Image reading device and image forming device

Abstract

To prevent a variation in size of images to be formed.SOLUTION: An image reading device reading both faces: a first face and a second face of a recording medium according to the present invention comprises: a first face reading unit that reads the first face; a second face reading unit that reads the second face; a generation unit that generates a first correction value for correcting the shift between the first face and the second face; an input unit that receives input of a second correction value; and a correction unit that corrects an image based on the first correction value and the second correction value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image reading device and an image forming device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known a method for adjusting the positions at which images are formed on the front and back sides of a sheet of paper so that the positions at which the images are formed coincide with each other.

[0003] For example, an image forming apparatus has a reading unit such as a scanner that reads patterns formed on the front and back of the image forming apparatus, and calculates the amount of deviation based on the position of the read pattern to calculate a correction value between the sides (see, for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional methods, there is often an error in magnification when reading one side of a recording medium (hereinafter referred to as the "first side") and when reading a side different from the first side (hereinafter referred to as the "second side"), which can result in variations in the size of the formed image.

[0005] An object of one aspect of the present invention is to suppress variation in size of a formed image. [Means for solving the problem]

[0006] According to an embodiment of the present invention, an image reading device is an image reading device that reads both a first side and a second side of a recording medium, a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit for inputting a second correction value; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with. Effect of the Invention

[0007] According to the embodiment of the present invention, it is possible to suppress variations in the size of the formed image. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of an image forming apparatus having an image reading device. [Diagram 2] FIG. 2 is a diagram illustrating an example of a functional configuration. [Diagram 3] FIG. 11 is a diagram showing an example of a reading result of the first surface. [Figure 4] FIG. 13 is a diagram showing an example of a reading result of the second surface. [Diagram 5] FIG. 13 is a diagram showing an example after correction. [Figure 6] 13 is a flowchart showing an example of an overall process. [Figure 7] FIG. [Figure 8] FIG. 13 is a diagram showing a first example using measured values. [Figure 9] FIG. 13 is a diagram showing a second example using measured values. [Figure 10] A diagram showing an example (first example) of calculating the correction values ​​for each of multiple basis weight categories [Figure 11] A diagram showing an example (second example) of calculating correction values ​​for multiple basis weight categories [Figure 12] FIG. 1 is a diagram showing a configuration of an image forming apparatus according to each embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The optimum and minimum mode for carrying out the invention will be described below with reference to the drawings. Note that in the drawings, when the same reference numerals are used, it indicates that the configuration is the same, and duplicated explanations will be omitted. Also, the specific examples shown in the drawings are merely examples, and the configuration may further include configurations other than those shown in the drawings.

[0010] First Embodiment <Example of overall configuration of image reading device and image forming device> FIG. 1 is a diagram showing an example of an image forming apparatus having an image reading device. The following will be described taking an image forming apparatus 100 having an image reading device 10 as an example, as shown in the figure. However, the image reading device 10 and the image forming apparatus 100 are not limited to the configuration as shown in the figure, and may be separate devices. In the following example, the target recording medium is paper PA. For example, the image forming apparatus 100 is an MFP (Multifunction Peripheral), a copier, a multifunction machine, or the like.

[0011] For example, the image forming apparatus 100 has a hardware configuration including hardware resources such as a first scanner SC1, a second scanner SC2, an image forming section 110, an input device 13, a calculation device 14, and a control device 15.

[0012] The first scanner SC1 reads the first side P1 of the paper PA.

[0013] The second scanner SC2 reads the second side P2 of the paper PA.

[0014] For example, the first scanner SC1 and the second scanner SC2 are configured with an optical sensor, a lens, and the like.

[0015] The input device 13 is, for example, a touch panel, etc. Note that the input device 13 may be an interface that transmits and receives data to and from an external device via a wired or wireless connection and inputs various settings.

[0016] The arithmetic device 14 and the control device 15 are, for example, devices such as a CPU (Central Processing Unit). Therefore, the arithmetic device 14 is a device that executes processing based on a program, etc. Also, the control device 15 is a device that controls each hardware resource.

[0017] The image forming unit 110 is a device that forms an image based on output image data generated by the image reading device 10. For example, the image forming unit 110 performs image formation processes such as conveying a recording medium, image processing, exposure, development, transfer, fixing, and cleaning, and forms an image on the recording medium.

[0018] Also, as shown in the figure, a configuration may be used in which there is a first surface background member BK1 and a second surface background member BK2. For example, as shown in the figure, the first surface background member BK1 and the second surface background member BK2 are installed at a position facing the scanner. The first surface background member BK1 and the second surface background member BK2 are members that become the background when reading an image. Note that it is preferable that the first surface background member BK1 and the second surface background member BK2 are configured to be switchable between different colors, such as a white surface and a black surface.

[0019] Hereinafter, as shown in the figure, an example will be described in which the image forming apparatus 100 reads both sides of a sheet of paper PA conveyed on a conveying path in a conveying direction 16 (from right to left in the illustrated example).

[0020] <Example of functional configuration> 2 is a diagram showing an example of a functional configuration of the image reading device 10. For example, the image reading device 10 has a functional configuration including a first side reading unit 101, a second side reading unit 102, an input unit 103, a generation unit 104, and a correction unit 105.

[0021] The first side reading unit 101 performs a first side reading procedure to read the first side P1. For example, the first side reading unit 101 is realized by a first scanner SC1 or the like.

[0022] The second side reading unit 102 performs a second side reading procedure to read the second side P2. For example, the second side reading unit 102 is realized by a second scanner SC2 or the like.

[0023] The input unit 103 performs an input procedure for inputting the second correction value. For example, the input unit 103 is realized by the input device 13, the arithmetic device 14, or the like.

[0024] The generating unit 104 performs a generating procedure for generating the first correction value. For example, the generating unit 104 is realized by the input device 13, the arithmetic device 14, or the like.

[0025] The correction unit 105 performs a correction procedure for correcting the image based on the first correction value and the second correction value. For example, the correction unit 105 is realized by the arithmetic device 14 or the like.

[0026] <Overall processing example> For example, the first correction value is generated as follows: First, the first surface P1 is read as follows, for example.

[0027] 3 is a diagram showing an example of the first side reading result. For example, it is assumed that a first image IMG1 is formed in advance on the first side P1 of a sheet PA. Then, when the first side P1 is read, image data showing the first image IMG1 (hereinafter referred to as "first side image data") is generated, and the first image IMG1 is formed on the first side of another recording medium based on this first side image data.

[0028] In the following, an example will be described in which the size of the first image IMG1 in the X-axis direction (left-right direction in the figure) is the "first dimension XP1." In the following example, the X-axis direction is the paper width direction (sometimes called the main scanning direction), and the Y-axis direction is the paper length direction (sometimes called the sub-scanning direction).

[0029] Therefore, when the first surface P1 is read, first surface image data is generated and the first dimension XP1 is obtained.

[0030] Next, after the first side is read as described above, the same paper PA is read, for example, as follows.

[0031] 4 is a diagram showing an example of the reading result of the second side. Hereinafter, it is assumed that the second image IMG2 is formed in advance on the second side P2 as well, similar to the first side P1. Then, when the second side P2 is read, image data showing the second image IMG2 (hereinafter referred to as "second side image data") is generated, and the second image IMG2 is formed on the second side of another recording medium based on this second side image data.

[0032] Also, it is assumed that a pattern PTN is formed in advance on the second surface P2 as an example of the target object. For example, it is assumed that the shape and the like of the pattern PTN are set in advance in the image forming apparatus 100. In this way, when the pattern PTN is included in the second surface image data, the image forming apparatus 100 recognizes the pattern PTN by pattern matching or the like. Therefore, by recognizing the pattern PTN, the image forming apparatus 100 can obtain, for example, the distance from the end of the second image IMG2 to the pattern PTN (hereinafter referred to as "pattern distance X2").

[0033] Therefore, when the second surface P2 is read, second surface image data is generated, and the pattern distance X2 and the second dimension XP2 are obtained.

[0034] Next, based on the results of reading the first and second sides, the image forming apparatus 100 calculates and generates a first correction value, for example, as follows. C1 = XP1 / XP2 (1) The above formula (1) is a formula showing an example of generating the first correction value C1 used to correct the image of the second surface. Specifically, as shown in the above formula (1), the first correction value C1 is a value calculated based on, for example, the ratio between the first dimension XP1 and the second dimension XP2. Then, based on the first correction value C1 and the second correction value C2 calculated by the above formula (1), the second surface image data is corrected as follows: X2A = X2 × C1 × C2 (2) The above formula (2) shows an example of correcting the pattern distance X2 in the image formed on the second surface. Therefore, when the object of correction (the corrected pattern distance X2A in the above formula (2)) is a different location, "X2" in the above formula (2) may be changed to match the object of correction.

[0035] Specifically, the pattern distance X2 in the above formula (2) is obtained from the second surface image data. Also, the first correction value C1 in the above formula (2) is the calculation result of the above formula (1), etc.

[0036] The second correction value C2 in the above formula (2) is, for example, a correction value for correcting the magnification deviation of the first scanner SC1 and the second scanner SC2 with high accuracy. The second correction value C2 is, for example, a value input in advance to the image reading device 10.

[0037] Therefore, when correction is performed based on the above formula (2), the correction result is, for example, as follows.

[0038] 5 is a diagram showing an example after the correction. In the following, as shown in the figure, an example will be described in which an image is formed on paper PB, which is a recording medium different from paper PA, based on the correction results.

[0039] For example, a first image IMG1 is formed on a first surface P1 of the paper PB based on the first image data. On the other hand, on a second surface P2 of the paper PB, as a result of correction based on the above formula (2), for example, an image is formed at a corrected pattern distance X2A after correction, which is different from the pattern distance X2 before correction.

[0040] In this way, when the second correction value can be input, the image is corrected taking the second correction value into consideration. For example, the user inputs the second correction value as intended, taking into account the magnification deviation, etc. When such a second correction value can be input, the image can be corrected to the size intended by the user, and correction can be performed with high accuracy, which is difficult to achieve using only the first correction value. Note that the second correction value may be input as a calculation result calculated based on a predetermined input value, etc.

[0041] By using the second correction value, the user can adjust the size of the image to be formed finely, and therefore, variation in the size of the image to be formed can be suppressed.

[0042] The above process is executed, for example, as follows.

[0043] FIG. 6 is a flowchart showing an example of the overall process.

[0044] In step S1, the input unit 103 inputs the second correction value. That is, the second correction value is set in advance, for example. Note that the second correction value only needs to be input before correction (corresponding to the following step S5), and the timing of input is not limited to the timing shown in the figure.

[0045] In step S2, the first side reading unit 101 reads the first side.

[0046] In step S3, the second side reading unit 102 reads the second side.

[0047] For example, when step S2 is performed, a read result such as that shown in Fig. 3 is obtained. Similarly, when step S3 is performed, a read result such as that shown in Fig. 4 is obtained.

[0048] In step S4, the generation unit 104 generates a first correction value. For example, in step S4, the first correction value is generated by performing calculation according to the above formula (1).

[0049] In step S5, the correction unit 105 corrects the image based on the first correction value and the second correction value. For example, by performing calculation as in the above formula (2), the dimensions after correction, that is, how to perform correction, etc. can be specified. Specifically, for example, an image as shown in FIG. 4 is corrected as shown in FIG. 5.

[0050] In step S6, the image forming unit included in the image forming apparatus 100 forms images on both sides of the recording medium.

[0051] Furthermore, after each surface is read, image processing such as shading may be performed on the image when generating image data for each surface.

[0052] <Comparative Example> For example, calculation may be performed as shown in the following formula (3) instead of the above formula (2). X2B = X2 × C1 (3) The above formula (3) shows an example of calculating the comparative example pattern distance X2B. Compared to the above formula (2), it differs in that it does not use the second correction value C2. If correction is performed using such a calculation result, for example, the following correction is obtained.

[0053] Fig. 7 is a diagram showing a comparative example, which is different from the correction shown in Fig. 5 in that the X-axis direction of the second image IMG2 is corrected to the comparative example pattern distance X2B.

[0054] In such a configuration, for example, the first surface P1 has no correction standard, so there may be a deviation in the size read due to scanner error, etc. Therefore, there may be a deviation between the first surface and the second surface, and the size of the formed image may vary.

[0055] <Second embodiment> The second embodiment differs from the first embodiment in that the correction values ​​are different for each direction, each type of recording medium, or each size. Below, the differences will be mainly described, and overlapping descriptions will be omitted. For example, the second correction values ​​are input as shown below (Table 1).

[0056] [Table 1] The above (Table 1) shows an example in which the second correction value is set separately for each type of recording medium and for each direction. Specifically, the above (Table 1) is an example in which the type of recording medium is "paper type" and there are "N" types. Therefore, the correction value is input separately for each "paper type" as "1" to "N".

[0057] "Paper type" is, for example, a classification such as coated paper or plain paper. Note that "paper type" may be classified as different types when, for example, the paper thickness is different. For example, "paper type" is associated with which type of recording medium is prepared for each paper tray, and different recording media are prepared for each paper tray. When the settings indicating this association are made in advance, different correction values ​​can be used for each "paper type."

[0058] For example, if the paper thickness differs, the distance between the optical system (such as a sensor) used for reading and the recording medium may differ. Therefore, more accurate reading can be achieved by adjusting the reading magnification individually according to the paper thickness.

[0059] Copy paper has a thickness of about 0.07 mm to about 0.3 mm, and the thickness varies depending on the type of paper. The distance between the optical system and the recording medium differs between the first and second sides due to the paper thickness. Therefore, differences in paper thickness, i.e., types of recording media, can cause deviations in magnification.

[0060] In addition, the type of recording medium may be classified, for example, taking into consideration the weight or surface type of the recording medium. For example, if the weight or surface type is different, the grip force, friction coefficient, or conveying speed of the conveying roller used to convey the recording medium may be different. Therefore, different types may be classified taking into consideration parameters that affect these.

[0061] Moreover, the above (Table 1) is an example in which the second correction value is input separately for the conveying direction and the perpendicular direction. Specifically, the above (Table 1) shows an example in which the second correction value is input separately as "α" which is a "correction value for the conveying direction" and "β" which is a "correction value for the perpendicular direction".

[0062] For example, for "paper type 1," "α1" is used for correction in the transport direction. On the other hand, for "paper type 1," "β1" is used for correction in the orthogonal direction. In this way, if correction values ​​can be input separately for the transport direction and the orthogonal direction, different corrections can be made for each direction.

[0063] In the orthogonal direction, magnification errors occur during reading. On the other hand, deviations in the conveying speed and the like may occur in the conveying direction. Therefore, since the cause of the error differs depending on the direction, it may be necessary to perform different corrections according to the cause for each direction. Therefore, if correction values ​​can be input separately for the conveying direction and the orthogonal direction, different corrections can be made for each direction, allowing for accurate corrections.

[0064] The first correction value may also be different for each direction, each type of recording medium, or each size.

[0065] <Third embodiment> The third embodiment differs from the first embodiment in that a correction value is generated or input based on a measurement value as follows. The following description will focus on the differences and omit redundant description.

[0066] FIG. 8 is a diagram showing a first example using measured values.

[0067] For example, the following describes an example of inputting the results of measuring patterns indicating the sizes of A3 (297 mm x 420 mm, a size defined by ISO 216) and A4 (210 mm x 297 mm, a size defined by ISO 216) (hereinafter referred to as "measurement values").

[0068] In such a case, a recording medium larger than the A3 size is used. In the following, an example will be described in which an A3 size pattern PTN1 and an A4 size pattern PTN2 are printed in advance on a sheet of paper PC having a size of SRA3 (320 mm x 450 mm, a size defined by ISO217).

[0069] For example, when making a correction in the Y-axis direction, a measurement value of the dimension in the Y-axis direction of the A3 size pattern PTN1 is input. Specifically, a value obtained by measuring the distance to the A3 size pattern PTN1 based on the edge of the paper PC in the figure (hereinafter referred to as the "first measurement value 21") is input. Similarly, a value obtained by measuring the distance to the A4 size pattern PTN2 based on the edge of the paper PC in the figure (hereinafter referred to as the "second measurement value 22") is input.

[0070] Furthermore, when making corrections in the X-axis direction, the measurement value of the dimension in the X-axis direction of the A3 size pattern PTN1 is input. Specifically, the value obtained by measuring the distance between the ends of the A3 size pattern PTN1 in the figure (hereinafter referred to as the "third measurement value 23") is input. Similarly, the value obtained by measuring the distance between the ends in the figure (hereinafter referred to as the "fourth measurement value 24") is input.

[0071] The size of the recording medium to be used is set in advance when forming an image. In this example, when an A4 size or A3 size recording medium is used, the size indicated by the read result is compared with the size indicated by the measurement value, and a second correction value etc. is generated so as to fill in the difference between the read result and the measurement value.

[0072] The measurement values ​​may be values ​​measured at the following locations, for example:

[0073] 9 is a diagram showing a second example using measurements. For example, the measurements may be a fifth measurement 25, a sixth measurement 26, a seventh measurement 27, etc. for an A3 size. Similarly, the measurements may be an eighth measurement 28, a ninth measurement 29, a tenth measurement 30, etc. for an A4 size.

[0074] As described above, the measurement value may be a value obtained by measuring a distance using a part of a predetermined pattern, a distance using an edge of a recording medium, or a combination of these. Even if the measurement values ​​are for the same direction and size, such as the fifth measurement value 25 and the sixth measurement value 26, it is preferable to measure multiple points.

[0075] For example, errors caused by uneven transport or bending of the optical system may vary depending on the position. Therefore, as shown in the figure, if multiple measurement values ​​are used, even if there is a local error, the error can be corrected with high accuracy.

[0076] When both the read result and the measurement value can be obtained, a correction value is generated or input so that the measurement value becomes "true." In addition, the correction value may be generated or input for each scanner according to the method, etc., as shown in Table 2 below, for example.

[0077] [Table 2] The method of "same size on both sides" in Table 2 above is used, for example, when the recording medium is paper. When the recording medium is paper, the shape of the recording medium is the same on the front and back, so the size can be the same on both sides. In this case, the reading result by the second reading unit is compared with the measurement value on the second side, and a second correction value is generated, etc.

[0078] On the other hand, the method of "separate size and pattern for each side" is used, for example, when a pattern is drawn on a recording medium other than paper. Then, the measurement result and the reading result of the pattern drawn on the first side are compared, and a second correction value is generated for the first side. Separately, the measurement result and the reading result of the pattern drawn on the second side are compared, and a second correction value is generated for the second side.

[0079] In this way, the patterns and correction values ​​may be separate for each surface.

[0080] <Fourth embodiment> The fourth embodiment has a configuration in which, for example, a chart is used as follows.

[0081] The image forming apparatus 100 forms an image of a chart that is input in advance on a recording medium and outputs the image. Then, the user measures a predetermined portion of the chart using a scale, and inputs the measurement result as a measurement value. In this manner, the measurement value may be input.

[0082] In this manner, with a configuration for forming a chart image, even when, for example, a new type of recording medium or a paper feed tray is used, correction values ​​can be easily generated or input.

[0083] In a configuration where the correction value is directly input, the user often has to go through the trouble of calculating the correction value. Therefore, if the measurement value obtained by measuring a chart including a predetermined dimension is input, the time and effort required for calculating the correction value is eliminated, and user convenience can be improved.

[0084] In addition, when forming images on both the first side (hereinafter referred to as the "front" side) and the second side (hereinafter referred to as the "rear" side), the magnification when forming an image on the rear side may be adjusted based on the image position formed on the front side. For example, first, a chart is image-formed on both the front and rear sides. Next, the user is made to measure the same portion of the chart on both sides (i.e., a portion that would have the same measurement value on the front and rear if there were no error) and input the measurement values ​​measured on each side. In this way, by making the user measure the same portion on the front and rear, the deviation between the front and rear can be identified from the measurement value. In this case, for example, a correction value is calculated for forming an image on the rear side so that the front side is the same as the front side, based on the front side. In this way, a configuration may be adopted in which a chart is image-formed on both sides, and a correction is made to adjust the difference between the front and rear sides based on the measurement value measured for the chart image-formed on either side of the chart image-formed on both sides.

[0085] <Fifth embodiment> The fifth embodiment is applicable to the case where an image is formed on one side, in which a recording medium with an image formed thereon is discharged to an output tray with the side on which the image is formed facing up, or a "face down" method, in which a recording medium with an image formed thereon is discharged to an output tray with the side on which the image is formed facing down.

[0086] For example, in the case of "face down," the front side (the upper side in FIG. 1, which is the side facing the first scanner SC1) may be read and used to calculate the correction value. On the other hand, the image used for image formation is an image generated based on the results of reading the back side (the lower side in FIG. 1, which is the side facing the second scanner SC2). Therefore, the image formed on the back side may be corrected using a correction value generated and input based on the results of reading the front and back sides.

[0087] Similarly, in the "face up" case, the back reading may be used to calculate the correction values.

[0088] Sixth Embodiment In the sixth embodiment, a calculation example of the correction value for each of a plurality of basis weight divisions will be described with reference to Table 3, FIG. 10 and FIG.

[0089] Table 3 shows an example of the correction value for each basis weight category. "Basis weight category" is an example of "type of recording medium".

[0090] [Table 3] Table 3 is held by a holding unit (not shown) included in the image forming apparatus 100. Table 3 shows N basis weight divisions, and shows main scanning correction values ​​and sub-scanning correction values ​​for each of the N basis weight divisions. The main scanning correction value is a correction value in a direction perpendicular to the conveying direction of the recording medium. The sub-scanning correction value is a correction value in the conveying direction of the recording medium. In Table 3, actual measurement values ​​are set as the main scanning correction value and the sub-scanning correction value for two basis weight divisions 1 and N. On the other hand, in Table 3, estimated values ​​estimated from the correction values ​​(actual measurement values) of the two basis weight divisions 1 and N are set as the main scanning correction value and the sub-scanning correction value for the other basis weight divisions 2 to N-1. These estimated values ​​are calculated by a calculation unit (not shown) included in the image forming apparatus 100. In this way, the image reading apparatus 10 of this embodiment can set actual measurement values ​​as correction values ​​for some basis weight divisions, and set estimated values ​​calculated based on the actual measurement values ​​as correction values ​​for some other basis weight divisions. As a result, the image reading device 10 of the present embodiment does not need to obtain actual measurements for all basis weight categories, and therefore the burden on the user can be reduced.

[0091] Fig. 10 is a diagram showing a calculation example (first example) of the correction value for each of a plurality of basis weight divisions. Fig. 10 shows an example in which a correction value is set for each of eight basis weight divisions based on the actual measured values ​​of two basis weight divisions. For example, when the basis weight range of the machine is 50 to 450 g / m 2 In this case, the basis weight category 1 is 50 to 100 g / m 2 Basis weight category 2 is 100-150g / m 2 Basis weight category 3 is 150-200g / m 2 , and grammage category 8 is 400~450g / m 2 It is.

[0092] For example, in the example shown in Fig. 10, actual measured values ​​are set as correction values ​​for basis weight divisions 1 and 8. On the other hand, in the example shown in Fig. 10, estimated values ​​calculated based on the correction value for basis weight division 1 and the correction value for basis weight division 8 are set as correction values ​​for each of basis weight divisions 2 to 7. For example, in the example shown in Fig. 10, the correction values ​​for each of basis weight divisions 2 to 7 are estimated on the assumption that the correction value changes linearly.

[0093] As a result, the image reading device 10 of the present embodiment does not need to obtain actual measurements for all basis weight categories, and therefore the burden on the user can be reduced.

[0094] In this embodiment, instead of the "grammage category", "paper thickness", "paper size", etc. may be used as the "type of recording medium". Also, in this embodiment, instead of using actual measurements as the correction values ​​for two grammage categories, the correction values ​​for three or more grammage categories may be actual measurements. This can improve the calculation accuracy of the correction values ​​(estimated values) for the other grammage categories.

[0095] 10, the correction value for the minimum basis weight division 1 and the correction value for the maximum basis weight division 8 are actual measured values, but the correction values ​​for the other basis weight divisions may be actual measured values. For example, the correction value for basis weight division 2 and the correction value for basis weight division 7 may be actual measured values. In this case, too, the correction value for each of basis weight divisions 1, 3 to 6, and 8 may be estimated on the assumption that the correction value changes linearly.

[0096] In the present embodiment, the correction value may be a correction value for correcting the speed of the transport roller. In this case, the image reading device 10 may correct the speed of the transport roller based on the correction value. This allows the image reading device 10 to set the speed of the transport roller to a predetermined target value, and therefore the reading length of the recording medium to a predetermined target value.

[0097] Fig. 11 is a diagram showing a calculation example (second example) of the correction value for each of a plurality of basis weight divisions. Fig. 11 shows an example in which a correction value is set for each of eight basis weight divisions similar to those in Fig. 10, based on the actual measurement value of one basis weight division and table data showing the correlations of the eight basis weight divisions.

[0098] For example, in the example shown in Fig. 11, an actual measurement value is set as the correction value for basis weight division 4. On the other hand, in the example shown in Fig. 11, an estimated value calculated based on the correction value for basis weight division 4 and table data is set as the correction value for each of basis weight divisions 1 to 3 and 5 to 8. For example, in the example shown in Fig. 10, the correction value for each of basis weight divisions 1 to 3 and 5 to 8 is estimated based on table data indicating a correlation in which the correction value changes linearly.

[0099] As a result, the image reading device 10 of the present embodiment does not need to obtain actual measurements for all basis weight categories, and therefore the burden on the user can be reduced.

[0100] In the example shown in FIG. 11, the correction value for basis weight division 4 is the actual measurement value, but the correction values ​​for the other basis weight divisions may be the actual measurement value.

[0101] The correlations between the basis weight categories shown in the table data are acquired in advance during the design period, production process, etc. The table data is linked to the characteristics of the image reading device 10, such as the conveying characteristics of the image reading device 10 (conveying roller diameter, motor variation, etc.) and the gap between the scanners SC1, SC2 and the recording medium. For this reason, it is preferable that the table data is managed together with the image reading device 10 and held by the image reading device 10. However, when the image reading device 10 is used as a post-processing peripheral device of the image forming device 100 as in this embodiment, the table data may be managed together with the image forming device 100 and held by the image forming device 100.

[0102] For example, in the example shown in FIG. 11, the correlations of the grammage classifications 1 to 8 are acquired in advance during the design period, production process, etc., and stored as table data. Then, the image reading device 10 obtains the actual measurement value (paper length, distance between patterns, etc.) of the grammage classification 4 during actual operation, and calculates the correction value of the grammage classification 4 based on the actual measurement value. As a result, even if various conditions (temperature, humidity, paper type, etc.) during actual operation have changed from the various conditions when the table data was created, the image reading device 10 can calculate a suitable correction value for the grammage classification 4 according to the various conditions during actual operation. Furthermore, the image reading device 10 calculates the correction value for each of the grammage classifications 1 to 3 and 5 to 8 based on the correction value based on the actual measurement of the grammage classification 4 and the table data. As a result, the image reading device 10 can calculate a suitable correction value for each of the grammage classifications 1 to 3 and 5 to 8 according to the various conditions during actual operation. Note that when creating the table data, it is preferable to apply a paper type that is used frequently, since this can further reduce errors due to grammage.

[0103] <Configuration of Image Forming Apparatus 100> 12 is a diagram showing the configuration of an image forming apparatus 100 according to each embodiment. As shown in FIG. 12, the image forming apparatus 100 includes at least an image forming unit 110, a medium conveying unit 120, an image reading device 10, and a control unit 150.

[0104] The image forming unit 110 includes a photoconductor drum 112 for forming a latent image corresponding to each color image, and is arranged to correspond to an image forming process using image forming materials (e.g., toners) of each color: yellow (Y), magenta (M), cyan (C), and black (K).

[0105] The photoconductor drums 112 are disposed along an intermediate transfer belt 111, which is an endless moving means. The intermediate transfer belt 111 is passed around at least one driving roller and multiple driven rollers, and moves between a primary transfer position where an image (toner image) developed on the photoconductor drum 112 is transferred, and a secondary transfer position where the image (toner image) is transferred to paper PA.

[0106] At the secondary transfer position, a transfer section 113 including a transfer roller 113a and an opposing roller 113b arranged opposite thereto is disposed. In the transfer section 113, a toner image is transferred from the intermediate transfer belt 111 to the paper PA, thereby forming an image at a predetermined position on the paper PA. Between the transfer roller 113a and the opposing roller 113b, a gap is formed that allows the intermediate transfer belt 111 and the paper PA to pass through while being sandwiched. An image is transferred onto the paper PA while it is sandwiched in this gap and transported in the transport direction (sub-scanning direction).

[0107] The media transport section 120 includes a supply tray 121 that stores the paper PA, a transport path 122 along which the paper PA is transported and which is composed of an arrangement of multiple roller pairs, a fixing roller 123 that is arranged downstream in the transport direction from the transfer section 113, a transport path switching section 124, and an inversion path 125.

[0108] During the execution of the image forming process, under the control of a predetermined control process by the control unit 150, the paper PA stored in the supply tray 121 is separated by a pickup roller or the like and transported along the transport path 122 to the transfer unit 113.

[0109] When the sheet PA reaches the transfer unit 113, a transfer process is performed. That is, the sheet PA is conveyed in a predetermined conveying direction while being sandwiched between the surface of the intermediate transfer belt 111, which is urged toward the opposing roller 113b by the transfer roller 113a, and the opposing roller 113b. When the sheet PA passes between the intermediate transfer belt 111 and the opposing roller 113b, the image forming material on the surface of the intermediate transfer belt 111 is transferred to the sheet PA. Through this transfer process, an image is formed on one side (first side P1) of the sheet PA.

[0110] The sheet of paper PA with the image formed on the first side P1 is further transported, and after the image is fixed by fixing rollers 123, it is transported to a transport path switching unit 124. Thereafter, the sheet of paper PA reverses its traveling direction and is transported to a reversing path 125. Then, the sheet of paper PA is transported again to the transfer position of transfer rollers 113a in a state in which the image formed on intermediate transfer belt 111 is transferred to the second side P2 of the sheet of paper PA.

[0111] The sheet PA with the image formed on the second side P2 is further transported, and after the image on the second side P2 is fixed by the fixing roller 123, the sheet PA is transported to the image reading device .

[0112] The image reading device 10 has a first scanner SC1 that reads a first side P1 of the sheet PA, and a second scanner SC2 that reads a second side P2 of the sheet PA. The sheet PA that has passed through the image reading device 10 is discharged onto a discharge tray 126.

[0113] The control unit 150 controls the overall operation of the image forming apparatus 100, and controls a series of processes for forming an image on paper PA, which is a sheet-like recording medium.

[0114] <Modification> Note that the image formed on the first side may be the subject of correction. For example, the image formed on the first side is corrected based on the second correction value. In this manner, both the image formed on the first side and the image formed on the second side may be corrected.

[0115] Note that the shape, position, size, color, number, and the like of the pattern PTN do not matter as long as the image forming apparatus 100 can obtain the pattern distance X2.

[0116] Furthermore, the object to be measured may be any image of a pattern, chart, etc., so long as its shape, etc., is determined in advance. In other words, the object may have any shape, color, size, etc., so long as it can be used as a comparison object for calculating the amount of deviation in magnification, etc.

[0117] The image may be a character, a number, a symbol, a picture, a design, a color, a mark, a code, or a combination of these formed on a recording medium. In other words, the image may be any object that can be read by a scanner or the like.

[0118] In addition, in each of the above embodiments, the image forming apparatus 100 measures the discharged paper after printing and reading and inputs the size to the machine, but this is not limited thereto, and the image forming apparatus 100 may measure the paper size in advance and input it to the machine, then print and read and calculate the correction value. In this case, if no pattern is formed on the paper, the image forming apparatus 100 may measure and correct only the paper size.

[0119] <Other embodiments> Each device does not have to be a single device. That is, each device may be a combination of multiple devices. Note that the configuration may further include devices other than those shown in the drawings.

[0120] All or part of each process according to the present invention may be realized by a program that causes a computer to execute the image reading method. That is, the arithmetic unit and the control unit of the computer perform calculations and control based on the program to execute each process. Also, the storage device of the computer stores data used in the process based on the program to execute each process.

[0121] The program may be distributed in a form recorded on a computer-readable recording medium. The recording medium may be a magnetic tape, a flash memory, an optical disk, a magneto-optical disk, a magnetic disk, or the like. The program may be distributed through a telecommunications line.

[0122] The embodiment of the present invention may be realized by an image reading system or an image forming system having a plurality of information processing devices. The image reading system or the image forming system may execute each process and data storage in a redundant, distributed, parallel, virtualized, or combination of these.

[0123] Although an example of the embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications and improvements are possible within the scope of the present invention. [Explanation of symbols]

[0124] 10 Image reading device 21 First measurement 22 Second measurement 23 Third measurement 24 Fourth measurement 25 5th measurement 26 6th measurement 27 7th measurement 28 8th measurement 29 9th measurement 30 10th measurement 100 Image forming device 101 First surface reading unit 102 Second surface reading unit 103 Input section 104 Generation part 105 Correction section C1 First correction value C2 Second correction value IMG1 1st image IMG2 2nd image P1 1st page P2 2nd page PA Paper PB Paper PC Paper PTN Pattern SC1 Primary Scanner SC2 Secondary Scanner X2 Pattern Distance X2A Corrected Pattern Distance XP1 1st dimension XP2 2nd dimension

Prior technical literature

Chartered Documents

[0125] [Patent Document 1] Patent No. 6142882

Claims

1. An image reading device for reading both a first side and a second side of a recording medium, a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit that receives an input of a second correction value, the second correction value being set to a suitable value determined in advance according to a direction and a type of the recording medium, and for suppressing a variation in size of the images on the first side and the second side; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with The second surface has a pattern formed thereon; The generation unit generates the first correction value using a first dimension on the first surface and a second dimension on the second surface based on the pattern. Image reading device.

2. the first correction value or the second correction value is different for a conveying direction in which the recording medium is conveyed and for an orthogonal direction perpendicular to the conveying direction, The correction unit performs different corrections in the transport direction and the orthogonal direction.

2. The image reading device according to claim 1.

3. the first correction value or the second correction value is different for each type of the recording medium, The correction unit performs different correction for each of the types.

3. The image reading device according to claim 1 or 2.

4. An image reading device for reading both a first side and a second side of a recording medium, comprising: a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit that receives an input of a second correction value, the second correction value being set to a suitable value determined in advance according to a direction and a type of the recording medium, and for suppressing a variation in size of the images on the first side and the second side; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with the first correction value or the second correction value is different for each size of the recording medium, The correction unit performs different correction for each size. Image reading device.

5. An image reading device for reading both a first side and a second side of a recording medium, comprising: a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit that receives an input of a second correction value, the second correction value being set to a suitable value determined in advance according to a direction and a type of the recording medium, and for suppressing a variation in size of the images on the first side and the second side; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with Enter the measurements of an object with a given dimension, Generate the first correction value or input the second correction value based on the measurement value. Image reading device.

6. An image reading device for reading both a first side and a second side of a recording medium, comprising: a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit that receives an input of a second correction value, the second correction value being set to a suitable value determined in advance according to a direction and a type of the recording medium, and for suppressing a variation in size of the images on the first side and the second side; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with the first correction value or the second correction value is different for each surface, The correction unit performs different correction for each of the surfaces. Image reading device.

7. An image reading device for reading both a first side and a second side of a recording medium, comprising: a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit that receives an input of a second correction value, the second correction value being set to a suitable value determined in advance according to a direction and a type of the recording medium, and for suppressing a variation in size of the images on the first side and the second side; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with The chart is image-formed on a recording medium; The correction unit performs correction based on the measurement value obtained by measuring the chart. Image reading device.

8. An image reading device for reading both a first side and a second side of a recording medium, comprising: a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit that receives an input of a second correction value, the second correction value being set to a suitable value determined in advance according to a direction and a type of the recording medium, and for suppressing a variation in size of the images on the first side and the second side; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with A chart is image-formed on both sides of a recording medium; The chart on which an image is formed on either one of the two sides is measured. Based on the result, the correction unit performs correction. Image reading device.

9. An image reading device for reading both a first side and a second side of a recording medium, comprising: a first surface reading unit that reads the first surface; a second surface reading unit that reads the second surface; a generation unit that generates a first correction value that corrects a misalignment between the first surface and the second surface; an input unit that receives an input of a second correction value, the second correction value being set to a suitable value determined in advance according to a direction and a type of the recording medium, and for suppressing a variation in size of the images on the first side and the second side; a correction unit that corrects an image based on the first correction value and the second correction value; Equipped with a storage unit that stores the first correction value for each type of the recording medium; a calculation unit that calculates the first correction values ​​of the other types of recording media based on the first correction values ​​of the other types of recording media; An image reading device comprising:

10. The type of recording medium is one of basis weight, paper thickness, and paper size.

10. The image reading device according to claim 9.

11. An image forming apparatus comprising the image reading device according to any one of claims 1 to 10.

Images