JP5853500B2 - Control device and image forming apparatus - Google Patents

Description

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

  Japanese Patent Application Laid-Open No. 2004-228561 describes that when an image density control request and an alignment request are made at the same time, a misregistration detection mark and an image density adjustment mark are formed and detected in the same sequence.

JP 2001-166553 A

An object of the present invention is to reduce the chance that the density adjustment and the position adjustment are performed at different timings, and to widen the interval from when one adjustment is performed to when the other adjustment is performed .

The control device according to claim 1 of the present invention is configured to perform density adjustment when a density condition that is a condition for performing density adjustment that brings the density of an image formed by the image forming unit closer to a target is satisfied. The position adjustment is performed when a position condition that is a condition for performing the position adjustment for bringing the position formed by the adjustment unit and the image forming unit closer to the target is satisfied, and Position adjustment means for performing the position adjustment in accordance with the execution of the density adjustment by the density adjustment means when the density condition is satisfied and an early position condition that is satisfied earlier than the position condition is satisfied. If, comprising a measuring means for measuring the number of image formed by the image forming means, the density adjusting means, the field in which the position adjustment is performed by the position adjusting means The, when the number measured by said measuring means after the said position adjustment is performed is equal to or greater than the determination threshold, if satisfied the density conditions, and characterized by carrying out said density adjustment To do.

The control device according to claim 3 of the present invention performs the position adjustment when a position condition that is a condition for performing the position adjustment for bringing the position where the image formed by the image forming unit is formed closer to the target is satisfied. The density adjustment is performed when a density condition that is a condition for performing the density adjustment that brings the density of the image formed by the image forming unit and the position adjusting unit to be performed closer to the target is satisfied, and Density adjustment means for performing the density adjustment in accordance with the execution of the position adjustment by the position adjustment means when an early density condition, which is a condition that is satisfied earlier than the density condition, is satisfied. If, comprising a measuring means for measuring the number of image formed by the image forming means, said position adjusting means places said density adjustment is performed by the density adjustment unit The, when the number measured by said measuring means after the said density adjustment is performed is equal to or greater than the determination threshold value, if the position condition is satisfied, and characterized by carrying out said position adjustment To do.

A control device according to a fourth aspect of the present invention is the control device according to any one of the first to third aspects, wherein the measurement unit includes a detection unit that detects a medium on which the image is formed. The number of times the detection means detects the medium is determined based on the size of the medium, whether to form an image on both sides of the medium, or the result of weighting according to the distance between the medium and the preceding and following media. It is characterized by measuring the number .

Control device according to claim 2 of the present invention, in the structure according to claim 1, wherein the position adjusting means, in a case where the density adjusting means for performing the density adjustment image the image forming means on the medium body When the early position condition is satisfied, the position adjustment is performed according to the density adjustment performed by the density adjustment unit, and when the image forming unit is not in the state, Even if the early position condition is satisfied, the position adjustment is not performed.

According to a fifth aspect of the present invention, there is provided an image forming apparatus comprising: the control device according to the third aspect; and a first sensor that reads a density and a position of the image, and the density adjusting unit reads the first sensor. The position adjustment means reads the position by the first sensor, the position condition is satisfied and the early density condition is satisfied, and the density adjustment means When the density adjustment is performed according to the position adjustment performed by the adjustment unit, the position adjustment is performed after the density adjustment unit performs the density adjustment.

An image forming apparatus according to a sixth aspect of the present invention is the control device according to any one of the first to fourth aspects, a first sensor that reads the density of the image, and a second sensor that reads the position of the image. The density adjustment means performs the density adjustment using the density read by the first sensor, and the position adjustment means uses the position read by the second sensor to adjust the position. It is characterized by implementing.

According to the first aspect of the present invention, the density adjustment and the position are compared with the case where there is no configuration in which the position adjustment is performed according to the density adjustment when the density condition is satisfied and the early position condition is satisfied. It is possible to reduce the chance that the adjustment is performed at different timings, and to widen the interval from when one adjustment is performed to when the other adjustment is performed .
In addition, according to the first aspect of the present invention, it is possible to secure the time required for the number measured by the measuring means to be equal to or greater than the determination threshold from when the position adjustment is performed until the density adjustment is performed. it can.
According to the third aspect of the present invention, the density adjustment and the position are compared with the case where the density adjustment is not performed according to the position adjustment when the position condition is satisfied and the early density condition is satisfied. It is possible to reduce the chance that the adjustment is performed at different timings, and to widen the interval from when one adjustment is performed to when the other adjustment is performed .
Further, the invention according to claim 3, to secure the time required for until the density adjustment is performed the position adjustment from being performed, the number measured by the measuring means is equal to or greater than the determination threshold value I can .
According to the invention of 請 Motomeko 2, the image forming means as compared with the case of adjusting the position when it is not in a state of forming an image on a medium, to suppress the number of times to carry out the position adjustment increases Can do.
According to the fifth aspect of the present invention, it is possible to improve the accuracy of the position adjustment as compared with the case where the position adjustment is performed before the density adjustment when the position condition is satisfied and the early density condition is satisfied. it can.
According to the invention of claim 6 , compared to the case where the density adjusting means and the position adjusting means use a common sensor, when one of the density adjustment or the position adjustment is performed according to the other implementation, the implementation is performed. The time required can be shortened.

1 is a diagram illustrating a structure of an image forming apparatus according to a first embodiment. 2 is a block diagram illustrating a hardware configuration of an image forming apparatus. It is a figure which shows the example in which both density adjustment and position adjustment were implemented. It is a table | surface which shows the example of implementation conditions and early implementation conditions. It is a flowchart which shows the procedure of the process which a control part performs. It is a flowchart which shows the procedure of the process which a control part performs. It is a block diagram which shows the functional structure of a control part. It is a flowchart which shows the procedure of the process which the control part which concerns on 2nd Embodiment performs. It is a block diagram which shows the functional structure of a control part. It is a flowchart which shows the procedure of the process which the control part which concerns on 3rd Embodiment performs.

[First Embodiment]
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram showing the structure of an image forming apparatus 100 according to the first embodiment of the present invention. The image forming apparatus 100 is an electrophotographic image forming apparatus having functions such as printing, copying, and facsimile, and forms an image corresponding to image data. The image forming units 1Y, 1M, 1C, and 1K form images of respective colors using yellow (Y), magenta (M), cyan (C), and black (K) toners, respectively. The exposure device 13 outputs light (exposure light) to the image forming units 1Y, 1M, 1C, and 1K, respectively, and forms an electrostatic latent image that is an original of each color image. The intermediate transfer belt 2 is wound around a plurality of rolls, and is rotated in the direction of arrow A by these rolls. The image formed by each image forming unit is primarily transferred onto the outer peripheral surface of the intermediate transfer belt 2 so as to be superimposed.

  The storage unit 4 stores a plurality of sheets as an example of a medium on which an image is formed. The sheet is sent out from the storage unit 4 and is conveyed along the conveyance path P in the direction of arrow B by a plurality of conveyance rolls. The secondary transfer roll 5 secondarily transfers the image primarily transferred to the intermediate transfer belt 2 onto a sheet. The cleaning blade 51 is provided in a state where the end portion is in contact with the secondary transfer roll 5, and removes adhering matter attached to the secondary transfer roll 5. The fixing device 6 heats and pressurizes the image secondarily transferred to the paper, thereby fixing the image on the paper. In this way, an image is formed on the paper. As described above, the image forming units 1Y, 1M, 1C, and 1K, the exposure device 13, the intermediate transfer belt 2, the secondary transfer roll 5, and the fixing device 6 function as an image forming unit that forms an image. . In addition to the paper, this medium may be a plastic such as an OHP sheet or a sheet of other materials, and may be any medium that can record an image on the surface. The sheet on which the image is formed is conveyed by a plurality of conveyance rolls and discharged to the discharge unit 7a or the discharge unit 7b. The cleaning device 3 removes toner remaining on the surface of the intermediate transfer belt 2 after the secondary transfer.

  The image reading sensor 8 is an optical sensor and is provided opposite to the outer peripheral surface of the intermediate transfer belt 2. The image reading sensor 8 measures the intensity of reflected light from the image formed on the intermediate transfer belt 2. Read density and position. The image reading sensor 8 is an example of a first sensor according to the present invention. The paper detection device 9 is provided at a position close to the transport path P and detects a paper transported on the transport path P. A display unit and an operation unit are provided on the upper surface of the casing of the image forming apparatus 100. The display unit includes a liquid crystal panel, and displays various information by driving the liquid crystal panel. The liquid crystal panel of the display unit also functions as a touch panel, and an operator performs various operations using the liquid crystal panel in addition to the operation unit.

  Next, the configuration of the image forming units 1Y, 1M, 1C, and 1K will be described by taking the configuration of the image forming unit 1K as an example. The image forming unit 1K performs on the photoconductor 11K exposure corresponding to K image data among the image data of each color of YMCK, and the photoconductor 11K, the charging device 12K that charges the photoconductor 11K to a predetermined charging potential. An exposure unit that forms an exposure path output from the exposure device 13 that forms an electrostatic latent image, and a developing device that develops the electrostatic latent image with black toner to form a black image on the surface of the photoreceptor 11K. 14K, a primary transfer roll 15K for primary transfer of an image to the intermediate transfer belt 2, and a cleaning device 16K for removing toner remaining on the surface of the photoreceptor 11K after the primary transfer. The developing device 14K has a storage space for storing a developer having a toner that is a non-magnetic material and a carrier that is a magnetic material, and supplies the toner contained in the developer to the above-described electrostatic latent image. To develop.

  The configurations of the image forming units 1Y, 1M, and 1C are the same as those of the image forming unit 1K except that the processing is performed on which color image of each of the YMCK colors. In the following description, the symbols “K”, “Y”, “M”, and “C” are attached when it is not necessary to distinguish the configurations of the image forming units 1Y, 1M, 1C, and 1K. No. For example, when referring to the photoconductor of the image forming unit 1K, the photoconductor 11K is referred to. When the photoconductors 11Y, 11M, 11C, and 11K need not be distinguished, they are simply referred to as the “photoconductor 11”.

  An image with a certain density as a target value may be formed on the outer peripheral surface of the intermediate transfer belt 2 in order to adjust the density of the image formed by each image forming unit 1. This image is called a density detection image, and the density is read by the image reading sensor 8. When there is a significant difference between the density thus detected and the target density, adjustment is performed so as to eliminate (or reduce) this difference. A significant difference here is a difference more than a predetermined threshold value, for example. Adjusting the image density so as to approach the target density in this way is called density adjustment.

In addition, on the outer peripheral surface of the intermediate transfer belt 2, a figure having a predetermined shape (for example, a straight line and a sub-scan along the main scanning direction) is detected in order to detect a positional shift between images formed by the image forming units. In some cases, each image forming unit forms an image representing a figure or a bowl-like figure that intersects a straight line along the direction at a target position. This image is referred to as a positional deviation detection image, and its position is read by the image reading sensor 8. If the read position is significantly different from the target position (position where each color image is to be formed), adjustment is performed so as to reduce this deviation. The significant deviation here is, for example, a deviation of a predetermined length or more. Adjusting so as to reduce the difference between the position where the image of each color is to be formed and the position where it is actually formed is called position adjustment.
In these density adjustment and position adjustment, since the detection image is not transferred to the paper, the toner forming the detection image adheres to the secondary transfer roll 5. In this case, the adhering toner is removed by the cleaning blade 51 by rotating the secondary transfer roll 5 several times. The operation of removing (cleaning) the deposits including the toner from the secondary transfer roll 5 in this way is called a cleaning operation of the secondary transfer roll 5.

  Next, the hardware configuration of the image forming apparatus 100 will be described with reference to the block diagram of FIG. The control unit 110 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an ASIC (Application Specific Integrated Circuit), and the like, and the CPU is stored in the ROM or the storage unit 120. The display unit 101, the transfer device 103, the fixing device 6, the charging device 12, the exposure device 13, and the developing device 14 are controlled by executing the program. The transfer device 103 includes a primary transfer roll 15 that performs primary transfer, an intermediate transfer belt 2, and a secondary transfer roll 5 that performs secondary transfer. The control unit 110 also has a time measuring function for measuring the current time based on the system clock. The control unit 110 is an example of the “control device” according to the present invention. The storage unit 120 is, for example, a hard disk, and stores a parameter group used when the control unit 110 performs processing in addition to the above program. The parameter group includes those relating to the voltage and period during charging, exposure, transfer, and fixing. The image reading sensor 8 supplies the result of reading the image formed on the outer peripheral surface of the intermediate transfer belt 2 to the control unit 110 as described above. The paper detection device 9 notifies the control unit 110 of the result of detecting the paper as described above. Inside the image forming apparatus 100, a temperature / humidity meter 10 is provided. The thermohygrometer 10 measures the temperature and humidity inside the image forming apparatus 100 and supplies the measured values to the control unit 110. When operated by the operator as described above, the operation unit 102 supplies operation data indicating the operation content to the control unit 110.

Next, the operation of the image forming apparatus 100 when the above-described density adjustment and position adjustment are performed will be described.
The control unit 110 controls the charging device 12, the exposure device 13, the developing device 14, and the transfer device 103 to form the above-described density detection image or displacement detection image on the outer peripheral surface of the intermediate transfer belt 2. The image reading sensor 8 reads one of (or both) formed detection images from the outer peripheral surface and reads the result (specifically, the detection image and the reflected light of the light applied to the medium). The control unit 110 is notified. The control unit 110 calculates the density or position of the detection image from the notified result, and performs processing for adjusting the density or position when there is a difference from the target density or position. Specifically, in the case of density adjustment, the control unit 110 changes the potential of the charging, exposure, or development bias so that the density of the read image approaches the target density, or the exposure device 13 performs exposure. Change the intensity. In some cases, the gradation value itself included in the image data is corrected. On the other hand, in the case of position adjustment, the control unit 110 changes the position at which the electrostatic latent image is formed on the photoconductor 11 by changing the exposure timing of the exposure device 13. A known technique may be used for the density adjustment or the position adjustment.

As the above density adjustment and position adjustment are performed with increasing frequency, the density difference and the position deviation from the target can be reduced. In the image forming apparatus 100, these adjustments are performed when factors that change the density and position of the image satisfy predetermined conditions, and the density difference and the position shift before these changes become too large. Can be kept small. For example, in the case of the density of an image, the factor referred to here is a change in temperature or humidity inside the image forming apparatus 100 from the time when the previous density adjustment was performed, the passage of time, or repeated image formation (that is, image The number of sheets on which the sheet is formed increases). On the other hand, in the case of the position of the image, the change in temperature inside the image forming apparatus 100 is the above factor. In addition, the predetermined condition is that these factors change more than a predetermined determination threshold (hereinafter referred to as “determination threshold”) from when the previous density adjustment (or position adjustment) was performed.
On the other hand, during these adjustments, a detection image is formed on the photoconductor 11 and the intermediate transfer belt 2, so that an image requested by the user (hereinafter referred to as “user request image”) is displayed. The photosensitive member 11 and the intermediate transfer belt 2 cannot be formed. Therefore, the more frequently these adjustments are performed, the more time or opportunity that the user request image cannot be formed, and the fewer the number of user request images formed over a predetermined period. The example is shown using FIG.

  FIG. 3 is a diagram illustrating an example in which density adjustment and position adjustment are performed. FIG. 3 shows a case where a series of processes for forming an image on 50 sheets of paper is executed according to a request from a certain user, for example. Hereinafter, a series of processes for forming an image (user request image) in accordance with one request from the user is referred to as an “image forming process”. Whether or not to perform density adjustment and position adjustment is determined every time an image is formed on a sheet. In FIG. 3A, these determinations are made using predetermined conditions in the image forming apparatus 100. Hereinafter, this condition is referred to as “implementation condition”. In addition, the execution condition set for the determination of the execution of density adjustment is called “density adjustment execution condition”, and the execution condition set for the determination of execution of position adjustment is called “position adjustment execution condition”. . The “density adjustment execution condition” is an example of the “density condition” according to the present invention, and the “position adjustment execution condition” is an example of the “position condition” according to the present invention. These implementation conditions are, for example, whether or not the temperature value that has changed since the previous density adjustment or position adjustment was performed is greater than or equal to the determination threshold, and more specific examples will be described later. In the example of FIG. 3A, after the 40th image formation is completed, it is determined that the density adjustment execution condition is satisfied and the density adjustment is performed, and the density adjustment is performed before the 41st image is formed. Has been implemented. Further, after the 42nd image formation is completed, it is determined that the position adjustment execution condition is satisfied and the position adjustment is performed, and the position adjustment is performed before the 43rd image is formed.

  In the example shown in FIG. 3A, when the density adjustment is performed, the position adjustment is also in a situation where the position adjustment execution condition is soon satisfied. For example, if the position adjustment execution condition is that the temperature change from the previous position adjustment is 2.0 degrees or more (that is, the temperature change determination threshold is 2.0 degrees), the 42nd image Since this condition is satisfied when the 40th image is formed, when the 40th image is formed, the temperature changes from before 2.0 degrees, for example, from about 1.8 degrees to about 1.9 degrees. Will be.

  In the image forming apparatus 100, when either one of the density adjustment or the position adjustment is satisfied, the control unit 110 satisfies the earlier implementation condition of the other in order to determine the other implementation condition. The conditions (hereinafter referred to as “early implementation conditions”) whose contents are defined are used. When the other is density adjustment, this condition is referred to as a density adjustment early execution condition, and when it is position adjustment, this condition is referred to as a position adjustment early execution condition. “Concentration early implementation conditions” is an example of “early density conditions” according to the present invention, and “Position adjustment early implementation conditions” is an example of “early position conditions” according to the present invention. As a result, when one of the above adjustments is performed, the control unit 110 performs one adjustment and the other adjustment when the other execution condition is soon satisfied. FIG. 3B shows an example in which the control unit 110 makes an execution determination using the early execution conditions in the situation shown in FIG. In this example, for example, the control unit 110 sets the temperature change determination threshold to 1.8 degrees, that is, a value that is satisfied earlier than the determination threshold of 2.0 degrees in the case of the original position adjustment execution condition. It is determined whether or not position adjustment is performed. In this case, after the image formation on the 40th sheet is completed, the density adjustment execution condition is satisfied and the position adjustment early execution condition is also satisfied. As a result, both the density adjustment and the position adjustment are performed before the 41st sheet. Has been. As described above, in the image forming apparatus 100, when both density adjustment and position adjustment are performed, the user-requested image formation is not interrupted twice as shown in FIG. ) Just be interrupted once as in). That is, in the image forming apparatus 100, the number of times that the user-requested image formation is interrupted by the density adjustment and the position adjustment is reduced.

  FIG. 4 is a table showing an example of execution conditions and early execution conditions for determining whether to perform density adjustment and position adjustment. FIG. 4A illustrates an example of the density adjustment execution condition and the early execution condition. These execution conditions and early execution conditions are the above-mentioned factors, that is, the elapsed time ("elapsed time"), the change in temperature ("temperature change"), the change in humidity ( “Humidity change”) and the number of images formed (“image formation number”), respectively, are represented by determination threshold values. For example, if this factor is elapsed time, the determination threshold for the execution condition is “12 hours” and the determination threshold for the early execution condition is “10 hours”. In addition, when the factor is a temperature change, the execution condition is “5.0 degrees” and the early execution condition is “4.0 degrees”. When the factor is a change in humidity, the execution condition is “12%” and the early execution condition is “10%”. When these conditions are satisfied, the density adjustment is performed at a timing determined for the currently executed image forming process. The timing is shown in the rightmost column of the table of FIG. For example, when the elapsed time becomes equal to or longer than the execution condition (for example, 12 hours), the timing at which the density adjustment is actually performed is when the image forming process is started next.

When the factor is the number of formed images, the timing for performing the density adjustment differs depending on the situation when the condition is satisfied. For example, when the number of image formations is 40 or more as the execution condition determination threshold or 30 or more as the early execution condition determination threshold, the density adjustment is performed when the currently executed image formation process is completed. The When the number of formed images is 60 sheets or more (50 sheets or more under the early execution conditions), the density adjustment is performed even during the image forming process.
FIG. 4B shows an example of the execution condition and the early execution condition in the position adjustment. Also in the position adjustment, conditions and timings following the density adjustment are determined. In this example, the determination threshold for the execution condition is 2.0 degrees and the determination threshold for the early execution condition is 1.8 degrees due to a temperature change. It is stipulated. When these conditions are satisfied, the position adjustment is performed even during the image forming process.

  Next, a procedure of processing performed by the control unit 110 according to a program will be described with reference to FIGS. The control unit 110 performs the processes shown in FIGS. 5 and 6 every time an image is formed on one sheet. Specifically, the control unit 110 determines whether or not the density adjustment execution condition is satisfied (step S1 in FIG. 5), and determines whether or not the position adjustment execution condition is satisfied (step S11 in FIG. 6). ). Specifically, in step S1, the control unit 110 measures the time elapsed since the previous density adjustment was performed by the timekeeping function provided by itself, and the time is shown in FIG. 4A. It is determined whether or not it is 12 hours or more. Moreover, the control part 110 measures the value from which the temperature and humidity changed from the last time density adjustment was performed with the value supplied from the thermohygrometer 10, and the value is the implementation condition shown in FIG. It is determined whether it is 5.0 degrees or 12% or more. Further, the control unit 110 measures the number of sheets on which an image is formed from the previous density adjustment based on the result notified from the sheet detection device 9, and the number of sheets is shown in FIG. 4A. It is determined whether or not the condition is 40 sheets or 60 sheets or more. Moreover, in step S11, the control part 110 measures the value from which temperature was changed from the time of performing previous position adjustment with the value supplied from the thermohygrometer 10, and the value was shown in FIG.4 (b). It is determined whether or not the implementation condition is 2.0 degrees or more. If the density adjustment execution condition is not satisfied in step S1 (step S1; NO), the control unit 110 ends the procedure shown in FIG. 5, and if the position adjustment execution condition is not satisfied in step S11 (step S11). NO), the procedure shown in FIG. 6 is terminated.

  When the density adjustment execution condition is satisfied in step S1 (that is, YES), the control unit 110 performs the remaining processing illustrated in FIG. First, the control unit 110 determines whether or not the position adjustment early execution condition is satisfied (step S2). Specifically, the control unit 110 performs the above-described processing in step S11 by replacing the execution condition with the early execution condition shown in FIG. That is, the control unit 110 determines whether or not the temperature value changed since the previous position adjustment is 1.8 degrees or more instead of 2.0 degrees. If this early execution condition is not satisfied (step S2; NO), the control unit 110 performs density adjustment (step S5), and ends the process of FIG. If the early execution condition is satisfied in step S2 (step S2; YES), the control unit 110 first performs density adjustment (step S3). Then, the controller 110 forms an image for detecting misregistration after the density adjustment is completed, that is, when the above-described potential change or exposure intensity change is performed. Then, position adjustment is performed using the formed image (step S4). In this way, the control unit 110 performs both density adjustment and position adjustment. At that time, the control unit 110 prevents an image from being formed on the sheet from the start of the density adjustment to the end of the position adjustment.

  The misregistration detection image formed at this time is formed after the density adjustment is performed, so the density desired to be obtained is higher than the configuration in which the position adjustment is performed before the density adjustment (Comparative Configuration 1). An image with a small density difference is formed. The image reading sensor 8 reads the image by measuring the reflected light from the image. For example, when the density of the edge portion of the image is lower than the desired density, the image reading sensor 8 reads an image that does not include the portion. There is. In that case, the result of reading by the image reading sensor 8, that is, the shape of the read image becomes inaccurate, and the position of the image calculated by the control unit 110 from the result also becomes inaccurate. On the other hand, the image for detecting the displacement formed in step S4 has a smaller density difference from the density desired to be obtained than the comparative configuration 1, and therefore the shape can be read more accurately by the image reading sensor 8. As a result, the position of the image calculated by the control unit 110 is also more accurate than that of the comparison configuration 1 described above.

  In the process of step S4, the control unit 110 passes the secondary transfer roll after both the detection image formed for density adjustment and the detection image formed for position adjustment pass through the secondary transfer roll. The transfer roll is cleaned. That is, in the image forming apparatus 100, when both density adjustment and positional deviation adjustment are performed, the time for cleaning the secondary transfer roll soiled by each detection image is shared. On the other hand, when the density adjustment and the positional deviation adjustment are performed at different timings, this time is spent when performing each adjustment. That is, in the image forming apparatus 100, both the density adjustment and the positional deviation adjustment are performed, so that the time required for the density adjustment and the position adjustment is reduced as compared with the case where these are performed at different timings. In other words, in the image forming apparatus 100, the number of user request images formed per unit time increases. When the process of step S4 ends, the control unit 110 ends the process of FIG.

  When the position adjustment execution condition is satisfied before the density adjustment execution condition (step S11; YES), the control unit 110 performs the remaining processing shown in FIG. First, the control unit 110 determines whether or not the density adjustment early implementation condition is satisfied (step S12). Specifically, the control unit 110 performs the processing in step S1 described above, replacing the execution conditions with the early execution conditions shown in FIG. For example, if the temperature value has changed since the previous density adjustment, the control unit 110 determines whether the temperature value is 4.0 degrees or more instead of 5.0 degrees. If this early execution condition is not satisfied (step S12; NO), the control unit 110 performs position adjustment (step S15) and ends the process of FIG. In step S12, when the early execution conditions are satisfied (step S12; YES), the control unit 110 performs the processes of steps S3 and S4 described above. Then, when the process of step S4 ends, the control unit 110 ends the process of FIG. As described above, the control unit 110 performs the density adjustment first even if the position adjustment execution condition is satisfied first. As a result, even when the position adjustment execution condition is satisfied, as described above, a misregistration detection image having a smaller density difference from the density desired to be obtained is formed as compared with the comparative configuration 1, and the image reading sensor The shape of this detection image is read more accurately by 8. For this reason, the position of the image calculated by the control unit 110 is also more accurate than that of the comparison configuration 1 described above.

Next, functions realized when the control unit 110 executes a program will be described.
FIG. 7 is a block diagram illustrating a functional configuration of the control unit 110. The control unit 110 implements a density adjustment execution determination unit 111, a position adjustment execution determination unit 112, a density adjustment execution control unit 113, and a position adjustment execution control unit 114 by executing a program. The density adjustment execution determination unit 111 determines that the density adjustment is performed when the density adjustment execution condition is satisfied, and supplies the result to the position adjustment execution determination unit 112, the density adjustment execution control unit 113, and the position adjustment execution control unit 114. . The position adjustment execution determination unit 112 determines that the position adjustment is performed when the position adjustment execution condition is satisfied, and supplies the result to the density adjustment execution determination unit 111, the density adjustment execution control unit 113, and the position adjustment execution control unit 114. . Also, the density adjustment execution determination unit 111 responds to the execution of the position adjustment when the density adjustment early execution condition is satisfied when the result supplied from the position adjustment execution determination unit 112 is a determination that the position adjustment is performed. It is determined that density adjustment will be performed. In this embodiment, performing the density adjustment according to the position adjustment here means that both the position adjustment and the density adjustment are performed as described above. The position adjustment execution determination unit 112 performs the density adjustment when the position adjustment early execution condition is satisfied when the result supplied from the density adjustment execution determination unit 111 is a determination that the density adjustment is performed. Accordingly, it is determined that the position adjustment is performed. In this embodiment, performing the position adjustment according to the density adjustment here means that both the density adjustment and the position adjustment are performed as described above. The density adjustment execution determination unit 111 and the position adjustment execution determination unit 112 supply the determination result when these early execution conditions are satisfied to the density adjustment execution control unit 113 and the position adjustment execution control unit 114, respectively.

  The density adjustment execution control unit 113 determines that the density adjustment execution determination unit 111 determines that the density adjustment is performed, that is, the density adjustment execution determination unit 111 determines that the density adjustment is performed. Then, each unit is controlled so that the density adjustment is performed using the density of the density detection image read by the image reading sensor 8. Each part here is a part that operates when an image of each color is formed on the intermediate transfer belt 2 in the image forming apparatus 100. Specifically, the intermediate transfer belt 2, the photoconductor 11, the charging device 12, and the exposure. An apparatus 13, a developing apparatus 14, and a primary transfer roll 15. The density adjustment execution control unit 113 uses the density of the density detection image read by the image reading sensor 8 when the density adjustment execution determination unit 111 determines that the density adjustment is performed according to the position adjustment. Thus, the above-described units are controlled so that the density adjustment is performed according to the position adjustment.

  The position adjustment execution control unit 114 determines that the position adjustment execution determination unit 112 determines that the position adjustment is performed, that is, if the position adjustment execution determination unit 112 determines that the position adjustment is performed. Then, the above-described units are controlled so that the position adjustment is performed using the position of the positional deviation detection image read by the image reading sensor 8. In addition, when the position adjustment execution control unit 114 determines that the position adjustment is performed according to the execution of the density adjustment, the position adjustment execution control unit 114 uses the position detected as described above to perform the density adjustment. The above-described units are controlled so as to adjust the position. The density adjustment execution determination unit 111 and the density adjustment execution control unit 113 cooperate to function as a “density adjustment unit” according to the present invention, and the position adjustment execution determination unit 112 and the position adjustment execution control unit 114 cooperate. Thus, it functions as the “position adjusting means” according to the present invention.

  According to the first embodiment described above, when one of density adjustment or position adjustment is performed, the other is not performed even if the other early implementation condition is satisfied (comparative configuration 2). As a result, there are fewer opportunities for density adjustment and position adjustment to be performed at different timings. That is, it is not possible to perform the other adjustment immediately after either the density adjustment or the position adjustment is performed. Further, if the other does not satisfy the early implementation condition, which is a milder condition than the implementation condition, then the implementation condition is not satisfied unless the above factors change by the difference between the determination threshold values of both conditions. In other words, according to the first embodiment, after one of these adjustments is performed, the other is not performed until the time that the factor changes by this difference elapses. When both of these adjustments are performed, both the density detection image and the positional deviation detection image are formed on the outer peripheral surface of the intermediate transfer belt 2, and the reading of the positional deviation detection image by the image reading sensor 8 is completed. After that, the time required for cleaning is shared by cleaning the secondary transfer roll. Thereby, compared with the comparison structure 2, the time required to implement either density adjustment or position adjustment according to the implementation of the other is shortened.

[Second Embodiment]
In the first embodiment described above, after one adjustment is performed, the other adjustment is performed after a time has elapsed in which the above factors change by the difference between the determination threshold values of the execution condition and the early execution condition. However, in this second embodiment, this time is set as a time when another factor changes more than the determination threshold or a time when the difference changes more than the determination threshold different from the difference between both determination thresholds.

  FIG. 8 is a flowchart illustrating a processing procedure performed by the control unit 110 included in the image forming apparatus 100 according to the present embodiment in accordance with a program. In this process, steps S1 to S4 are common to the process shown in FIG. Then, when the early position adjustment execution condition is not satisfied in step S2 (that is, NO), the control unit 110 determines whether the image forming process is being executed at that time. (Step S31). When determining that the image forming process is not being executed (step S31; NO), the control unit 110 executes a density adjustment process (step S33). In addition, when the control unit 110 determines that the image forming process is being executed (step S31; YES), when the previous position adjustment measured based on the result notified from the paper detection device 9 is performed. From this, it is determined whether or not the number of sheets on which images are formed is equal to or greater than a determination threshold (20 sheets in the present embodiment) (step S32). If this number is less than the determination threshold (step S32; NO), the control unit 110 ends the procedure of FIG. 8 without performing density adjustment. If this number is equal to or greater than the determination threshold (step S32; YES), the control unit 110 proceeds to step S33 and performs density adjustment. By performing the process as described above, after the position adjustment is performed, the density adjustment is performed only after the time that the “number of sheets on which the image is formed”, which is another factor, changes by more than the determination threshold has elapsed. Will not be implemented.

  Further, when the position adjustment execution condition is satisfied first, the control unit 110 replaces the process from step S15 shown in FIG. 6 with the process from steps S31 to S33 shown in FIG. Change the adjustment and execute. In this case, after the density adjustment is performed, the position adjustment is not performed unless the time that the “number of sheets on which the image is formed”, which is another factor, changes more than the determination threshold has elapsed. Become.

  FIG. 9 is a block diagram illustrating a functional configuration of the control unit 110 according to the present embodiment. The control unit 110 is different from the control unit 110 according to the first embodiment described above in that the measurement unit 115 is realized by executing a program. Each determination result is supplied to the measurement unit 115 from the density adjustment execution determination unit 111 and the position adjustment execution determination unit 112. The measurement unit 115 measures the number of times the result of detecting the paper is notified from the paper detection device 9 since the supplied determination result is that these adjustments are performed. The measuring unit 115 determines the number of times of the measurement, the number of sheets on which the image of each color formed by the above-described detection image forming unit is transferred, that is, the above-described image forming unit (the image forming unit 1Y). 1M, 1C, 1K, exposure device 13, intermediate transfer belt 2, secondary transfer roll 5, and fixing device 6) are measured as values representing the number of images formed. The measurement unit 115 supplies the value measured from when the density adjustment is performed to the density adjustment execution control unit 113, and supplies the value measured from when the position adjustment is performed to the position adjustment execution control unit 114. . The measurement unit 115 and the paper detection device 9 cooperate to function as a “measurement unit” according to the present invention. When the position adjustment is performed, the density adjustment execution control unit 113 has a value indicating the number of sheets measured by the measurement unit 115 and the sheet detection device 9 after the position adjustment is equal to or greater than the determination threshold. When the density adjustment execution condition is satisfied, the detection image forming unit is controlled to perform the density adjustment. Further, the position adjustment execution control unit 114 performs the operation common to the operation of the density adjustment execution control unit 113 described here in a form in which the density adjustment and the position adjustment are interchanged.

  According to the second embodiment described above, the adjustment of the other is performed from when one adjustment is performed until after the image is formed on the number of sheets (20 sheets in the present embodiment) determined as the determination threshold. Will not be implemented. In other words, at least a time for forming an image on 20 sheets of paper is provided from the time when one adjustment is performed until the other adjustment is performed.

[Third Embodiment]
In the third embodiment, the state of the image forming process is taken into consideration when determining whether or not the position adjustment is performed together with the density adjustment.
FIG. 10 is a flowchart illustrating a processing procedure performed by the control unit 110 according to the present embodiment in accordance with a program. First, the control unit 110 executes the process of step S1 shown in FIG. If the density adjustment execution condition is satisfied (step S1; YES), the control unit 110 determines whether or not the image forming process is currently being continued (step S41). Here, the state in which the image forming process is continuing means a state in which an image to be formed on the sheet remains and the image forming process is continued. The image to be formed on the sheet includes not only one request from one user but also one request from one user multiple times, one from a plurality of user requests, and the like. In some cases. When the control unit 110 determines that the current state is present (step S41; YES), the control unit 110 executes the processing after step S2 shown in FIG. That is, if the early execution condition is satisfied, the position adjustment is executed together with the density adjustment. On the other hand, when it is judged that it is not in the state (step S41; NO), the control part 110 performs the process (implementation of density adjustment) of step S5 shown in FIG. 5, and complete | finishes a process. That is, in this case, the control unit 110 does not determine whether or not the position adjustment early execution condition is satisfied, and therefore does not perform position adjustment.

  According to the third embodiment described above, since the density adjustment is performed even after the image forming process is completed, this is compared with the case where the density adjustment is performed when the image forming process is started next. When starting, the time required for forming an image on the first sheet is shortened. In addition, since the position adjustment is not performed in a state where the image forming process is completed, the position adjustment performing condition is not changed when the image forming process is started next time, regardless of how many times the position adjusting performing condition is satisfied in this state. If it is not satisfied, the position adjustment is not performed, and even if the position adjustment execution condition is satisfied, the position adjustment is performed only once at that time. As a specific example, after the position adjustment is performed, the next image forming process is started when the temperature rises by 6 degrees and then decreases again by 6 degrees in the state where the image forming process is completed. If so, the position adjustment execution condition is satisfied six times, but as a result, the position adjustment is never performed. Even if the next image forming process is started when the temperature rises by 6 degrees, the position adjustment execution condition is satisfied three times, but the position adjustment is performed only once. As described above, according to the third embodiment, an increase in the number of times of position adjustment is suppressed, and as a result, consumption of toner, power, and consumables is suppressed.

[Modification]
Each of the above-described embodiments is merely an example of an embodiment of the present invention, and various modifications can be made as follows. Moreover, each embodiment mentioned above and the following each modification can also be combined as needed.

(Modification 1)
In each of the above-described embodiments, the image reading sensor 8 reads both the density detection image and the positional deviation detection image. However, separate sensors may read the images. For example, an image forming apparatus according to the present modification includes an image reading sensor 8 (first sensor) that measures the density of each color image, and an image reading sensor (second sensor) that is different from the image reading sensor 8 and that reads an image position. Sensor: An image reading sensor 8a) indicated by a dotted line in FIG. In this case, the control unit 110 controls each unit to perform both adjustments together. At that time, the control unit 110 may start both adjustments together, or may start so that the shorter time ends before the longer time required for the adjustment ends. In either case, according to the present modification, the time required to complete both adjustments is shorter than when the density adjustment and the position adjustment are performed in order. The image reading sensor 8 is an optical sensor in each of the above-described embodiments, but may be another type of sensor as long as it detects the density and position of an image.

(Modification 2)
The control unit 110 determines whether to perform density adjustment and position adjustment every time an image is formed on one sheet in each of the above-described embodiments, but may be performed at other timings. For example, the control unit 110 may perform this determination every time an image is formed on a plurality of sheets, or may be performed every time a predetermined time or a predetermined time elapses. Alternatively, it may be performed when the image forming apparatus 100 is turned on or when the image forming process is completed. In any case, it is desirable that these determinations be made before the density change or misregistration of the formed image becomes larger than a predetermined level.

(Modification 3)
In each of the above-described embodiments, the control unit 110 performs the density adjustment before the position adjustment even when any of the early execution conditions is satisfied, but the position adjustment is performed before the density adjustment. May be. In each embodiment described above, the control unit 110, after both the detection image formed for density adjustment and the detection image formed for position adjustment pass through the secondary transfer roll, Although the time required for cleaning the secondary transfer roll was shared by performing the cleaning operation of the secondary transfer roll, the cleaning operation of the secondary transfer roll was performed after these detection images passed through the secondary transfer roll. It may be performed separately. In any case, compared to the above-described comparative configuration 2, there are fewer opportunities for density adjustment and position adjustment to be performed at different timings. In addition, in each of the above-described embodiments, the control unit 110 forms the position adjustment detection image after the density adjustment when performing both the density adjustment and the position adjustment. An adjustment detection image may be formed. As a result, the time during which the user-requested image formation is interrupted for density adjustment and position adjustment is shorter than in the former case.

  In short, the control unit 110 may perform the other in accordance with one implementation when the implementation condition of either density adjustment or position adjustment is satisfied and the other early implementation condition is satisfied. Implementing according to one implementation here means implementing the other so as to have a predetermined relationship with respect to one implementation. For example, as described above, this relationship is a relationship in which the other is implemented together with one implementation, and more specifically, a relationship in which the other is implemented when one implementation is completed, or both For example, the cleaning operation of the secondary transfer roll is performed after the detection image used by has passed through the secondary transfer roll. In addition, this relationship may be a relationship in which the time elapsed from the start (or end) of one implementation to the start of the other implementation is within a threshold. Regardless of the relationship, the control unit 110 may prevent the image from being formed on the sheet from the start of one implementation to the end of the other implementation. In addition, this relationship is preferably such that the time required from the start of one implementation to the completion of the other implementation is shorter. When any early execution condition is satisfied during the image forming process, the shorter this time is, the shorter the time during which the image forming process is interrupted, and the shorter the time required for the image forming process. In other words, the shorter this time is, the more easily the number of user-requested images formed over a predetermined period.

(Modification 4)
Implementation conditions and early implementation conditions are not limited to those shown in FIG. These conditions may be obtained by changing the size of the determination threshold for each factor, and the factors used for the determination themselves are different from those shown in FIG. 4 (time, temperature and humidity, number of images formed). Also good. For example, this factor may be the rotational speed, rotational time, rotational distance, or the like of a member such as the developing device 14 or the photoreceptor 11. In addition to this, it is sufficient that these conditions are satisfied before the change in image density or the positional deviation of the image becomes larger than a predetermined level. Moreover, these conditions should just be defined so that the early implementation conditions may be satisfied earlier than the implementation conditions in any case. As a result, in the image forming apparatus 100, the above factor is the difference between the determination threshold value of the execution condition and the early execution condition from when one of the density adjustment or the position adjustment is performed until the other is performed. Time to change is secured. As a result, when a certain image forming process is being performed, there are fewer opportunities for density adjustment and position adjustment to be performed at different timings.

(Modification 5)
The timing at which the control unit 110 performs each adjustment when the execution condition or the early execution condition is satisfied is not limited to that illustrated in FIG. 4. For example, in the density adjustment, when the elapsed time satisfies these conditions, the control unit 110 performs the current image forming process instead of performing the density adjustment when starting the next image forming process. It may be performed in the middle or when the image forming process is completed. In the position adjustment, when the temperature change satisfies these conditions, the control unit 110 finishes the image forming process instead of performing the position adjustment during the current image forming process. It may be performed when the next image forming process is started. Preferably, the position adjustment is performed during the current image forming process or when the next image forming process is started. As a result, since the position adjustment is not performed in a state where the image forming process is completed, as described in the third embodiment, the temperature is changed after the position adjustment is performed, and then the image forming process is started. The position adjustment is not performed again before or when it is started.

(Modification 6)
In each of the above-described embodiments, the control unit 110 measures the number of sheets on which an image is formed based on the number of times the sheet is notified by the sheet detection device 9. For example, whether the image is formed on the sheet size or both sides. Each detected result may be weighted depending on whether or not it is present or the distance from the front and back sheets. For example, even when an image is formed on one sheet, the control unit 110 sets the number of sheets to 1.5 if the sheet size is A3, 1 if A4, and B4. If so, it is measured as 0.8 sheets. In this case, the paper detection device 9 includes a sensor that detects the size of the paper, notifies the control unit 110 of the detected paper size together with the detection result of the paper, and the control unit 110 notifies the size of the notified paper. The number of sheets weighted with respect to is measured. In addition to this, the weighting value may be determined to be various values. In short, the weighting value only needs to be determined so as to increase as the density or the positional deviation is changed greatly. Thereby, as compared with the case where the weighting is not performed, the possibility that each adjustment is performed before the change in the density of the image or the positional deviation of the image becomes larger than the predetermined level is increased.
In addition, the number of sheets on which an image is formed may be measured by a program instead of measuring the number of sheets on which an image is formed based on the number of times the sheet is notified by the sheet detection device 9. Further, instead of measuring the number of sheets on which images are formed, the number of times images are formed on the image holding member such as the intermediate transfer belt 2 or the photosensitive member 11 may be measured. In any case, in short, it is only necessary that the measurement unit 115 measures a value representing the number of images formed by the image forming unit described above.

(Modification 7)
In the second embodiment described above, the control unit 110 measures the number of times the paper is detected by the paper detection device 9 as the number of sheets on which an image is formed in step S33 shown in FIG. However, the position adjustment is not limited to this. For example, weighting may be performed as in Modification 6 above, and position adjustment is performed when the rotation speed, rotation time, rotation distance, or the like of a member such as the developing device 14 or the photoreceptor 11 is equal to or greater than a determination threshold value. May be. Alternatively, the position adjustment may be performed after a predetermined time has elapsed. In short, the control unit 110 controls each unit so that the other adjustment is not performed unless a time required for the predetermined factor to change by more than the determination threshold has elapsed since one adjustment was performed. Good.

(Modification 8)
In the second embodiment described above, the control unit 110 may process step S33 illustrated in FIG. 8 before step S31 or before step S32. In any case, the control unit 110 does not perform the position adjustment unless the number of sheets on which images are formed after the previous position adjustment is equal to or greater than the determination threshold.

(Modification 9)
In the image forming apparatus 100, in each of the above-described embodiments, the image reading sensor 8 reads the density detection image formed on the intermediate transfer belt 2, but a sensor provided at a position close to the photoconductor 11 is You may make it read this image formed in the photoconductor 11. FIG. Thereby, the density of the image formed on the photoconductor 11 is adjusted.

(Modification 10)
In each embodiment described above, the control unit 110 reads each detection image (density detection image and positional deviation detection image) formed on the intermediate transfer belt 2 and performs each adjustment (density adjustment and position adjustment). However, each adjustment may be performed by reading each detection image formed on the sheet. In this case, the image forming apparatus 100 has the same function as the image reading sensor 8 and includes an image reading sensor that reads each detection image formed on the sheet. The image reading sensor notifies the control unit 110 of the read result, and the control unit 110 calculates the density or position of the detection image from the notified result.

(Modification 11)
The present invention can also be understood as a control device (a “control unit” according to the above-described embodiment or modification) or an image forming apparatus including the control device. The present invention can also be specified as a program for causing a computer to function as a control device. Such a program may be provided in a form recorded on a recording medium such as an optical disc, or may be provided in a form such that the program is downloaded to a computer via a communication line such as the Internet, and is installed and used. .

(Modification 12)
A condition may be added to the density adjustment execution condition as to whether or not the number of times of image formation (or the number of sheets on which an image has been formed) since the previous position adjustment was performed is equal to or greater than a threshold value. In addition, a condition may be added to the position adjustment execution condition as to whether or not the number of times of image formation (or the number of sheets on which an image has been formed) since the previous density adjustment was performed is greater than or equal to a threshold value. As a result, after one adjustment is performed, the other adjustment is prevented from being performed before the image formation is performed a threshold number of times (or images are formed on the threshold number of sheets). Can do.

  DESCRIPTION OF SYMBOLS 1Y, 1M, 1C, 1K ... Image forming unit, 2 ... Intermediate transfer belt, 3 ... Cleaning device, 4 ... Storage unit, 5 ... Transfer device, 6 ... Fixing device, 7a, 7b ... Discharge unit, 8, 8a ... Image Reading sensor, 9 ... paper detection device, 10 ... thermo-hygrometer, 11 ... photosensitive member, 12 ... charging device, 13 ... exposure device, 14 ... developing device, 15 ... primary transfer roll, 100 ... image forming device, 101 ... display , 102 ... operation section, 110 ... control section, 111 ... density adjustment execution determination section, 112 ... position adjustment execution determination section, 113 ... density adjustment execution control section, 114 ... position adjustment execution control section, 115 ... measurement section, 120 ... memory part

Claims (6)

When a density condition that is a condition for performing density adjustment for bringing the density of an image formed by the image forming unit close to a target is satisfied, a density adjusting unit that performs the density adjustment;
The position adjustment is performed when the position condition, which is a condition for performing the position adjustment for bringing the position where the image formed by the image forming unit is formed closer to the target, is satisfied, and the density condition is satisfied. Position adjustment means for performing the position adjustment according to the execution of the density adjustment by the density adjustment means when an early position condition that is satisfied earlier than the position condition is satisfied ,
Comprising a measuring means for measuring the number of images formed by the image forming means,
In the case where the position adjustment is performed by the position adjustment unit, the density adjustment unit is configured such that when the number measured by the measurement unit is equal to or greater than a determination threshold after the position adjustment is performed. A control device that performs the density adjustment if a density condition is satisfied . Said position adjusting means, in a case where the density adjusting means for performing the density adjustment, when the image forming means is a state in which forming an image on media body, the said early position condition is satisfied concentration The position adjustment is performed according to the density adjustment performed by the adjustment unit, and when the image forming unit is not in the state, the position adjustment is not performed even if the early position condition is satisfied. Item 2. The control device according to Item 1 . A position adjusting unit that performs the position adjustment when a position condition that is a condition for performing a position adjustment that brings a position where an image formed by the image forming unit is formed closer to a target is satisfied;
The density adjustment is performed when a density condition that is a condition for performing a density adjustment that brings the density of an image formed by the image forming unit closer to a target is satisfied, and the position condition is satisfied and the A density adjusting unit that performs the density adjustment in accordance with the execution of the position adjustment by the position adjusting unit when an early density condition that is a condition that is satisfied earlier than the density condition is satisfied ;
Comprising a measuring means for measuring the number of images formed by the image forming means,
In the case where the density adjustment is performed by the density adjustment unit, the position adjustment unit is configured such that when the number measured by the measurement unit is equal to or greater than a determination threshold after the density adjustment is performed. If the position condition is satisfied, the position adjustment is performed . The measuring unit includes a detecting unit that detects a medium on which the image is formed, and the number of times the detecting unit detects the medium determines whether to form an image on the size of the medium and on both sides of the medium. Alternatively, the number of images is measured based on the result of weighting according to the distance between the medium and the front and rear media.
The control device according to claim 1, wherein the control device is a control device. A control device according to claim 3 ;
A first sensor for reading the density and position of the image,
The density adjusting means performs the density adjustment using the density read by the first sensor,
The position adjusting unit reads the position by the first sensor, the position condition is satisfied and the early concentration condition is satisfied, and the concentration adjusting unit performs the position adjustment according to the position adjustment performed by the position adjusting unit. When performing the adjustment, the position adjustment is performed after the density adjustment unit has performed the density adjustment. A control device according to any one of claims 1 to 4 ,
A first sensor for reading the density of the image;
A second sensor for reading the position of the image,
The density adjusting means performs the density adjustment using the density read by the first sensor,
The image forming apparatus, wherein the position adjustment unit performs the position adjustment using a position read by the second sensor.

Images