JP7140592B2 - Measuring device, image forming device - Google Patents

Description

The present invention relates to a measuring device that measures an image pattern on a sheet conveyed from an image forming apparatus.

A system is known in which a measuring device is connected downstream of an image forming apparatus in the sheet conveying direction. For example, in the system disclosed in Japanese Patent Application Laid-Open No. 2002-200300, the image pattern formed on the adjustment sheet conveyed from the image forming apparatus is measured by the measuring unit of the measuring apparatus, and based on the measurement result, the characteristics of the image forming apparatus are determined. (print density, front/back position, color tone, etc.).

JP 2016-166916 A

By the way, when the sheet is conveyed through the sheet conveying path in the measuring device, foreign substances such as paper powder and dust may adhere to the measuring section. If such a foreign matter adheres to the measurement unit, it may affect the measurement accuracy of the image pattern.

However, the measuring apparatus described in Patent Document 1 has a configuration in which the adjustment chart and the sheet as the product are conveyed along a common conveying path. In such a configuration, even sheets for normal print jobs whose image patterns are not measured by the measuring section pass through the common sheet conveying path, so the measuring section must be cleaned frequently. , which may lead to a decrease in system availability.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a means for suppressing adhesion of foreign matter such as paper dust and dust to a measuring section.

In order to solve the above-described problems, the measuring apparatus of the present invention is a measuring apparatus connected to an image forming apparatus that forms an image on a sheet, wherein the sheet discharged from the image forming apparatus is measured in the sheet conveying direction of the measuring apparatus. a first sheet conveying path for conveying to a post-processing device connected downstream; and an image pattern formed on a sheet discharged from the image forming apparatus and conveyed along the second sheet conveying path. and a sheet of a print job that is not measured by the measuring unit along the first sheet conveying path without going through the second sheet conveying path to the post-processing device. a switching unit for switching a conveying path so as to convey a sheet of a measurement job to be conveyed and to be measured by the measuring unit to the second sheet conveying path; and a sheet conveyed along the second sheet conveying path. and notification means for notifying the image forming apparatus of the measurement result of the image pattern formed in the second sheet conveying path, wherein the second sheet conveying path includes a curved conveying path that is curved and a horizontal conveying path that extends in the horizontal direction. , wherein the measuring unit is provided in the horizontal conveying path .

Further, in order to solve the above-mentioned problems, an image forming apparatus of the present invention provides an image forming unit that forms an image on a sheet according to image forming conditions, and a sheet conveyed from the image forming unit that is connected downstream in the sheet conveying direction. and a second position extending downward from a first position in the first sheet transport path and located downstream of the first position in the sheet transport direction. a second sheet conveying path that merges with the first sheet conveying path; and a measuring section that measures an image pattern formed on a sheet conveyed along the second sheet conveying path from the image forming means. and conveying sheets of a print job not to be measured by the measuring unit to the post-processing device along the first sheet conveying path without passing through the second sheet conveying path, and a switching unit for switching the conveying path so as to convey the sheet of the measurement job to be measured by the second sheet conveying path to the second sheet conveying path; and an image pattern formed on the sheet conveyed along the second sheet conveying path. correction means for correcting the image forming conditions based on the measurement result of ( 1), wherein the second sheet conveying path has a curved conveying path and a horizontal conveying path extending in the horizontal direction. , wherein the measuring unit is provided on the horizontal conveying path .

ADVANTAGE OF THE INVENTION According to this invention, it can suppress that foreign substances, such as paper dust and garbage, adhere to a measuring part.

Cross-sectional view of an image forming apparatus Cross-sectional view of the measuring device Control block diagram Configuration of the first measurement unit (colorimetry unit 400) ICC profile Schematic diagram of a color management environment Configuration diagram of the second measurement unit (reading unit 700) A diagram showing an example of an image pattern for measurement Diagram showing paper library Screen example for instructing print position adjustment Flowchart for explaining the operation when a print job or measurement job is submitted Diagram for explaining the operation when a print job is executed FIG. 4 is a diagram for explaining the operation when the first colorimetry unit executes a measurement job; A diagram for explaining the operation (branch→measurement→merge) when a measurement job is executed by the second measurement unit. Sectional drawing of the measuring apparatus in other embodiment Sectional view of an image forming apparatus according to another embodiment

(Image forming system)
EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing. FIG. 1 shows an image forming system including an image forming apparatus 100 , a measuring apparatus 200 and a post-processing apparatus 600 .

The image forming apparatus 100 is an electrophotographic image forming apparatus. The measuring device 200 is connected downstream of the image forming apparatus 100 in the sheet conveying direction, reads an image pattern on a sheet on which an image is formed by the image forming apparatus 100, performs measurement, and notifies the image forming apparatus 100 of the measurement result. do. The measuring device 200 is an automatic adjustment unit provided as an option, and can be attached to and detached from the image forming apparatus 100 . The post-processing device 600 is a device (finisher) connected further downstream of the measuring device 200 in the sheet conveying direction. Perform various post-processing such as punching, alignment, etc.

The image forming apparatus 100 includes mechanisms constituting the engine section shown in FIG. 1, an engine control section 312 (FIG. 3) that controls each printing process performed by each mechanism, a printer controller 103 (FIG. 3), and an operation unit. a portion 180; Each mechanism constituting the engine section will be described with reference to FIG. The laser scanner unit 107 has a laser driver that turns on and off a laser beam emitted from a semiconductor laser (not shown) according to image data output from the printer controller 103 . A laser beam emitted from a semiconductor laser is polarized in a scanning direction by a rotating polygon mirror. The polarized laser light is guided to the photosensitive drum 105 via the reflecting mirror 109, and exposes the photosensitive drum 105 in the main scanning direction.

An electrostatic latent image formed on the photosensitive drum 105 by being charged by the primary charger 111 and exposed to laser light is developed into a toner image by toner supplied by the developing device 112 . Then, the developed toner image on the photosensitive drum 105 is transferred (primary transfer) onto the intermediate transfer member 106 . When forming a color image, toner images are sequentially formed on the intermediate transfer member 106 for each of Y (yellow), M (magenta), C (cyan), and K (black) stations 120 to 123 . As a result, a full-color visible image is formed on intermediate transfer member 106 . The visible image formed on the intermediate transfer member 106 is transferred (secondary transfer) onto the sheet 110 fed by the paper feed processing mechanism.

Around the intermediate transfer member 106 are an image formation start position detection sensor 115 for determining the print start position, a paper feed timing sensor 116 for determining the timing of paper feed of the sheet 110, and measuring the density of the patch during density control. A density sensor 117 is arranged. When density control is performed, the density sensor 117 measures the density of the patch.

The first fixing device 150 has a fixing roller 151 for applying heat to the sheet 110, a pressure belt 152 for pressing the sheet 110 against the fixing roller 151, and a post-fixing sensor 153 for detecting completion of fixing. The fixing rollers 151 are hollow rollers, each having a heater inside, and conveying the sheet 110 while being rotationally driven. The second fixing device 160 is positioned downstream of the first fixing device 150 in the sheet conveying direction, and adds gloss to the toner image on the sheet 110 fixed by the first fixing device 150 or improves fixability. It is placed for the purpose of securing The second fixing device 160 has a fixing roller 161 , a pressure roller 162 , and a post-fixing sensor 163 like the first fixing device 150 .

Some types of sheets 110 do not need to pass through the second fixing device 160 . In this case, a conveying path 130 is provided for discharging the sheet 110 without going through the second fixing device 160 for the purpose of reducing energy consumption. The sheet 110 can be guided to the transport path 130 by the transport path switching flapper 131 .

After passing through the fixing processing mechanism, the sheet 110 is guided to the conveying path 135 by the flapper 132, and after the position of the sheet 110 is detected by the reversing sensor 137, the sheet 110 is reversed by switching back at the reversing section 136. be.

(Measuring device 200)
The configuration of the measuring device 200 will be described with reference to FIG. The measuring apparatus 200 includes an entrance conveying path 229 that receives a sheet from the image forming apparatus 100, a through path 230 that horizontally extends from the entrance conveying path 229 to a discharge path 232, and a discharge path 232 that delivers the sheet to the post-processing apparatus 600. and have The entrance conveying path 229, the through path 230, and the discharge path 232 are examples of the first sheet conveying path. The entrance conveying path 229 is a conveying path from the image forming apparatus to the sheet receiving port to the branch position A (first position). The through-path 230 is a transport path from a branch position A (first position) to a merging position B (second position) for transporting sheets of a print job, which will be described later. The discharge path 232 is a conveying path from the merging position B to the discharge port.

The measurement device 200 also has a measurement path 231 . The measurement path 231 is a conveying path that extends downward in the gravity direction from the branch position A and joins the first sheet conveying path at the merging position B, and is an example of the second sheet conveying path. The measurement path 231 includes a first curved conveying path that curves in an S shape downward in the direction of gravity from the branch position A, a horizontal conveying path that extends in the horizontal direction, and a reverse S from the horizontal conveying path toward the joining position B. and a second curved transport path that curves like a letter. The first curved conveying path is a conveying path from the branch position A to the conveying rollers 208 . A horizontal transport path is a transport path from the transport roller 208 to the transport roller 209 . The second curved conveying path is a conveying path from the conveying roller 209 to the merging position B. FIG. The measurement path 231 is composed of a first curved transport path, a horizontal transport path, and a second curved transport path. is provided with a reading unit 700 .

The system of this embodiment can execute two types of jobs, a print job and a measurement job. A print job sheet is conveyed along a through path 230, and a measurement job sheet is conveyed along a measurement path 231. be. A print job is a job that outputs a sheet as a normal product. Specifically, it is a job of forming an image based on image data input from a scanner, and a job of forming an image based on print data received from an external device such as a PC. A measurement job is a job that forms an image pattern for adjustment on a sheet, reads the image pattern formed on the sheet, and corrects image forming conditions such as print density, print position, and color. Specifically, the job includes a colorimetry job and a front/back alignment (front/back adjustment) job, which will be described later.

Sheets for a print job are preferably conveyed from the image forming apparatus 100 toward the downstream post-processing apparatus 600 in the shortest distance. That is, it is preferable that the through path 230 is as short as possible. On the other hand, for the sheet of the adjustment job, the image pattern must be measured by the measurement unit after the trailing edge of the long paper having a long length in the conveying direction passes through the image forming apparatus 100 for the reason described later. Therefore, the measuring path 231 needs to ensure a long conveying distance as much as possible. In view of such circumstances, the measurement path 231 has a longer transport distance than the through path 230 in this embodiment. In addition, by forming part of the measurement path 231 as a transport path curved in an S shape or an inverted S shape, the transport distance is lengthened and the size of the measuring apparatus 200 as a whole is reduced.

As described above, the measurement path 231 is provided with the colorimetry section 400 and the reading section 700, which are examples of the measurement section. The colorimetry section 400 is provided on the horizontal transport path of the measurement path 231 . A colorimetry unit 400 is a measurement unit that reads an image pattern on a sheet and performs colorimetry. The reading unit 700 reads the image patterns formed on the front and back surfaces of the sheet and calculates an adjustment amount for aligning the front and back printing positions.

Next, the sheet conveying path when a print job and a measurement job are input will be described. When a print job is input, the sheet is conveyed inside the measuring device 200 along the inlet conveying path 229 , the through path 230 and the discharge path 232 . In this case, the control unit 251 controls the flapper switching motor 204 to cause the first flapper 221 as the switching unit at the branch position A to stand by in a downward position. The sheet received by the entrance conveying path 229 is transferred directly to the downstream post-processing device 600 by the through-pass rollers 201 to 203 without passing through the measuring path 231 .

On the other hand, when a measurement job is input, the sheet is conveyed inside the measuring apparatus 200 along the inlet conveying path 229, the measuring path 231, and the discharge path. The control unit 251 causes the first flapper 221 as the switching unit at the branch position A to stand by in an upward state. Accordingly, the sheet conveyed from the image forming apparatus 100 is guided from the inlet conveying path 229 to the measurement path 231 . After passing through the measurement path 231 , the sheet merges with the first sheet conveying path at the merging position B (second position), passes through the discharge path 232 , and is transferred to the post-processing device 600 . In addition, in order to read the image pattern with high precision by the measurement unit, it is necessary to convey at a second conveying speed that is lower than the first conveying speed which is a normal conveying speed. Therefore, after the trailing edge of the sheet reaches the entrance conveying path 229, the measuring apparatus 200 switches the conveying speed to the second conveying speed to convey the sheet.

(Colorimetry unit 400)
The structure and colorimetry operation of the colorimetry unit 400 as the first measurement unit provided in the measurement apparatus 200 will be described with reference to FIG. The colorimetry unit 400 has a white LED 401 , a diffraction grating 402 , line sensors 403 ( 403 - 1 to 403 -n), a calculation unit 404 and a memory 405 . When the white LED 401 irradiates the toner patch (image pattern) 420 on the sheet 110 with light, the diffraction grating 402 separates the light reflected from the toner patch 420 into wavelengths. The line sensor 403 detects the light that has been separated by wavelength by the diffraction grating 402 . The calculation unit 404 performs various calculations from the light intensity value of each pixel detected by the line sensor 403 and stores the calculation results in the memory 405 . The calculation unit 404 has, for example, a spectral calculation unit that performs spectral calculation from light intensity values and a Lab calculation unit that calculates Lab values. The colorimetry unit 400 also has a lens 406 that collects the light emitted from the white LED 401 onto the toner patch 420 on the sheet 110 and collects the light reflected from the toner patch 420 onto the diffraction grating.

The colorimetry unit 400 is arranged on a linear transport path instead of a curved transport path in the measurement path 231 . The reason for this is to prevent the reaction force that the sheet receives from the conveying guide from affecting the speed unevenness during measurement.

Image forming apparatus 100 achieves excellent color reproducibility by executing color conversion using a color conversion profile created based on the measurement result of colorimetry unit 400 . A color conversion profile is an example of image forming conditions. As the color conversion profile, an ICC (International Color Consortium) profile, which has recently been accepted in the market, is used. However, the present invention is not limited to this. For example, besides the ICC profile, CRD (Color Rendering Dictionary) adopted from PostScript level 2 advocated by Adobe may be used. Alternatively, a color separation table in Photoshop, a CMYK simulation in EFI's ColorWise that maintains black plate information, or the like may be used.

(Spectral reflectance is measured by the colorimetric unit 400 and chromaticity is calculated)
Image forming apparatus 100 creates a color conversion profile based on the measurement result of colorimetry unit 400 . The signal that is colorimetrically measured by the colorimetry unit 400 and input is the light emitted from the white LED reflected by the measurement object, the reflected light is separated by a diffraction grating, and the CMOS array arranged in each wavelength region of 380 nm to 720 nm. It becomes the spectral reflectance detected on the sensor. In this embodiment, in order to improve detection calculation accuracy, the spectral reflectance is converted into L*a*b* via a color matching function or the like as specified by CIE. The patch information converted to L*a*b* obtains the relationship with the signal value of the patch, and creates an ICC profile, which is a color conversion profile. Note that the method for calculating the chromaticity value (L*a*b*) from the spectral reflectance is a method defined by ISO 13655, and therefore the description is omitted here.

(Profile creation process)
Processing for creating a color conversion profile will be described with reference to FIG. A color conversion profile can be created when a customer engineer replaces a part, before a job that requires color matching accuracy, or when you want to know the color of the final output at the design concept stage. done according to the instructions.

In response to the color conversion profile creation instruction, the printer controller 103 transmits CMYK (Cyan Magenta Yellow Black) signals of the ISO 12642 test form to the engine control unit 312 . At the same time, the printer controller 103 sends a colorimetric instruction to the measuring device 200 . The image forming apparatus 100 transfers and fixes the ISO 12642 test form (image pattern) onto the sheet 110 through processes of charging, exposure, development, transfer, and fixation. The colorimetry unit 400 of the measurement device 200 reads the image pattern on the sheet conveyed from the image forming apparatus 100 and performs colorimetry. Spectral reflectance data corresponding to the measured 928 patches is notified to the printer controller 103 as a result of colorimetry. The printer controller 103 that has received the notification of the colorimetry result converts it into L*a*b* data via the Lab calculation unit 303 and inputs the L*a*b* data to the profile creation unit 301 .

In this embodiment, an example of converting spectral reflectance data into L*a*b* data will be described. can be converted to

The profile creation unit 301 creates an output ICC profile based on the relationship between the output CMYK signals and the input L*a*b* data, and updates the output ICC profile stored in the output ICC profile storage unit 305 . Accordingly, the image forming conditions are corrected.

The ISO 12642 test form includes CMYK color signal patches that cover the color gamut that can be output by a general image forming device. Create a conversion table.

FIG. 5 is a diagram showing the structure of an ICC profile. An ICC profile consists of a header and tags. The tag also describes whether the color represented by the white point or the Lab value defined inside the profile is inside or outside the reproducible reproduction range of the hard copy.

In this embodiment, an example in which an instruction to create a color conversion profile is received via the operation unit 180 will be described, but an instruction to create a color conversion profile may be received from an external device such as a PC. In that case, the created output ICC profile may be uploaded to the external device so that color conversion can be performed on the external device using an application compatible with the ICC profile.

In color conversion in normal color output, the printer controller 103 sends an image signal input via an external I/F 308 such as a scanner unit to the input ICC profile storage unit 307 for external input. The printer controller 103 performs RGB→L*a*b* or CMYK→L*a*b* conversion in the input ICC profile storage unit 307 according to the image signal input from the external I/F 308 . The input ICC profile is composed of a one-dimensional LUT (lookup table) that controls the gamma of the input signal, a multicolor LUT called direct mapping, and a one-dimensional LUT that controls the gamma of the generated conversion data. The printer controller 103 uses these tables to convert the device-dependent color space into device-independent L*a*b* data.

As shown in FIG. 6, the CMM 306 is a module that controls color management, and performs color conversion using an input profile and an output profile.

(Reading unit 700)
The structure of the reading section 700 as the second measuring section will be described with reference to FIG. The reading unit 700 measures the shape of the sheet, the shape of the image pattern printed on the sheet, and the like. In order to obtain highly accurate measurement results, it is necessary to average the variations in shape and printing position for each sheet, so a plurality of sheets are measured. Therefore, it is desirable to shorten the adjustment time as much as possible and to reduce the device size by measuring the image pattern while conveying the sheet, and a contact image sensor (CIS) is used.

The reading unit 700 has a front side CIS 701 for reading the measurement image pattern formed on the front side of the sheet and a back side CIS 702 for reading the measurement image pattern formed on the back side of the sheet. Since the reading unit 700 needs to read the measurement image patterns formed on the front surface and the back surface of the sheet almost simultaneously, the CIS 701 for the front surface and the CIS 702 for the back surface are arranged opposite to each other. Similarly, sheet conveying roller pairs 211, 212, 213, glass/guide members 703, 704, and black backing/conveyance guide members 705, 706 are also arranged to face each other. The glass-cum-guide members 703 and 704 are members for stabilizing the position of the CIS in the depth-of-focus direction, and also play a role of guiding the conveyance of the sheet. Black backing/conveyance guide members 705 and 706 are members for clarifying the contrast with the sheet edge, and also play a role of guiding the conveyance of the sheet. The sheet conveying roller pairs 211, 212 and 213 are driven by driving means (not shown).

The reading unit 700 has a front side CIS 701 and a back side CIS 702 , and the front side CIS 701 is arranged downstream of the back side CIS 702 . As a result, the shift timing to the measurement speed can be shifted further downstream than in the front/back measurement, so there is an effect of lengthening the support paper size in the mode of adjusting the print position on one side.

The reading unit 700 is arranged on a linear transport path in the measurement path 231 . The reason for this is to prevent the reaction force that the sheet receives from the conveying guide from affecting the speed unevenness during measurement.

(Print position adjustment)
Next, the print position adjustment operation using the reading unit 700 will be described. Image forming apparatus 100 receives an instruction to execute print position adjustment via screen 1001 in FIG. 10 displayed on operation unit 180 . FIG. 10 shows a screen for editing the paper library. When the user presses the print position adjustment button 1002 on the screen 1001, the screen transitions to the screen shown in FIG. 10B. When the "read test page and adjust" button 1005 is pressed via the screen of FIG. 10B, a job for executing print position adjustment is submitted.

Upon receiving the print position adjustment job execution instruction, the printer controller 103 instructs the engine control unit 312 to output image patterns 802 and 803 for measurement shown in FIG. The image forming apparatus 100 transfers and fixes an image pattern onto a sheet 110 through processes of charging, exposure, development, transfer, and fixing. The measuring apparatus 200 conveys the sheet 110 having the image patterns 802 and 803 for measurement conveyed from the image forming apparatus 100 by the sheet conveying roller pairs 211 , 212 and 213 , while conveying the CIS 701 for the front side and the CIS 701 for the back side. Read continuously with CIS702. The image processing unit 260 of the measuring device 200 synthesizes image data by connecting the detected line images, and performs measurement from the synthesized image data. Specifically, the image processing unit 260 detects the sheet 110 detection coordinates (X ₀₁ , Y ₀₁ ) to (X ₃₁ , Y ₃₁ ) of the test pattern 802 for the front side.
and the detection coordinates of the test image pattern 820 (X ₄₁ , Y ₄₁ ) to (X ₇₁ , Y ₇₁ )
, geometric adjustment parameters (lead position, side position, magnification, perpendicularity, amount of rotation, etc.) that allow the image shape correction unit 320 to measure the amount of image distortion and the positional deviation from the sheet 110 and instruct shape correction. Calculate

The geometric adjustment values calculated by the image processing unit 260 are sent to the paper library 900 in the image forming apparatus 100 through the communication unit 250 and stored in geometric adjustment amounts 901 and 902 . The geometric adjustment amounts 901 and 902 are examples of image forming conditions. FIG. 9 is a diagram showing the geometric adjustment amount for each paper name registered in the paper library.

The paper setting 910 in the paper library 900 thus obtained is used when executing a print job using the same paper. As a result, it is possible to output a print image in which the image position and distortion are corrected and the front and back print positions are corrected with high accuracy.

(Description of operation when print job or measurement job is input)
The operation when a job is submitted will be described with reference to the flowchart of FIG. 11 and the operation explanatory diagrams of FIGS. The flowchart in FIG. 11 starts when a print job or a measurement job is input (S1101).

When a print job is input (YES in S1102), each member of the image forming apparatus 100 and measuring apparatus 200 waits at the home position (HP). At this time, the control unit 251 of the measuring apparatus 200 controls the flapper switching motor 204 and switches the flapper (switching unit) 221 downward in order to guide the sheet conveyed from the image forming apparatus 100 to the through path 230 (S1104). . After that, the image forming apparatus 100 forms an image on the sheet (S1105), and the sheet is conveyed to the measuring apparatus 200 (S1106, FIG. 12A). Then, the through-pass rollers 201 to 204 pass through the through-pass 230 and discharge path 232 forming the first sheet conveying path, and deliver the sheet to the downstream post-processing device 600 (S1107, FIG. 12B). Then, the post-processing device 600 performs post-processing such as binding, bookbinding, punching, alignment, etc. according to the contents of instructions specified in the print job, and discharges the printed sheets to the discharge tray.

On the other hand, when a colorimetry job, which is an example of a measurement job, is input (“colorimetry” in S1103), the control unit 251 of the measurement apparatus 200 controls the flapper switching motor 204 to switch the flapper 221 upward (S1120). ). As a result, the sheet conveyed from the image forming apparatus 100 is guided to the measurement path 231, which is the second sheet conveying path. The image forming apparatus 100 forms toner patches 420, which are image patterns for measurement, on a sheet (S1121), and conveys the sheet to the measuring apparatus 200. FIG. The measuring apparatus 200 receives the sheet from the image forming apparatus 100 and conveys it to the measuring path 231 by the flapper 221 (S1123, FIG. 13A).

The control unit 251 changes the conveying speed to V1 at which a large number of toner patches 420 can be read by the colorimetric unit 400 (FIG. 13(b)). Measurement path rollers 205 to 209 convey the sheet to colorimetry section 400, and colorimetry section 400 performs colorimetry of toner patches 420 on the sheet (S1124). The transport speed V<b>1 is a transport speed lower than the transport speed V<b>0 when the sheet of the print job is transported through the through path 230 . The measuring device 200 notifies the image forming apparatus 100 of the colorimetry result of the colorimetry unit 400 through the communication unit 250 (S1125). The printer controller 103 of the image forming apparatus 100 that has received the notification of the colorimetry result calculates the ΔE value based on the above Lab information and creates a color conversion profile (S1126). The sheet for which colorimetry has been completed is conveyed along a measurement path 231 by measurement path rollers 208 to 214 (FIG. 13(c)). After the sheet conveyed through the measurement path 231 joins the through-path 202 at the joining position B (S1127), it is conveyed to the discharge path 232 by the through-pass third roller 203 (S1109, FIG. 13D).

Next, the flow of measurement when a job for adjusting the print position on the front and back sides (both sides adjustment job) is input by selecting the paper setting 910 from the paper library 900 and selecting the print position adjustment button 1002. explain. A front/back adjustment job is an example of a measurement job. When a front/back adjustment job is input (“front/back adjustment” in S1103), the control unit 251 of the measuring apparatus 200 switches the flapper (switching unit) 221 upward to guide the sheet to the measurement path 231 (S1130). After that, the image forming apparatus 100 forms image patterns 802 and 803 for measurement as images for measurement (S1131), and conveys the sheet to the measurement apparatus 200. FIG. The measurement apparatus 200 that has received the sheet on which the image pattern for measurement is formed is transported from the inlet transport path 229 to the measurement path 231 by the flapper (switching unit) 221 as shown in FIG. S1133).

As shown in FIG. 14(b), the measuring device 200 shifts to a second conveying speed V2 lower than the first conveying speed V0. After that, the measuring apparatus 200 conveys the sheet to the reading unit 700 by the measurement path rollers 205 to 209, and measures the print position deviation of the test image pattern 820 for measurement formed on the sheet and the shape of the sheet 110 (S1134). ). The reason for changing the conveying speed from the first conveying speed V0 to the second conveying speed V2 is to perform high-definition line image synthesis in the reading unit 700 and perform highly accurate measurement.

The control unit 251 notifies the printer controller 103 of the image forming apparatus 100 through the communication unit 250 of the geometric adjustment value parameter calculated by the image processing unit 260 as a measurement result. The printer controller 103 that has received the notification of the measurement result stores the geometric adjustment value parameter in the paper library 900 (S1135). The measuring device 200 conveys the sheet that has passed through the reading section 700 by measurement path rollers 208 to 214 (FIG. 14(c)). Thereafter, the measuring apparatus 200 merges the sheet into the first sheet conveying path (S1127), and then conveys the sheet to the discharge path 232 by the third through-path roller 203 (S1107, FIG. 14D). The post-processing device 600 discharges the sheet of the measurement job to the discharge tray. Note that it is preferable to discharge the sheets for the print job and the sheets for the measurement job to different discharge trays so that they are not mixed. In this embodiment, the post-processing device 600 has two paper discharge trays, and the print job is discharged to one of the paper discharge trays, and the sheet of the measurement job is discharged to the other paper discharge tray.

The above-described image formation, sheet conveyance, colorimetry, or front/back printing position adjustment are repeated from the first sheet to the last sheet, and the job is completed (S1109).

(Effect of this embodiment)
The system configuration and operation of this embodiment have been described above. The measuring apparatus 200 of the present embodiment conveys a print job sheet along a through path 230 and conveys a measurement job sheet along a measurement path 231 . In other words, a configuration is adopted in which a transport path for a product sheet that is not measured and a transport path for a measurement sheet are provided separately. As a result, the sheets conveyed on the measurement path 231 are limited to adjustment sheets for the measurement job.

According to this embodiment, the frequency of conveying sheets to the measurement path 231 can be reduced to 1/10 or less compared to the case where the measurement section is arranged in the through path 230 . Therefore, the frequency of paper dust adhering to the measurement section in the measurement path can be significantly reduced.

As a result, the risk of erroneous detection of color by the colorimetry unit 400 and the risk of erroneous detection of dimensions by the reading unit 700 can be reduced. Therefore, maintenance intervals such as contamination check and cleaning of each measuring unit can be lengthened, so downtime of the apparatus can be reduced, and the operating rate of the system can be improved.

In the print job, the heat of the sheet heated by the fixing device tends to escape upward as an ascending air current. It is possible to reduce the measurement error due to the temperature characteristics of the color sensor and the measurement error of the amount of positional deviation due to the thermal expansion distortion of the CIS.

Further, in the present embodiment, the transport distance L from the reading position of the reading unit 700 to the paper discharge port of the image forming apparatus 100 is ensured to be equal to or greater than the transport direction length of the maximum paper size supported by the measuring device 200. . In the present embodiment, the measuring device 200 supports a long sheet of 1200 mm in length in the conveying direction, so the distance from the reading position of the reading unit 700 to the discharge port of the image forming apparatus 100 is longer than 1200 mm. Designed. The reason for this is that if the trailing edge of the sheet is held by the image forming apparatus 100 when the leading edge of the sheet reaches the reading unit 700, a slight shake or shock of the sheet during image formation may cause a measurement error during reading. This is because an error may occur.

Note that the paper size supported by the image forming apparatus 100 and the paper size measurable by the measuring device 200 do not necessarily match. For example, the image forming apparatus 100 may support a wide range of paper sizes, from postcard size to 1200 mm long paper, and the measuring device 200 may be configured to measure only a narrower range of paper sizes. In this case, it is sufficient to secure the transporting distance L corresponding to the transporting direction length of the paper size that can be measured by the measuring device 200 .

In addition, in this embodiment, two measurement units (the colorimetry unit 400 and the reading unit 700) are arranged on the measurement path 231. FIG. The two measurement units are arranged such that the colorimetry unit 400 is located upstream in the sheet conveying direction, and the reading unit 700 is located downstream in the sheet conveying direction. This is based on the following reasons. That is, if the colorimetry unit 400 can form a required number of patches on a sheet, there is no problem in terms of measurement accuracy even if a measurement job is executed using a small size sheet. On the other hand, for the reading unit 700, it is necessary to use a sheet of the same size as that used in a normal print job. The image forming apparatus 100 supports a wide range of paper sizes, from postcard size to 1200 mm long paper. Therefore, it is necessary to cause the reading unit 700 to read an image formed on a sheet of the maximum size to be supported (a long sheet of 1200 mm in this embodiment). In order to read an image formed on a long paper of 1200 mm with high accuracy, it is necessary to start reading by the reading unit 700 after the trailing edge of the long paper passes through the image forming apparatus 100, as described above. . Therefore, in the present embodiment, the width of the measuring device 200 is prevented from increasing by arranging the reading unit 700, which is a measuring unit that needs to read a longer size sheet, downstream.

(Other embodiments)
In this embodiment, the measuring device 200 has an example of a configuration having two measuring units (the colorimetric unit 400 and the reading unit 700). However, the present invention is not limited to this, and the measurement device 200 may have only one measurement unit (for example, the colorimetry unit 400) as shown in FIG.

Further, in the present embodiment, the measurement path 231 is located below the through path 230 in the gravitational direction. However, the present invention is not limited to this, and a configuration in which the measurement path 231 is above the through path 230 may be used.

Further, in the present embodiment, a configuration is exemplified in which heat influence of the measurement unit is suppressed by arranging the measurement unit downward in the direction of gravity. However, the airflow may be configured to exhaust heat upward from the through-path 230 .

Further, in the present embodiment, the measuring device 200 has been described as a device detachably connected downstream of the image forming apparatus. However, the present invention is not limited to this, and the measuring device 200 may be arranged inside the image forming apparatus as shown in FIG.

Further, in the present embodiment, an electrophotographic image forming apparatus has been described as an example, but the present invention can also be applied to an ink jet image forming apparatus and a sublimation printer.

REFERENCE SIGNS LIST 100 image forming apparatus 101 housing 102 engine control section 103 printer controller 105 photosensitive drum 106 intermediate transfer member 107 laser scanner section 112 developing device 113 paper feed cassette 114 transfer roller 115 image formation start position detection sensor 116 paper feed timing sensor 117 density sensor 131, 132 Flapper 135 Conveyance path 136 Reversing unit 137 Reversing sensor 150 First fixing device 151 Fixing roller 152 Pressure belt 153 Post-fixing sensor 160 Second fixing device 161 Fixing roller 162 Pressure roller 163 Post-fixing sensor 180 Operation unit 200 Measurement device 201 to 204 through pass rollers 205 to 214 measurement pass roller 221 flapper 229 entrance conveying path 230 through pass 231 measurement path 232 discharge path 250 communication section 251 control section 260 image processing section 301 profile creation section 303 Lab calculation section 305 output ICC profile storage section 306 color management module 307 input ICC profile storage unit 308 external I/F
400 colorimetric unit 401 white LED
402 diffraction grating 403-1 to 403-n line sensor 404 arithmetic unit 405 memory 406 lens 600 post-processing device 700 image reading unit 701 surface CIS
702 CIS for back surface
703, 704 Conveyance guide member 705, 706 Conveyance guide member 802 Front side test pattern 803 Back side test pattern 820 Toner patch 900 Paper library 901, 902 Geometric adjustment amount 910 Sheet type

Claims (11)

A measuring device connected to an image forming device that forms an image on a sheet,
a first sheet conveying path for conveying a sheet discharged from the image forming apparatus to a post-processing device connected downstream of the measuring device in the sheet conveying direction;
A second sheet extending downward from a first position in the first sheet transport path and joining the first sheet transport path at a second position downstream of the first position in the sheet transport direction. a transport path;
a measuring unit for measuring an image pattern formed on a sheet discharged from the image forming apparatus and conveyed along the second sheet conveying path;
Sheets of a print job not to be measured by the measuring unit are conveyed to the post-processing device along the first sheet conveying path without passing through the second sheet conveying path, and the measuring unit a switching unit that switches the conveying path so as to convey the sheet of the measurement job to be measured to the second sheet conveying path;
notification means for notifying the image forming apparatus of measurement results of the image pattern formed on the sheet conveyed along the second sheet conveying path;
has
A measuring apparatus , wherein the second sheet conveying path has a curved conveying path and a horizontal conveying path extending in a horizontal direction, and the measuring unit is provided in the horizontal conveying path . The length from the first position to the second position on the second sheet transport path is longer than the length from the first position to the second position on the first sheet transport path. The measuring device according to claim 1, characterized in that: 3. A measuring apparatus according to claim 1, wherein said first sheet conveying path is a horizontally extending conveying path. 4. The measuring device according to any one of claims 1 to 3 , wherein the measuring unit is a measuring unit that performs colorimetry. 4. The measuring unit according to any one of claims 1 to 3 , wherein the measuring unit has a reading unit that reads an image formed on the front surface of the sheet and a reading unit that reads the image formed on the back surface of the sheet. The measuring device according to the item. The measurement unit includes a first measurement unit that reads an image pattern formed on a sheet and performs colorimetry, and a first measurement unit that reads image patterns formed on the front surface and the back surface of the sheet and adjusts printing positions on the front and back surfaces. and a second measuring unit that calculates an adjustment amount for
4. The measuring apparatus according to claim 1 , wherein the second measuring section is arranged downstream of the first measuring section in the sheet conveying direction. A conveying speed when the sheet of the measurement job passes through the measuring section of the second sheet conveying path is lower than a conveying speed of the sheet of the print job when conveying the sheet on the first sheet conveying path. 7. The measuring device according to any one of claims 1 to 6 , characterized in that: After the trailing edge of the sheet of the measurement job reaches the first sheet conveying path, the conveying speed of the sheet conveyed along the second sheet conveying path is changed from the first conveying speed to the first 7. The measuring device according to any one of claims 1 to 6 , characterized in that it switches to a second conveying speed that is lower than the conveying speed. an image forming means for forming an image on a sheet according to image forming conditions;
a first sheet conveying path for conveying the sheet conveyed from the image forming unit to a post-processing device connected downstream in the sheet conveying direction;
A second sheet extending downward from a first position in the first sheet transport path and joining the first sheet transport path at a second position downstream of the first position in the sheet transport direction. a transport path;
a measuring unit that measures an image pattern formed on the sheet conveyed along the second sheet conveying path from the image forming unit;
Sheets of a print job not to be measured by the measuring unit are conveyed to the post-processing device along the first sheet conveying path without passing through the second sheet conveying path, and the measuring unit a switching unit that switches the conveying path so as to convey the sheet of the measurement job to be measured to the second sheet conveying path;
correction means for correcting the image forming conditions based on the measurement result of the image pattern formed on the sheet conveyed along the second sheet conveying path;
has
The image forming apparatus , wherein the second sheet conveying path has a curved conveying path and a horizontal conveying path extending in a horizontal direction, and the measuring unit is provided in the horizontal conveying path. . 10. The image forming apparatus according to claim 9 , wherein the image forming condition is a profile for color conversion of input image data. 10. The image forming apparatus according to claim 9 , wherein the image forming condition is a geometric adjustment amount for adjusting the position of the image formed on the sheet.

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