, the amount of toner consumption increases.

  An operation panel (not shown) of the image forming apparatus 100 includes a switch that can select either the normal speed operation mode or the high speed operation mode, and a switch that can select either the normal toner consumption mode or the low toner consumption mode. Arranged so that the user can select one of the operation modes.

  Here, the high-speed operation mode is an operation mode in which the adjustment process using the color patch is completed in as short a time as possible and the waiting time of the user is shortened as much as possible. The low toner consumption mode is an operation mode in which toner consumption is suppressed. Note that it is not possible to select both the normal toner consumption mode and the low toner consumption mode.

(Example of processing)
For example, when an image is formed on a predetermined number of recording sheets, a test image is formed on the transfer belt 107 and data acquisition for adjusting the image quality of the image to be formed is performed. At this time, a test image is formed for each color of YMCK, and information on image quality used for adjusting these colors is acquired. In the present embodiment, an example of processing performed at a stage before acquiring information on the image quality of each basic color will be described.

  FIG. 3 is a flowchart illustrating an example of processing performed in the controller 200. The processing shown in FIG. 3 is executed by the controller 200 in accordance with an operation program stored in a memory (not shown) in the controller 200. The operation program may be stored in an appropriate identification medium and provided from there.

  3 is started at the timing when the image forming apparatus 117 is turned on or when the image forming apparatus 117 is returned from the standby state (step S301). When the process is started, a prediction determination of curling of the transfer belt 107 is performed (step S302). In this prediction determination, first, a clock function in the controller 200 is referred to, and a stop time (a time during which the transfer belt 107 has not moved) is calculated. If the stop time is less than a predetermined period (threshold), the process proceeds to step S303.

  If the stop time is less than a predetermined period (threshold), it is further determined whether or not the amount of change in humidity and temperature (change width) within the period is equal to or greater than a predetermined threshold. (Step S302). If the amount of change (change width) in humidity and temperature during the stop period is equal to or greater than a predetermined threshold value, the process proceeds to step S305; otherwise, the process proceeds to step S303. Note that a value that is experimentally determined in advance is used as the threshold value in step S302.

  In step S303, the processing in FIG. 3 (processing for changing the test image detection method) is cancelled. In this case, the initial detection method shown in Table 1 is selected.

  In step 304, a detection value (Vcln) of specular reflection light on the clean surface (portion where no toner image is formed) of the transfer belt 107 is acquired using the image detection sensor 120, and the transfer belt 107 is acquired using Vcln. The state of curling and surface roughness is determined. In this example, this determination is made based on whether or not Vcln is equal to or greater than a predetermined threshold value.

  In step S305, if Vcln is equal to or greater than a predetermined threshold value, the process proceeds to step S306. Otherwise, the process proceeds to step S303, and the process illustrated in FIG. 3 is canceled.

  By proceeding to step S306, the test image detection method (formation method) is changed. In step S306, a determination is made regarding selection of a detection method that takes into account two points of time required for patch detection and toner consumption required for patch detection. That is, in step S306, if the image forming apparatus 100 is set to the high-speed operation mode, X = 0 is selected, and the process proceeds to step S307. In this case, the determination regarding other requirements is not performed. If the low toner consumption mode is set, X = 1 is selected, and the process proceeds to step 308. Also in this case, the determination regarding other requirements is not performed.

  In step S307, one of the two types of processing is selected. One of the settings is to increase the patch length. The other is a setting for detecting a K-color patch by forming a K-color patch on the color patch as a base and detecting it with a diffuse reflection sensor. In step S307, which process is to be selected can be determined by setting an initial state or setting by a user.

  In step S308, a setting for detecting Vcln and Vpatch at the same position on the transfer belt 107 is selected. After the process of step S307 or S308 ends, the process of FIG. 3 ends. Thus, any one of the settings shown in Table 1 is selected, and color density adjustment processing using the patch is performed according to the selection.

  When the setting for forming Vcln and Vpatch at the same position on the transfer belt 107 is selected, Vcln is detected after Vpatch is detected. By doing so, the interval between both detection timings can be minimized, and the processing time can be shortened. Further, in the method of detecting Vcln after detecting Vpatch, a toner mark capable of specifying the position of Vpatch is formed near the position where Vcln where Vpatch is formed should be detected, and Vcln should be detected synchronously. Make it easy to specify the position. By doing so, the synchronization accuracy can be increased.

(Superiority)
The curl or deformation of the transfer belt 107 is mainly caused by moisture absorption of the transfer belt 107. This phenomenon becomes more prominent as the humidity and temperature are higher, and the longer the operation is not performed. Therefore, in the present embodiment, the actual curl detection is not performed in the process of step S302, and the curl prediction is determined based on the measured values of the temperature and humidity environment up to that point. Thereby, the detection time and power consumption required for curl detection are suppressed.

  Table 2 shows the actual measurement results that are the basis for the determination in step S302. Table 2 shows that a polyimide amide belt member (thickness: 2 mm) used for the transfer belt 107 is cut into a size of 200 mm × 200 mm, and is cut for one week in a container in which the temperature and humidity environment can be precisely adjusted. The result of measuring the amount of unevenness after being left is shown.

  Table 2 shows a phenomenon in which the transfer belt is deformed due to the influence of temperature and humidity. As apparent from Table 2, the deformation (unevenness) of the transfer belt increases as the temperature is higher and the humidity is higher. This indicates that the transfer belt is deformed due to moisture absorption. In addition, when this phenomenon occurs in the portion wound around the guide roll, curling occurs.

  If it is determined in step S302 that there is a possibility that curling has occurred on the transfer belt 107 based on the recording of the temperature and humidity environment since the previous stoppage, the processing from step S304 onward is executed. Actually, the degree of curling of the transfer belt 107 is detected by optical measurement.

  In step S305, if it is determined that there is a curl that is expected to hinder patch detection, then in step 307 (prioritizing reduction in detection time) or step S308 (low toner consumption) from the viewpoint of detection time and toner consumption. Is selected). Thereby, in addition to the detection accuracy of the color correction information using the patch, selection is performed from the viewpoint of the operation speed and the toner consumption, and a detection method that balances these requirements is selected.

  FIG. 5 is a graph showing the relationship between the length of the patch (length in the moving direction of the belt) and detection output fluctuation (detected by regular reflection). Here, the detection output is a fluctuation of a value normalized by (Vpatch / Vcln), and Vcln and Vpatch are detected at different locations. As can be seen from FIG. 5, by increasing the length of the patch, the probability of obtaining area information without a curl portion increases, and therefore the fluctuation in detection output decreases.

  FIG. 6 shows the patch length (length in the belt movement direction) and detection output fluctuation (detected by regular reflection) when Vcln and Vpatch are formed at the same position on the transfer belt in addition to the conditions shown in FIG. It is a graph which shows the relationship. Again, the detected output is a variation in the value normalized by (Vpatch / Vcln).

  FIG. 6 shows the same tendency as in FIG. 5, but compared to the case of FIG. 5, the fluctuation in the detection output is greatly suppressed even when the length of the patch is short. This is because the influence of deformation of the transfer belt is canceled and reduced because Vcln and Vpatch are detected at the same position of the transfer belt.

(Other)
In step S306, only the determination regarding whether or not to shorten the detection time may be performed. In this case, if the detection time is to be shortened, the process proceeds to step S307, and if not, the process proceeds to step S308. In step S306, it may be determined only whether or not the toner consumption is to be reduced. In this case, if the toner consumption is to be reduced, the process proceeds to step S308; otherwise, the process proceeds to step S307.

  Examples of the background color in the method of changing the background of K color to colors include the case of selecting one color in YMC and the case of selecting two or more colors in YMC. Further, the test image may be detected by combining a plurality of methods shown in Table 1. That is, you may comprise a test image combining 4 types of test images shown in FIG. In this case, the amount of toner consumed and the time required for processing increase, but the detection accuracy of the image quality using the test image increases.

  The present invention can be used for an image forming apparatus and its operation control.

  DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 101 ... Recording paper storage apparatus, 102 ... Recording paper, 103 ... Conveyance path, 104 ... Conveyance roll mechanism, 105 ... Conveyance roll mechanism, 106 ... Secondary transfer part, 107 ... Transfer belt, 108 ... Guide Roll, 109 ... guide roll, 110 ... photosensitive drum, 111photosensitive drum, 112 ... photosensitive drum, 113 ... photosensitive drum, 114 ... image fixing unit, 115 ... conveying roll mechanism, 116 ... discharge mechanism, 117 ... recording Paper discharge surface, 118... Reversing device, 119... Backside image forming conveyance path, 120.

Claims (6)

Test image forming means for forming a test image on a test image carrying medium for carrying the test image;
Deformation determining means for determining deformation of the test image carrying medium;
An image forming apparatus comprising: test image changing means for changing the test image. In addition to the determination result of the deformation determination means, based on a comparison with the value of possessing a plurality of request modes for the consumption of image forming material required for forming the test image and / or the time required for forming the test image The image forming apparatus according to claim 1, further comprising: a selecting unit that selects one or more of the plurality of test image forming methods. A temperature / humidity detecting means for detecting temperature and humidity during the stop period of the test image carrying medium;
The image forming apparatus according to claim 1, wherein the deformation determination unit determines the deformation of the test image carrying medium based on an output of the temperature / humidity detection unit. Image detecting means for optically detecting the test image carrying medium;
The image forming apparatus according to claim 1, wherein the deformation determination unit determines the deformation of the test image carrying medium based on an output of the image detection unit. The plurality of forming methods include:
A first standard method;
A second method in which the size of the detected portion of the test image is larger than the first method;
A third method for forming a reference image to be compared with the test image by changing a formation position of the test image in the first method;
The test image includes a plurality of types, and includes a fourth method of forming a base of a specific test image included in the test image using colors of other test images, and
The selection means is any one of the second method to the fourth method, based on a consumption amount of an image forming material consumed in forming the test image and / or a time required for forming the test image. The image forming apparatus according to claim 2, wherein the image forming apparatus is selected. On the computer,
A test image forming function for forming a test image on a test image carrying medium for carrying the test image;
A deformation determination function for determining deformation of the test image carrying medium;
Or a test image changing function for changing the test image based on the consumption of image forming material and / or the time required for forming the test image based on or in addition to the deformation determination function. A featured program.

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