Printing system including static eliminator, control method of the same and program

Abstract

To solve the problem that when conveyance paths on which sheets are conveyed in a printer are different, charging amounts when the sheet is discharged from the printer are different, and the sheet is stuck.SOLUTION: A printing system 1,000 including a printer (100) for executing printing on a sheet and a static eliminator (200-3a) for performing static elimination processing of the sheet has: determination means (S807) for determining a sheet conveyance path on the basis of a printing job; and setting means (S808) for setting an applied voltage value in the static elimination processing according to the determined sheet conveyance path.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 printed sheet, and a control method and program for the printing system. [Background technology]

[0002] Recording media used in printing (hereafter referred to as "sheets") are transported with static electricity, either due to residual charge in the electrophotographic process or due to slight friction with transport rollers and guides that occurs during sheet transport. This static electricity can cause sheets of paper to stick together. It can also cause dust and paper powder to adhere to the finished product, resulting in a decrease in the quality of the finished product. Here, since ordinary paper has a low electrical resistance and charges move easily within the sheet, the charge amount itself is small and is quickly eliminated, but the toner layer on the sheet acts as a resistor. Therefore, 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 to retain charge. Furthermore, in the case of double-sided printing, toner layers are formed on the front and back of the sheet, making it difficult for charge to move within the sheet. As a result, the more toner is placed on the sheet, the more likely it is to become charged and the more likely it is that a charge will remain. Also, the tendency for charging to vary depending on the material of the sheet. For example, synthetic paper made mainly from synthetic resin has a high volume resistance and tends to retain charge. The above are examples of factors that tend to cause charges to remain, but there are also factors that can eliminate charges. For example, printing devices that use electrophotographic processes are generally installed with a ground wire connected. In this case, the charge on the sheet tends to move from the sheet through the transport rollers and guides, and the static electricity on the sheet tends to be eliminated. In this way, the amount of static electricity remaining on the sheet when it is discharged from the printing device is determined by factors that tend to cause charges to be easily charged and to remain, and factors that tend to cause charges to be easily eliminated and to not remain. If post-processing is performed in a state where sheets are stuck together due to the static electricity remaining on the sheets caused by these multiple factors, it will affect the sheet alignment process and reduce the quality of the post-processing.In addition, it may lead to a jam (sheet jam) when the discharged sheets are set in an offline finisher and post-processing is performed there.

[0003] Therefore, it is desirable to remove static electricity from the sheet after the printing process before performing post-processing. 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 the charge on the sheet. (See Patent Document 1) In the case of removing static electricity using a configuration in which a voltage is applied to a transport roller (hereinafter referred to as a "discharging roller"), a charge opposite to the charge on the sheet is applied to the sheet through the discharging roller, thereby canceling the static electricity. Therefore, the control of removing static electricity using the discharging roller (application of a charge opposite to that of the sheet to the discharging roller) needs to be performed according to the amount of charge on the sheet. In other words, this means that there is an optimal charge adjustment value for removing static electricity for each printing environment such as humidity and each brand of sheet. If the control of removing static electricity is performed on the sheet in an inappropriate charge adjustment state, it may cause charging on the contrary, which may lead to further sticking of the sheet. In the process of finding the optimum applied voltage value for static elimination (hereinafter referred to as the "adjustment process"), the optimum applied voltage value for static elimination is determined by setting the applied voltage value by a static elimination device having a static elimination roller for the sheet conveyed from the printing device. The applied voltage value determined in the adjustment process is the optimum applied voltage value for the 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, even if the applied voltage value is set for each sheet in the adjustment process, if the transport path along which the sheet is transported in the printing device when the sheet is printed is different, the amount of charge on the sheet when it is discharged from the printing device will also be different. In that case, depending on the transport path, the applied voltage value is not optimal, which can lead to the sheet sticking. In view of the above-mentioned problems, an object of the present invention is to provide a mechanism for appropriately removing static electricity from a sheet having a different amount of charge due to a difference in the sheet transport path. [Means for solving the problem]

[0006] The present invention is a printing system including a printing device that prints on a sheet and a discharge device that performs a discharge process on the sheet, and is characterized in having a determination means that determines a sheet transport path based on a print job, and a setting means that sets an applied voltage value in the discharge process in accordance with the determined sheet transport path. Effect of the Invention

[0007] According to the present invention, it is possible to perform appropriate static elimination even on a sheet whose charge amount has changed due to a difference in the sheet transport path. [Brief description of the drawings]

[0008] [Figure 1] Overall configuration diagram of the system according to this embodiment [Diagram 2] Hardware block diagram of the printing device [Diagram 3] Cross-section of the printing system [Figure 4] FIG. 1 is a diagram illustrating an example of an operation unit provided in a printing device. [Diagram 5] Hardware block diagram of the static eliminator [Figure 6] An example of an operation unit provided in a static eliminator [Figure 7] Schematic diagram of static elimination processing [Figure 8] Basic flow chart of this embodiment [Figure 9A] 13 is an example of an application voltage setting screen in the printing device of the present embodiment. [Figure 9B] 13 is an example of an application voltage setting screen in the printing device of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the components described in the embodiment are merely examples, and are not intended to limit the scope of the present invention. (Embodiment 1)

[0010] Overall system configuration Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 shows the overall configuration of the system of this embodiment, which includes a printing system 1000 and a client computer 102 (hereinafter referred to as "PC"), which are connected to each other via a network 101. The PC 102 is capable of transmitting PDL (Page Description Language) code data, which is a print job, to the printing system 1000 via the network 101.

[0011] Printing system hardware configuration (block diagram) Next, FIG. 2 is a block diagram showing the hardware configuration of the printing system 1000. 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 example of an MFP (Multi Function Peripheral) having multiple functions such as a copy function and a printer function. However, the printing apparatus 100 may 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 various components described below. 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 execute sheet processing as described below. A 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 the input image data onto a sheet. 4, the operation unit 204 has a hard key input unit 402 and a touch panel unit 401, and receives instructions from a user via them. The operation unit 204 also displays various information on the touch panel unit 401 that the operation unit 204 has.

[0012] The control unit 205 is a so-called CPU (Central Processing Unit) and controls the overall processing and operation of various units included in the printing system 1000. In other words, it 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 of flowcharts described later, and a display control program required for displaying various setting screens described later. The ROM 207 also stores a program for the control unit 205 to interpret PDL code data received from the PC 102 and expand it into raster image data (image data). The ROM 207 also stores a boot sequence, font information, and the like. The RAM 208 stores image data and PDL code data sent from the scanner unit 201 and the 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 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 by the printer unit 203 based on an instruction from a 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 a print job and store it in the HDD 209. The control unit 205 can also manage print jobs stored in the HDD 209, and can also acquire the number of print jobs stored and setting information made for the print jobs. In addition, the HDD 209 stores an optimum applied voltage value for each type as a parameter. This parameter is a value written as a default recommended value for each type when the printing device 100 is shipped from the factory. When the user turns on the static elimination function and selects printing, the applied voltage value set for the selected type is read from the HDD 209 and reflected. When the control unit 205 receives the applied voltage value for the selected type determined in the adjustment process via the operation unit 204, it updates the parameter corresponding to the type and stores it in the HDD 209. In addition, as described later, in the static elimination process, the control unit 205 calculates the amount of toner used when printing on a sheet from the input image data and the image data stored in the HDD 209. Then, the applied voltage value stored in the HDD 209 is further adjusted according to the amount of toner used, and a process is performed to obtain the optimum applied voltage value. A 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.

[0013] Printing system mechanism (cross-section) Next, the mechanical structure of the printing system 1000 will be described with reference to FIG. 3 is a cross-sectional view of the printing apparatus 100 and a sheet processing apparatus 200 connected to the printing apparatus 100. In this figure, the sheet processing apparatus 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 a loading surface of a document tray in page order, starting with the first page, and conveys the documents onto a document glass platen for scanning by a scanner 302 . The scanner 302 reads an image of a document conveyed onto a glass platen, and converts the image into image data by a CCD. A rotating polygon mirror (polygon mirror or the like) 303 causes a light beam, such as a laser beam, modulated according to image data to enter the rotating polygon mirror 303, and irradiates the light 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 on a transfer drum 305. A full-color image is formed by sequentially executing 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 on which the full-color image has been formed 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 about a swing axis and determines the conveying direction of the sheet material. When the discharge flapper 309 swings in the clockwise direction 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 by the above-mentioned series of sequences.

[0014] On the other hand, when images are to be formed on both sides of the sheet material, the discharge flapper 309 swings counterclockwise in the figure, and the sheet material is changed to a downward path and sent to a double-sided conveying section. The double-sided conveying section 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 swinging shaft to determine the conveying direction of the sheet material. When processing a double-sided printing job, the control unit 205 controls the reversing flapper 311 to swing the sheet, the first side of which has been printed by the printer unit 203, in the counterclockwise direction in the figure, and to feed the sheet to the reversing guide 313 via the reversing roller 312. Then, the reversing roller 312 is stopped once with the rear end of the sheet material being pinched by the reversing roller 312, and the reversing flapper 311 continues to swing in the clockwise direction in the figure. Also, the reversing roller 312 is rotated in the reverse direction. As a result, the sheet is switched back and conveyed, and the sheet is controlled to be guided to the double-sided tray 314 with the rear end and the front end of the sheet switched. The sheet material is temporarily stacked in the double-sided tray 314, and then the sheet material is sent again to the registration roller 316 by the re-feed roller 315. At this time, the sheet material is sent with the side opposite to the transfer process of the first side facing the photosensitive drum. Then, the second side image is formed on the second side of the sheet in the same manner as the process described above. Then, images are formed on both sides of the sheet material, and the sheet is discharged from inside the main body of the printing device 100 to the outside of the machine via the paper discharge roller 310 after a fixing process. The control unit 205 controls the printing device 100 to perform double-sided printing by the above-mentioned series of sequences. In this way, the sheet transport path when performing double-sided printing is called the path of double-sided printed sheets. Also, the sheet transport path when performing single-sided printing is called the path of single-sided printed sheets. When performing double-sided printing, the sheet always passes through the path of double-sided printed sheets. When performing single-sided printing, the sheet passes through the path of single-sided printed sheets or the path of double-sided printed sheets. For example, in the case of a print job in which double-sided printed sheets and single-sided printed sheets are mixed, the single-sided printed sheets may also be transported using the path of double-sided printed sheets in order to omit the process of switching between the path of single-sided printed sheets and the path of double-sided printed sheets. In this manner, the printing apparatus 100 determines for each sheet whether the sheet will pass through the path for single-sided printed sheets or the path for double-sided printed sheets. Now, as described here, the route along which a sheet is transported using a path for double-sided printed sheets is longer than when a path for single-sided printed sheets is used, and accordingly the number of transport rollers and guides with which the sheet comes into contact is greater than when a path for single-sided printed sheets is used. As described in the background art, the charge of the sheet tends to be discharged through the transport rollers and guides, so even for the same sheet, when the sheet is transported using a path for double-sided printed sheets, the amount of charge on the sheet tends to be smaller than when a path for single-sided printed sheets is used.

[0015] The printing device 100 also has a paper feed section that stores sheets required for printing processing. The paper feed section includes paper feed cassettes 317 and 318 (each capable of storing, for example, 500 sheets), a paper feed deck 319 (capable of storing, for example, 5,000 sheets), and a manual feed tray 320. The paper feed cassettes 317 and 318 and the paper feed deck 319 can be used to set various sheets of different sizes and materials separately for each paper feed section. Furthermore, the manual feed tray 320 can be used to set various sheets including special sheets such as overhead projector sheets. (static eliminator) Next, the static eliminator 200-3a will be described. First, FIG. 5 is a system block diagram of the static eliminator 200-3a. The static eliminator 200-3a also has a control unit 501 separate from the printing device 100, and this control unit 501 controls 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). The control unit 501 is also a so-called CPU. [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 the static elimination processing only when the switch is ON. The adjustment dial 602, which is a thumb rotary switch, adjusts the strength of the static elimination control 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 applied from the voltage application controller 321 to the static elimination roller 322, and can set the value from "00" to "99". For example, setting "10" with the adjustment dial 602 indicates setting the applied voltage value to +1.0 [kV]. Note that 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 is fixed to +6.0 [kV], and it is not possible to set the applied voltage higher than that. In general, the optimal applied voltage value for the sheet used in that environment is adjusted and derived with the adjustment dial 602, and then printing is performed by setting the applied voltage value. For example, consider a case where the charge of a sheet that is charged to -6 kV at the time of transfer by the adjustment process is set to 0 kV (discharged) by setting the applied voltage to +6 kV. By setting the adjustment dial 602 to "60", the voltage application controller 321 controls the charge discharging roller 322 to +6 kV, and discharging the conveyed sheet is performed. Note that the optimal applied voltage value varies depending on the sheet characteristics and the usage environment of the static elimination device 200-3a, so when printing a sheet that is easily charged, it is desirable to start the printing process after deriving the applied voltage value by the adjustment process before printing. In this embodiment, the configuration of the operation unit 502 has been described using a physical mode setting switch and a thumb rotary switch, but the touch panel unit 401 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, providing the information input to the operation unit 204, and the control unit 501, upon receiving this, provides the static elimination processing unit 503 with the information necessary for the static elimination processing described below.

[0016] The static elimination processing unit 503 is composed 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 realizes control of applying 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 elimination device 200-3a, a control program for the operation unit 205, a static elimination processing program for the static elimination processing unit 503, etc. Then, the control unit 501 loads necessary programs from the ROM 504 into the RAM 505 as appropriate and executes them. (Static charge removal process) Here, the static elimination process performed by the static elimination unit 503 will be described with reference to Fig. 7. Fig. 7 is a schematic diagram showing how the static elimination process is performed by the static elimination device 200-3a on a sheet that has been printed by the printing device 100. First, the sheet 701 is conveyed to the developing and transferring section consisting of the photosensitive drum 304 and the transfer drum 305 via a conveying path, and toner is placed on the sheet 701. The charged toner 702 placed on the sheet 701 is negatively charged, and the sheet is then conveyed to the charge removing device 200-3a with the print surface 703 side negatively charged after being fixed through the fixing device 308. The charge removing device 200-3a is equipped with a positively charged charge removing roller 322, and applies a positive charge (applied voltage value) to the negatively charged print surface 703 by contact charge removal with the roller, thereby eliminating the charged state. The charge removing roller 322 performs charge removal processing by the applied voltage value set by the control unit 501. By changing the charge amount by the control unit 501 during the process, the voltage applied to the sheet 701 during the process can be changed, and the charge removal effect can be changed for each area within a single sheet. However, it is expected that negative charges that could not be completely removed by the charge removal process using the charge removal roller 322, or conversely, positive charges that have been charged, will remain on the sheet 705 after it has passed through the charge removal roller. Therefore, the static eliminator 200-3a in this embodiment is further configured to include an ionizer 323 downstream of the static elimination roller 322. The ionizer 323 is a device that generates a corona discharge by applying a voltage to an electrode needle provided in the device itself, and uses the ions thus generated to eliminate the charge. In this way, the static electricity is roughly eliminated by the static elimination roller 322, and the remaining charge is adjusted by the ionizer, so that the sheet 707 after the static elimination process discharged from the static elimination device 200-3a is in a state where the static electricity has been eliminated.

[0017] Returning to the explanation using the cross-sectional view of Fig. 3, the static eliminator 200-3a has a static elimination roller 322 and a pair of rollers, and the sheet transported to the static eliminator 200-3a is transported while being sandwiched between the two rollers, and the above-mentioned static elimination is performed by the static elimination roller 322. Thereafter, the sheet is transported outside the device by the transport roller 324, and the residual charge is eliminated by the ionizer 323. (Saddle stitching machine) Next, the saddle stitching machine 200-3b will be described with reference to FIG. The 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 device 100 to the saddle stitching machine 200-3b, and then the control unit 205 causes the saddle stitching machine 200-3b to execute sheet processing of this job. Then, the control unit 205 holds the printed matter of the saddle stitching job that has been subjected to sheet processing by the saddle stitching machine 200-3b in the discharge destination Z of the saddle stitching machine 200-3b. Note that there are multiple discharge destination candidates for the discharge destination Z. This is used when the saddle stitching machine 200-3b can execute multiple types of sheet processing and a discharge destination is divided for each sheet processing. In this embodiment, a detailed description of the conveying procedure of the saddle stitching job is omitted.

[0018] -Adjustment of applied voltage according to the transport path Next, a method of using an optimal applied voltage value taking into consideration whether the path along which a sheet is transported is a path for double-sided printed sheets or a path for single-sided printed sheets will be described with reference to example screens in Figures 9A and 9B (hereinafter, Figures 9A and 9B will be collectively referred to as "Figure 9") and the flow chart in Figure 8. In this embodiment, a PDL will be described as a print job, but other print jobs such as copying may also be used. In this embodiment, a case will be described in which an input of an applied voltage value according to a transport path is received from a user.

[0019] (Applied voltage input screen) Fig. 9 is an example of an input screen, which the printing device 100 displays on the operation unit 204 to accept operations and inputs from the user. First, an overview of the process in which the printing device 100 accepts input of an applied voltage value from the user and screen transitions will be described with reference to Fig. 9. 9A is an editing screen for sheet settings, and can be used for each sheet type. Examples of sheet types include standard sheets that come pre-installed in the printing device 100, such as plain paper, thick paper, coated paper, and polyester, and user-defined sheets that users create based on these standard sheets. A screen 901 is an example in which a sheet type is created as a user-defined sheet named "User-defined 1" based on a standard sheet (polyester), and the screen transitions to the setting and editing screen.

[0020] Displays 902 and 903 are locations for viewing and setting the applied voltage value when printing is performed through a path for single-sided printed sheets and the applied voltage value when printing is performed through a path for double-sided printed sheets, respectively. When the user presses [Change] buttons 904 and 905, the screen transitions to screen 906 shown in Fig. 9(b), which accepts input of the applied voltage value from the user. A screen 906 is a screen for accepting input of the applied voltage value when the path for single-sided printed sheets is used in response to pressing of the [Change] button 904, and the currently set applied voltage value is displayed. As shown in the figure, a range of settable values ​​may be displayed. The user changes the setting value using the hard key input unit 402 or the touch panel unit 401 provided in the operation unit 204, and ends the setting using the [Reflect] button 909 or the [Cancel] button 908. When the [Reflect] button 909 is pressed, the printing device 100 saves the changed setting value in the HDD 209 and displays the previous screen, the screen 901. When the [Cancel] button 908 is pressed, the printing device 100 returns to the screen 901 without changing the setting value saved in the HDD 209. Depending on the sheet type, there are cases where the path for double-sided printed sheets cannot be transported. In that case, the display 903, which is the applied voltage value when the path for double-sided printed sheets is used, may not be displayed or may be grayed out in the screen 901. In the present embodiment, the case has been described where input of the applied voltage value is received from the user by displaying screens 901 and 906 on the operation unit 204. Alternatively, the printing device 100 may record in the HDD 209 a default applied voltage value according to the basis weight and surface properties, without direct input from the user. In this case, the printing device 100 records in the HDD 209 the applied voltage value when using a pass for single-sided printed sheets and the applied voltage value when using a pass for double-sided printed sheets for each sheet type, according to the basis weight and surface properties. This concludes the explanation of FIG. 9.

[0021] (Static charge removal process flow) Next, an example of a process in which the printing apparatus 100 uses the applied voltage value corresponding to the sheet transport path, using the applied voltage value set on the setting screen shown in FIG. 9 and recorded in the HDD 209, will be described with reference to the flowchart of FIG. The following processing flow is realized by the control unit 205 of the printing device 100 loading a program stored in the HDD 209 or ROM 207 onto the RAM 208 and executing it. 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 in the ON or OFF state. Specifically, this process is first performed by the control unit 205 of the printing device 100 making an inquiry to the control unit 501 of the static eliminator 200-3a. The control unit 501 then acquires the state of the mode setting switch 601 of the operation unit 502 of the static eliminator 200-3a and the voltage value to be applied that is set by the adjustment dial 602, and returns the information 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. Next, in S803, the control unit 205 of the printing device 100 determines whether a print job has been submitted. If the determination in S803 is No, the control unit 205 returns the process to S801, continues to display ON / OFF of the static elimination process, and waits. If the determination in S803 is Yes, the control unit 205 of the printing device 100 advances the process to S804. In S804, the input print job is interpreted as PDL data and RIP processing is performed. In S805, the control unit 205 determines whether the static elimination process of the static elimination device 200-3a is ON or OFF. If the static elimination process is ON, the control unit 205 advances the process to S806, and if the static elimination process is OFF, the control unit 205 does not perform the static elimination process, i.e., sets the applied voltage value to "0", and advances the process to S810.

[0022] In S810 (when the static electricity removal process is OFF), the printing apparatus 100 performs printing of the job without performing the static electricity removal process, and ends this process. On the other hand, if the static electricity removal process is ON, the process proceeds to the loop process of S806. This process is repeatedly executed for each sheet until the final sheet of the print job input in S803 is printed. First, in S807, the printing apparatus 100 determines the sheet transport path of the next sheet of the print job. If the next sheet is to be printed on both sides, the sheet transport path is the path for the double-sided printed sheet. If the next sheet is to be printed on one side, the method of determining the sheet transport path follows the conventional technique, and the following two processing examples are given. (1) Sheets that are single-sided printed will always be passed as single-sided printed sheets. (2) A sheet transport path is determined so that the number of times that the path for single-sided printed sheets and the path for double-sided printed sheets are switched is kept below a predetermined number while a predetermined number of sheets are printed.

[0023] (1) is a method for determining that a sheet printed on one side must use the path for a sheet printed on one side. (2) is a method of limiting the number of times the sheet transport path is switched in order to prevent a decrease in printing speed due to switching between the path for single-sided printed sheets and the path for double-sided printed sheets. For example, this method sets a condition to prevent the number of times the sheet transport path is switched too many times, such as "switching between the path for single-sided printed sheets and the path for double-sided printed sheets is limited to two times or less during printing of 10 sheets." In addition, a condition may be set that the number of times the sheet transport path is switched over for the entire job and not to exceed this upper limit. When the sheet transport path is determined by such an existing method, the control unit 205 advances the process to S808. Note that if the sheet transport path is not switched, the process may skip S808 and advance to S809. In S808, the printing apparatus 100 sets the applied voltage value for the next sheet. Here, if the print transport path for the next sheet is a path for single-sided printed sheets, the applied voltage value during the pass for single-sided printed sheets set in FIG. 9A and recorded in the HDD 209 is set. Then, if the next sheet is transported using a path for double-sided printed sheets, the applied voltage value during the pass for double-sided printed sheets is used. The applied voltage value determined here is set in the static elimination processing unit 503 via the control unit 501. Next, in S809, the printing apparatus 100 prints the next sheet. That is, the sheet is neutralized with the applied voltage value set in S808 based on the print transport path determined in S807, and it is possible to deal with the difference in the amount of charge caused by the difference in the sheet transport path. When this process has been completed for all sheets, the printing apparatus 100 exits the loop of S806 and ends the process of this flowchart. Another example of the method of determining the sheet transport path explained in S807 will be described. In the above explanation of S807, it was stated that the determination method follows the conventional technology, but in addition to this, in a job in which single-sided printing and double-sided printing are mixed, there is also a method of determining the sheet transport path of all pages as the path for double-sided printed sheets. In this way, the applied voltage values ​​determined in S808 are all applied voltage values ​​when using the path for double-sided printed sheets. The effect of this is that the applied voltage value is constant for all sheets of one job, so the process of changing the applied voltage value in the static elimination processing unit 503 can be omitted.

[0024] (Embodiment 2) In the first embodiment, in FIG. 9(a), a case is described in which there are two applied voltage settings for the path for single-sided printed sheets and the path for double-sided printed sheets, but the number and types of applied voltage settings are not limited to these two. As explained in the background art, the object of the present invention is to deal with the difference in the amount of charge caused by contact with parts such as transport rollers and guides on the sheet transport path. Therefore, it is desirable to determine the number and types of applied voltage settings provided in the printing device 100 according to the length of the transport path and the number of parts that come into contact. In the second embodiment, as shown in FIG. 9C, an example is shown in which the setting of the applied voltage of the static eliminator is changed when the number of fixing units is different as the number of parts that come into contact on the transport path. Some printing apparatuses 100 have two fusers 308 shown in FIG. 3 on the transport path, and dynamically determine whether to use one or two fusers for a sheet depending on the sheet and the print image. In such a case, when two fusers are used for the same sheet, there is more contact with the components and a greater static elimination effect than when only one fuser is used. In order to accommodate such cases, FIG. 9(c) shows an example in which a combination of one or two fusers is used is added to the two types of paths for double-sided printed sheets and single-sided printed sheets described in FIG. 9(a), making a total of four types. Display 911 shows applied voltage settings for a path for single-sided printed sheets with one fuser, display 912 shows applied voltage settings for a path for double-sided printed sheets with one fuser, display 913 shows applied voltage settings for a path for single-sided printed sheets with two fusers, and display 914 shows applied voltage settings for a path for double-sided printed sheets with two fusers. In this way, the number and types of applied voltage settings are not limited to two types, a path for single-sided printed sheets and a path for double-sided printed sheets, and are desirably determined according to the length of the transport path and the number of components that come into contact. The effect of the applied voltage value control described in this embodiment is that an optimal applied voltage value can be applied to a sheet in response to a difference in the amount of charge on the sheet caused by a difference in the sheet transport path.

[0025] (Other embodiments) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a 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 implements one or more of the functions. The disclosure of this embodiment includes the following configuration, method, and program. (Configuration 1) A printing system including a printing device that prints on a sheet and a static elimination device that performs a static elimination process on the sheet, A determination unit that determines a sheet transport path based on a print job; and a setting unit for setting an applied voltage value in the charge removal process in accordance with the determined sheet transport path. A printing system comprising: (Configuration 2) The sheet transport path determined by the determining means is A conveying path for single-sided printed sheets or a conveying path for double-sided printed sheets. 2. The printing system according to configuration 1. (Configuration 3) For print jobs that contain a mixture of single-sided and double-sided sheets, The determining means determines that the transport path for single-sided printed sheets is the transport path for single-sided printed sheets. 3. The printing system according to configuration 2. (Configuration 4) For print jobs that contain a mixture of single-sided and double-sided sheets, The determining means determines the number of times the transport path for single-sided printed sheets and double-sided printed sheets is switched so as not to exceed a predetermined upper limit. 3. The printing system according to configuration 2. (Configuration 5) The sheet transport path determined by the determining means is The number of fixing units through which the sheet passes is different. 5. The printing system according to any one of configurations 1 to 4. (Method 1) A method for controlling a printing system including a printing device that prints on a sheet and a static elimination device that performs a static elimination process on the sheet, comprising: A determination step of determining a sheet transport path based on a print job; and a setting step of setting an applied voltage value in a static elimination process in accordance with the determined sheet transport path. A method for controlling a printing system comprising: (Program 1) A program for causing a computer to execute the printing system control method according to the first method. [Explanation of symbols]

[0026] 1000 printing system 100 Printing equipment 205 Control Unit 200-3a Static eliminator 200-3b Saddle stitching machine 501 Control section 503 Static electricity removal processing unit 322 Antistatic roller

Claims

1. A printing system including a printing device that prints on a sheet and a static elimination device that performs a static elimination process on the sheet, A determination unit that determines a sheet transport path based on a print job; and a setting unit for setting an applied voltage value in the charge removal process in accordance with the determined sheet transport path. A printing system comprising:

2. The sheet transport path determined by the determining means is A conveying path for single-sided printed sheets or a conveying path for double-sided printed sheets.

2. The printing system according to claim 1.

3. For print jobs that contain a mixture of single-sided and double-sided sheets, The determining means determines that the transport path for single-sided printed sheets is the transport path for single-sided printed sheets.

3. The printing system according to claim 2.

4. For print jobs that contain a mixture of single-sided and double-sided sheets, The determining means determines the number of times the transport path for single-sided printed sheets and double-sided printed sheets is switched so as not to exceed a predetermined upper limit.

3. The printing system according to claim 2.

5. The sheet transport path determined by the determining means is The number of fixing units used is different for each transport path.

5. The printing system according to claim 1, wherein the first and second printing units are arranged in a first and second directions.

6. A method for controlling a printing system including a printing device that prints on a sheet and a static elimination device that performs a static elimination process on the sheet, comprising: A determination step of determining a sheet transport path based on a print job; and a setting step of setting an applied voltage value in a static elimination process in accordance with the determined sheet transport path. A method for controlling a printing system comprising:

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

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