JP6673152B2 - Image reading apparatus and image forming system - Google Patents

Description

  The present invention relates to an image reading device and an image forming system.

2. Description of the Related Art Conventionally, image forming apparatuses such as copiers and printers use an image on paper after image formation in order to adjust the color, position, magnification, etc. of the image and to check whether the image is appropriate. An image reading device that reads an image is used. The image reading apparatus is arranged downstream of the image forming apparatus main body, and a scanner for reading an image formed on one side or both sides of a sheet is provided in a sheet transport path. Information read by the image reading device is fed back to the image forming device.
Further, in order to correct the color information read by the scanner to correct color information, a colorimeter capable of measuring color information with high accuracy is provided in the paper transport path.

In an image forming apparatus that forms an image on both sides of a sheet, before outputting an image to be printed, the image on the both sides of the sheet formed by the image forming apparatus is read by a scanner, and the read image information is fed back to the image forming apparatus. To align the front and back images.
Positioning of the front and back images is performed using the distance between the registration mark of the front and back images read by the scanner and the edge of the sheet. The both sides of the sheet are read by a scanner, the positions of the registration marks on the front and back sides are detected from the read image, and these positions are corrected so as to be set at predetermined positions from the edge of the sheet, thereby aligning the image positions.

  Also, in an image reading apparatus that reads an original while transporting the original, the image reading device is designed to solve the problem of image expansion and contraction that can occur in the separate paper feed mode, the non-separable paper feed mode, the U-turn path discharge, and the straight path discharge. In order to change the image reading conditions of a document in accordance with the selected transport mode, a method has been proposed (see Patent Document 1).

JP 2012-182662 A

  However, not only the difference in the paper transport speed depending on the transport mode, but also when the paper is transported along the transport path, a shock is applied to the leading or trailing edge of the paper, and the transport rollers that pinch the paper and the paper vibrate. Then, a speed fluctuation occurs in the sheet conveyance. A reading position shift in the sheet conveyance direction occurs due to a change in the speed of sheet conveyance during image reading. If the position of the register mark actually formed on the paper is misaligned with the position of the register mark read by the scanner, an accurate reading result cannot be obtained, and the image registration is correctly performed in the image forming apparatus main body. There was a problem that you can not.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the related art, and has as its object to accurately grasp the position of a register mark formed on a sheet.

In order to solve the above-mentioned problems, the invention according to claim 1 includes a conveying unit that conveys a sheet on which an image is formed by an image forming apparatus, an image reading unit that reads an image formed on a sheet, Storage means for storing a speed fluctuation profile indicating a characteristic of speed fluctuation at each position along the paper transport direction, which occurs while the sheet passes through the reading area of the image reading means, and a registration mark formed by the image forming apparatus. For the formed sheet, based on the speed variation profile stored in the storage unit, while controlling the transport unit to cancel the speed variation at each of the positions indicated by the speed variation profile, A control unit for causing the image reading unit to read the formed register mark and obtaining a formation position of the register mark. It is.

According to a second aspect of the invention, conveying means for conveying the sheet on which the image is formed by the image forming apparatus, an image reading means for reading an image formed on the sheet, one sheet reading said image reading means Storage means for storing a speed fluctuation profile showing the characteristics of speed fluctuation at each position along the paper conveyance direction generated while passing through the area, and conveying the paper on which the register mark has been formed by the image forming apparatus; while conveying by means of register marks formed on the paper to read the image reading means, based on the characteristics of the speed variation in each of positions indicated by the speed fluctuation profile stored in the storage means, the image Control means for calculating a registration mark formation position from a registration mark reading position obtained by the reading means.

  According to a third aspect of the present invention, in the image reading apparatus according to the first or second aspect, the speed variation profile is stored in the storage unit for each combination of a paper type and a paper transport speed.

  According to a fourth aspect of the present invention, in the image reading apparatus according to the third aspect, the paper type is classified by basis weight, rigidity, thickness, size, or a combination thereof.

  According to a fifth aspect of the present invention, in the image reading apparatus according to any one of the first to fourth aspects, the control unit is configured such that the image forming apparatus arranges a plurality of straight lines at equal intervals in a sheet conveying direction. While the sheet on which the formed image is formed is conveyed by the conveying unit, the image formed on the sheet is read by the image reading unit, and based on a plurality of straight line reading results obtained by the image reading unit. To calculate a speed fluctuation profile, and store the calculated speed fluctuation profile in the storage means.

  According to a sixth aspect of the present invention, there is provided the image reading apparatus according to any one of the first to fifth aspects, wherein the image reading apparatus is connected via a communication network to another image reading apparatus of the same model as the own apparatus. And a communication unit for transmitting and receiving data by the control unit, and the control unit causes the speed fluctuation profile to be shared with the another image reading apparatus via the communication unit.

  According to a seventh aspect of the present invention, there is provided an image forming system including the image reading apparatus according to any one of the first to sixth aspects and the image forming apparatus, wherein the image forming apparatus includes the registration mark. A correction unit that adjusts a position of an image formed by the image forming apparatus based on a mark forming position;

  ADVANTAGE OF THE INVENTION According to this invention, the position of the register mark formed on the paper can be accurately grasped.

FIG. 1 is a schematic configuration diagram of an image forming system according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a functional configuration of the image forming system. (A) is an example of a speed fluctuation profile. (B) is an example of the conveyance speed control at the time of image reading. (C) is a result of performing the transport speed control shown in (b) on the transport during image reading having the speed variation characteristic shown in (a). It is an example of a chart image. FIG. 5A is a diagram illustrating an example in which register marks are formed at four corners of a sheet. (B) is an enlarged view of the area where the register mark is formed. 9 is a flowchart illustrating a first image alignment process. FIG. 11 is a diagram illustrating a correspondence between an image forming position and a reading position according to the second embodiment of the present invention. 9 is a flowchart illustrating a second image alignment process. FIG. 13 is a configuration diagram of an information sharing system according to a third embodiment of the present invention.

[First Embodiment]
First, an image reading apparatus and an image forming system according to a first embodiment of the present invention will be described with reference to the drawings. The present invention is not limited to the illustrated example.

FIG. 1 shows a schematic configuration of an image forming system 100 according to the first embodiment.
As shown in FIG. 1, the image forming system 100 includes an image forming apparatus main body 10, an image reading unit 20, a paper feeding unit 30, and a paper discharging unit 40. The sheet on which the image is formed by the image forming apparatus main body 10 is carried into the image reading unit 20 as it is.

The image forming apparatus main body 10 includes an image forming unit 50.
The image forming unit 50 forms an image on a sheet based on image data.
The image forming unit 50 includes photosensitive drums 51Y, 51M, 51C, and 51K corresponding to respective colors of yellow (Y), magenta (M), cyan (C), and black (K), an intermediate transfer belt 52, and a secondary transfer roller. 53, a fixing unit 54, a reversing mechanism 55, and the like.

After the photosensitive drum 51Y is uniformly charged, the photosensitive drum 51Y is scanned and exposed by a laser beam based on yellow image data to form an electrostatic latent image. Then, yellow toner is attached to the electrostatic latent image on the photosensitive drum 51Y, and development is performed.
The photoconductor drums 51M, 51C, and 51K are the same as the photoconductor drum 51Y except that the colors to be handled are different, and thus the description is omitted.

The toner images of each color formed on the photosensitive drums 51Y, 51M, 51C, 51K are sequentially transferred onto the rotating intermediate transfer belt 52 (primary transfer). That is, a color toner image in which four color toner images are superimposed is formed on the intermediate transfer belt 52.
The color toner images on the intermediate transfer belt 52 are collectively transferred onto the paper supplied from the paper supply unit 30 by the secondary transfer roller 53 (secondary transfer).

The fixing unit 54 includes a heating roller that heats the sheet onto which the color toner image has been transferred, and a pressure roller that presses the sheet, and fixes the color toner image on the sheet by heating and pressing.
The reversing mechanism 55 is a transport path for reversing the front and back sides of the sheet and supplying the sheet to the secondary transfer position again when images are formed on both sides of the sheet.

  The image reading unit 20 includes a first scanner 21A, a second scanner 21B, a spectrophotometer 22, and the like. The first scanner 21A, the second scanner 21B, and the spectrocolorimeter 22 are provided on the downstream side of the image forming apparatus main body 10 in the paper transport path, and the image forming surface of the paper after image formation is It can be read before it is discharged to

The first scanner 21A and the second scanner 21B are configured by line sensors in which CCDs (Charge Coupled Devices) are linearly arranged in a direction (paper width direction) perpendicular to the paper transport direction and parallel to the paper surface. ing. The first scanner 21A and the second scanner 21B are image reading units that read an image formed on a conveyed sheet, and output the obtained image data to the control unit 11 (see FIG. 2).
Hereinafter, when the first scanner 21A and the second scanner 21B are not particularly distinguished, the first scanner 21A and the second scanner 21B are collectively referred to as the scanner 21.

  The spectral colorimeter 22 detects the spectral reflectance for each wavelength of the image formed on the paper, and measures the color of the image. The spectral colorimeter 22 recognizes color information with high accuracy, and is used to correct the color information read by the first scanner 21A and the second scanner 21B to correct color information.

The paper supply unit 30 includes a plurality of paper supply trays, and supplies paper to the image forming unit 50. Each paper feed tray stores paper of a predetermined paper type for each paper feed tray.
The paper discharge unit 40 includes a paper discharge tray, and discharges the paper after image formation.

FIG. 2 is a block diagram illustrating a functional configuration of the image forming system 100.
As shown in FIG. 2, the image forming system 100 includes a control unit 11, an operation unit 12, a display unit 13, an image forming unit 50, a paper feeding unit 30, a paper discharging unit 40, an image reading unit 20, a conveying unit 60, a communication unit And a storage unit 80 and the like. Note that a description of the functional units already described is omitted.

  The control unit 11 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU reads out various processing programs stored in the ROM, expands them in the RAM, and centrally controls the operation of each unit of the image forming system 100 according to the expanded programs.

  The operation unit 12 includes a touch panel formed so as to cover the display screen of the display unit 13 and various operation buttons such as a number button and a start button, and outputs an operation signal based on a user operation to the control unit 11.

  The display unit 13 is configured by an LCD (Liquid Crystal Display), and displays various screens according to instructions of a display signal input from the control unit 11.

  The transport unit 60 includes a transport roller for transporting the paper, and transports the paper in the image forming system 100. Specifically, the transport unit 60 transports the paper from the paper feeding unit 30 to the image forming apparatus main body 10, transports the paper on which the image is formed by the image forming apparatus main body 10 in the image reading unit 20, and reads the image. The sheet is transported from the unit 20 to the sheet discharge unit 40.

  The communication unit 70 transmits and receives data to and from an external device connected to a communication network such as a LAN (Local Area Network) or the Internet.

  The storage unit 80 is configured by a hard disk, a flash memory, or the like, and stores various data. The storage unit 80 stores, for each combination of the paper type and the paper transport speed, a speed variation profile indicating the speed variation of the paper transport by the transport unit 60 when an image is read by the scanner 21. Paper types are classified according to basis weight, rigidity, thickness, size, or a combination thereof.

  The speed fluctuation profile is information indicating the characteristics of the speed fluctuation along the paper transport direction, and a corresponding portion on the paper corresponds to the distance from the leading edge of the paper (each position on the paper) in the paper transport direction. The speed at the time of passing through the reading area is associated.

At the time of image reading, the impact applied to the leading or trailing edge of the paper when the paper is transported causes the transport roller (roller drive unit) that sandwiches the paper and the paper to vibrate in the same manner. Occur. This speed fluctuation has high reproducibility, and if the paper type and the transport speed of the transported paper are constant, the reading position shift in the paper transport direction occurs every time in the same manner.
The speed fluctuation during image reading is periodic along the paper transport direction.

  The reproducibility of the speed fluctuation profile stored in the storage unit 80 is ensured, and it is assumed that the speed fluctuation profile does not fluctuate depending on the use situation and environment.

The control unit 11 conveys the sheet on which the register mark has been formed by the image forming apparatus main body 10 based on the speed fluctuation profile stored in the storage unit 80 so as to cancel the speed fluctuation indicated by the speed fluctuation profile. While controlling the unit 60, the registration mark formed on the sheet is read by the scanner 21 to obtain the formation position of the registration mark.
Specifically, the control unit 11 outputs a speed control signal having a phase opposite to the speed fluctuation indicated by the speed fluctuation profile to the driving roller of the transport unit 60 based on the speed fluctuation profile stored in the storage unit 80, and In step 21, the reading speed for reading the register mark is corrected to the target value.
The registration mark may be a mark used for image alignment, and its shape is not limited to a cross.

FIG. 3A shows an example of the speed variation profile, and FIG. 3B shows an example of the transport speed control for the transport unit 60 during image reading. FIG. 3C shows the result (image reading speed) of performing the conveyance speed control shown in FIG. 3B on the conveyance at the time of reading the image having the speed fluctuation characteristic shown in FIG.
As shown in FIG. 3B, when the rotation speed of the drive roller of the transport unit 60 is controlled so as to be in an opposite phase to the speed variation of the sheet conveyance during the image reading, the speed variation of the sheet conveyance during the image reading becomes As a result, the image reading speed approaches the target value (constant value) in the paper transport direction, as shown in FIG.

  It is necessary to match the start point in the paper transport direction indicated by the speed variation profile with the read start timing of the leading edge of the paper transported by the transport unit 60. , Can be accurately grasped.

  When the speed variation profile is not stored in the storage unit 80 for the combination of the paper type and the transport speed to be used, the control unit 11 calculates the speed variation profile for the corresponding paper type and the transport speed, It is added to the storage unit 80.

When acquiring a new speed fluctuation profile, the control unit 11 controls the image forming unit 50 to form an image (chart image) in which a plurality of straight lines are arranged at equal intervals in the sheet conveyance direction on the sheet. Let it. FIG. 4 shows an example of a chart image. As the chart image, for example, an image having a line interval of 0.254 mm and a line thickness of 0.085 mm can be used, but the chart image is not limited thereto. Note that the chart image does not need to be formed on the entire surface of the sheet, and may be formed at least in an area where the speed fluctuation profile of the sheet is to be obtained.
The control unit 11 causes the image forming apparatus main body 10 to convey a sheet on which an image in which a plurality of straight lines are arranged at equal intervals in the sheet conveyance direction is formed by the conveyance unit 60 while transferring the image formed on the sheet. The scanner 21 is caused to read, a speed fluctuation profile is calculated based on a plurality of straight line reading results obtained by the scanner 21, and the calculated speed fluctuation profile is stored in the storage unit 80.

It should be noted that no positional deviation due to the image forming apparatus main body 10 occurs when a chart image used for obtaining a speed fluctuation profile is formed.
If the chart image formed by the image forming apparatus main body 10 originally has a positional deviation, an incorrect speed fluctuation profile is calculated. However, adjustment is performed based on the corrected reading position acquired with the incorrect speed fluctuation profile. It is sufficient that the corrected image forming position to be (aligned) can secure the accuracy required as the image forming position of the image forming apparatus main body 10.

  The control unit 11 adjusts the position of the image formed by the image forming apparatus main body 10 based on the acquired registration mark formation position. That is, the control unit 11 functions as a correction unit. The registration of the image by the registration mark may be performed each time an image is formed in the image forming system 100, or may be performed at a predetermined number of image forming intervals.

  FIG. 5A shows an example in which register marks are formed at four corners of the sheet P. FIG. 5B is an enlarged view of a region Q shown in FIG. Based on the position of the register mark 91 formed on the surface of the sheet P, the position of the register mark 91 is adjusted so that the distance of the register mark 91 from the end of the sheet becomes predetermined set values H1 and H2. adjust. The same applies to the register mark 92 formed on the back surface of the sheet.

  The control unit 11, the scanner 21, the transport unit 60, and the storage unit 80 constitute an image reading apparatus according to the present invention.

Next, an operation in the image forming system 100 according to the first embodiment will be described.
FIG. 6 is a flowchart illustrating a first image alignment process performed in image forming system 100. This processing is realized by software processing in cooperation with the CPU of the control unit 11 and a program stored in the ROM.

  First, when the user selects the paper type and the transport speed of the paper on which an image is to be formed from the operation unit 12, the control unit 11 performs settings according to the selected paper type and the transport speed (step S1). If the paper transport speed is determined according to the selection of the paper type, it is not necessary to select the transport speed.

Next, the control unit 11 determines whether or not a speed variation profile corresponding to the set paper type and transport speed is stored in the storage unit 80 (Step S2).
If the speed variation profile corresponding to the set paper type and transport speed is not stored in the storage unit 80 (Step S2; NO), the control unit 11 controls the image forming unit 50 to A chart image in which a plurality of straight lines are arranged at regular intervals in the sheet transport direction is formed on a sheet of paper type (step S3).

  When the sheet on which the chart image has been formed by the image forming unit 50 is carried into the image reading unit 20, the control unit 11 conveys the sheet on which the chart image has been formed at a conveyance speed set by the conveyance unit 60. (Step S4), the chart image formed on the sheet is read by the scanner 21, and the result of reading the chart image from the scanner 21 (read image data) is obtained (Step S5).

  Next, the control unit 11 calculates a speed fluctuation profile based on a plurality of straight line reading results obtained by the scanner 21 (Step S6). Specifically, the control unit 11 detects the positions of a plurality of straight lines from the read image data, and obtains a speed fluctuation profile based on the deviation of each straight line from a desired position.

  Next, the control unit 11 causes the storage unit 80 to store the calculated speed fluctuation profile in association with the paper type and the transport speed (step S7).

  In step S2, when the speed variation profile corresponding to the set paper type and transport speed is stored in the storage unit 80 (step S2; YES), or after step S7, the control unit 11 The control unit 50 controls the registration mark to form a registration mark on the paper of the set paper type (step S8).

  When the paper on which the register mark is formed by the image forming unit 50 is carried into the image reading unit 20, the control unit 11 controls the speed variation profile (the paper type and the transport speed set in step S1) stored in the storage unit 80. Based on the speed fluctuation profile corresponding to the speed fluctuation profile, the driving motor of the conveying unit 60 is controlled by a speed control signal having a phase opposite to that of the speed fluctuation indicated by the speed fluctuation profile, and the paper on which the register mark is formed is conveyed ( In step S9, the registration mark formed on the paper is read by the scanner 21, and the result of reading the registration mark from the scanner 21 (read image data) is obtained (step S10).

  Next, the control unit 11 detects the position of the registration mark from the read image data acquired by the scanner 21 and acquires the position as the formation position of the registration mark (step S11).

Next, the control unit 11 adjusts the position of the image formed in the image forming apparatus main body 10 based on the acquired registration mark formation position (step S12). The result of the alignment is applied in the subsequent image formation.
Thus, the first image alignment processing ends.

As described above, according to the first embodiment, at the time of image reading, the reading speed is controlled by controlling the driving roller of the transport unit 60 with the speed control signal having the opposite phase to the speed fluctuation indicated by the speed fluctuation profile. Corrected to the target value. As the reading speed of the image approaches the target value, the reading position shift amount of the register mark read by the scanner 21 decreases. Therefore, the position of the register mark formed on the sheet can be accurately grasped.
Further, the position of the registration mark can be accurately acquired and fed back to the image forming operation of the image forming apparatus main body 10, so that the position of the image can be accurately adjusted.

Further, since the speed variation profile differs for each paper type and paper transport speed, storing the speed variation profile for each paper type and transport speed makes it possible to accurately acquire the registration mark formation position. .
When using a speed variation profile for the paper type and the transport speed that are not stored in the storage unit 80, the paper on which an image in which a plurality of straight lines are arranged at equal intervals in the paper transport direction is read is read. A speed fluctuation profile can be calculated.

[Second embodiment]
Next, a second embodiment to which the present invention is applied will be described.
Since the image forming system according to the second embodiment has the same configuration as the image forming system 100 shown in the first embodiment, FIG. 1 and FIG. The description of the operation will be omitted. Hereinafter, the configuration and processing characteristic of the second embodiment will be described.

  The control unit 11 causes the scanner 21 to read the register mark formed on the sheet while the sheet on which the register mark is formed by the image forming apparatus main body 10 is conveyed by the conveying unit 60, and is stored in the storage unit 80. Based on the speed fluctuation profile, the formation position of the register mark is calculated from the read position of the register mark obtained by the scanner 21.

  Specifically, the control unit 11 calculates the correspondence between the image forming position and the reading position based on the speed fluctuation profile. The control unit 11 sends the register mark formed on the sheet to the scanner 21 while causing the transfer unit 60 to transfer the sheet on which the register mark has been formed at the transfer speed having the speed change characteristic indicated by the speed change profile. The registration mark forming position is calculated from the registration mark reading position based on the read and calculated correspondence.

  FIG. 7 shows an example of the correspondence between the image forming position obtained from the speed fluctuation profile and the reading position.

  The control unit 11 adjusts the position of the image formed by the image forming apparatus main body 10 based on the calculated registration mark formation position.

Next, an operation of the image forming system according to the second embodiment will be described.
FIG. 8 is a flowchart illustrating a second image alignment process performed in the image forming system according to the second embodiment. This processing is realized by software processing in cooperation with the CPU of the control unit 11 and a program stored in the ROM.

  The processing of steps S21 to S28 is the same as the processing of steps S1 to S8 of the first image alignment processing (see FIG. 6), and thus the description is omitted.

After step S28, when the sheet on which the register mark is formed by the image forming unit 50 is carried into the image reading unit 20, the control unit 11 transports the sheet on which the register mark is formed by the transport set by the transport unit 60. While being transported at the speed (Step S29), the registration mark formed on the paper is read by the scanner 21, and the result of reading the registration mark from the scanner 21 (read image data) is obtained (Step S30).
In the second embodiment, the conveyance speed control at the time of image reading as in step S9 in the first image alignment processing is not performed.

  Next, the control unit 11 acquires the reading position of the register mark from the read image data acquired by the scanner 21 (Step S31).

  Next, the control unit 11 reads a speed variation profile corresponding to the set paper type and transport speed from the storage unit 80, and calculates a correspondence between an image forming position and a reading position based on the speed variation profile. (Step S32). Specifically, the control unit 11 calculates a reading position for each forming position in the paper transport direction from a speed for a distance (each position on the paper) from the leading edge of the paper in the paper transport direction.

  Next, based on the correspondence between the forming position and the reading position, the controller 11 calculates the forming position of the register mark from the reading position of the register mark (step S33).

Next, the control unit 11 adjusts the position of the image formed in the image forming apparatus main body 10 based on the calculated registration position of the register mark (step S34). The result of the alignment is applied in the subsequent image formation.
Thus, the second image positioning process ends.

As described above, according to the second embodiment, the correspondence between the image forming position and the reading position of the scanner 21 can be calculated from the speed variation profile of the conveyed sheet. By using the correspondence, the formation position of the registration mark with no deviation in the reading position can be calculated from the reading position of the registration mark read by the scanner 21. Therefore, the position of the register mark formed on the sheet can be accurately grasped.
In addition, the position of the registration mark can be accurately calculated and fed back to the image forming operation of the image forming apparatus main body 10, so that the position of the image can be accurately adjusted.

Further, since the speed variation profile differs for each paper type and paper transport speed, storing the speed variation profile for each paper type and transport speed makes it possible to accurately calculate the registration mark formation position. .
When using a speed variation profile for the paper type and the transport speed that are not stored in the storage unit 80, the paper on which an image in which a plurality of straight lines are arranged at equal intervals in the paper transport direction is read is read. A speed fluctuation profile can be calculated.

[Third Embodiment]
Next, a third embodiment to which the present invention is applied will be described.
In the third embodiment, a case will be described in which image forming systems of the same model are connected via a communication network and share information.

  FIG. 9 shows the configuration of the information sharing system 200. The information sharing system 200 includes image forming systems 101 to 106. The image forming systems 101 to 106 are the first to sixth machines of the same model having the same specifications.

The image forming systems 101 to 103 are installed at a site A and are connected to each other via an in-house network NA so as to be able to perform data communication.
The image forming systems 104 to 106 are installed at the base B and are connected to each other via an in-house network NB so as to be able to perform data communication.
The site A and the site B are mutually connected via the Internet NC, and the image forming systems 101 to 106 can perform data communication with an image forming system installed at a site different from the own system. .

  Since the image forming systems 101 to 106 have the same configuration as the image forming system 100 shown in the first embodiment, FIGS. 1 and 2 are used, and illustrations and descriptions common to the image forming system 100 are omitted. I do.

  When the control unit 11 of the image forming system 101 uses the speed variation profile corresponding to the paper type and the transport speed that is not stored in the storage unit 80, the control unit 11 performs step S1 of the first image alignment process (see FIG. 6). To step S7, and the calculated speed fluctuation profile is stored in the storage unit 80 in association with the paper type and the transport speed.

  The control unit 11 of the image forming system 101 uses the communication unit 70 to transmit the newly acquired speed fluctuation profile together with the conditions of the paper type and the transport speed together with the image forming system 102 in the site A connected via the in-house network NA. , 103. The control unit 11 of the image forming systems 102 and 103 stores the speed fluctuation profile received from the image forming system 101 in the storage unit 80 in the own system in association with the paper type and the transport speed.

  Further, the control unit 11 of the image forming system 101 uses the communication unit 70 to transmit the newly acquired speed fluctuation profile together with the paper type and the transport speed conditions, and the image forming system in the base B connected via the Internet NC. Send to 104-106. The control unit 11 of the image forming systems 104 to 106 stores the speed fluctuation profile received from the image forming system 101 in the storage unit 80 in the own system in association with the paper type and the transport speed.

  As described above, the speed fluctuation profile acquired by the image forming system 101 can be shared with the other image forming systems 102 to 106 of the same model, and the newly acquired speed fluctuation profile can be shared by the image forming systems 102 to 106 as well. The profile becomes available.

  As described above, according to the third embodiment, the speed fluctuation profile between the own system and another image forming system of the same model connected via the in-house networks NA and NB and the Internet NC is provided. Since the image is shared, the position of the register mark formed on the sheet can be accurately grasped by using the speed fluctuation profile acquired by one image forming system in another image forming system.

  The image forming systems 102 to 106 may receive the speed fluctuation profile from the image forming system 101 in response to a user instruction from the image forming systems 102 to 106.

  Further, in the third embodiment, the image forming systems 101 to 106 do not perform the conveyance speed control to cancel the speed fluctuation at the time of reading the image, and the image forming systems 101 to 106 according to the second embodiment do not perform the conveyance speed control. As described above, the formation position of the registration mark may be calculated from the reading position of the registration mark obtained by the scanner 21 based on the speed variation profile.

  The descriptions in the above embodiments are examples of the image reading apparatus and the image forming system according to the present invention, and the present invention is not limited to these. The detailed configuration and detailed operation of each unit constituting the device or the system can be appropriately changed without departing from the spirit of the present invention.

  In each of the above embodiments, the case where the control unit 11 of the image forming apparatus (the image forming apparatus main body 10 and the like) also serves as the control unit of the image reading apparatus (the scanner 21 and the transport unit 60 and the like) has been described. And the image reading device may have separate control means. In that case, the image reading device side may acquire or calculate the registration mark forming position (corrected reading position) and transmit it to the image forming device, or the image reading device may set the correction value at the time of image formation. The calculated value may be transmitted to the image forming apparatus.

  When the first scanner 21A and the second scanner 21B have different speed fluctuation profiles at the time of image reading, the speed fluctuation profiles are separately managed and correspond to the first scanner 21A or the second scanner 21B for reading an image. What is necessary is just to use the speed fluctuation profile to be performed.

Further, in each of the above-described embodiments, the case where the image forming system includes two scanners (the first scanner 21A and the second scanner 21B) that respectively read the front surface and the back surface of the sheet has been described. It may be a reading device.
Further, in an image reading apparatus having one scanner and a reversing mechanism, after reading one side of a sheet on which an image is formed, the reversing mechanism reverses the front and back of the sheet and reads the other side of the sheet. Is also good.

Reference Signs List 10 Image forming apparatus main body 11 Control unit 21A First scanner 21B Second scanner 50 Image forming unit 60 Transport unit 70 Communication unit 80 Storage unit 100 Image forming systems 101 to 106 Image forming system 200 Information sharing system NA In-house network NB In-house network NC the Internet

Claims (7)

Conveying means for conveying a sheet on which an image is formed by the image forming apparatus;
Image reading means for reading an image formed on paper;
Storage means for storing a speed fluctuation profile indicating a characteristic of a speed fluctuation at each position along the paper transport direction, which is generated while one sheet passes through the reading area of the image reading means ;
For the sheet on which the register mark has been formed by the image forming apparatus, based on the speed variation profile stored in the storage unit, the transport unit is configured to cancel the speed variation at each position indicated by the speed variation profile. Control means for causing the image reading means to read the register mark formed on the sheet while controlling the
An image reading device comprising: Conveying means for conveying a sheet on which an image is formed by the image forming apparatus;
Image reading means for reading an image formed on paper;
Storage means for storing a speed fluctuation profile indicating a characteristic of a speed fluctuation at each position along the paper transport direction, which is generated while one sheet passes through the reading area of the image reading means ;
A sheet register mark has been formed by the image forming apparatus, while being conveyed by said conveying means, a register mark formed on the paper to read the image reading unit, the speed fluctuation profile stored in said storage means Control means for calculating the formation position of the register mark from the read position of the register mark obtained by the image reading means, based on the characteristic of the speed fluctuation at each position indicated by
An image reading device comprising:   The image reading apparatus according to claim 1, wherein the storage unit stores the speed variation profile for each combination of a paper type and a paper conveyance speed.   The image reading apparatus according to claim 3, wherein the paper type is classified by basis weight, rigidity, thickness, size, or a combination thereof.   The control unit is configured to convey the image formed on the sheet by conveying the sheet on which an image in which a plurality of straight lines are arranged at equal intervals in the sheet conveyance direction is formed by the image forming apparatus. 5. The image reading device according to claim 1, wherein a speed variation profile is calculated based on a plurality of straight line reading results obtained by said image reading device, and the calculated speed variation profile is stored in said storage device. The image reading device according to claim 1. A communication unit that transmits and receives data to and from another image reading apparatus of the same model as the own apparatus, which is connected via a communication network,
The image reading device according to claim 1, wherein the control unit causes the speed variation profile to be shared with the another image reading device via the communication unit. An image forming system comprising: the image reading device according to claim 1; and the image forming device.
An image forming system comprising: a correction unit that adjusts a position of an image formed by the image forming apparatus based on a position where the register mark is formed.

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