JP2020044788A - Image forming device - Google Patents

Abstract

To efficiently adjust a parameter of print processing.SOLUTION: A close contact image sensor 63 is arranged on a subsequent stage conveyance path on a subsequent stage of an image forming part 4 out of a conveyance path, and reads an image from a sheet 9. A parameter adjustment part 80e compares a first read image which is read by the close contact image sensor 63 and a second read image which is read by the close contact image sensor 63 on an image based on data to be printed which is same as the first read image, and adjusts a parameter of print processing in response to a comparison result.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus capable of adjusting print processing parameters.

  The image forming apparatus includes a transport mechanism that transports a sheet, and an image forming unit that executes a printing process. The printing process is a process of forming an image on the conveyed sheet.

  Further, it is known that the image forming apparatus includes a contact image sensor disposed on a sheet conveying path from a manual feed tray to an image forming unit (for example, see Patent Document 1). In this case, the manual feed tray doubles as a tray on which the sheet for printing is placed and a tray on which a document from which an image is to be read by the contact image sensor is placed.

JP 2006-234860 A

  Incidentally, the image forming apparatus may execute a parameter adjustment process for adjusting the parameters of the print process. In the parameter adjustment processing, the image forming apparatus develops a predetermined test image, detects the density of the test image with a density sensor, and adjusts the parameters of the print processing based on the detected density.

  In addition, when the repetitive print processing based on the same print target data is performed, in order to prevent a change in the image quality of the print image, it is necessary to adjust the parameters during the repetitive print processing.

  If the test image is developed during the repetitive print processing, the repetitive print processing is interrupted for a relatively long time during the repetitive print processing, thereby deteriorating the processing efficiency.

  SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus capable of efficiently adjusting parameters of a printing process.

  An image forming apparatus according to one aspect of the present invention includes an image forming unit, an image sensor, and a parameter adjusting unit. The image forming unit executes a printing process for forming an image based on print target data on a sheet conveyed along a conveyance path. The image sensor is arranged in a post-stage conveyance path after the image forming unit in the conveyance path, and reads an image from the sheet on which the image is formed. The parameter adjustment unit is configured to perform a first sample image obtained by sampling and reading by the image sensor at a first time when a repetitive printing process for forming the same image on a plurality of sheets is performed by the image forming unit. And a second sample image obtained by the sampling reading by the image sensor at a second time after the first time, and adjusting a parameter of the print processing according to the comparison result. Execute the process.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the image forming apparatus which can adjust the parameter of print processing efficiently.

FIG. 1 is a front view of the image forming apparatus according to the first embodiment of the present invention. FIG. 2 is a configuration diagram of the main housing and the relay unit in the image forming apparatus according to the first embodiment of the present invention. FIG. 3 is a configuration diagram of a post-processing device in the image forming apparatus according to the first embodiment of the present invention. FIG. 4 is a block diagram illustrating a configuration of a control device in the image forming apparatus according to the first embodiment of the present invention. FIG. 5 is a first configuration diagram of a main housing and a relay unit in the image forming apparatus according to the second embodiment of the present invention (a state where the CIS is located at a reference position). FIG. 6 is a second configuration diagram of the main housing and the relay unit in the image forming apparatus according to the second embodiment of the present invention (the CIS is located at the retracted position). FIG. 7 is a block diagram illustrating a configuration of a control device in the image forming apparatus according to the second embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments are examples embodying the present invention and do not limit the technical scope of the present invention.

[First Embodiment: Overall Configuration of Image Forming Apparatus 10]
As shown in FIG. 1, the image forming apparatus 10 according to the first embodiment of the present invention includes a main housing 1, a relay unit 6, and a post-processing device 5. Further, the image forming apparatus 10 also includes a control device 8, an operation device 8a, and a display device 8b.

  The operation device 8a is a device that receives a user operation. For example, the operation device 8a includes one or both of a push button and a touch panel. The display device 8b includes a panel display unit that displays information.

  For example, the image forming apparatus 10 is a printer, a copying machine, or a multifunction peripheral having a copying function and a facsimile communication device function. The image forming apparatus 10 further includes the image reading device 2. The image reading device 2 executes a document reading process for reading an image from a document.

  The image reading device 2 is connected to an upper portion of the main housing 1, and the relay unit 6 is mounted on the main housing 1 in a space between the main housing 1 and the image reading device 2. The post-processing device 5 is connected to side portions of the main housing 1 and the relay unit 6.

[Main housing 1]
As shown in FIG. 2, the main housing 1 is a housing including the sheet storage unit 100, the main transport mechanism 3, and the image forming unit 4. The main housing 1 and the devices included in the main housing 1 constitute a main body of the image forming apparatus 1. A main transport path 30 communicating with the sheet storage unit 100 is formed in the main housing 1.

  The sheet storage section 100 stores a plurality of sheets 9. In the example illustrated in FIG. 2, the image forming apparatus 10 includes a plurality of sheet storage units 100. The sheet 9 is a sheet-like image forming medium such as paper or a resin film.

  The main transport mechanism 3 sends out the sheet 9 from the sheet storage unit 100 to the main transport path 30, and further transports the sheet 9 along the main transport path 30. In the main transport mechanism 3, a plurality of pairs of main transport rollers 31 that rotate while sandwiching the sheet 9 transport the sheet 9.

  The main transport mechanism 3 includes a plurality of main transport roller pairs 31, a plurality of main transport motors 1M, and a main transport gear mechanism (not shown) (see FIG. 2). The main transport motor 1M is a drive source for rotating the plurality of main transport roller pairs 31. The main transfer gear mechanism transmits the rotational force of the plurality of main transfer motors 1M to a plurality of pairs of main transfer rollers 31.

  Further, the plurality of pairs of main transport rollers 31 include a pair of registration rollers 31 a for temporarily stopping the transport of the sheet 9 and controlling the timing of sending the sheet 9 to the image forming unit 4. The main transport motor 1M includes a registration motor 2M that drives the registration roller pair 31a.

  The image forming unit 4 executes a printing process for forming an image based on print target data on the sheet 9 conveyed by the main conveyance mechanism 3. The print target data is data including information on an output image.

  In the example shown in FIG. 1, the image forming unit 4 executes the print processing by an electrophotographic method. Therefore, the image forming unit 4 includes an image forming device 40, a transfer device 44, and a fixing device 45.

  In the image forming device 40, the charging device 42 charges the surface of the drum-shaped photoconductor 41, the optical scanning unit 46 writes an electrostatic latent image on the charged surface of the photoconductor 41, and the developing device 43 The electrostatic latent image on the body 41 is developed into the toner image. The photoconductor 41 is an example of an image carrier.

  The transfer device 44 transfers the toner image on the surface of the photoconductor 41 to the sheet 9 conveyed along the main conveyance path 30. The fixing device 45 fixes the toner image on the sheet 9 by heating the toner image on the sheet 9 while applying pressure.

  The image forming unit 4 shown in FIG. 2 can execute the printing process of a color image in a tandem system. Therefore, the image forming unit 4 includes four image forming devices 40 corresponding to toners of different colors.

  The transfer device 44 transfers the toner images of the four colors from the surfaces of the four photoconductors 41 onto the sheet 9 in a superimposed manner.

  The main conveyance path 30 includes a former main conveyance path 301 from the exit of the sheet storage unit 100 to the image forming unit 4 and a latter main conveyance path 302 after the fixing device 45. The latter main conveyance path 302 is a conveyance path from the outlet of the fixing device 45 to the first main body discharge port 302p and the second main body discharge port 302q.

  The first main body discharge port 302p and the second main body discharge port 302q are discharge ports of the sheet 9 in the main housing 1. The rear main transport path 302 includes a first rear main transport path 302a that branches to a first main body outlet 302p, and a second rear main transport path 302b that branches to a second main body outlet 302q.

  Further, a main body course switching mechanism 32 and a reversing switching mechanism 33 are provided in the main housing 1. The main body path switching mechanism 32 selectively guides the sheet 9 conveyed from the fixing device 45 to one of a first rear main conveyance path 302a and a second rear main conveyance path 302b that are branched into two in the latter main conveyance path 302. I do.

  The main body course switching mechanism 32 includes a movable guide member 321 and an actuator 322 for displacing the movable guide member 321. The actuator 322 displaces the movable guide member 321 to a position where the sheet 9 is guided to one of the first rear-stage main transport path 302a and the second rear-stage main transport path 302b according to a control signal from the control device 8. For example, the actuator 322 may be a solenoid.

  The plurality of pairs of main transport rollers 31 also include a pair of reverse transport rollers 31b disposed at the second main body discharge port 302q. The second rear-stage main transport path 302b is a transport path that guides the sheet 9 from the main body path switching mechanism 32 to the pair of reverse transport rollers 31b.

  The reverse transport roller pair 31b discharges the sheet 9 from the second main body discharge port 302q by rotating in a predetermined forward direction, and reverses the sheet 9 by rotating in a direction opposite to the forward direction, The sheet is transported to the reverse transport path 303.

  The reverse transport path 303 is a transport path that branches off from the second rear-stage main transport path 302b and joins the front-stage main transport path 301.

  The reversing switching mechanism 33 guides the sheet 9 conveyed from the fixing device 45 to the reversing conveyance roller pair 31b, and guides the sheet 9 conveyed from the reversing reversing conveyance roller pair 31b to the reversing conveyance path 303. And a mechanism that switches between two states. The reversing switching mechanism 33 also has the same configuration as the main body course switching mechanism 32.

  When the double-sided printing process is performed, the reverse conveyance roller pair 31b conveys the sheet 9 on which the image is formed on the first surface to the reverse conveyance path 303 by rotating in the reverse direction. As a result, the printing process on the second surface of the sheet 9 is performed.

  The image forming section 4 further includes a charging bias applying device 42a, a developing bias applying device 43a, and a transfer bias applying device 44a.

  The charging bias application device 42a includes a circuit that applies a charging bias to the charging device 42. The developing bias applying device 43a includes a circuit that applies a developing bias to the developing device 43. The transfer bias applying device 44a includes a circuit that applies a transfer bias to the transfer device 44.

  It is also conceivable that the image forming unit 4 is an apparatus that executes the print processing by a method other than the electrophotographic method, such as an inkjet method.

[Relay unit 6]
The relay unit 6 is disposed between the main housing 1 and the post-processing device 5, and conveys the image-formed sheet 9 discharged from the main housing 1 to the post-processing device 5. The relay unit 6 is an example of a relay transport device.

  The relay unit 6 includes a relay transport path 60 through which the sheet 9 after image formation is transported. The relay conveyance path 60 is a conveyance path between the first rear main conveyance path 302a in the main housing 1 and the post-processing conveyance path 50 in the post-processing device 5 shown in FIG.

  The relay conveyance path 60 is a conveyance path from the relay conveyance port 60p, which is the conveyance port of the sheet 9 in the relay unit 6, to the relay discharge port 60q, which is the same discharge port. The relay unit 6 is attached to the main housing 1 with the relay entrance 60p facing the first main body outlet 302p of the main housing 1.

  Note that the first rear-stage main conveyance path 302a, the second rear-stage main conveyance path 302b, the relay conveyance path 60, and the post-processing conveyance path 50 are a part of the conveyance path of the sheet 9 of the entire image forming apparatus 10 that is a rear part of the image forming unit 4. FIG.

  The first rear main conveyance path 302a is an example of a first upstream rear conveyance path in the main housing 1 located on the upstream side in the conveyance direction of the sheet 9 in the rear conveyance path. Further, the second downstream main transport path 302b is an example of a second upstream rear transport path that branches off from the first upstream rear transport path in the main housing 1 in the rear transport path.

  Further, the relay unit 6 has an intermediate discharge tray 600. The intermediate discharge tray 600 is a portion that receives the sheet 9 discharged from the second rear-stage main transport path 302b. When there is no need to send the sheet 9 to the post-processing device 5, the sheet 9 guided to the second rear-stage main transport path 302b by the main body path switching mechanism 32 is discharged onto the intermediate discharge tray 600.

  On the other hand, the sheet 9 guided to the first rear main transport path 302a by the main body path switching mechanism 32 is carried into the relay transport path 60 from the relay entrance 60p.

  The relay unit 6 includes a relay transport mechanism 6C that transports the sheet 9 along the relay transport path 60 (see FIG. 2). The relay transport mechanism 6C includes a plurality of relay transport roller pairs 61, a relay transport motor 6M, and a relay transport gear mechanism (not shown).

  The plurality of relay conveyance roller pairs 61 convey the sheet 9 by rotating with the sheet 9 interposed therebetween. The relay conveyance motor 6M is a driving source that rotationally drives a plurality of pairs of the relay conveyance rollers 61. The relay conveyance gear transmits the rotational force of the relay conveyance motor 6M to a plurality of pairs of relay conveyance rollers 61.

[Post-processing device 5]
As shown in FIG. 3, the post-processing device 5 includes a post-processing transport path 50 through which the sheet 9 that has passed through the relay transport path 60 of the relay unit 6 is transported. The post-processing conveyance path 50 is branched into a plurality on the way.

  The post-processing conveyance path 50 is connected to the first post-processing discharge port 50q, the second post-processing discharge port 50r, and the third post-processing from the post-processing conveyance port 50p, which is the conveyance port of the sheet 9 in the post-processing device 5, to the discharge port. This is a transport path leading to the discharge port 50s.

  The post-processing device 5 includes a post-processing transport mechanism 5C that transports the sheet 9 along the post-processing transport path 50 (see FIG. 3). The post-processing transport mechanism 5C includes a plurality of post-processing transport roller pairs 51, a post-processing transport motor 5M, and a post-processing transport gear mechanism (not shown).

  The plurality of post-processing conveyance roller pairs 51 convey the sheet 9 by rotating with the sheet 9 interposed therebetween. The post-processing transport motor 5M is a drive source that rotationally drives a plurality of pairs of the post-processing transport rollers 51. The post-processing conveyance gear transmits the rotational force of the post-processing conveyance motor 5M to a plurality of pairs of post-processing conveyance rollers 51.

  The post-processing conveyance path 50 also includes stock trays 54a and 55a for temporarily stocking a plurality of overlapping sheets 9. The main transport mechanism 3, the relay transport mechanism 6C, and the post-processing transport mechanism 5C constitute a sheet transport mechanism that transports the sheet 9 along the transport path.

  The post-processing device 5 also includes a plurality of post-processing path switching mechanisms 52 arranged at a plurality of branch positions of the post-processing transport path 50. The post-processing path switching mechanism 52 includes, similarly to the main body path switching mechanism 32, a movable guide member 521 and an actuator 522 that displaces the movable guide member 521. The actuator 522 displaces the movable guide member 521 to a position for guiding the sheet 9 to one of a plurality of branch destinations according to a control signal from the control device 8.

  The post-processing device 5 performs post-processing on the sheet 9 after image formation. For example, the post-processing apparatus 5 performs one or both of the processing of the sheet 9 and the alignment of the sheet 9 in the post-processing conveyance path 50.

  In the example shown in FIG. 3, the post-processing device 5 includes a punching device 53, an alignment device 54, and a sheet folding device 55. The punching device 53 performs a hole punching process on the sheet 9. The aligning device 54 performs an aligning process in which the plurality of sheets 9 are overlapped and aligned, and the aligned plurality of sheets 9 are stapled. The sheet folding device 55 performs a folding process for forming a fold on one sheet 9 or a plurality of stacked sheets 9.

  Note that the sheet folding device 55 also includes a stapling device (not shown). The stapling apparatus staples a plurality of sheets 9 to be folded.

  Further, the post-processing device 5 includes a first stacking tray 501, a second stacking tray 502, and a third stacking tray 503. For example, when a job with a small number of prints is executed, the sheet 9 is ejected to the first stacking tray 501 and a job with a large number of prints is executed, or when the alignment processing of the sheet 9 is executed. The sheet 9 is discharged to the second stacking tray 501.

  The sheets 9 that have not been subjected to the alignment processing or the folding processing are discharged one by one from the post-processing conveyance path 50 onto the first stacking tray 501 through the first post-processing discharge port 50q. For example, the sheet 9 subjected to only the perforation processing is discharged onto the first stacking tray 501.

  The plurality of sheets 9 subjected to the alignment processing are discharged from the post-processing conveyance path 50 onto the second stacking tray 502 through the second post-processing discharge port 50r. In addition, one or a plurality of the folded sheets 9 are discharged onto the third stacking tray 503 through the third post-processing discharge port 50s.

[Control device 8]
The control device 8 executes various data processing related to the print processing and the like, and further controls various electric devices.

  As shown in FIG. 4, the control device 8 includes a CPU (Central Processing Unit) 80, a RAM (Random Access Memory) 81, a secondary storage device 82, and the like.

  The CPU 80 operates as a main control unit 80a, a job control unit 80b, an image data processing unit 80c, a course control unit 80d, and the like by executing the program.

  The main control unit 80a executes a job selection process, a setting process of various data, and the like according to an operation on the operation device 8a.

  The job control unit 80b executes various data processing and control relating to various jobs such as the job of the document reading process, the job of the printing process, and the job of the copying process. The copying process includes the document reading process and the printing process based on an image obtained by the document reading process.

  For example, the job control unit 80b causes the image forming unit 4 to execute the print processing. The image data processing unit 80c performs various image processing such as processing and data conversion on the print target data obtained through the image reading device 2 or a communication device (not shown).

  The course control unit 80d controls the main body course switching mechanism 32 according to the content of the job to be executed. Thus, the destination of the sheet 9 after image formation is controlled according to the content of the job.

  The secondary storage device 82 is a computer-readable non-volatile storage device. The secondary storage device 82 stores a program executed by the CPU 80 and various data referred to by the CPU 80. For example, one or both of a flash memory and a hard disk drive are employed as the secondary storage device 82.

  The RAM 81 is a computer-readable volatile storage device. The RAM 81 temporarily stores a program to be executed by the CPU 80 and data to be output and referred to in a process in which the CPU 80 executes the program.

  The CPU 80 also operates as the parameter adjusting unit 80e by executing a program stored in the secondary storage device 82 in advance. The parameter adjusting unit 80e executes a parameter adjusting process including a process of adjusting the parameters of the printing process.

  For example, the parameter adjustment unit 80e adjusts parameters such as the charging bias, the developing bias, the transfer bias, or the timing at which the optical scanning unit 46 starts writing the electrostatic latent image.

  Meanwhile, the conventional image forming apparatus develops a predetermined test image in the parameter adjustment process, detects the density of the test image with a density sensor, and adjusts the parameters of the print process based on the detected density. .

  In addition, when the repetitive print processing based on the same print target data is performed, in order to prevent a change in the image quality of the print image, it is necessary to adjust the parameters during the repetitive print processing.

  If the test image is developed during the repetitive print processing, the repetitive print processing is interrupted for a relatively long time during the repetitive print processing, thereby deteriorating the processing efficiency.

[Details of relay unit 6]
The image forming apparatus 10 includes a CIS (contact image sensor) 63 and a color reference member 64 arranged in a relay conveyance path 60 at a subsequent stage of the image forming unit 4 (see FIG. 2).

  The CIS 63 and the color reference member 64 are formed to extend in a width direction orthogonal to the sheet 9 in the conveyance direction. In FIG. 2, the width direction is a depth direction toward the paper surface. The CIS 63 is a line image sensor that continuously reads an image of one line in the width direction on the sheet 9. The CIS 63 is an example of an image sensor that reads a two-dimensional image formed on the sheet 9.

  The color reference member 64 is disposed to face the CIS 63 with a gap through which the sheet 9 passes. The color of the surface of the color reference member 64 facing the CIS 63 is a predetermined reference color such as white or light yellow. In the present embodiment, the color reference member 64 is a roller-shaped member that rotates in contact with the sheet 9, and the color of the entire outer peripheral surface of the color reference member 64 is the reference color.

  In the present embodiment, the CPU 80 operates as the image sensor adjustment unit 80f by executing a program stored in the secondary storage device 82 in advance. The image sensor adjustment unit 80f executes the image sensor adjustment processing when the print processing is not performed.

  In the image sensor adjustment processing, the image sensor adjustment unit 80f causes the CIS 63 to read the surface of the reference color on the color reference member 64. Further, the image sensor adjustment unit 80f adjusts the CIS 63 such as shading correction in accordance with the difference between the density of each pixel of the image read from the color reference member 64 and a predetermined reference density.

  On the other hand, the parameter adjustment unit 80e executes the parameter adjustment processing based on the image read by the CIS 63 when the print processing is performed. Thereby, the image forming apparatus 10 can efficiently adjust the parameters of the print processing.

  As shown in FIG. 2, the relay transport path 60 includes a first relay transport path 601 and a second relay transport path 602 that are branched into two in the relay unit 6. The second relay transport path 602 branches off from the first relay transport path 601 at a branch position 601a, and joins the first relay transport path 601 at a junction position 601b.

  Further, a relay route switching mechanism 62 is provided in the relay unit 6. The relay route switching mechanism 62 is controlled by the route control unit 80d.

  The relay path switching mechanism 62 selectively guides the sheet 9 transported from the main housing 1 into the relay unit 6 to one of the first relay transport path 601 and the second relay transport path 602. The first relay conveyance path 601 and the second relay conveyance path 602 are examples of a first rear conveyance path and a second rear conveyance path, respectively.

  The relay route switching mechanism 62 includes a movable guide member 621 and an actuator 622 for displacing the movable guide member 621, similarly to the main body route switching mechanism 32. The actuator 322 displaces the movable guide member 621 to a position for guiding the sheet 9 to one of the first relay conveyance path 601 and the second relay conveyance path 602 according to a control signal from the path control unit 80d.

  The CIS 63 is arranged in the second relay conveyance path 602, and reads an image from the sheet 9 conveyed along the second relay conveyance path 602. In the following description, when the print processing is performed on a plurality of sheets 9, reading of an image from some of the sheets 9 by the CIS 63 is referred to as sampling reading. A read image obtained by the sampling read by the CIS 63 is referred to as a sample image.

  In the parameter adjustment process, the parameter adjustment unit 80e compares the first sample image and the second sample image obtained by the sampling reading by the CIS 63, and adjusts the parameters of the print process based on the comparison result.

  The first sample image and the second sample image are images obtained by the sampling reading by the CIS 63 when the image forming unit 40 performs a repetitive print process of repeatedly forming the same image on the plurality of sheets 9. is there. The parameter adjusting unit 80e specifies image quality information of each of the first sample image and the second sample image.

  For example, the image quality information includes one or more of an average density and a maximum density of each toner color, a positional relationship between a plurality of toner colors, and a color of an image. The parameter adjustment unit 80e sets the image quality information of the first sample image as target image quality information.

  Further, the parameter adjusting unit 80e adjusts the parameters of the print processing in a direction in which target image quality information, which is the image quality information of the second sample image, approaches the target image quality information.

  The parameter adjustment process in the present embodiment is a process of comparing the target image quality information with the target image quality information and determining whether a difference between the target image quality information and the target image quality information exceeds a predetermined allowable range. And adjusting the parameters of the printing process when it is determined that the difference between the target image quality information and the target image quality information exceeds the allowable range.

  In the parameter adjustment process, the parameter adjustment unit 80e adjusts parameters of the subsequent print process in the repetitive print process. That is, the parameter adjustment unit 80e adjusts the parameters of the printing process during the repeated printing process. However, when it is determined that the difference between the target image quality information and the target image quality information does not exceed the allowable range, the process of adjusting the parameter is skipped.

  For example, the parameter adjusting unit 80e corrects the frequency or amplitude of the AC component in the charging bias according to the difference between the average density of the target image quality information and the target image quality information. For example, when the average density of the target image quality information is lower than the average density of the target image quality information, the frequency or amplitude of the AC component in the charging bias is corrected in the increasing direction.

  Further, the parameter adjusting unit 80e corrects the frequency or amplitude of the AC component in the developing bias according to the difference between the maximum density of the target image quality information and the target image quality information. For example, when the maximum density of the target image quality information is lower than the maximum density of the target image quality information, the frequency or amplitude of the AC component in the developing bias is corrected in an increasing direction.

  Further, the parameter adjusting unit 80e is configured to control the electrostatic latent image corresponding to the plurality of toner colors by the optical scanning unit 46 in accordance with the positional relationship between the images of the plurality of toner colors in the target image quality information and the target image quality information. The image writing start timing is corrected.

  More specifically, when the image forming unit 4 executes a repetitive print process of repeatedly executing the print process on a plurality of sheets 9 based on the same print target data, The parameter adjustment processing is performed.

  When the print processing of the first predetermined number of sheets is performed in the repetitive print processing, the parameter adjusting unit 80e acquires the first sample image from the CIS 63.

  The first number is the number of sheets from the top of the sheet 9 to be sampled of the first sampled image among the plurality of sheets 9 after image formation that are sequentially conveyed in the repetitive print processing. Is a numerical value that specifies

  For example, it is conceivable that the first sheet is the first sheet in the repetitive printing process or a predetermined first plurality of sheets. When the first number is the first plurality, information representing the average of the image quality information of the plurality of first sample images obtained from the first plurality of sheets 9 is set as the target image quality information. Can be considered.

  Thereafter, each time a predetermined second number of the printing processes are performed in the repetitive printing process, the parameter adjustment unit 80e acquires the second sample image, and further obtains the second sample image based on the acquired second sample image. Execute parameter adjustment processing. In the parameter adjustment processing, the parameter adjustment unit 80e adjusts parameters of the subsequent print processing in the repetitive print processing.

  In the parameter adjustment process, if the difference between the target image quality information based on the first sampled image and the target image quality information based on the second sample image does not exceed the allowable range, the parameter adjustment is performed. Skipped.

  The second number is a numerical value that specifies a sampling interval of the second sampling image based on the number of prints in the repetitive print processing. The timing at which the print processing of the first sheet is performed is an example of a first timing. Further, each time the second number of print processing is performed after the first number of print processing is performed is an example of a second time.

  When one of the second sample images read from one sheet 9 is used for the parameter adjustment processing, the target image quality information is the image quality information of one of the second sample images.

  On the other hand, when the plurality of second sample images read from the plurality of sheets 9 are used for the parameter adjustment processing, the target image quality information is information representing an average of the image quality information of the plurality of second sample images. It is.

  The image forming apparatus 10 can execute the parameter adjustment processing while executing the print processing. Therefore, the parameters of the print processing can be adjusted efficiently. Further, in the repetitive printing process, it is possible to prevent a change in image quality of a print image.

  In the present embodiment, the course control unit 80d guides the sheet 9 to the second relay conveyance path 602 when the CIS 63 performs the sampling reading when the print processing is performed. Control to a state where

  On the other hand, when the printing process is executed, the route control unit 80d controls the relay route switching mechanism 62 to guide the sheet 9 to the first relay transport path 601 when the CIS 63 does not perform the sampling reading. To control.

  Therefore, the frequency at which the surface of the CIS 63 contacts the sheet 9 decreases. As a result, it is possible to reduce the possibility that erroneous parameter adjustment processing is performed due to contamination of the surface of the CIS 63.

  In the present embodiment, the CPU 80 operates as the transport control unit 80g by executing a program stored in the secondary storage device 82 in advance.

  In the following description, the sheet 9 to be subjected to the sampling reading by the CIS 63 is referred to as a sample sheet. Further, the sheet 9 not subjected to the sampling reading by the CIS 63 is referred to as a normal sheet.

  When the print processing is performed, the transport control unit 80g sets the transport speed of the sheet 9 by the relay transport mechanism 6C to be greater than when the sampling reading is performed by the CIS 63 when the CIS 63 performs the sampling reading. Also control to slow speed.

  That is, the transport control unit 80g controls the transport speed of the sample sheet by the relay transport mechanism 6C to a speed lower than the transport speed of the normal sheet by the relay transport mechanism 6C. The transport control unit 80g controls the transport speed of the sheet 9 in the relay transport path 60 by controlling the relay transport motor 6M.

  In the present embodiment, the case where the sampling reading is performed by the CIS 63 is a case where the sheet 9 is guided to the second relay conveyance path 602. The case where the sampling reading by the CIS 63 is not performed is a case where the sheet 9 is guided to the first relay conveyance path 601.

  Further, the conveyance control unit 80g controls the distance between the sample sheet and the normal sheet to be kept constant. Specifically, the conveyance control unit 80g determines a time interval between the time when the sample sheet is sent to the image forming unit 4 and the time when the next normal sheet is sent to the image forming unit 4, and the time when the normal sheet is sent to the image forming unit 4. The main transport mechanism 3 is controlled so as to be longer than the time interval from when the sheet is sent to the next sample sheet or the next normal sheet to the image forming unit 4.

  By controlling the time interval, it is possible to prevent the time required for the repetitive printing process, that is, the print productivity, from being significantly reduced due to the restriction on the image reading speed by the CIS 63. Further, the conditions of the printing process need not be changed regardless of whether the sheet 9 is the sample sheet.

  The conveyance control unit 80g controls the conveyance timing of the sheet 9 to the image forming unit 4 by controlling the registration motor 2M.

  In addition, the image forming apparatus 10 including the post-processing device 5 often executes the repetitive print processing with a large number of sheets. Further, in the repetitive print processing with a large number of sheets, a change in the image quality of a print image is likely to occur. Therefore, in the course of the repetitive print processing, the parameter adjustment processing based on the sampling image is performed, and the parameters of the subsequent print processing are adjusted as necessary. As a result, it is possible to effectively prevent a change in the image quality of the print image in the repetitive print processing with a large number of sheets.

[Second embodiment]
Next, an image forming apparatus 10A according to a second embodiment will be described with reference to FIGS. 5 to 7, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals.

  Hereinafter, differences between the image forming apparatus 10A and the image forming apparatus 10 will be described. The image forming apparatus 10A has a configuration in which the second relay conveyance path 602 and the relay path switching mechanism 62 of the relay unit 6 in the image forming apparatus 10 are replaced with a variable support mechanism 65.

  In the present embodiment, the CIS 63 is arranged on the relay conveyance path 60 and reads an image from the sheet 9 conveyed along the relay conveyance path 60.

  Further, in image forming apparatus 10A, CPU 80 operates as support position control unit 80h by executing a program stored in secondary storage device 82 in advance (see FIG. 7).

  The variable support mechanism 65 supports the CIS 63 so as to be displaceable between a reference position close to the relay conveyance path 60 and a retreat position separated from the relay conveyance path 60. FIG. 5 shows a state where the CIS 63 is located at the reference position, and FIG. 6 shows a state where the CIS 63 is located at the retracted position.

  The CIS 63 can contact the sheet 9 at the reference position, but does not contact the sheet 9 at the retracted position.

  The variable support mechanism 65 includes a sensor support mechanism 651 and a sensor displacement actuator 652. The sensor support mechanism 651 supports the CIS 63 movably. The sensor displacement actuator 652 drives the sensor support mechanism 651.

  The support position control unit 80h outputs a control signal to the sensor displacement actuator 652 to hold the variable support mechanism 65 in one of the reference state and the retracted state.

  The reference state is a state in which the sensor support mechanism 651 holds the CIS 63 at the reference position by the action of the sensor displacement actuator 652. The retracted state is a state in which the sensor support mechanism 651 holds the CIS 63 at the retracted position by the action of the sensor displacement actuator 652.

  For example, the sensor support mechanism 651 includes a cam mechanism that reciprocates the CIS 63 and a link mechanism that connects the cam mechanism and the sensor displacement actuator 652.

  In the present embodiment, the variable support mechanism 65 also includes a color reference member support mechanism 653 that works in conjunction with the sensor support mechanism 651. Therefore, the sensor displacement actuator 652 also serves as an actuator for driving the color reference member support mechanism 653.

  When the variable support mechanism 65 is in the reference state, the color reference member support mechanism 653 holds the color reference member 64 at the opposed reference position close to the relay conveyance path 60, and the variable support mechanism 65 is in the retracted state. At this time, the color reference member 64 is held at the opposed retreat position separated from the relay conveyance path 60.

  In the present embodiment, the support position control unit 80h controls the variable support mechanism 65 to the reference state when the CIS 63 performs the sampling reading when the print processing is executed.

  On the other hand, the support position controller 80h controls the variable support mechanism 65 to the retracted state when the CIS 63 does not perform the sampling reading when the print processing is executed.

  Therefore, the frequency at which the surface of the CIS 63 and the surface of the color reference member 64 contact the sheet 9 is reduced. As a result, it is possible to reduce the possibility that erroneous parameter adjustment processing is performed due to contamination of the surface of the CIS 63. Further, the possibility that the CIS 63 is adjusted to an inappropriate state due to the dirt on the surface of the color reference member 64 can be reduced.

[Application example]
In the image forming apparatus 10 or the image forming apparatus 10A, the CIS 63 may be provided in the post-processing conveyance path 50 in the post-processing apparatus 5. For example, when the post-processing device 5 is directly connected to the main housing 1 without requiring the relay unit 6, the CIS 63 may be provided in the post-processing transport path 50.

  In the image forming apparatus 10A, an actuator for driving the color reference member support mechanism 653 may be provided separately from the sensor displacement actuator 652.

1: Main housing 1M: Main transport motor 2M: Registration motor 2: Image reading device 3: Main transport mechanism 4: Image forming unit 5: Post-processing device 5C: Post-processing transport mechanism 5M: Post-processing transport motor 6: Relay unit 6C: relay transport mechanism 6M: relay transport motor 8: control device 8a: operating device 8b: display device 9: sheet 10: image forming device 10A: image forming device 30: main transport path 31: main transport roller pair 31a: registration roller Pair 32: body path switching mechanism 40: image forming device 41: photoconductor 42: charging device 42a: charging bias applying device 43: developing device 43a: developing bias applying device 44: transfer device 44a: transfer bias applying device 45: fixing device 46: optical scanning unit 50: post-processing conveyance path 50p: post-processing carry-in port 50q: first post-processing discharge port 50r: second Processing outlet 50s: third aftertreatment outlet 51: postprocessing transport roller pair 52: post-processing path switching mechanism 53: punching device 54: aligning device 55: sheet folding apparatus 60: a relay transport path (subsequent conveyance path)
60p: relay entrance 60q: relay outlet 61: relay transport roller pair 62: relay path switching mechanism 64: color reference member 65: variable support mechanism 80: CPU
80a: Main control unit 80b: Job control unit 80c: Image data processing unit 80d: Path control unit 80e: Parameter adjustment unit 80f: Image sensor adjustment unit 80g: Transport control unit 80h: Support position control unit 81: RAM
82: secondary storage device 100: sheet storage section 301: front main transport path 302: rear main transport path 302a: first rear main transport path 302b: second rear main transport path 302p: first main body discharge port 302q: second Main body discharge port 321: movable guide member 322: actuator 501: first loading tray 502: second loading tray 503: third loading tray 521: movable guide member 522: actuator 600: intermediate discharge tray 601: first relay conveyance path 601 a : Branch position 601b: Merging position 602: Second relay conveyance path 621: Movable guide member 622: Actuator 651: Sensor support mechanism 652: Sensor displacement actuator 653: Color reference member support mechanism

Claims (7)

An image forming unit that performs a print process of forming an image based on print target data on a sheet conveyed along the conveyance path,
An image sensor that is arranged in a subsequent conveyance path after the image forming unit in the conveyance path and reads an image from the sheet on which the image is formed,
A first sample image obtained by sampling and reading by the image sensor at a first time when a repetitive printing process for repeatedly forming the same image on a plurality of sheets is performed by the image forming unit; Comparing the second sample image obtained by the sampling reading with the image sensor at a second timing after the timing of the above, and adjusting the remaining parameters of the printing process in the repetitive printing process according to the comparison result. An image forming apparatus comprising: a parameter adjustment unit that executes a parameter adjustment process.   The parameter adjuster acquires the first sample image when the print processing of the first predetermined number of sheets is performed, when the repetitive print processing is performed, and thereafter, sets the predetermined first sample image. The image forming apparatus according to claim 1, wherein each time two print processes are performed, the process of acquiring the second sample image and the parameter adjustment process based on the acquired second sample image are performed. Path switching for selectively guiding the sheet to one of the first and second post-conveying paths when the post-conveying path includes a first post-conveying path and a second post-conveying path branched into two. Mechanism and
A path control unit that controls the path switching mechanism,
The image sensor is provided in the second rear-stage transport path,
The path control unit controls the path switching mechanism to a state in which the sheet is guided to the second rear conveyance path when the sampling reading is performed when the repetitive print processing is performed, and in other cases, 3. The image forming apparatus according to claim 2, wherein the path switching mechanism is controlled to guide the sheet to the first rear conveyance path. A variable support mechanism that displaceably supports the image sensor between a reference position close to the rear conveyance path and a retracted position separated from the rear conveyance path,
A support position control unit that controls the variable support mechanism,
The support position control unit controls the variable support mechanism to support the image sensor at the reference position when the sampling reading is performed when the print processing is executed, and in other cases, the control unit controls the variable support mechanism. The image forming apparatus according to claim 2, wherein the variable support mechanism is controlled to support the image sensor at the retracted position.   When the print processing is performed, the image processing apparatus further includes a conveyance control unit that controls a conveyance speed of the sheet by a sheet conveyance mechanism to a speed lower than other cases when the sampling reading is performed by the image sensor. The image forming apparatus according to claim 2. A post-processing device that performs post-processing on the sheet on which the image is formed,
A relay transport device that is disposed between the main housing including the image forming unit and the post-processing device, and that transports the sheet discharged from the main housing to the post-processing device,
The image forming apparatus according to claim 1, wherein the image sensor is provided on the relay conveyance path in the rear conveyance path. The image forming unit,
A developing device for developing the toner image on the image carrier,
A transfer device for transferring the toner image on the image carrier to the sheet,
The image forming apparatus according to claim 1, further comprising: a fixing device that heats the toner image on the sheet while applying pressure.

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