JP4740100B2 - Image evaluation apparatus, image evaluation method, and image forming apparatus - Google Patents

Description

  The present invention relates to an image evaluation apparatus, an image evaluation method, and an image forming apparatus for evaluating an image of a linear object such as ruled lines, cracks, grooves, and the like, and in particular, toner removal of a line image output from a printer or a copying machine. The present invention relates to an image evaluation apparatus, an image evaluation method, and an image forming apparatus using the same.

2. Description of the Related Art Conventionally, a method of copying a linear object such as a form or drawing by an electrophotographic method and forming an image as a linear image, that is, a linear image, has been performed. When this linear image is formed, the copied linear image may not be displayed or printed as a clear line, and may be printed as a linear image in which toner has partially dropped. Therefore, it is necessary to adjust the image forming conditions. For this reason, the image forming conditions are adjusted while visually determining the printed line image. However, this adjustment is not only complicated, but also has a problem that it takes a long time.
In order to remedy such problems, the copied linear image is processed by an image processing apparatus to obtain color density level data in each unit pixel of the process, and the color density level data thus obtained are completely Compared with the normal color density level obtained from a standard sample of color density, the portion of the color density less than the normal level is calculated as a white area, and the ratio of the white area to the area of the measurement target area It has been proposed to perform the quality accurately and automatically (see, for example, Patent Document 1).
JP-A-4-145770

However, in the method described in Patent Document 1, a threshold value is used as a method for discriminating image quality when measuring a missing amount that the image should generally have in a line image composed of a background area portion and a line image. Since the binarization process is performed and the method of representing the binarized area ratio is adopted, if the binarization process is performed after the classification by the threshold value, a part of information is lost. For example, when missing occurs in an area lower than the threshold, the result is equivalent to a state where there is no toner.
In other words, an optical device having a line image 11 formed on a white paper 10 as shown in FIG. 1 is scanned in the direction of the arrow X, and the image density, for example, the luminance output is profiled in relation to the measurement position (X axis). When displayed as data, as shown in FIG. 2, when the luminance output is set to 120 as the threshold value and the missing amount shown by curve 2 is medium, an ideal case where there is no missing toner image (curve 3). ) Is used as a reference to obtain an area ratio that is equal to or less than the threshold value, whereby the missing rate of the linear image is obtained, and the quality of the image can be evaluated. However, as shown by the curve 1, when the toner image is missing over the entire area of the toner image, the area ratio is 0, which is the same result as the background state where there is no toner image, resulting in an erroneous evaluation. End up.

On the other hand, when a linear image with minute toner missing is measured, the result is equivalent to an ideal line with no toner missing. Therefore, there is a problem in that the evaluation result of the amount of toner missing varies greatly depending on the threshold value to be set.
The present invention has been made in consideration of the above-described circumstances, and it is possible to correctly evaluate the amount of toner missing in a line image without losing information on the change even when toner missing reaches a large area or is minute. An object of the present invention is to provide an image evaluation apparatus, an image evaluation method, and an image forming apparatus.

In order to solve the above-mentioned problem, the invention according to claim 1 includes an optical device that reads a line image composed of a background area portion and a line image for each line in a direction orthogonal to the line image. An image evaluation apparatus that evaluates the toner omission amount of the line image, and creates profiling data indicating the relationship between the measurement position and the brightness line by line based on the brightness signal of the line image read by the optical device. and profiling data creating means creates a histogram showing the frequency of luminance signal values from the profiling data of a plurality of lines including the lines to be measured that is created line by line in this profiling data creating means by one line, the plurality of lines Rights of the luminance signal value indicating the peak value of the background area portion occupying the largest area of the line image in each histogram of It means replaces replaces the luminance signal of the background area portion of the feature amount of該地skin area unit to determine the feature amount of the background area portion in the profiling data and by the average value calculated values, in the profiling data creating means the average value of the feature amount of the background area of 1 per line is calculated respectively from the profiling data of a plurality of lines including the lines to be measured that is created line by line, the measurement target in the profiling data from the replacement means a linear image feature quantity calculating means for said plurality of lines differencing of each line position and the average value of each luminance signal in the product sum, wherein the amount of said linear image containing become line, said line image The luminance signal value obtained by reading the solid image of the same color as the linear image with the optical device, the feature amount of the background area portion, and the Calculating a luminance signal of a range surrounded by both sides of the boundary of the measurement position of the image, and normalized feature quantity calculating means for the luminance signal amount and the normalized feature value, the normalized feature calculation the difference between the area S2 of the normalizing range of the feature amount of the linear image and the normalized feature amounts S1 calculated by means and toner leakage amount S3, the toner exits amount (rate) (S3 / S1) × And a toner missing amount calculating means calculated as 100 .
According to a second aspect of the present invention, in the image evaluation apparatus according to the first aspect, the linear image feature quantity calculating means includes a plurality of measurement lines in a direction orthogonal to the linear image to be measured. The feature amount of the background area portion calculated from the profiling data of this line is used as the feature amount of the background area portion of one line to be measured.

Further, the invention according to claim 3 is the image evaluation apparatus according to claim 2, wherein the linear image feature amount calculation unit includes the dust in the background area portion and the profiling data from the replacement unit includes the profiling data. When there is a line image area and the dust area, the area closer to the position of the line image area measured before is selected from the line image area and the dust area. And a position setting means for determining that the other area is the dust area and replacing the luminance signal value of the dust area with the feature amount of the background area portion.
According to a fourth aspect of the present invention, in the image evaluation apparatus according to any one of the first to third aspects, the linear image feature amount calculating unit generates a line image in which at least two colors of toner are superimposed. A feature is provided for setting a boundary line on both sides of a measurement position in which color misregistration is corrected in advance as a boundary line on both sides of the measurement position of the line image with respect to a color shift line image generated at the time of formation. To do.
According to a fifth aspect of the present invention, a line image composed of a background area portion and a line image is read by an optical device for each line in a direction orthogonal to the line image, and the toner of the line image is read. An image evaluation method for evaluating a missing amount, a profiling data creation step for creating one line at a time of profiling data indicating a relationship between a measurement position and luminance based on a luminance signal of the line image read by the optical device; A histogram indicating the frequency of the luminance signal value is created line by line from the profiling data of a plurality of lines including the measurement target line created one line at a time in the profiling data creation step, and the line in each histogram of the plurality of lines flat and the average value of the luminance signal value indicating the peak value of the background area portion occupying the largest area of the image A step replacement replaces the luminance signal of the background area portion of the feature amount of該地skin area unit to determine the feature amount of the background area portion in the profiling data by value, one line was created by the profiling data creation step the containing an average value of the feature amount of the background area of 1 per line is calculated respectively from the profiling data of a plurality of lines, the line to be measured in the profiling data from the replacement process that includes the line to be measured a linear image feature amount calculation step of the difference component of each line position and the average value of each luminance signal in a plurality of lines in the product-sum wherein the amount of said linear images, the linear images of the same color as the line image The luminance signal value obtained by reading the solid image with the optical device, the feature amount of the background area portion, and the measurement position of the line image Calculating a luminance signal of a range surrounded by both sides of the boundary line, a normalized feature value calculation step of the luminance signal amount and the normalized feature value, positive calculated in this normalization feature value calculating step and-normalized feature value S1 and toner leakage amount and S3 difference between the area S2 of the normalizing range of the feature amount of the linear image, omission toner obtains toner exit amount (ratio) as (S3 / S1) × 100 And a quantity calculating step.

The invention according to claim 6 is the image evaluation method according to claim 5, wherein the linear image feature value calculating step includes a measurement line in a direction orthogonal to the linear image to be measured. The feature amount of the background area portion calculated from the profiling data of a plurality of lines is used as the feature amount of the background area portion of one line to be measured.
The invention according to claim 7 is the image evaluation method according to claim 5 or 6, wherein the normalized feature value calculation step occurs when forming a linear image obtained by superimposing toner of at least two colors For the color-shifted linear image, the measurement range is limited by setting boundary lines on both sides of the measurement position where the color shift is corrected in advance.

According to an eighth aspect of the present invention, there is provided a photosensitive member that carries an electrostatic latent image of an image and carries the electrostatic latent image as a toner image by toner supplied from a developing device, and the photosensitive member. An intermediate transfer member that transfers the toner image to the recording medium by transferring the toner image to the recording medium by transferring the toner image to the recording medium by contacting the toner image with the photosensitive member; 5. The image forming apparatus having a control device that controls the speed and the conveyance speed of the toner image on the intermediate transfer member, wherein the control device is obtained from the image evaluation device according to claim 1. The conveyance speed of the toner image on the photosensitive member and the intermediate transfer member is controlled based on the amount of toner missing .
According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect of the present invention, the image forming apparatus includes an optical device that captures a toner image of the intermediate transfer member, and reads an image density signal of the toner image from the optical device. An image evaluation device for evaluating a toner missing amount rate of a line image is provided, and the image evaluation device is the image evaluation device according to any one of claims 1 to 4 .

According to a tenth aspect of the present invention, in the image forming apparatus according to the eighth or ninth aspect, the image forming apparatus is based on an image reading unit that reads an image from a document and image information read by the image reading unit. And an image writing unit for forming an electrostatic latent image and a toner image on the photosensitive member .

  According to the present invention, by adopting the above-described configuration, an image that can correctly evaluate the amount of toner missing in a line image without losing information on the change even when toner missing reaches a large area or is minute. It is possible to provide an evaluation apparatus, an image evaluation method, and an image forming apparatus.

  In the present invention, as shown in FIG. 1 described above, basically, an optical device in which a linear image 11 is formed on a sheet 10 is orthogonal to the linear image 11 (arrow X direction). 3 is calculated by calculating the profiling data as shown in FIG. 3 based on the relationship between the luminance output and the measurement position (X axis), and using this profiling data, the missing amount of the toner image is obtained.

(A) Evaluation of toner missing amount of line image on transfer paper In order to obtain the toner image missing amount rate using the profiling data shown in FIG. 3, (1) calculation of feature amount of background area, (2 It can be appropriately obtained by calculating the feature amount of the line image, (3) calculating the normalized feature amount, and (4) calculating the toner missing amount.
Next, the above (1) to (4) will be described.
(1) Calculation of feature amount of background area portion First, as an optical device for reading the line image 11 of the paper 10, a CCD camera is used, and a line image 11 composed of the linear image 12 including the background area portion 13 is obtained. Then, each line is read in a direction orthogonal to the line image 11 (arrow X direction) (see FIG. 1). Here, the background is paper and the toner is magenta. The RGB (red, green, blue) value profiling data read by the CCD camera is converted into luminance signal output and profiling data of the measurement position (X axis) (see FIG. 3).
Subsequently, a histogram indicating the frequency with respect to the output of the luminance signal is created from the profiling data shown in FIG. 3 (see FIG. 4). From this histogram, since it is the background region 13 occupying the maximum area, the feature amount of the background region portion 13 is determined by the luminance output value indicating the peak P1 (see FIG. 4). Actually, there are two peaks, a toner area color peak P2 and a background area color peak P1, but here, since the background area portion 13 is paper, a high value P1 of the two peaks obtained from the histogram is obtained from the background. The feature amount of the area unit 13 is used. Here, as illustrated in FIG. 5, when dust D such as large dust or dust exists on the measurement target line X <b> 1, the histogram peak of the background region 13 may not appear clearly. Therefore, when calculating the feature amount of the background region portion 13, in order to calculate the histogram peak value P1 of the stable background region portion 13, a plurality of line positions X1 to X1 in the region including the line position X1 to be measured. A histogram of each luminance output and frequency taking into account the profiling data of X3 is created (see FIG. 6), and the luminance output at the histogram peak value P1 of the background region portion 13 is determined so that the peak value P1 of the histogram becomes clear. calculate.

  As described above, when the dust D exists in the background region portion 13, the value becomes large in the process of calculating the feature amount of the line image 11. Therefore, the evaluation result of removing the dust D from the background region portion 13 by replacing the luminance output at the histogram peak value P1 obtained as described above with the profiling data of the region other than the toner region 11 by the feature amount of the background region portion 13. (See FIG. 7). That is, if there is a large amount of dust D, profiling is performed as shown in FIG. 8, and it may not be possible to determine which is a linear image. In this case, the peak position P3 (position 100 in FIG. 10) closer to the previously measured position P3 ′ (for example, position 99 in FIG. 9) of the linear image 12 is determined as the linear image 12, and FIG. The 50 peak position P4 of 10 is judged to be dust, the peak position P4 is excluded, and the replacement process is performed with the feature amount of the background area 13 just described.

In more line position (X1 to X3) including the line position X1 to be calculated measurement object feature amount of (2) a linear image, the average value of the characteristic quantity of earth skin region 13, the average value of the luminance profiling data of the feature amount of the sum of products is linear image difference (hatched portion component of FIG. 11).
(3) Calculation of normalized feature amount When the line image 11 is read by an optical device, the RGB absolute values differ depending on the combination of the color of the background region 13 and the color of the linear image 12. Here, a solid image of the same color as the line image 11 on the paper 10 is read by a CCD camera, and the output value of the luminance signal calculated from the obtained RGB values is a value in the ideal line image and is set as the lower base value L1. . The upper base value L2 is a feature amount of the background area, and the right side value L3 and the left side value L4 are measurement positions of the line image 11. Four sides are defined as normalized boundary lines, and an area S1 surrounded by the boundary lines is defined as a normalized feature amount.

(4) Calculation of Toner Omission Amount Within the normalized range of the normalized feature amount S1 calculated in (3) above and the feature amount of the linear image 12 calculated in (2) above (the area S2 of the right oblique line portion in FIG. 12) ) Is the toner missing amount (left hatched portion S3 in FIG. 12), and the toner missing amount (rate) is obtained as (S3 / S1) × 100.
The method for evaluating the toner missing amount rate for each line in the direction orthogonal to the line images (1) to (4) described above for the entire vertical line 11 drawn on the A4 size paper shown in FIG. Was performed by scanning in the direction orthogonal to the line image (X axis), and further, in order to evaluate the entire line image, the optical device was moved in the parallel direction (Y axis). FIG. 14 shows the result of evaluation of the toner loss amount for the entire line image 11. This result means that the larger the toner missing amount (rate), the larger the toner missing amount. Since this evaluation method is performed for each line in the direction orthogonal to the line image 11, it can be seen from the result shown in FIG. 14 that the toner removal amount has periodicity in the Y-axis direction. . Based on this evaluation result, it becomes possible to appropriately analyze and evaluate problems such as fluctuations in image forming conditions due to wear damage of the photosensitive drum and intermediate transfer belt of the image forming apparatus and take appropriate measures. .
When dust D is present in the background area 13 in the peripheral part of the line image 11 for evaluating the toner removal amount, an error may occur in the process of calculating the feature amount of the background area 13, or the line Even in the process of calculating the feature amount of the image 12, there is a possibility that an error occurs because the feature amount is calculated using the feature amount of the background region portion 13. However, in the present invention, as described above, the feature amount of the background region portion 13 and the feature amount of the linear image 12 are calculated by recognizing a dust region such as dust and excluding the output value of the region. Therefore, it is possible to accurately evaluate the toner removal amount.

(B) Evaluation of toner loss amount of line image on transfer paper subjected to image processing Next, in the image evaluation apparatus according to the present invention, image processing is performed instead of the linear image shown in FIG. The amount of toner missing from the line image on the transfer paper can also be evaluated based on the above (1) to (4). In this case, (2 ′) calculation of the feature amount of the linear image and (3 ′) normalization feature amount calculation shown in (2) and (3) are slightly different. These differences will be described.
(2 ′) Calculation of feature amount of linear image When a line image on a transfer sheet is formed by image processing of an image processing pattern as shown in FIG. 15, a plurality of lines are set at a cycle of the pattern. Here, an example of one cycle will be described. In the image processing pattern as shown in FIG. 15, one cycle is four pixels when viewed in the horizontal direction with respect to the line image. This is defined as one cycle of the image processing pattern, and the difference between the average value of the feature amount of the background region 13 and the average value of the luminance profiling data in this region is summed and used as the feature amount of the toner linear image 12.

(3 ′) Normalized feature value calculation When the line image 11 is read by an optical device, the RGB absolute values differ depending on the combination of the color of the background region 13 and the color of the linear image 12. Here, a solid image containing the same color image processing as that of the line image 11 is read on a paper by a CCD camera, and an average value of luminance signals calculated from RGB values in an area of one cycle of the image processing pattern is obtained as an ideal line image. And the lower base value L1. The upper base value L2 is the feature amount of the background region 13, and the right side value L3 and the left side value L4 are the positions of the line images. Four sides are defined as normalized boundary lines, and an area surrounded by the boundary lines is defined as a normalized feature amount.
In this example as well, the feature amount of the background area portion is calculated in the same manner as described above using (1) calculation of the feature amount of the background area portion and (4) calculation of the toner missing amount ratio in the item (A). Calculation and toner missing amount rate can be obtained.
As described above, the toner omission of the toner image shown in FIG. 15 which is the image processing pattern can be appropriately evaluated.

(C) Evaluation of the amount of toner missing from the color-shifted line image on the transfer paper When the line image is read by an optical device, the combination of the color of the background area 13 and the color of the toner linear image 12 The absolute values of the three primary colors red (R), green (G), and blue (B) are different. Further, in the line image 11 formed by overlapping toners of at least two colors or more, there arises a problem that the misregistration between colors causes the line image to become thick. In the present invention, such a color misregistration line image causes a problem. It is also possible to perform evaluation with the positional deviation removed.
A case where the amount of toner missing of the color misregistration line image 11 on the transfer paper is evaluated will be described. In the case of a color misalignment line image, the misaligned portion is removed from the entire line image including the color misregistration, and the range is limited to the target line area for evaluation. That is, FIG. 16 shows profiling data for red (R), green (G), and blue (B) colors. From this figure, the R, G, and B colors cause misalignment due to magenta toner and cyan toner, and the boundary position deviates from the actual line image position. On the left side of FIG. On the right side, there is a misalignment due to magenta toner. Therefore, in the case of performing an accurate evaluation, it is necessary to correct these deviations and set the evaluation range. FIG. 17 shows the luminance output and measurement position profiling data in the line image 11 that forms a blue line image using magenta toner and cyan toner. As described above, the color image of the cyan toner and magenta toner has color misregistration. Therefore, as shown in FIG. 16, the left and right boundary lines at the measurement position where the color misregistration is corrected are set in advance and normalized. The toner missing amount is calculated by calculating the feature amount and the feature amount of the toner linear image.
As described above, since the color misregistration due to magenta toner and cyan toner is corrected and the normalized feature amount and the feature amount of the toner linear image are calculated, it is possible to evaluate the toner missing amount with higher accuracy. It becomes.

(D) Evaluation of toner loss amount of line image on transfer belt Next, evaluation of toner loss amount on the transfer belt onto which a linear toner image formed on the photoreceptor of the image forming apparatus is transferred Will be described. As will be described later, the toner linear image formed on the photoconductor is transferred to the transfer belt. Can be obtained.
The process of calculating the histogram peak described in the section (1) Calculation of the feature amount of the background area in the item (A) is the same. However, in this case, since the background is a transfer belt using a carbon-based material, the color is close to black, and the luminance output is reversed from the case where white paper 10 is used. The toner area 12 using magenta toner has a higher output than the background area 13. Therefore, the background region portion 13 uses the level indicated by L2 in FIG. 18 as the feature amount of the background region portion.
Similarly, the value of the ideal line image in the toner linear image 12 is set as the upper base value L1, and the left and right side values L3 and L4 are obtained from the measurement positions of the line image, and the normalized feature amount and the toner image feature amount are obtained. To determine the toner removal amount.
In this way, it is possible to appropriately determine the toner missing amount of the toner image transferred to the transfer belt.

  Hereinafter, an image forming apparatus using an image evaluation apparatus according to the present invention will be described with reference to the drawings.

  FIG. 19 is a diagram showing a schematic configuration in which an image evaluation apparatus according to an embodiment of the present invention is used in an image forming apparatus. In the figure, reference numeral 100 denotes a copying machine main body which is an image forming apparatus, 101 denotes a document table on which a document is placed, and 102 denotes a document placed on the document table 101, which is an optical device (not shown) that is perpendicular to the document. This is an image reading unit that irradiates and scans light every time, reads the reflected light by a CCD, converts image information of a document into a digital signal, and reads the information. The document information read by the image reading unit 102 is subjected to photosensitivity of each color by laser light modulated for each of yellow (Y), cyan (C), magenta (M), and black (B) through the image writing unit 103. The body drum 1 is exposed. At this time, the photosensitive drum 1 is rotating and the surface portion of the photosensitive drum 1 that has passed through the charging device 60 is charged, and an electrostatic latent image of an original image corresponding to each color is formed by the exposure. To the electrostatic latent image, toner is attached by the developing drum 2 of the developing device 61 to form Y, C, M, and B monochromatic toner linear images. Thereafter, the toner linear images are respectively transferred by the primary transfer roller 62 onto the endless intermediate transfer belt 80 which is stretched and rotated by the driving roller 14 and the stretching roller 15. Thereby, on the intermediate transfer belt 80, the toner images of the respective colors are superimposed to form a full color image. After the photosensitive drum 1 is transferred to the intermediate transfer belt 80, residual toner is removed by the cleaning device 63, and the charge is removed by the charge removal device 64.

On the other hand, one sheet is selected from the sheet feed tray 106 through the sheet feed roller 107 and conveyed to the registration roller 110 through the conveyance rollers 108 and 109. Then, the toner image on the intermediate transfer belt 80 is transferred by the secondary transfer roller 111 onto the sheet conveyed by the registration roller 110 in time. The toner linear image transferred onto the sheet is fixed by the fixing device 112 and discharged onto the discharge tray 113.
The copying machine main body 100 incorporates a correction unit 105, and the correction unit 105 determines the speed difference between the photosensitive drum 1 and the intermediate transfer belt 80 based on the evaluation of the toner missing amount of the line image on the transfer paper. Appropriate image formation is performed under control. The operation of the correction unit 105 will be described.

  The transfer paper on which the original is copied by the copying machine as described above is placed on the original table 101 of the copying machine main body 100, the linear image on the transfer paper is read by the image reading unit 102, and the luminance signal and measurement for each line are measured. The position data is sent to the arithmetic unit 204 provided outside the copying machine main body 100. In the arithmetic unit 204, profiling data creating means based on the luminance signal and measurement position data, histogram forming means formed based on the profiling data, background area portion feature quantity calculating means obtained from the histogram forming means, and the profiling Toner linear image feature amount calculating means obtained from data and background region portion feature amount, normalized background portion feature amount calculating means from profiling data, background region portion feature amount and measurement position data when there is no toner omission, Toner loss amount calculation means is provided, and using these means, the toner loss amount (rate) in (4) is calculated from (1) calculation of the feature amount of the background area described in the above section (A). Further, the measurement data obtained by calculating the average value of the total toner loss amount of the line image 11 is sent to the correction unit 105.

  The correction unit 105 creates profiling data of the toner missing amount when the transfer speed of the photosensitive drum 1 and the intermediate transfer belt 80 is increased. That is, the transfer speed of the photosensitive drum 1 and the intermediate transfer belt 80 is changed at a constant interval, and a difference in speed is set between the transfer speeds of the photosensitive drum 1 and the intermediate transfer belt, and a plurality of toner images are transferred by changing this speed difference. Form on paper. The transfer paper on which the line images having different speed differences are formed is read by the image reading unit 102 of the copying machine main body 100, and the toner missing amount for each speed difference is measured by the arithmetic unit 204 as described above. In this way, profiling data of the toner missing amount with respect to the speed difference is created from the toner missing amount corresponding to the speed difference (see FIG. 20).

  FIG. 21 shows profiling data of the speed difference and the toner missing amount. Generally, when the linear velocity difference is set, the transfer efficiency is increased and the toner omission is reduced. A value that minimizes the speed difference between the surface speed of the photosensitive member and the moving speed of the intermediate transfer belt 80 in an area that is equal to or less than a certain threshold is calculated from the profiling data. Here, if the threshold is set to 20%, the area of 20% or less is the portion outside points A and B. Since the value at which the speed difference between the surface speed of the photosensitive drum 1 and the moving speed of the intermediate transfer belt 80 is the minimum is the A point, the value at the A point is derived as an appropriate speed difference.

Next, the rotational speed of the photosensitive drum 1 is calculated from the value of the point A thus obtained (see FIG. 20), and the clock signal corresponding to the speed is sent to the motor of the photosensitive drum 1 and the intermediate transfer belt 80. It transmits to 205 (refer FIG. 20).
In this way, by controlling the rotation speed of the photosensitive drum 1 and the transfer speed of the intermediate transfer belt 60 by the correction unit 105, it is possible to form an appropriate toner image with less toner loss.
In this embodiment, the example in which the rotation speed of the photosensitive drum 1 and the transfer speed of the intermediate transfer belt 80 are controlled based on the measurement data of toner loss is shown. However, the measurement data of toner loss is shown in this example. Not limited to this, it can be effectively used for failure diagnosis of the photosensitive drum 1 and the intermediate transfer belt 80 and the like.

FIG. 22 is a diagram showing a schematic configuration of an image forming apparatus and an image evaluation apparatus according to another embodiment of the present invention. In FIG. 22, the same components as those in the first embodiment shown in FIG.
In the present embodiment, unlike the first embodiment, the image forming apparatus does not include the image reading unit 103 and forms an image by an input signal from the outside. Therefore, in this embodiment, when the correction unit 105 controls the rotation speed of the photosensitive drum 1 and the transfer speed of the intermediate transfer belt 80, the toner image formed on the transfer paper by the image forming apparatus 200 of this embodiment. In the case of evaluating the toner missing amount, an external image reading device 202 and an arithmetic device 204 are used.

Using this external image reading device 202, a toner linear image formed by the image forming device 200 is read, and a luminance signal and measurement position data are sent to the arithmetic device 204. As in the case of 1, the amount of toner missing is calculated, and this measurement data is sent to the correction unit 105 to control the rotational speed of the photosensitive drum 1 and the intermediate transfer belt 80.
As described above, even in an image forming apparatus that does not include an image reading unit, it is possible to appropriately control the rotational speed of the photosensitive drum 1 and the intermediate transfer belt 80.

FIG. 23 is a diagram showing a schematic configuration of an image forming apparatus according to another embodiment of the present invention. In FIG. 23, the same components as those of the first embodiment shown in FIG.
In this embodiment, the calculation unit 104 is built in the main body of the image forming apparatus 300 so that the same operation as that of the external calculation device used in the first embodiment is performed. As described above, by incorporating the calculation unit 104 in the image forming apparatus 300, it is possible to easily and reliably evaluate toner loss. In addition, the evaluation of the toner loss of the line image on the transfer paper by the image processing described in the section (B) and the evaluation of the toner loss of the color misalignment line image on the transfer paper described in the section (C) can be easily performed. .

FIG. 24 is a diagram showing a schematic configuration of an image forming apparatus according to another embodiment of the present invention. In FIG. 24, the same components as those of the first embodiment shown in FIG.
In this embodiment, the image reading device 16 of Embodiment 3 described above is arranged in the intermediate transfer belt 80 in the main body of the image forming apparatus 400 to read the toner linear image transferred onto the intermediate transfer belt 80. Different from the image forming apparatus 300. Therefore, it is possible to perform the evaluation of the toner missing amount on the transfer belt described in the above section (D) without forming it on the transfer paper, and there is an advantage that a quicker evaluation is possible.

FIG. 3 is a front view of a sheet on which a line image is formed. The figure which shows the profiling data of the luminance output at the time of reading a line image with an optical apparatus, and a measurement position with a graph. The figure which shows the profiling data of the luminance output at the time of reading the paper of FIG. 1 with an optical apparatus, and a measurement position with a graph. The figure which shows the histogram produced based on the profiling data of FIG. The surface figure of the paper which has a line image to which dust adhered. The figure which shows the histogram produced by reading the paper of FIG. 5 with an optical apparatus. The figure which shows the profiling data replaced by the surface area part feature-value. FIG. 6 is a diagram showing profiling data when the paper of FIG. 5 is read by an optical device. The figure which shows the profiling data at the time of reading the paper which has a line image which dust does not adhere with an optical apparatus. The figure which shows the profiling data for demonstrating deleting the data of dust. FIG. 8 is a diagram showing profiling data for obtaining a toner linear image feature quantity from the profiling data of FIG. 7. The figure which shows the profiling data for calculating | requiring the normalization feature-value from the profiling data of FIG. FIG. 5 is a front view of A4 size paper on which a toner vertical line image is formed. The figure which shows the relationship between the measurement position which measured the paper of FIG. FIG. 6 is a surface view of a toner linear image formed on a transfer paper subjected to image processing. The figure which shows the profiling data which shows color shift. FIG. 6 is a diagram showing profiling data of a blue line image using magenta toner and cyan toner. FIG. 4 is a diagram showing profiling data of a toner image formed on a transfer belt. 1 is a diagram illustrating a schematic configuration of an image evaluation apparatus and an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a schematic configuration of a correction unit used in the image forming apparatus according to the first exemplary embodiment of the present invention. FIG. 4 is a diagram showing profiling data created by the correction unit of the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating a schematic configuration of an image evaluation apparatus and an image forming apparatus according to a second embodiment of the present invention. FIG. 6 is a diagram illustrating a schematic configuration of an image forming apparatus according to a third embodiment of the present invention. FIG. 6 is a diagram illustrating a schematic configuration of an image forming apparatus according to a fourth embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Photosensitive drum, 2 Image roller, 10 Paper, 11 line image, 12 Line image, 13 Background area part, 14 Drive roller, 15 Stretch roller, 16 Image reading element, 60 Charging apparatus, 61 Developing apparatus, 62 Primary Transfer roller, 63 Cleaning device, 64 Static elimination device, 80 Intermediate transfer belt, 100 Copier body, 102 Image reading unit, 103 Image writing unit, 104 Calculation unit, 105 Correction unit, 200, 300, 400 Image forming device, 202 Image Reading device, 204 arithmetic device, D dust

Claims (10)

An image evaluation apparatus that includes an optical device that reads a line image composed of a background area portion and a line image for each line in a direction orthogonal to the line image, and evaluates a toner removal amount of the line image. Te, creating the the profiling data creating means for creating a profiling data indicating the relationship between groups and the measurement position and the luminance of the luminance signal of the line image read by the optical device line by line by one line in the profiling data creating means A histogram indicating the frequency of the luminance signal value is created one line at a time from the profiling data of a plurality of lines including the measured measurement line, and the background region portion occupying the maximum area of the line image in each histogram of the plurality of lines feature quantity of the seeking of the average value of the luminance signal value indicating the peak value by the average value background area portion Means replaces replaces the feature amount of該地skin area unit luminance signal of the background area portion in the profiling data and determines and, a plurality of lines including the lines to be measured that is created line by line by the profiling data creating means the average value of the feature amount of the background area of 1 per line is calculated respectively from the profiling data, the average value of each luminance signal of the plurality of lines including the lines to be measured in the profiling data from the replacement means reading a linear image feature quantity calculating means a difference amount in the product sum, wherein the amount of said linear images for each of the line positions of the linear images of the same color solid image of the line image by the optical device Of the range surrounded by the obtained luminance signal value, the feature amount of the background area portion, and the boundary lines on both sides of the measurement position of the line image Calculating a degree signal amount, and the normalized feature quantity calculating means for the luminance signal amount and the normalized feature amount, the normalization feature quantity calculated by the calculating means and the normalized feature amounts S1 the linear image wherein the difference between the area S2 of the normalizing range of the feature amount and the toner leakage amount S3, comprising: the toner leakage amount calculating means for calculating the toner exit amount (ratio) as (S3 / S1) × 100, the An image evaluation apparatus. The image evaluation apparatus according to claim 1, wherein the linear image feature amount calculating unit is calculated from the profiling data of a plurality of lines including a measurement line in a direction orthogonal to the linear image to be measured. An image evaluation apparatus characterized in that a feature amount of a background region portion is set as a feature amount of a background region portion of one line to be measured.   The image evaluation apparatus according to claim 2, wherein the linear image feature amount calculating unit includes dust in the background region portion and the linear image region and the dust region in the profiling data from the replacement unit. If there is a region of the linear image and the region of the dust, the region closer to the position of the region of the linear image measured before is determined as the region of the linear image, and the other region is determined. An image evaluation apparatus, comprising: a position setting unit that determines a dust region and replaces a luminance signal value of the dust region with a feature amount of the background region portion.   4. The image evaluation apparatus according to claim 1, wherein the linear image feature amount calculating unit is configured to detect a color misalignment line image generated when a line image in which at least two colors of toner are superimposed is formed. An image evaluation apparatus comprising: means for setting boundary lines on both sides of the measurement position in which color misregistration has been corrected in advance as boundary lines on both sides of the measurement position of the line image. An image evaluation method in which a line image composed of a background area portion and a line image is read by an optical device for each line in a direction orthogonal to the line image and the amount of toner missing from the line image is evaluated. Te, and profiling data creating step of creating profiling data showing the relationship between the measurement position and the luminance based on the luminance signal of the line image read by the optical device line by line, each line in the profiling data creation step creates A histogram showing the frequency of the luminance signal value is created line by line from the profiling data of a plurality of lines including the measured measurement line, and the background region portion occupying the maximum area of the line image in each histogram of the plurality of lines Patent of the background area part by the average value the average value of the luminance signal value indicating the peak value of Multiple comprising the step replacing the feature amount of該地skin area unit replaces the luminance signal of the background area portion in the profiling data by determining the amount, the profiling data producing step the measurement target created line by line by line the average of each luminance signal of said plurality of lines include a mean value of the feature amount of the background area of 1 per line is calculated respectively from the profiling data of the line, the line to be measured in the profiling data from the replacement step a linear image feature amount calculation step of the difference component of each line position between the value by product-sum wherein the amount of said linear images, the linear images of the same color solid image of the line image by the optical device The range surrounded by the luminance signal value obtained by reading, the feature amount of the background area portion, and the boundary lines on both sides of the measurement position of the line image. Of calculating the luminance signal amount, and the normalized feature value calculation step of the luminance signal amount and the normalized feature amount, the normalization feature amount calculated in the calculation step the normalized feature value S1 and the linear the difference between the area S2 of the normalizing range of the feature amount of the image and toner leakage amount S3, the toner leakage amount calculating step of obtaining toner leakage amount (ratio) as (S3 / S1) × 100, in that it comprises A characteristic image evaluation method . 6. The image evaluation method according to claim 5, wherein the linear image feature value calculating step is calculated from the profiling data of the plurality of lines including a measurement line in a direction orthogonal to the linear image to be measured. An image evaluation method characterized in that the feature amount of the background region portion is the feature amount of the one-line background region portion to be measured. An image evaluation method according to claim 5 or 6, wherein the normalized feature value calculating step for linear image color shift that occurs when forming a linear image obtained by superimposing toner of at least two colors, An image evaluation method characterized by setting a boundary line on both sides of a measurement position where color misregistration has been corrected in advance to limit the measurement range. A photosensitive member that carries an electrostatic latent image of the image and carries the electrostatic latent image as a toner image by toner supplied from a developing device, and a toner image carried on the photosensitive member abuts the photosensitive member. And an intermediate transfer member that contacts the recording medium and transfers the toner image to the recording medium. The transfer speed of the toner image on the photosensitive member and the toner image on the intermediate transfer member In an image forming apparatus having a control device for controlling the conveyance speed of
The control device controls a toner image conveyance speed of the photosensitive member and the intermediate transfer member based on a toner missing amount obtained from the image evaluation device according to any one of claims 1 to 4. An image forming apparatus.   9. The image forming apparatus according to claim 8, further comprising an optical device that captures a toner image of the intermediate transfer body, and reading an image density signal of the toner image from the optical device to evaluate a toner missing amount rate of the line image. An image forming apparatus comprising: an image evaluation apparatus, wherein the image evaluation apparatus is the image evaluation apparatus according to claim 1.   10. The image forming apparatus according to claim 8, wherein the image forming apparatus reads an image from a document, and an electrostatic latent image on the photosensitive member based on image information read by the image reading unit. An image forming apparatus comprising an image writing unit for forming a toner image.

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