Printing system including charge removing apparatus, method of controlling the same, and program

Abstract

To solve such the problem that it is necessary to properly control charge removing processing by a printing system including a charge removing apparatus in accordance with a toner placed position on a sheet.SOLUTION: A printing system 1000 including a printing apparatus 100 configured to print image data of a print job received via a network on a sheet, and a charge removing apparatus 200-3a configured to perform charge removing processing on the sheet on which the image is printed, has: control means S807 for controlling an application voltage of the charge removing processing based on a use amount of toner for one page of the image data; and displaying means S810 for displaying, in a case where a toner placed region in the one page is deviated, a screen for prompting a user to select whether or not to adjust the application voltage of the charge removing processing, on an operation unit.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a printing system including a static eliminator that eliminates static electricity from a charged recording medium, and a control method and program for the printing system. [Background technology]

[0002] Recording media (hereinafter referred to as "sheets") used in printing operations carry static electricity when transported, either due to residual charge from the electrophotographic process or due to slight friction with transport rollers and guides during sheet transport. This static electricity can cause sheets to stick together. It can also cause dust and paper powder to adhere to the finished product, reducing the quality of the finished product. Plain paper has low electrical resistance, making it easy for charges to move within the paper, and the charge itself is small and dissipates quickly. The toner layer on the sheet acts as a resistor, so even with the same type of sheet, the more toner used, the more likely it is to become charged and the more likely it is that a charge will remain. Furthermore, in the case of double-sided printing, toner layers are formed on both sides of the sheet, making it difficult for charges to move within the paper. As a result, the more toner there is on the sheet, the more likely it is to become charged and the more likely it is that a charge will remain. If post-processing is performed on sheets that are stuck together, this will affect sheet alignment, not only reducing the quality of post-processing but also potentially causing jams during post-processing.

[0003] Therefore, to prevent such risks, it is desirable to remove static electricity from the sheet after the printing process before post-processing is performed.Therefore, a proposal has been made to apply a voltage to a pair of transport rollers located downstream in the sheet transport direction to cancel out the charge on the sheet (see Patent Document 1). Discharge using a configuration in which a voltage is applied to a transport roller (hereinafter referred to as a "discharge roller") cancels static electricity by applying a charge opposite to the charge on the sheet via the discharge roller. Therefore, discharge control using the discharge roller (applying a charge opposite to that of the sheet to the discharge roller) must be performed according to the amount of charge on the sheet. This means that there is an optimal charge adjustment value for discharge depending on the printing environment, such as humidity, and the brand of sheet. If discharge control is performed on a sheet with an inappropriate charge adjustment, it may actually cause charging, which could lead to further sheet sticking. The process of finding the optimum applied voltage value for static elimination (hereinafter referred to as the "adjustment process") determines the optimum applied voltage value for static elimination by setting the applied voltage value to the sheet conveyed from the printing device using a static elimination device with a static elimination roller. The applied voltage value determined in the adjustment process is the optimum applied voltage value for each printing environment and sheet type used in the adjustment process. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 11-258881 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because the toner layer in the area where the toner of the job submitted by the user is actually applied acts as a resistor, the applied voltage value may not be optimal depending on the amount of toner used and the area where the toner is applied, which could lead to sheet sticking. While it is possible to use the print job the user plans to submit for the adjustment process, this requires performing the adjustment process each time before submitting the job, which is time-consuming. Furthermore, if the job contains multiple pages, the optimal applied voltage value differs for each page, which could also lead to sheet sticking. Therefore, it is conceivable that by calculating the amount of toner used and the area where the toner is applied for each page in advance and setting the optimal applied voltage value for each page, it would be possible to provide an appropriate output without paper sticking. However, with this method, the same applied voltage value is set for the same toner usage amount and toner area, so if the toner placement position is biased to one part of the sheet, an inappropriate applied voltage value may be set, which could result in electrostatic adhesion. The present invention has been made to solve the above-mentioned problems, and aims to provide a printing system that appropriately controls the charge removal process according to the toner placement position on the sheet. [Means for solving the problem]

[0006] The present invention is a printing system comprising a printing device that prints image data of a print job received via a network onto a sheet, and a discharge device that discharges the printed sheet, characterized in that it has an adjustment means that adjusts the applied voltage for the discharge process according to the amount of toner used for one page of the image data, and a display means that displays on an operation unit a screen that allows the user to select whether or not to adjust the applied voltage for the discharge process if there is a page that is determined to have an uneven area where toner is applied. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a printing system that appropriately controls the charge removal process in accordance with the toner placement position on the sheet. [Brief explanation of the drawings]

[0008] [Figure 1] Minimum system configuration diagram in this embodiment [Figure 2] Printing device software block diagram [Figure 3] Cross-section of the printing system [Figure 4] 1 is a diagram illustrating an example of an operation unit 204 provided in a printing device. [Figure 5] Software block diagram of static eliminator [Figure 6] An example of an operation unit 502 provided in the static eliminator [Figure 7] Schematic diagram of static elimination processing [Figure 8] Basic Flowchart [Figure 9] Print job example illustration [Figure 10] Flowchart for determining toner usage coefficient [Figure 11] Flowchart for determining the applied voltage value to be adjusted [Figure 12] Other print job example diagrams [Figure 13] Table for calculating deviation due to toner placement position [Figure 14] UI screen when uneven toner placement is detected [Figure 15] UI screen for adjusting applied voltage using user images DETAILED DESCRIPTION OF THE INVENTION

[0009] [Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the components described in the embodiments are merely examples and are not intended to limit the scope of the present invention. Overall system configuration 1 shows the simplest configuration of this embodiment, which includes a printing system 1000 and a client computer 102 (hereinafter referred to as "PC"), which is an information processing device, which are connected to each other via a network 101. The PC 102 can transmit PDL (page description language) code data, which is a print job, to the printing system 1000 via the network 101. Printing system hardware configuration FIG. 2 is a block diagram illustrating an example of the hardware configuration of the printing system 1000. As shown in FIG. The printing system 1000 includes a printing apparatus 100, which is enclosed by a dotted line in the figure, and a sheet processing apparatus 200. Any number of sheet processing apparatuses 200 can be connected to the printing apparatus 100. In this embodiment, the printing apparatus 100 will be described as an MFP (Multi Function Peripheral) having multiple functions, such as a copy function and a printer function. However, the printing apparatus 100 may also be a single-function printing apparatus having only a copy function or only a printer function. In this embodiment, as an example, the printing system 1000 is assumed to have the various components described below.

[0010] The printing system 1000 is configured so that sheet processing for sheets printed by the printing device 100 can be performed by a sheet processing apparatus 200 connected to the printing device 100. However, it is also possible to configure the printing system 1000 using only the printing device 100 without connecting the sheet processing apparatus 200. The sheet processing apparatus 200 is configured to be able to communicate with the printing apparatus 100, and can receive instructions from the printing apparatus 100 and perform sheet processing as described below. (Printing device) The scanner unit 201 reads an image on a document, converts it into image data, and transfers it to other units. The external I / F 202 transmits and receives data to and from other devices connected to the network 101. The printer unit 203 prints an image based on input image data onto a sheet. The operation unit 204 has a configuration as shown in Fig. 4, and includes a hard key input unit (key input unit) 402 and a touch panel unit 401, through which instructions from the user are received. The operation unit 204 also displays various information on the touch panel unit 401.

[0011] The control unit 205 is, for example, a CPU (Central Processing Unit). The control unit 205 comprehensively controls the processing and operation of various units included in the printing system 1000. In other words, the control unit 205 also controls the operation of the printing apparatus 100 and the sheet processing apparatus 200 connected to the printing apparatus 100. The ROM 207 stores various computer programs executed by the control unit 205. For example, the ROM 207 stores a program for causing the control unit 205 to execute various processes in flowcharts described below, and a display control program required to display various setting screens described below. The ROM 207 also stores a program for the control unit 205 to interpret PDL code data received from the PC 102, which is an information processing device, and expand it into raster image data (image data). The ROM 207 also stores boot sequence information, font information, etc. The RAM 208 stores image data and PDL code data sent from the scanner unit 201 and external I / F 202, various programs loaded from the ROM 207, and setting information. The RAM 208 also stores information related to the sheet processing apparatus 200 (such as information related to the type and function of each sheet processing apparatus 200 connected to the printing apparatus 100). The control unit 205 can use the information related to the sheet processing apparatus 200 stored in the RAM 208 for control. The HDD (hard disk drive) 209 is composed of a hard disk and a drive unit that reads and writes data from and to the hard disk. The HDD 209 is a large-capacity storage device for storing scanned image data input from the scanner unit 201 and compressed by the compression / decompression unit 210. The control unit 205 can print image data stored in the HDD 209 using the printer unit 203 based on instructions from the user. The HDD 209 is also used as a spooler, and the control unit 205 can manage PDL code data received from the PC 102 as print jobs and store them in the HDD 209. The control unit 205 can also manage print jobs stored in the HDD 209 and obtain the number of print jobs stored and setting information for the print jobs. The compression / decompression unit 210 compresses and decompresses image data stored in the RAM 208 and HDD 209 using various compression methods such as JBIG and JPEG. The HDD 209 stores optimal applied voltage values for each sheet type as sheet parameters. These sheet parameters are values written as defaults as recommended values for each sheet type when the printing apparatus 100 is shipped from the factory. When the user turns on the static elimination function and selects a sheet for printing, the applied voltage value set for the selected sheet type is read from the HDD 209 and reflected. When the control unit 205 receives the applied voltage value for the sheet determined in the adjustment process via the operation unit 204, it updates the sheet parameters corresponding to the sheet type and stores them in the HDD 209. The control unit 205 also calculates the amount of toner used when printing on the sheet from the input image data and image data stored in the HDD 209, and further adjusts the applied voltage value stored in the HDD 209 according to the amount of toner used to obtain the optimal applied voltage value.

[0012] Printing system configuration details Next, the configuration of the printing system 1000 will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view of the printing device 100 and the sheet processing device 200 connected to the printing device 100. In this figure, the sheet processing device 200 is configured to include a static eliminator 200-3a and a saddle stitcher 200-3b. (Printing device) First, the printing device 100 will be described. An automatic document feeder (ADF) 301 separates a stack of documents set on the loading surface of a document tray in page order, starting with the first page, and transports them onto a document glass platen for scanning by a scanner 302. The scanner 302 reads an image of an original conveyed onto a platen glass, and converts the image into image data using a CCD. A rotating polygon mirror (polygon mirror or the like) 303 receives a beam of light, such as a laser beam, modulated according to image data, and irradiates the beam as reflected scanning light onto a photosensitive drum 304 via a reflecting mirror. A latent image formed on the photosensitive drum 304 by the laser beam is developed with toner, and the toner image is transferred to a sheet material attached to a transfer drum 305. A full-color image is formed by sequentially performing this series of image formation processes for yellow (Y), magenta (M), cyan (C), and black (K) toners. After four image formation processes, the sheet material on the transfer drum 305 with the full-color image formed thereon is separated by a separation claw 306 and conveyed to a fixing device 308 by a pre-fixing conveyor 307. The fixing device 308 is made up of a combination of rollers and belts, and has a built-in heat source such as a halogen heater, and melts and fixes the toner on the sheet material onto which the toner image has been transferred, by using heat and pressure. The discharge flapper 309 is configured to be swingable around a swing axis and determines the conveying direction of the sheet material. When the discharge flapper 309 swings clockwise in the figure, the sheet material is conveyed straight and is discharged outside the machine by the discharge rollers 310. The control unit 205 controls the printing device 100 to perform single-sided printing through the above-described sequence.

[0013] On the other hand, when forming images on both sides of the sheet material, the discharge flapper 309 swings counterclockwise in the figure, and the sheet material is changed course downward and sent to the double-sided conveying section, which includes a reversing flapper 311, a reversing roller 312, a reversing guide 313, and a double-sided tray 314. The reversing flapper 311 swings around a swing axis to determine the conveyance direction of the sheet material. When processing a double-sided printing job, the control unit 205 controls the reversing flapper 311 to swing counterclockwise in the figure after printing on the first side of the sheet in the printer unit 203, and to feed the sheet into the reversing guide 313 via the reversing roller 312. Then, with the trailing edge of the sheet material sandwiched between the reversing roller 312, the control unit 205 temporarily stops the reversing roller 312, and then causes the reversing flapper 311 to swing clockwise in the figure, causing the reversing roller 312 to rotate in the reverse direction. This causes the sheet to switch back and be conveyed, and controls the sheet to be guided to the double-sided tray 314 with the trailing edge and leading edge of the sheet swapped.

[0014] The sheet material is temporarily stacked in the double-sided tray 314, and then the sheet material is sent again to the registration rollers 316 by the re-feed rollers 315. At this time, the sheet material is sent so that the side opposite to the first side transfer process faces the photosensitive drum. Then, in the same process as described above, a second-side image is formed on the second side of the sheet. Then, after the images are formed on both sides of the sheet material and the sheet undergoes a fixing process, it is discharged from inside the main body of the printing apparatus 100 to the outside via the discharge rollers 310. The control unit 205 controls the printing device 100 to perform double-sided printing through the above-described series of sequences. The printing device 100 also has a paper feed unit that stores sheets required for printing. The paper feed unit includes paper feed cassettes 317 and 318 (each capable of storing, for example, 500 sheets), paper feed deck 319 (capable of storing, for example, 5,000 sheets), and manual feed tray 320. Various sheets of different sizes and materials can be set in paper feed cassettes 317 and 318 and paper feed deck 319, separated into the respective paper feed units. Furthermore, various types of sheets, including special sheets such as overhead projector sheets, can be set in manual feed tray 320.

[0015] (static eliminator) Next, the static eliminator 200-3a will be described. 5 is a system block diagram of the static eliminator 200-3a. The static eliminator also has a control unit 501 separate from the printing device 100. The control unit 501 is, for example, a CPU (Central Processing Unit). This control unit 501 controls and manages the entire static eliminator 200-3a while communicating with the control unit 205 of the printing device 100 in FIG. 2 via a bus (not shown). <Operation section> The operation unit 502 has a configuration as shown in FIG. 6, and the user can perform settings for the static eliminator 200-3a via the operation unit 502. The mode setting switch 601 in FIG. 6 switches whether or not static elimination is performed by the static elimination device 200-3a (ON / OFF), and the control unit 501 controls the static elimination processing unit 503 (described later) to execute static elimination processing only when the switch is ON. Furthermore, the adjustment dial 602, which is configured as a thumb rotary switch, adjusts the strength of the static elimination control that is performed when the mode setting switch 601 is ON, and is controlled by the control unit 501 so that it is effective only when the mode setting switch 601 is ON. The adjustment dial 602 sets the voltage value to be applied from the voltage application controller 321 to the static elimination roller 322, and can be set to a value between "00" and "99." For example, setting the adjustment dial 602 to "10" indicates that an applied voltage value of +1.0 [kV] is to be set. If the maximum applied voltage of the static elimination roller is +6.0 [kV], even if the adjustment dial 602 is set to "61" to "99", the applied voltage value will be fixed at +6.0 [kV], and it is not possible to set an applied voltage higher than this. Generally, the optimal applied voltage value for the sheet to be used in that environment is determined by adjusting the adjustment dial 602, and then that applied voltage value is set and printing is performed. For example, if a sheet is charged to −6 kV during transfer by the adjustment process, setting the applied voltage to +6 kV reduces the sheet charge to 0 kV (de-electrified). In this case, by setting the adjustment dial 602 to “60,” the voltage application controller 321 controls the charge removal roller 322 to +6 kV, thereby eliminating static electricity from the conveyed sheet. Note that the optimal applied voltage varies depending on the sheet characteristics and the operating environment of the static removal device 200-3a. Therefore, when printing on a sheet that is prone to static electricity, it is desirable to determine the applied voltage value through the adjustment process before printing and then start the printing process. In this embodiment, the operation unit 502 is described as being configured with a physical mode setting switch and thumb rotary switch. However, the touch panel unit 401 (FIG. 4) of the operation unit 204 can also be used to display, turn on / off, and change the applied voltage value on the UI. In this case, the control unit 205 of the printing device 100 communicates with the control unit 501 via a bus not shown, provides the information input to the operation unit 204, and the control unit 501, upon receiving this, provides the information necessary for the static elimination processing described below to the static elimination processing unit 503.

[0016] The static elimination processing unit 503 is made up of a static elimination roller 322 and an ionizer 323, which will be described later, and a voltage application controller 321 for each of them, and is responsible for eliminating static electricity from the conveyed sheet. The control unit 501 controls the application of voltage to the static elimination roller 322 and the ionizer 323 via the voltage application controller 321. The ROM 504 stores a boot program for the static eliminator 200-3a, a control program for the operation unit 502, a static elimination processing program for the static elimination processing unit 503, etc. The control unit 501 then loads necessary programs from the ROM 504 into the RAM 505 as needed and executes them. -Static elimination treatment Here, the static elimination process performed by static elimination processing unit 503 will be further explained using FIG. 7. FIG. 7 is a diagram that schematically shows how static elimination device 200-3a performs static elimination on a sheet that has been printed by printing apparatus 100. First, sheet 701 is transported via transport path 710 to a developing and transferring unit consisting of photosensitive drum 304 and transfer drum 305, where toner is placed on sheet 701. Charged toner 702 placed on sheet 701 is negatively charged, and after the toner is fixed through fuser 308, the sheet is transported to static elimination device 200-3a with the print surface 703 side negatively charged. The static elimination device 200-3a is equipped with a positively charged static elimination roller 322, which applies a positive charge (applied voltage value) to the negatively charged print surface 703 by contact static elimination with the roller, thereby eliminating the charge. The static elimination roller 322 performs static elimination processing using an applied voltage value set by the control unit 501, but by changing the amount of charge midway through the process using the control unit 501, it is possible to change the static elimination effect for each region on a single sheet by changing the voltage applied to the sheet midway through the process. However, it is expected that negative charges that were not completely removed by the static elimination processing by the static elimination roller 322, or conversely charged positive charges, will remain on the sheet 705 after it has passed through the static elimination roller. Therefore, the static eliminator 200-3a of this embodiment is further configured to include an ionizer 323 downstream of the static elimination roller 322. The ionizer 323 is a device that applies a voltage to an electrode needle provided within the device to generate a corona discharge and uses the ions thus generated to eliminate the charge. In this way, by performing rough static elimination with the static elimination roller 322 and then adjusting the remaining charge with the ionizer, the static elimination-processed sheet 707 discharged from the static eliminator 200-3a is in a neutralized state. 3, the static eliminator 200-3a has a static eliminator roller 322 and its paired roller, and the sheet conveyed to the static eliminator 200-3a is conveyed while being sandwiched between the two rollers, and is subjected to rough static elimination by the static eliminator roller 322. Thereafter, the sheet is conveyed outside the apparatus by conveyance roller 324, and the remaining charge is removed by ionizer 323.

[0017] (saddle stitching machine) Next, the saddle stitching machine 200-3b will be described. Sheet processing by the saddle stitching machine 200-3b includes, for example, saddle stitching, punching, cutting, shift discharge, folding, stapling, etc. Here, these jobs are called "saddle stitching jobs." When processing a saddle stitching job, the control unit 205 first conveys the sheets of this job printed by the printing apparatus 100 to the saddle stitching machine 200-3b, and then causes the saddle stitching machine 200-3b to perform sheet processing for this job. The control unit 205 then causes the printed material of the saddle stitching job, which has undergone sheet processing by the saddle stitching machine 200-3b, to be held in the paper discharge destination Z of the saddle stitching machine 200-3b. Note that there are multiple paper discharge destination candidates for the paper discharge destination Z. This is used when the saddle stitching machine 200-3b can perform multiple types of sheet processing and separates the paper discharge destinations for each sheet processing. In this embodiment, a detailed description of the conveyance procedure for a saddle stitching job will be omitted.

[0018] -Static elimination setting process Next, the processing described in this paper will be explained using the flowchart in FIG. 8. For the sake of explanation, the flow will be described in which the received print job prints and neutralizes image 900 in FIG. 9 and images 1201 and 1202 in FIG. 12. Image 900 and images 1201 and 1202 are A4 data, and "image" here refers to the image formed on each page of the print job before RIP processing. In this embodiment, PDL will be described as the print job, but other print jobs such as copying may also be used. First, in S801, the control unit 205 of the printing device 100 acquires whether the static elimination process of the static eliminator 200-3a is ON or OFF. This process is realized when the control unit 501 of the static eliminator 200-3a, which has received an inquiry from the control unit 205 of the printing device 100, acquires the state of the mode setting switch 601 of the operation unit 502 of the static eliminator 200-3a and the applied voltage value set with the adjustment dial 602. The control unit 501 of the static eliminator 200-3a then sends a reply to the control unit 205 of the printing device 100. Next, in S802, the control unit 205 of the printing apparatus 100 displays on the operation unit 204 of the printing apparatus 100 the ON / OFF state of the static elimination process of the static eliminator 200-3a and the applied voltage value acquired in S801. In S803, the control unit 205 of the printing device 100 determines whether a print job has been submitted. If a print job has not been submitted (if No is determined in S803), the control unit 205 returns the process to S801 and continues to display the ON / OFF status of the static elimination process. On the other hand, if a print job has been submitted (if Yes is determined in S803), the control unit 205 of the printing device 100 proceeds to S804. In S804, image 900 is interpreted as PDL data and RIP processing is performed. Figure 9 shows an example of image data 911 to 913, in which the coordinate values of each pixel in image 900 and the cyan, magenta, yellow, and black (CMYK) gradation values (0 to 255) of those pixels are converted into image data through RIP processing. For example, image data 911 indicates that the color (C,M,Y,K) = (0,0,0,0) is applied to the pixel at coordinates (2500,100).

[0019] In S805, the control unit 205 acquires the ON / OFF state of the static elimination process of the static elimination device 200-3a. If the static elimination process is ON (Yes in S805), the control unit 205 proceeds to S806. On the other hand, if the static elimination process is OFF (No in S805), the control unit 205 sets the applied voltage value to 0 and proceeds to S814. (Calculation process of correction value of applied voltage) The processing in S806 will now be described with reference to the flowchart in FIG. S806 is a process for calculating the amount of toner required for printing from the image data and determining a coefficient that will result in an appropriate applied voltage value according to the amount of toner used, in order to derive the optimal applied voltage value for the received image data. In S1001, the control unit 205 of the printing device 100 converts the image data for each pixel using a toner usage table to calculate the amount of toner required for each pixel. The toner usage table is a table for converting the amount of toner from the density of each of CMYK. Using the data in FIG. 9 as an example, image data 912 is converted using the toner usage table in S1001 to derive toner usage data 922. Note that image data, toner usage data, and toner usage amounts (described later) exist for all pixels within a page, but for the sake of explanation, this embodiment will use image data 911 to 913 as an example. The toner usage data 922 indicates that the pixel at coordinates (2500, 3000) requires toner amounts (0 to 255) for each color (C, M, Y, K) = (200, 200, 200, 255). Furthermore, a value representing the total toner required for this pixel in a range of 0 to 255 is calculated as the toner usage amount. If the toner usage data 922 is (200+200+200+255) / (255+255+255+255)×255=214 , and the toner usage amount 932 can be calculated as 214. When the toner usage amount data 921 and 923 are calculated in the same way, the toner usage amount 931 becomes 0 and the toner usage amount 933 becomes 214. The control unit 205 adds up the calculated amounts of toner used and calculates the amount of toner used for one page. In this embodiment, the toner usage amount 940 for one page is calculated by assuming that the colored area of the image 900 is 4000×7000=28,000,000 and the toner usage amount per pixel is 214. The result is as follows: 28,000,000×214=5,992,000,000 This amounts to 940 toner used per page. Although the details of the calculations are omitted for the image data of FIG. 12, similar calculations were performed, and the toner usage for one page of images 1201 and 1202 is assumed to be 5,992,000,000, the same as for image 900.

[0020] In S1003, the control unit 205 determines a toner usage coefficient from the toner usage for one page. The toner usage coefficient is a coefficient for correcting the currently set applied voltage value by the amount of toner usage. Here, a coefficient is derived assuming that 100% is when toner is applied to the entire sheet. Since the image 900 is A4 size (total number of pixels: 4960 x 7015) and the maximum toner usage is 255, the maximum toner usage for the sheet is 4960×7015×255=8,872,572,000 In other words, with a toner usage coefficient of 950, 5,992,000,000 / 8,872,572,000×100=67.5% 12, images 1201 and 1202 are the same A4 size as image 900 and have the same toner usage per page, so the toner usage coefficient is also the same as image 900, 67.5%. In this embodiment, steps S804 to S806 have been described as the process in which the control unit 205 of the printing device 100 calculates a correction value for the applied voltage value for image data after RIP processing. However, these steps may also be performed by the PC 102, which is an information processing device, before transmitting a print job. In this case, the PC 102 inputs the applied voltage value (or a correction value for the applied voltage value) as a sheet parameter along with the PDL data to be transmitted. The control unit 205 of the printing device 100 then stores the applied voltage value as a sheet parameter in the HDD 209 upon receiving the print job. In this case, the control unit 205 does not perform step S806, but instead proceeds to the next step S807 using the received applied voltage value.

[0021] (Applied voltage adjustment process) In S807, the control unit 205 adjusts the applied voltage value using the toner usage amount coefficient calculated in S806. The processing of S807 will now be described with reference to the flowchart of Fig. 11. S807 is processing for finding the optimum applied voltage value for the received print job by adjusting the applied voltage value preset in the printing device 100 using the toner usage coefficient. In S1101, the control unit 205 acquires an applied voltage value from the sheet parameters set for each sheet type of the print job in the static eliminator 200-3a from the control unit 501. In this embodiment, the acquired applied voltage value is set to +3 kV. In S1102, the control unit 205 adjusts the applied voltage value for image 900 from the toner usage coefficient 950 calculated in S806 based on the acquired applied voltage value. The adjustment is performed by first measuring the charge state (applied voltage value set in the sheet parameters) of a blank sheet (without toner) of that sheet type and the charge state of a full solid image (C, M, Y, K) = (255, 255, 255, 255). The toner usage coefficient is then calculated by multiplying the charge difference between these values. For example, if the charge amount of the blank sheet is -1.0 kV and the charge amount of the full solid image is -7.0 kV, this indicates that the toner layer will charge up to -6.0 kV. Based on this, the applied voltage value is calculated by adjusting the applied voltage value according to the toner usage amount to offset this. In this embodiment, since the toner usage coefficient is 67.5%, the charge amount of image 900 is: (-1.0) + (-6.0 × 0.675) = -5.1 [kV] In order to offset this, the control unit 205 sets +5.1 kV as the applied voltage value in the static elimination processing unit 503 via the control unit 501. In S1103, the control unit 205 resets the applied voltage value calculated in S1102 to the control unit 501 of the static eliminator 200-3a. In the above example, in step S1102, the flow for adjusting the applied voltage value was described, where a state in which toner is applied to the entire sheet, starting from blank paper, is set to 100%. However, depending on the sheet, the required applied voltage value may not necessarily be proportional to the amount of toner used, so the applied voltage value may be adjusted in stages to match the sheet characteristics. For example, the applied voltage value may be adjusted in stages, such that no adjustment is required when the toner usage coefficient is 70 or less, +1 kV for values between 71 and 90, and +2 kV for values between 91 and 100.

[0022] Returning to the explanation of the flowchart in FIG. In S808, the control unit 205 of the printing device 100 acquires the toner placement position within the page and calculates whether there is a bias based on the variance value. Specifically, as a calculation method, the control unit 205 divides the page into multiple regions and calculates the toner usage amount for each divided region. In this embodiment, an example in which the page is divided into four equal parts will be described, but the means for obtaining the variance value for the toner usage amount is not limited, and calculation can be performed from the toner usage amount for each pixel, or by scan line or block. The control unit 205 calculates the toner usage amounts for the first to fourth regions of the four divided images 900, 1201, and 1202 in the same manner as described in S806. The results are summarized in table 1300 in FIG. 13 (M is Mega = 10 6(The following expression represents the difference between the average toner usage amount and the standard deviation.) The average toner usage amount for each region of image 900, image 1201, and image 1202 is 1498 M, and the variance values (standard deviation) are 898.8 M and 0.2594.6 M for image 900, image 1201, and image 1202, respectively. To determine whether an image has a bias, a threshold value within the average value ± standard deviation is used. Images with regions with toner usage amounts exceeding the threshold are determined to be biased. The control unit 205 determines that there is no bias in image 900 and image 1201 because the toner usage amounts in both regions are within the threshold. Image 1202 is determined to have a bias because the first region exceeds the threshold. In this embodiment, the variance value is used statistically to determine whether there is a bias in the toner application position within a page. However, the method for determining whether there is a bias in the toner application position within a page is not limited to certain methods. For example, an image may be divided and compared with a fixed toner usage amount as a threshold. If a certain number of regions exceed the threshold, the image may be deemed to have a bias.

[0023] In S809, if the control unit 205 of the printing device 100 determines from the result calculated in S808 that there is a bias in the toner placement position within the page (Yes in S809), the control unit 205 proceeds to S810. On the other hand, if it determines that there is no bias (No in S809), the control unit 205 assumes that the optimal applied voltage value has been set and proceeds to S814. In step S810, which is the case when there is a bias in the toner placement position, the calculated applied voltage value may not be optimal, which may result in electrostatic adhesion. Therefore, the control unit 205 of the printing apparatus 100 displays a screen on the operation unit 204 that prompts the user to select whether to continue printing or adjust the applied voltage value. The screen that the control unit 205 causes the operation unit 204 to display will be described with reference to a screen 1400 in FIG. Screen 1400 prompts the user to reset the applied voltage value to match the print job submitted, rather than the current setting and the applied voltage value adjusted from that setting, based on the results of analyzing the toner usage and its location for the submitted print job. Screen 1401 informs the user that the current applied voltage value may cause electrostatic adhesion, and presents the user with the options to resolve the issue: to continue "printing" with the current applied voltage value, or to "adjust" the applied voltage value again. When the operation unit 204 detects that the [Job Details] button 1402 has been pressed, the control unit 205 displays on the operation unit 204 detailed information such as which page of the print job exceeded the threshold. In S811, if the operation unit 204 detects that the [Adjust Applied Voltage Value] button 1403 has been pressed using a user image, i.e., if there has been a user instruction for readjustment (Yes in S811), the control unit 205 proceeds to S812. If the operation unit 204 detects that the [Print] button 1404 has been pressed, i.e., if there has not been a user instruction for readjustment (No in S811), the control unit 205 proceeds to S814.

[0024] In S812, the control unit 205 of the printing apparatus 100 cancels the submitted print job. In S813, the control unit 205 displays an applied voltage value adjustment screen based on a user image on the operation unit 204. The screen displayed on the operation unit 204 in S813 will be described using screen 1500 in FIG. 15. When adjusting the applied voltage value based on a user image, adjustments are made using the print job used by the user, rather than a chart stored in the printing apparatus 100, so it is possible to set the optimal applied voltage value for that print job. For this reason, screen 1501 displays information for selecting the type of sheet to be corrected for the print job. Screen 1502 indicates that the sheet sizes stored in each cassette are A4 for cassette 1, A3 for cassette 2, and A5 for cassette 3, and that the sheet type for each sheet is plain paper 1. When the operation unit 204 detects that the [detailed information] button 1503 has been pressed, the control unit 205 displays detailed information about each cassette on the operation unit 204 . When the operation unit 204 detects that the [Start Adjustment] button 1504 has been pressed, the control unit 205 adjusts the applied voltage value using the user image. At this point, the processing flow in FIG. 8 ends. When the operation unit 204 detects that the [Cancel] button 1505 has been pressed, the control unit 205 cancels the adjustment of the applied voltage value using the user image. In this case, the processing flow in FIG. 8 also ends. If there is no bias in the toner placement position within the page or if there is no instruction to readjust the applied voltage, in S814 the control unit 205 executes printing processing in the printing device 100, and performs static elimination processing in the static eliminator 200-3a using the applied voltage value adjusted in S807. Note that when printing is executed without an instruction to readjust the applied voltage, it is also possible to specify the paper discharge destination Z. If the state of the static elimination process is OFF, the printing process is executed in S814, and the static elimination process is not executed thereafter. After the printing process in S814 is completed, this process ends. As described above, by notifying the user to readjust when there is a possibility that the applied voltage value will not be optimal depending on the amount of toner used on the sheet to be printed and the toner placement position, it is possible to prevent unexpected paper discharge adhesion and provide an appropriate output. In the above embodiment, if there is uneven toner deposition, a screen is displayed asking the user whether or not to readjust the applied voltage for the static elimination process, but static elimination may also be performed by dividing the print area into multiple areas and applying variable applied voltages. Specifically, this is realized by the static elimination process applied voltage control means controlling the static elimination roller and ionizer so that an applied voltage corresponding to the amount of charge in the area through which the sheet passes is applied.

[0025] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions. The disclosure of this embodiment includes the following configuration, method, and program. (Configuration 1) A printing system including a printing device that prints image data of a print job received via a network onto a sheet, and a static eliminator that performs static elimination processing on the printed sheet, an adjusting means for adjusting the applied voltage for the charge removal process in accordance with the amount of toner used for one page of the image data; When a page is found to have a biased toner area, a display unit is provided to display a screen on the operation unit that allows the user to select whether or not to adjust the applied voltage for the charge removal process. A printing system characterized by: (Configuration 2) The bias in the area where toner is applied is determined by dividing one page of a print job into multiple areas and judging the variance of the amount of toner used in each area. 2. The printing system according to configuration 1, (Configuration 3) When an instruction to adjust the applied voltage for the static elimination process is received on the screen, the print job is canceled. 3. The printing system according to configuration 1 or 2. (Configuration 4) The applied voltage value for the static elimination process for each page of the print job is calculated from the image data that has been RIP-processed. 4. The printing system according to any one of configurations 1 to 3. (Configuration 5) The applied voltage value for the static elimination process for each page of the print job is calculated by the information processing apparatus that transmits the print job. 4. The printing system according to any one of configurations 1 to 3. (Method 1) A control method for a printing system including a printing device that prints image data of a print job received via a network onto a sheet, and a static eliminator that performs static elimination processing on the printed sheet, an adjusting step of adjusting an applied voltage for the static elimination process in accordance with the amount of toner used for one page of the image data; a display step of displaying a screen on an operation unit that allows a user to select whether or not to adjust the applied voltage for the static elimination process when there is a page that is determined to have a bias in the area where the toner is applied; A method for controlling a printing system. (Program 1) A program for causing a computer to execute the printing system control method described in Method 1. [Explanation of symbols]

[0026] 205 Control section 205 200-3a Static eliminator 501 Control section 503 Static elimination processing unit 322 Anti-static roller

Claims

1. A printing system including a printing device that prints image data of a print job received via a network onto a sheet, and a static eliminator that performs static elimination processing on the printed sheet, an adjusting means for adjusting the applied voltage for the charge removal process in accordance with the amount of toner used for one page of the image data; When a page is found to have a biased toner area, a display unit is provided to display a screen on the operation unit that allows the user to select whether or not to adjust the applied voltage for the charge removal process. A printing system characterized by:

2. The bias in the area where toner is applied is determined by dividing one page of a print job into multiple areas and judging the variance of the amount of toner used in each area.

2. The printing system according to claim 1.

3. When an instruction to adjust the applied voltage for the static elimination process is received on the screen, the print job is canceled.

3. The printing system according to claim 1, wherein the printing system includes: a printer;

4. The applied voltage value for the static elimination process for each page of the print job is calculated from the image data that has been RIP-processed.

3. The printing system according to claim 1, wherein the printing system includes: a printer;

5. The applied voltage value for the static elimination process for each page of the print job is calculated by the information processing apparatus that transmits the print job.

3. The printing system according to claim 1, wherein the printing system includes: a printer;

6. A control method for a printing system including a printing device that prints image data of a print job received via a network onto a sheet, and a static eliminator that performs static elimination processing on the printed sheet, an adjusting step of adjusting an applied voltage for the static elimination process in accordance with the amount of toner used for one page of the image data; a display step of displaying a screen on an operation unit that allows a user to select whether or not to adjust the applied voltage for the static elimination process when there is a page that is determined to have a bias in the area where the toner is applied; A method for controlling a printing system.

7. 7. A program for causing a computer to execute the printing system control method according to claim 6.

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