Image forming device

Abstract

To suppress the influence on the printing quality of a change in the meandering or feeding speed of a belt for printing.SOLUTION: Image formation apparatuses 100, 300 comprise: one or more printing units 101A, 101B, 101C, 101D for performing printing on a sheet; a loop-like belt 102 which conveys the sheet to a printing position; rollers 103A, 103B, 103C which feed the belt 102; a phase detection unit 105 which detects the phase of the belt 102; a behavior detection unit 104 which detects the behavior of the belt 102; a control unit which determines the placement position of the sheet on the belt 102 on the basis of the behavior for each phase of the belt 102; and a sheet feeding unit which conveys the sheet to the determined placement position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus, and more particularly to a technique for determining a paper placement position on a printing belt. [Background technology]

[0002] Inkjet image forming apparatuses are known as devices that form images by linking a printing means and a paper transport means. Inkjet image forming apparatuses transport paper placed on an endless belt (a loop-shaped belt, hereinafter referred to as the "belt") and form images by ejecting ink onto the surface of the paper being transported.

[0003] The belt is looped by connecting one end to the other. For example, if the belt joint comes into contact with the belt transport roller, the belt's feed speed may change and / or the belt may move perpendicular to the feed direction (hereinafter, belt movement perpendicular to the feed direction is referred to as "meandering"). Such belt speed changes and / or belt meandering can affect print quality.

[0004] Regarding belt control, for example, Japanese Patent Application Laid-Open No. 10-139202 (Patent Document 1) discloses a control device that "inputs the position of the side edge of the paper transport belt based on the detection timing of a home position mark formed on the paper transport belt, and calculates differential data from the position detected at the same point on the previous rotation. This differential data is corrected based on the belt meandering period to provide meandering data, and meandering control is performed based on this meandering data" (see [Abstract]). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 10-139202 Summary of the Invention [Problem to be solved by the invention]

[0006] While the technology disclosed in Patent Document 1 may be able to reduce the impact of belt meandering on print quality to some extent, belt meandering or changes in feed speed may still affect print quality depending on the position of the paper on the belt (for example, near the belt joints, etc.). Therefore, there is a need for technology that can more stably reduce the impact of belt meandering or changes in feed speed on print quality.

[0007] The present disclosure has been made in consideration of the above-described background, and an object of one aspect is to provide a technology that more stably suppresses the effects of belt meandering or changes in feed speed on print quality. [Means for solving the problem]

[0008] According to one embodiment, there is provided an image forming apparatus including one or more printing units that print on paper, a looped belt that transports the paper to a printing position, rollers that feed the belt, a phase detection unit that detects the phase of the belt, a behavior detection unit that detects the behavior of the belt, a control unit that determines a paper placement position on the belt based on the behavior of the belt for each phase, and a paper feed unit that transports the paper to the determined placement position.

[0009] In one aspect, determining the paper placement position on the belt based on the behavior of the belt at each phase includes determining the paper placement position so that the belt behavior is minimal or below a predetermined threshold during the period in which the paper passes through one or more printing units.

[0010] In one aspect, determining the paper loading position so that the behavior of the belt is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units includes determining the paper loading position so that the change in the speed of the belt in the feed direction is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units.

[0011] In one aspect, determining the paper loading position so that the behavior of the belt is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units includes determining the paper loading position so that the cumulative change in the speed of the belt in the feed direction is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units.

[0012] In one aspect, determining the paper placement position so that the belt behavior is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units includes determining the paper placement position so that the change in the belt's meandering speed is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units.

[0013] In one aspect, determining the paper loading position so that the behavior of the belt is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units includes determining the paper loading position so that the change in the amount of belt meandering is minimized or below a predetermined threshold during the period in which the paper passes through one or more printing units.

[0014] In one aspect, the one or more printing units include printing units of each of a plurality of colors, and the period during which the paper passes through the one or more printing units is the period during which the paper passes through all of the printing units of each of the plurality of colors.

[0015] In one aspect, the one or more printing units include printing units for each of a plurality of colors, and the control unit selects one or more printing units to be used for the printing process from among the printing units for the plurality of colors, and the period during which the paper passes through the one or more printing units is the period during which the paper passes through the selected one or more printing units.

[0016] In one aspect, the image forming apparatus further includes an input unit and a communication unit. Selecting one or more print units to be used for the print process from among the print units of the plurality of colors includes selecting one or more print units to be used for the print process from among the print units of the plurality of colors based on color designation input received via the input unit or the communication unit.

[0017] In one aspect, the control unit analyzes image data to be printed on paper, and selecting one or more print units to be used for the printing process from among the print units of the plurality of colors includes selecting one or more print units to be used for the printing process from among the print units of the plurality of colors based on the analysis result of the image data.

[0018] In one aspect, the analysis result of the image data includes coverage in the image data for each of a plurality of colors.

[0019] In one aspect, the behavior detection unit includes a plurality of behavior detection units, each of which is provided near a corresponding one of the plurality of colored printed portions and detects the behavior of the belt near the corresponding one of the plurality of colored printed portions.

[0020] In one aspect, determining a paper placement position on the belt based on the behavior of the belt at each phase includes selecting multiple sections on the belt as paper placement positions on the belt based on the behavior of the belt at each phase.

[0021] In one aspect, the control unit estimates deterioration of the belt based on the detection result of the behavior of the belt.

[0022] In one aspect, the control unit outputs a notification based on the result of the estimation of belt deterioration. [Effects of the Invention]

[0023] According to an embodiment, it is possible to more stably suppress the effects of belt meandering or changes in feed speed on print quality.

[0024] The above and other objects, features, aspects and advantages of the present disclosure will become apparent from the following detailed description of the disclosure taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 illustrates an example of a hardware configuration related to a printing process on paper in an image forming apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of an outline of the operation of the image forming apparatus 100. [Figure 3] FIG. 10 is a diagram illustrating another example of a hardware configuration related to a printing process on paper in an image forming apparatus according to an embodiment. [Figure 4] FIG. 2 illustrates an example of a hardware configuration of image forming apparatuses 100 and 300. [Figure 5] 10 is a diagram showing an example of a mechanism for determining a paper placement position using a time-series belt speed detected by a behavior detection unit 104. FIG. [Figure 6] 10 is a diagram showing an example of a mechanism for determining a paper placement position using the cumulative change in belt speed over time detected by the behavior detection unit 104. FIG. [Figure 7] 10 is a diagram showing an example of a mechanism for determining a placement position of a sheet using a time-series meandering speed detected by a behavior detection unit 104. FIG. [Figure 8] 10 is a diagram showing an example of a mechanism for determining a placement position of a sheet using a change in the amount of meandering over time detected by a behavior detection unit 104. FIG. [Figure 9] 10 is a flowchart showing an example of a procedure for determining a preliminary placement position in the image forming apparatuses 100 and 300. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the technical idea according to the present disclosure will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0027] <A. Configuration of Image Forming Apparatus> First, referring to FIGS. 1 to 4, the hardware configuration and operation outline of the image forming apparatus according to the present embodiment will be described. Hereinafter, the image forming apparatus will be described on the premise that it is an inkjet printer, but the applicable range of the technology of the present disclosure is not limited to inkjet printers. In a certain aspect, the image forming apparatus may be a laser printer.

[0028] FIG. 1 is a diagram showing an example of the hardware configuration related to the printing process on paper in the image forming apparatus according to the present embodiment. Referring to FIG. 1, the hardware configuration related to the printing process on paper of the image forming apparatus 100 will be described.

[0029] As hardware related to the printing process on paper, the image forming apparatus 100 includes a plurality of printing units 101A, 101B, 101C, 101D, a belt 102, conveying rollers 103A, 103B, 103C, a behavior detection unit 104, and a phase detection unit 105. There is a joint 110 on the belt 102. Hereinafter, when collectively referring to the plurality of printing units 101A, 101B, 101C, 101D, it may be expressed as the printing unit 101. Similarly, when collectively referring to the conveying rollers 103A, 103B, 103C, it may be expressed as the roller 103. Also, the number and arrangement of the printing unit 101 and the roller 103 shown in FIG. 1 are examples, and the image forming apparatus 100 may include an arbitrary number of printing units 101 and rollers 103, and the arrangement of these printing units 101 and rollers 103 can be determined at an arbitrary position as needed.

[0030] Printing unit 101 is a unit that forms an image on paper. In one aspect, printing unit 101 may be an inkjet printing unit. In this case, printing unit 101 forms an image by ejecting ink from a nozzle at the tip onto the surface of paper being transported on belt 102. In another aspect, printing unit 101 may be a toner printing unit. In this case, belt 102 may be, for example, an intermediate transfer belt. Printing unit 101 first forms a toner image on the intermediate transfer belt via a photosensitive member. The toner image is then transported on the intermediate transfer belt and transferred to paper by a transfer roller.

[0031] When printing unit 101 is an inkjet type, the technology of the present disclosure determines the paper placement position (printing position) on belt 102 in order to maintain constant print quality. On the other hand, when printing unit 101 is a toner type, the technology of the present disclosure determines the transfer position of the toner image on belt 102 in order to maintain constant print quality. Hereinafter, the technology of the present disclosure will be described using the inkjet type as an example, but by replacing "paper placement position on belt 102" with "transfer position of the toner image on belt 102," the technology of the present disclosure can also be applied to toner type image forming apparatuses.

[0032] Belt 102 is an endless belt (a loop-shaped belt) that transports paper below printing unit 101. When the paper is transported directly below printing unit 101, an image is formed on its surface. In the case of a toner-type image forming device, the image is transferred directly onto belt 102 (an intermediate transfer belt). Belt 102 is driven by one or more rollers 103.

[0033] The rollers 103 are rotated by a motor or the like to drive the belt 102. In one aspect, all of the rollers 103 may be driven by a motor. In another aspect, some of the rollers 103 may be driven by a motor. In this case, the rollers 103 that are not connected to the motor function as pulleys, for example.

[0034] The rollers 103 or the motors that drive the rollers 103 may be equipped with encoders. The image forming apparatus 100 can estimate the amount of drive of the belt 102 or the amount of paper transport by receiving and analyzing the signals from the encoder. In one aspect, all of the rollers 103 may be equipped with encoders. In another aspect, some of the rollers 103 may be equipped with encoders.

[0035] The behavior detection unit 104 detects the behavior of the belt 102. "Behavior" can include both the movement of the belt 102 in the feeding direction (speed change (acceleration), cumulative speed change, movement amount, etc.) and the movement of the belt 102 in the meandering direction (speed change, cumulative speed change, movement amount, etc.). Hereinafter, the speed of the belt 102 in the feeding direction may also be referred to as the "belt speed." Furthermore, the direction perpendicular to the feeding direction of the belt 102 may also be referred to as the "meandering direction," the speed of the belt 102 in the direction perpendicular to the feeding direction of the belt 102 may also be referred to as the "meandering speed," and the movement amount of the belt 102 in the direction perpendicular to the feeding direction of the belt 102 may also be referred to as the "meandering amount." Furthermore, movement of the belt 102 in the meandering direction may also be referred to as "meandering."

[0036] In one aspect, behavior detection unit 104 may include any type of sensor, such as a laser, infrared, or camera. In another aspect, behavior detection unit 104 may include multiple sensors. In this case, the sensors may be located in a single location or in separate locations.

[0037] Behavior detection unit 104 outputs information related to the behavior of belt 102 to a CPU (Central Processing Unit) 401 (see FIG. 4 ) of image forming apparatus 100. In one aspect, behavior detection unit 104 may output signals from each sensor to CPU 401 as information related to the behavior of belt 102. In another aspect, behavior detection unit 104 may output digital data of the behavior amount of belt 102 calculated based on the signals from each sensor by a circuit such as a built-in control unit to CPU 401.

[0038] The phase detection unit 105 detects the phase of the belt 102. The "phase" can also be referred to as the position of the belt 102. For example, if the joint 110 is set as a reference position, the phase of the belt 102 can indicate the current position of the joint 110. In one aspect, the phase detection unit 105 may include any type of sensor, such as a light-receiving sensor or an encoder. In another aspect, the phase detection unit 105 may include multiple sensors. In this case, the sensors may be located in one location or in remote locations. In another aspect, an encoder attached to the roller 103 or a motor connected to the roller 103 may be used as part of the phase detection unit 105. Alternatively, the phase detection unit 105 may include an encoder. In yet another aspect, the phase detection unit 105 may be used as part of the behavior detection unit 104 to detect the behavior of the belt 102 in the feed direction (such as a speed change (acceleration), cumulative speed change, or movement amount).

[0039] Phase detection unit 105 outputs information relating to the phase (position) of belt 102 to CPU 401 of image forming apparatus 100. In one aspect, phase detection unit 105 may output a signal from each sensor to CPU 401 as information relating to the phase of belt 102. In another aspect, phase detection unit 105 may output digital data of the phase of belt 102 calculated based on the signal from each sensor by a circuit such as a built-in control unit to CPU 401.

[0040] Based on information about the behavior of the belt 102 acquired from the behavior detection unit 104 and phase information about the belt 102 acquired from the phase detection unit 105 (based on the behavior of the belt 102 for each phase), the CPU 401 determines the placement position of the paper on the belt 102 so as to minimize the impact of the behavior of the belt 102 on print quality. In one aspect, the CPU 401 may select a phase or section (or a section from a certain phase of the belt) in which the behavior of the belt 102 is minimal, and determine the placement position of the paper so that the printing process is performed in the selected phase or section. In another aspect, the CPU 401 may select a phase or section in which the behavior of the belt 102 is equal to or less than a predetermined threshold, and determine the placement position of the paper so that the printing process is performed in the selected phase or section. In other words, the CPU 401 may determine the placement position of the paper so that the behavior of the belt is minimized or equal to or less than a predetermined threshold during the period in which the paper passes through one or more printing units 101 used for printing.

[0041] 2 is a diagram showing an example of an outline of the operation of image forming apparatus 100. With reference to FIG. 2, the influence of the behavior of belt 102 on print quality and a series of operations until image forming apparatus 100 determines the paper placement position will be described.

[0042] In the example shown in Fig. 2, belt 102 rotates counterclockwise. Paper 220 is transported by rollers or the like from paper feed unit 408 (see Fig. 4) and placed on belt 102. Each of printing units 101A, 101B, 101C, and 101D ejects ink when paper 220 passes directly below the nozzle. Paper 220 with an image formed on it is transported downstream and then ejected.

[0043] If the conveying speed of the belt 102 changes or the belt 102 meanders when each printing unit 101 ejects ink, the image formed on the paper 220 may be distorted. For this reason, it is desirable for the belt 102 to convey the paper 220 at a constant speed without meandering. However, due to factors such as hardware errors, hardware deterioration, and the joint 110 of the belt 102, it is not realistic to completely eliminate meandering of the belt 102 and changes in the conveying speed.

[0044] Therefore, the image forming apparatus 100 detects the behavior of the belt 102 for each phase based on information about the behavior of the belt 102 acquired from the behavior detection unit 104 and information about the phase (position) of the belt 102 acquired from the phase detection unit 105. Then, the image forming apparatus 100 places the paper at a position that is less susceptible to the influence of the behavior of the belt 102.

[0045] One factor that can cause a significant change in the behavior of the belt 102 is when the joint 110 passes over the rollers 103. The joint 110 can cause distortion or unevenness on the surface of the belt 102. When the joint 110 passes over the rollers 103, the conveyance speed of the belt 102 can change, or the belt 102 can meander. The behavior of the belt 102 when the joint 110 passes over the rollers 103 can have an adverse effect on the printing process.

[0046] Therefore, image forming apparatus 100 determines the placement position of paper 220 so that printing can be performed at a timing when seam 110 does not pass roller 103. More specifically, image forming apparatus 100 needs to feed belt 102 a distance of section 210 to perform printing on paper 220. Section 210 indicates the distance required for the leading edge of paper 220 to reach directly below the nozzles of printing unit 101D (print start position) and for the trailing edge of paper 220 to pass directly below the nozzles of printing unit 101A (print end position). In this case, image forming apparatus 100 determines the placement position of paper 220 so that paper 220 can be transported the distance of section 210 at a timing when seam 110 does not pass roller 103. In other words, image forming apparatus 100 selects a section from the entire belt 102 that is least affected by the behavior of belt 102 and that includes the distance required for printing. That is, the image forming apparatus 100 can determine the placement position of the paper 220 so that the movement of the belt 102 during the period when the paper 220 passes through each of the multiple printing units 101 is minimized.

[0047] The above-described process of selecting a section from the entire belt 102 that is less affected by the behavior of the belt 102 and that includes the distance required for the printing process is effective against all factors that affect the behavior of the belt 102. For example, even if the behavior of the belt 102 is disturbed due to manufacturing errors in the components related to printing, or the behavior of the belt 102 changes due to deterioration of the components related to printing, the image forming apparatus 100 can always maintain consistent print quality by selecting a section from the entire belt 102 that is less affected by the behavior of the belt 102 and that includes the distance required for the printing process.

[0048] In one aspect, image forming apparatus 100 may determine the distance of section 210 based on the image printed on paper 220. For example, if the image is printed near the center of paper 220, section 210 indicates the distance required for the leading edge of the printing position of the image on paper 220 to reach the printing start position and for the trailing edge of the printing position of the image on paper 220 to pass the printing end position. As another example, if the image uses only a specific ink (such as the ink of printing unit 101A), section 210 may indicate the distance required for the leading edge of the printing position of the image on paper 220 to reach directly below a specific printing unit 101 (such as printing unit 101A) and for the trailing edge of the printing position of the image on paper 220 to pass directly below printing unit 101 (such as printing unit 101A). That is, the image forming device 100 can select one or more printing units 101 to use for the printing process from among the printing units 101 of multiple colors, and determine the placement position of the paper 220 so that the behavior of the belt 102 is minimized during the period when the paper 220 passes through the one or more printing units 101 used for the printing process.

[0049] When some of the printing units 101 are used for printing, the image forming apparatus 100 may select one or more printing units 101 to use for printing based on input from the user (such as color specification), or may select one or more printing units 101 to use for printing based on the analysis results of the image data (such as the type of ink to be used).

[0050] The analysis results of the image data may include ink coverage. In this case, the image forming apparatus 100 may adjust the paper placement position by referring to the ink coverage. "Ink coverage" refers to the proportion of ink contained in an image. For example, when printing units 101A and 101B (inks A and B) are used in a printing process, the proportion of ink A in the image is assumed to be 80% and the proportion of ink B is assumed to be 20%. In this case, the image forming apparatus 100 may adjust the paper placement position to preferentially suppress the influence of the behavior of the belt 102 when ink A is ejected. The image forming apparatus 100 may adjust the paper placement position according to priority by multiplying the behavior of the belt 102 near each printing unit 101, the value (threshold value) at which the behavior of the belt 102 near each printing unit 101 is acceptable, and the like, by a coefficient (e.g., a coefficient based on coverage) according to the ink coverage. In this way, image forming apparatus 100 can flexibly adjust the paper placement position according to the amount of ink used (ink coverage).

[0051] In another aspect, image forming apparatus 100 may select multiple sections from the entire belt 102 to be used for the printing process. In this case, for example, image forming apparatus 100 detects a phase in which the influence of the behavior of belt 102 is equal to or less than a predetermined threshold, based on information about the behavior of belt 102 obtained from behavior detection unit 104 and information about the phase (position) of belt 102 obtained from phase detection unit 105. Image forming apparatus 100 may then select multiple sections so as to include only phases in which the influence of the behavior of belt 102 is equal to or less than the predetermined threshold. These sections may be contiguous or spaced apart. In this way, image forming apparatus 100 may efficiently execute the printing process by selecting multiple sections that are less likely to be influenced by the behavior of belt 102.

[0052] In another aspect, image forming apparatus 100 may estimate deterioration of belt 102 based on the detected behavior of belt 102. As an example, image forming apparatus 100 may determine that belt 102 has deteriorated based on the fact that either or both of the behavior of belt 102 in the feed direction and the behavior of belt 102 in the meandering direction exceed a predetermined threshold. When image forming apparatus 100 determines that belt 102 has deteriorated, image forming apparatus 100 may output a notification to output unit 407 (see FIG. 4 ) that includes a display or the like of image forming apparatus 100, or may output (transmit) the notification to another device via communication unit 409, or may output the notification to both output unit 407 and communication unit 409. In this way, image forming apparatus 100 can maintain constant print quality and notify a user or administrator of the deterioration of belt 102.

[0053] 3 is a diagram showing another example of the hardware configuration related to the printing process on paper in the image forming apparatus according to the present embodiment. The hardware configuration related to the printing process on paper in image forming apparatus 300 will be described with reference to FIG.

[0054] Unlike image forming apparatus 100, image forming apparatus 300 includes a plurality of behavior detection units 104 and a plurality of phase detection units 105. Each of the plurality of behavior detection units 104 and phase detection units 105 is disposed near each printing unit 101. CPU 401 uses each of the plurality of behavior detection units 104 and phase detection units 105 disposed near each printing unit 101 to detect the behavior of belt 102 for each phase near each printing unit 101.

[0055] Image forming apparatus 300 can determine the placement position of paper based on the detected behavior of belt 102 for each phase near each printing unit 101 and the image printed on the paper. As an example, when only printing unit 101A (ink A) is used in the printing process, image forming apparatus 300 can determine the placement position of paper based on the detection results of behavior detection unit 104 and phase detection unit 105 provided near printing unit 101A. As another example, when multiple printing units (e.g., printing units 101A (ink A) and 101B (ink B)) are used in the printing process, image forming apparatus 300 can determine the placement position of paper based on the detection results of each of multiple behavior detection units 104 and phase detection units 105 provided near each of the multiple printing units 101 used in the printing process.

[0056] In one aspect, similar to image forming apparatus 100, image forming apparatus 300 may determine the placement position of paper 220 so as to minimize the movement of belt 102 while paper 220 passes through each of multiple printing units 101. Furthermore, image forming apparatus 300 may select one or more printing units 101 to be used for printing processing from among multiple color printing units 101, and determine the placement position of paper 220 so as to minimize the movement of belt 102 while paper 220 passes through one or more printing units 101 used for printing processing. In this case, image forming apparatus 300 may select one or more printing units 101 to be used for printing processing based on input from a user (e.g., color specification) or analysis results of image data (e.g., type, amount, and ratio of color or ink used). Furthermore, image forming apparatus 300 may adjust the placement position of paper by referring to ink coverage.

[0057] In another aspect, image forming apparatus 300 may determine the coefficients based on print settings (arbitrary settings such as which inks to use, the ink usage ratios, and the importance of each ink) input by the user via input unit 406 (see FIG. 4). In this way, image forming apparatus 300 can flexibly adjust the paper placement position according to the user's wishes (such as which inks are particularly important).

[0058] In another aspect, there may be only one phase detection unit 105. In this case, image forming apparatus 300 can perform the above processing based on the common phase obtained from one phase detection unit 105 and the behavior of the belt near each printing unit 101.

[0059] Furthermore, in another aspect, image forming apparatus 100 may use one behavior detection unit 104 and one phase detection unit 105 to perform processing similar to that of image forming apparatus 300. For example, image forming apparatus 100 may store in advance information about the distance from behavior detection unit 104 to each printing unit 101, and may perform processing similar to that of image forming apparatus 300 by estimating the behavior of belt 102 near each printing unit 101 based on the behavior of belt 102 acquired from behavior detection unit 104.

[0060] FIG. 4 is a diagram illustrating an example of the hardware configuration of image forming apparatuses 100 and 300. In one aspect, the components illustrated in FIG. 4 may be implemented entirely as hardware. In another aspect, some of the components illustrated in FIG. 4 may be implemented as software. In this case, CPU 401 implements the components by executing software deployed on RAM (Random Access Memory) 402. Furthermore, in another aspect, the components implemented as hardware may be configured by at least one CPU, at least one FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a combination thereof.

[0061] The image forming apparatuses 100 and 300 include a CPU 401, a RAM 402, a ROM (Read Only Memory) 403, a non-volatile memory 405, an input unit 406, an output unit 407, a paper feed unit 408, a communication unit 409, a phase detection unit 410, a behavior detection unit 411, and a printing unit 412. These components can be connected to each other via a bus 413 so that they can communicate with each other.

[0062] CPU 401 executes or references various programs and data loaded into RAM 402. In some aspects, CPU 401 may be an embedded CPU, an FPGA, or a combination of these. CPU 401 can execute programs for implementing various functions of image forming apparatuses 100 and 300.

[0063] RAM 402 stores programs executed by CPU 401 and data referenced by CPU 401. In some aspects, a dynamic random access memory (DRAM) or a static random access memory (SRAM) may be used as RAM 402. Data stored in ROM 403 and nonvolatile memory 405 is read out to RAM 402 once, and can then be referenced by CPU 401.

[0064] ROM 403 can store programs, various settings, and the like for image forming apparatuses 100 and 300. ROM 403 can be used to store programs or setting information that is not normally updated or is updated very infrequently. In some aspects, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), or flash memory may be used as ROM 403.

[0065] Nonvolatile memory 405 can store data even when image forming apparatus 100, 300 is powered off. Nonvolatile memory 405 can store any programs and data executed or referenced by CPU 401. In some aspects, a hard disk drive (HDD) or a solid state drive (SSD) may be used as nonvolatile memory 405. CPU 401 can load various programs from nonvolatile memory 405 into RAM 402 as needed and execute the loaded programs.

[0066] The input unit 406 accepts setting input from the user. The input unit 406 outputs a signal corresponding to the input to the CPU 401. The CPU 401 executes a program based on the setting input. In one aspect, the input unit 406 may include a button, a touch sensor, a voice input, any other input means, or a combination thereof. The touch sensor may be disposed over the display of the output unit 407.

[0067] Output unit 407 displays various information such as setting screens of image forming apparatuses 100 and 300, job execution status, error information, etc. In one aspect, output unit 407 may include a liquid crystal monitor, an organic EL (Electro Luminescence) monitor, or the like.

[0068] In one aspect, image forming apparatus 100, 300 may include an operation panel that has the functions of both input unit 406 and output unit 407. In this case, the operation panel may include, for example, a plurality of buttons and a display including a touch sensor (touch panel).

[0069] Paper feed unit 408 transports paper from a paper storage location along a transport path in image forming apparatus 100, 300. In some aspects, the paper storage location may be a tray or a roller for winding long paper. In cases where the paper to be transported is long, image forming apparatus 100, 300 may be provided with a cutting device downstream.

[0070] Communication unit 409 communicates with other devices via a wired or wireless network. For example, communication unit 409 may receive jobs, receive firmware updates for image forming apparatuses 100 and 300, send logs, and the like. In one aspect, communication unit 409 may be implemented by a wired local area network (LAN) port, a Wi-Fi (registered trademark) (Wireless Fidelity) module, or the like. In another aspect, communication unit 409 may send and receive data using a communication protocol such as TCP / IP (Transmission Control Protocol / Internet Protocol), UDP (User Datagram Protocol), or the like.

[0071] Phase detection unit 410 corresponds to phase detection unit 105 described with reference to FIGS. 1 to 3. Image forming apparatus 100 includes one phase detection unit 410. In one aspect, image forming apparatus 100 may include two or more phase detection units 410 as spares or to improve the accuracy of phase detection. Image forming apparatus 300 includes the same number of phase detection units 410 as print units 101. In one aspect, image forming apparatus 300 may include fewer phase detection units 410 than print units 101 in order to reduce manufacturing costs. In another aspect, image forming apparatus 300 may include more phase detection units 410 than print units 101 as spares or to improve the accuracy of phase detection.

[0072] The behavior detection unit 411 corresponds to the behavior detection unit 104 described with reference to FIGS. 1 to 3. The image forming apparatus 100 includes one behavior detection unit 411. In a certain aspect, the image forming apparatus 100 may include two or more behavior detection units 411 as a backup or to improve the accuracy of behavior detection. The image forming apparatus 300 includes the same number of behavior detection units 411 as the printing units 101. In a certain aspect, the image forming apparatus 300 may include fewer behavior detection units 411 than the number of printing units 101 in order to reduce manufacturing costs. Also, in another aspect, the image forming apparatus 300 may include more behavior detection units 411 than the number of printing units 101 as a backup or to improve the accuracy of behavior detection.

[0073] The printing unit 412 executes printing processing on the paper. As an example, the printing unit 412 may control the ink ejection timing and ejection amount of each printing unit 101, and further control the drive timing and drive amount of each roller 103.

[0074] <B. Information on the behavior of the belt 102> Next, referring to FIGS. 5 to 8, the behavior detected by the behavior detection unit 104 will be described. The graphs shown in FIGS. 5 to 8 show various values related to the time-series behavior detected by the behavior detection unit 104. Actually, the image forming apparatuses 100 and 300 can obtain various values related to the behavior as time-series discrete values from the behavior detection unit 104.

[0075] FIG. 5 illustrates an example of a mechanism for determining a paper placement position using a time-series belt speed detected by the behavior detection unit 104. The belt speed is the speed of the belt 102 in the feed direction. Graph 500 shows the change in the belt speed during one revolution of the belt 102. When the belt 102 is continuously operating, the change in the belt speed shown in graph 500 is repeatedly detected. However, due to the influence of the condition of the belt 102, changes in the temperature around the belt 102, and the like, the belt speed during one revolution of the belt 102 may change from week to week. Similarly, due to the influence of changes in the temperature around the belt 102, and the like, the cumulative change in the belt speed during one revolution of the belt 102 shown in FIG. 6, the meandering speed of the belt 102 during one revolution of the belt 102 shown in FIG. 7, and the meandering amount of the belt 102 during one revolution of the belt 102 shown in FIG. 8 may also change from week to week.

[0076] 5, the belt speed changes before belt 102 makes one revolution. Graph 500 also shows three sudden changes in belt speed. The sudden changes in belt speed indicate the belt speed at the time when belt joint 110 contacts roller 103.

[0077] Based on the measured belt speed, the image forming apparatus 100, 300 determines the paper placement position so that the printing process is performed at a timing when the belt speed variation range is small. For example, when performing printing using only one color of printing unit 101, the image forming apparatus 100, 300 determines the paper placement position so that the printing process is performed during the period indicated by the passing time 510 (the period when the belt speed variation range is small throughout the entire period of printing using one color of ink). In other words, the image forming apparatus 100, 300 determines the paper placement position so that the paper printing process is performed at the timing when the behavior detection unit 104 detects the belt speed during the passing time 510. For example, the image forming apparatus 100, 300 stores the distance (offset) from the behavior detection unit 104 to each printing unit 101 in the nonvolatile memory 405 in advance. The image forming apparatus 100, 300 can then determine the timing to place the paper on the belt 102 (or the position to place the paper on the belt 102) based on the timing when the behavior detection unit 104 detects the belt speed and the distance from the behavior detection unit 104 to each printing unit 101.

[0078] As another example, when performing printing processing using all colors or multiple printing units 101, the image forming device 100, 300 determines the paper placement position so that the printing processing is performed during the period indicated by the passing time 520 (the period during which the range of change in belt speed is small throughout the entire period of printing using multiple inks).

[0079] In one aspect, image forming apparatus 100, 300 may determine a paper placement position so that printing is performed during a period (or interval) in the cycle of belt 102 in which the belt speed variation is the smallest. In another aspect, image forming apparatus 100, 300 may determine a paper placement position so that printing is performed during a period (or interval) in the cycle of belt 102 in which the belt speed variation is equal to or less than a predetermined threshold. In still another aspect, image forming apparatus 100, 300 may select multiple paper placement positions so that printing is performed during multiple periods (or intervals) in the cycle of belt 102. In this case, the selected placement position is a placement position in which the belt speed variation is equal to or less than a predetermined threshold.

[0080] As described above, the image forming apparatuses 100 and 300 determine the paper placement position so that the printing process is performed during a period (or interval) where the belt speed change width is small within the cycle of the belt 102. This allows the image forming apparatuses 100 and 300 to, for example, suppress distortion of the image in the feed direction of the belt 102 due to the influence of changes in the belt speed, thereby stabilizing the print quality.

[0081] FIG. 6 is a diagram showing an example of a mechanism for determining a paper placement position using the accumulation of belt speed changes over time detected by behavior detection unit 104. Image forming apparatuses 100 and 300 may determine a paper placement position so that printing is performed at a timing when the accumulation (integral value) of belt speed changes during printing becomes small, instead of the belt speed changes, as shown in FIG. 6. In one aspect, behavior detection unit 104 may integrate the detected belt speed changes and output the integration result (integration) to CPU 401. In another aspect, CPU 401 may integrate (accumulate) the belt speed changes acquired from behavior detection unit 104.

[0082] For example, when performing printing processing using only one color of printing unit 101, image forming apparatus 100, 300 determines the paper placement position so that printing processing is performed during the period indicated by passage time 610 (the period during which the cumulative change in belt speed is small throughout the entire period of printing using one color of ink). In other words, image forming apparatus 100, 300 determines the paper placement position so that printing processing is performed at the timing when behavior detection unit 104 detects the belt speed during passage time 610. In one aspect, image forming apparatus 100, 300 may determine the paper placement position so that printing processing is performed during the period (or section) during the cycle of belt 102 during which the cumulative change in belt speed is smallest. In another aspect, image forming apparatus 100, 300 may determine the paper placement position so that printing processing is performed during the period (or section) during the cycle of belt 102 during which the cumulative change in belt speed is equal to or less than a predetermined threshold.

[0083] Even when the cumulative change in belt speed is used, image forming apparatuses 100 and 300 store in advance in non-volatile memory 405 the distance (offset) from behavior detection unit 104 to each printing unit 101. Then, image forming apparatuses 100 and 300 can determine the timing to place paper on belt 102 (or the position to place paper on belt 102) based on the timing at which behavior detection unit 104 detects the belt speed and the distance from behavior detection unit 104 to each printing unit 101.

[0084] As another example, when performing printing processing using all colors or multiple printing units 101, the image forming device 100, 300 determines the paper placement position so that the printing processing is performed during the period indicated by the passing time 620 (the period during which the cumulative change in belt speed becomes small throughout the entire period of printing using multiple inks).

[0085] As described above, the image forming apparatuses 100 and 300 determine the paper placement position so that the printing process is performed during a period (or interval) in which the cumulative (integral) value of the belt change is small within the cycle of the belt 102. This allows the image forming apparatuses 100 and 300 to, for example, suppress distortion of the image in the feed direction of the belt 102 due to the influence of changes in the belt speed, thereby stabilizing the print quality.

[0086] Furthermore, by determining the paper placement position based on the change in belt speed, image forming apparatuses 100 and 300 can effectively stabilize print quality when the speed change of belt 102 is relatively rapid. Furthermore, by determining the paper placement position based on the accumulation of changes in belt speed, image forming apparatuses 100 and 300 can effectively stabilize print quality when the speed change of belt 102 is relatively gradual. In one aspect, image forming apparatuses 100 and 300 may select whether to use the change in belt speed or the accumulation of changes in belt speed as a parameter for determining the paper placement position, depending on the magnitude of the speed change of belt 102.

[0087] FIG. 7 is a diagram showing an example of a mechanism for determining a paper placement position using a time-series meandering speed detected by the behavior detection unit 104. The meandering speed is the speed of the belt 102 in a direction perpendicular to the feed direction (meaning the meandering direction). Graph 700 shows the change in meandering speed while the belt 102 makes one revolution. When the belt 102 is operating continuously, the change in meandering speed shown in graph 700 is repeatedly detected. In the example of FIG. 7, the meandering speed changes before the belt 102 makes one revolution. The meandering speed may increase when the joint 110 of the belt 102 comes into contact with the roller 103.

[0088] Based on the measured meandering speed, the image forming apparatus 100, 300 determines the paper placement position so that the printing process is performed at a timing when the change in meandering speed becomes small. For example, when performing printing using only one color of printing unit 101, the image forming apparatus 100, 300 determines the paper placement position so that the printing process is performed during the period indicated by the passing time 710 (the period when the change in meandering speed becomes small throughout the entire period of printing using one color of ink). In other words, the image forming apparatus 100, 300 determines the paper placement position so that the printing process is performed at the timing when the behavior detection unit 104 detects the meandering speed during the passing time 710. For example, the image forming apparatus 100, 300 stores the distance (offset) from the behavior detection unit 104 to each printing unit 101 in the non-volatile memory 405 in advance. The image forming apparatus 100, 300 can then determine the timing to place the paper on the belt 102 (or the position to place the paper on the belt 102) based on the timing when the behavior detection unit 104 detects the meandering speed and the distance from the behavior detection unit 104 to each printing unit 101.

[0089] As another example, when performing printing processing using all colors or multiple printing units 101, the image forming device 100, 300 determines the paper placement position so that the printing processing is performed during the period indicated by the passing time 720 (the period during which the range of change in the meandering speed becomes small throughout the entire period of printing using multiple inks).

[0090] In one aspect, image forming apparatus 100, 300 may determine a paper placement position so that printing is performed during a period (or interval) in the cycle of belt 102 in which the variation in meandering speed is the smallest. In another aspect, image forming apparatus 100, 300 may determine a paper placement position so that printing is performed during a period (or interval) in the cycle of belt 102 in which the variation in meandering speed is equal to or less than a predetermined threshold. In still another aspect, image forming apparatus 100, 300 may select multiple paper placement positions so that printing is performed during multiple periods (or intervals) in the cycle of belt 102. In this case, the selected placement position is a placement position in which the variation in meandering speed is equal to or less than a predetermined threshold.

[0091] As described above, the image forming apparatuses 100 and 300 determine the paper placement position so that the printing process is performed during a period (or interval) where the range of change in the meandering speed is small within the cycle of the belt 102. This allows the image forming apparatuses 100 and 300 to, for example, suppress distortion of the image in the meandering direction of the belt 102 due to the influence of changes in the meandering speed, thereby stabilizing the print quality.

[0092] FIG. 8 is a diagram illustrating an example of a mechanism for determining a paper placement position using a time-series change in the meandering amount detected by behavior detection unit 104. Graph 800 shows the change in the meandering amount during one revolution of belt 102. Image forming apparatuses 100 and 300 may determine a paper placement position so that printing is performed at a timing when the change in the meandering amount during printing is small, instead of using the change in meandering speed, as shown in FIG. 8. In one aspect, behavior detection unit 104 may calculate the meandering amount from the detected meandering speed and output the calculation result (meandering amount) to CPU 401. In another aspect, CPU 401 may calculate the meandering amount from the meandering speed obtained from behavior detection unit 104.

[0093] For example, when performing printing processing using only one color printing unit 101, image forming apparatus 100, 300 determines the paper placement position so that printing processing is performed during the period indicated by passage time 810 (the period during which the range of change in the amount of meandering becomes small throughout the entire period of printing using one color of ink). In other words, image forming apparatus 100, 300 determines the paper placement position so that printing processing of the paper is performed at the timing when behavior detection unit 104 detects the amount of meandering during passage time 810.

[0094] Even when the meandering amount is used, image forming apparatuses 100 and 300 store the distance (offset) from behavior detection unit 104 to each printing unit 101 in nonvolatile memory 405 in advance. Image forming apparatuses 100 and 300 can then determine the timing to place paper on belt 102 (or the position to place paper on belt 102) based on the timing at which behavior detection unit 104 detects the meandering speed (or the meandering amount) and the distance from behavior detection unit 104 to each printing unit 101. In one aspect, image forming apparatuses 100 and 300 may determine the paper placement position so that printing is performed during a period (or section) in the cycle of belt 102 when the change in the meandering amount is the smallest. In another aspect, image forming apparatuses 100 and 300 may determine the paper placement position so that printing is performed during a period (or section) in the cycle of belt 102 when the change in the meandering amount is equal to or less than a predetermined threshold.

[0095] As another example, when performing printing processing using all colors or multiple printing units 101, the image forming device 100, 300 determines the paper placement position so that the printing processing is performed during the period indicated by the passing time 820 (the period during which the change in the amount of meandering becomes small throughout the entire period of printing using multiple inks).

[0096] As described above, the image forming apparatuses 100 and 300 determine the paper placement position so that the printing process is performed during a period (or interval) where the variation in the meandering amount is small within the cycle of the belt 102. This allows the image forming apparatuses 100 and 300 to, for example, suppress distortion of the image in the meandering direction of the belt 102 due to the influence of the variation in the meandering amount, thereby stabilizing the print quality.

[0097] Furthermore, by determining the paper placement position based on changes in meandering speed, image forming apparatuses 100 and 300 can effectively stabilize print quality when the meandering speed changes relatively rapidly. Furthermore, by determining the paper placement position based on changes in meandering amount, image forming apparatuses 100 and 300 can effectively stabilize print quality when the meandering speed changes relatively slowly. In one aspect, image forming apparatuses 100 and 300 may select whether to use the change in meandering speed or the change in meandering amount as a parameter for determining the paper placement position, depending on the magnitude of the change in meandering speed.

[0098] The methods for determining the paper placement position described with reference to FIGS. 5 to 8 above may be used in combination as appropriate. As an example, the image forming apparatuses 100 and 300 may multiply the belt speed, cumulative belt speed, meandering speed, and meandering amount by coefficients and sum the results to calculate a value indicating the behavior of the belt 102. The image forming apparatuses 100 and 300 may then determine the paper placement position so that the value indicating the behavior of the belt 102 is minimized. The image forming apparatuses 100 and 300 may also determine the paper placement position so that the value indicating the behavior of the belt 102 is equal to or less than a predetermined threshold. Furthermore, the image forming apparatuses 100 and 300 may select multiple paper placement positions at which the value indicating the behavior of the belt 102 is equal to or less than a predetermined threshold. The image forming apparatuses 100 and 300 may also calculate the value indicating the behavior of the belt 102 using part of the belt speed, cumulative belt speed, meandering speed, and meandering amount.

[0099] In this way, the image forming apparatuses 100 and 300 can suppress image distortion in the feed direction and meandering direction of the belt 102 and stabilize print quality by using a combination of multiple parameters that indicate the behavior of the belt 102.

[0100] In some aspects, image forming apparatus 100, 300 may estimate deterioration of belt 102 using all or some of the belt speed, cumulative belt speed, meandering speed, and meandering amount. For example, image forming apparatus 100, 300 may multiply each of belt speed, cumulative belt speed, meandering speed, and meandering amount by a coefficient and sum the results to calculate a value indicating the behavior of belt 102. Image forming apparatus 100, 300 may then estimate deterioration of belt 102 based on whether the value indicating the behavior of belt 102 is equal to or greater than a predetermined threshold. If image forming apparatus 100, 300 estimates that belt 102 has deteriorated, image forming apparatus 100, 300 may output a notification to output unit 407, which may be equipped with a display or the like, or may output (transmit) a notification to another device via communication unit 409, or may output a notification to both output unit 407 and communication unit 409. This allows the image forming apparatus 100, 300 to estimate the deterioration of the belt 102 based on the behavior of the belt 102 in the feeding direction and / or the meandering direction, and to notify the user or administrator that the belt 102 has deteriorated.

[0101] <C.フローチャート> 9 is a flowchart showing an example of a procedure for determining a preliminary placement position in image forming apparatus 100, 300. In one aspect, CPU 401 may load a program for executing the processing of FIG. 9 from ROM 403 or nonvolatile memory 405 into RAM 402 and execute the program. In another aspect, some or all of the processing may be realized as a combination of circuit elements configured to execute the processing.

[0102] In step S910, CPU 401 detects the phase of belt 102. More specifically, CPU 401 detects the phase of belt 102 based on a signal acquired from phase detection unit 105. CPU 401 of image forming apparatus 300 may detect the phase of belt 102 immediately below or near each printing unit 101 based on a signal acquired from each phase detection unit 105 provided near each printing unit 101.

[0103] In step S920, CPU 401 detects the behavior of belt 102 in a direction perpendicular to the feeding direction (meandering direction). More specifically, CPU 401 detects the behavior of belt 102 in the meandering direction based on a signal acquired from behavior detection unit 104. In one aspect, the behavior in the meandering direction detected by CPU 401 may include information on the meandering speed, the meandering amount, or both of belt 102.

[0104] In step S930, CPU 401 calculates the amount of change in speed in the feed direction for each phase of belt 102. More specifically, CPU 401 may calculate the amount of change in speed in the feed direction for each phase of belt 102 based on a signal acquired from behavior detection unit 104. As an example, CPU 401 may calculate the change in speed in the feed direction for an arbitrary short section (e.g., from phase A of belt 102 to phase B of belt 102). In one aspect, CPU 401 may calculate the amount of change in speed in the feed direction for each phase of belt 102 based on a signal acquired from phase detection unit 105 (e.g., using the phase and a timestamp at which the phase was detected).

[0105] In step S940, the CPU 401 calculates the cumulative change in speed in the feed direction for each phase of the belt 102. As an example, the CPU 401 may calculate the cumulative change in speed in the feed direction in an arbitrary short section (for example, from phase C of the belt 102 to phase D of the belt 102). In this case, the CPU 401 may add up the change in speed in the feed direction for each phase of the belt 102 calculated in step S930.

[0106] In step S950, CPU 401 calculates the meandering speed for each phase of belt 102. More specifically, CPU 401 calculates the meandering speed for each phase of belt 102 based on a signal acquired from behavior detection unit 104. As an example, CPU 401 may calculate the meandering speed in an arbitrary short section (for example, from phase E of belt 102 to phase F of belt 102). CPU 401 of image forming apparatus 300 calculates the meandering speed directly below or near each print unit 101 based on a signal acquired from each behavior detection unit 104 provided near each print unit 101.

[0107] In step S960, CPU 401 calculates the amount of meandering for each phase of belt 102. As an example, CPU 401 may calculate the amount of meandering in an arbitrary short section (for example, from phase G of belt 102 to phase H of belt 102). In this case, CPU 401 may calculate the amount of meandering based on the meandering speed calculated in step S950.

[0108] In step S970, CPU 401 determines the placement position of the paper. In one aspect, CPU 401 may use one of the amount of change in belt speed, the cumulative amount of change in belt speed, the meandering speed, and the amount of meandering as a parameter for determining the placement position of the paper.

[0109] In another aspect, CPU 401 may use any combination of the amount of change in belt speed, the cumulative amount of change in belt speed, the meandering speed, and the amount of meandering as parameters for determining the sheet placement position.

[0110] CPU 401 may determine the paper placement position so that the parameter value is the smallest, or may determine the paper placement position so that the parameter value is equal to or less than (less than) a predetermined threshold value.

[0111] As described above, the image forming apparatuses 100 and 300 according to the present embodiment detect the behavior of the printing belt 102 for each phase. Then, based on the behavior of the belt 102 for each phase, the image forming apparatuses 100 and 300 place paper at a position on the belt 102 where the influence of the behavior is minimal. In this way, the image forming apparatuses 100 and 300 can suppress the influence of the behavior of the belt 102 in the feed direction and / or the meandering direction during printing. Note that the image forming apparatuses 100 and 300 may use some or all of the following parameters indicating the behavior of the belt 102 for each phase: the speed change in the feed direction of the belt 102, the cumulative speed of the belt 102 in the feed direction, the speed in the meandering direction of the belt 102, and the meandering amount of the belt 102.

[0112] In one aspect, image forming apparatus 100, 300 may place paper at multiple positions on belt 102 where the influence of the behavior is small, based on the behavior of belt 102 for each phase. In this way, image forming apparatus 100, 300 can suppress the influence of the behavior of belt 102 on printing and suppress a decrease in printing efficiency.

[0113] Furthermore, in another aspect, image forming apparatus 100, 300 can estimate the deterioration of belt 102 based on the behavior of belt 102 for each phase, and when it estimates that belt 102 has deteriorated, output a notification to output unit 407 and / or communication unit 409. In this way, image forming apparatus 100, 300 can prompt a user or administrator to replace deteriorated belt 102, thereby maintaining the quality of belt 102 at a certain level or higher.

[0114] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims. Furthermore, the disclosures described in the embodiments and each modification are intended to be implemented, as far as possible, either alone or in combination. [Explanation of symbols]

[0115] 100,300 Image forming device, 101A,101B,101C,101D Printing unit, 102 Belt, 103A,103B,103C Roller, 104,411 Behavior detection unit, 105,410 Phase detection unit, 110 Joint, 210 Section, 220 Paper, 401 CPU, 402 RAM, 403 ROM, 405 Non-volatile memory, 406 Input unit, 407 Output unit, 408 Paper feed unit, 409 Communication unit, 412 Printing unit, 413 Bus, 510,520,610,620,710,720,810,820 Passing time.

Claims

1. one or more printing units for printing on paper; a loop-shaped belt that transports the paper to a printing position; a roller for feeding the belt; a phase detector that detects the phase of the belt; a behavior detection unit that detects the behavior of the belt; a control unit that determines a paper placement position on the belt based on the behavior of the belt for each phase; a paper feed unit that transports paper to the determined placement position, determining a paper placement position on the belt based on the behavior of the belt for each phase includes determining a paper placement position so that the behavior of the belt is minimized or equal to or less than a predetermined threshold during a period in which the paper passes through the one or more printing units; An image forming apparatus, wherein determining the paper placement position so that the behavior of the belt is minimized or below a predetermined threshold during the period in which the paper passes through the one or more printing units includes determining the paper placement position so that the change in the belt's meandering speed is minimized or below the predetermined threshold during the period in which the paper passes through the one or more printing units.

2. One or more printing units that print on paper; a loop-shaped belt that transports the paper to a printing position; a roller for feeding the belt; a phase detector that detects the phase of the belt; a behavior detection unit that detects the behavior of the belt; a control unit that determines a paper placement position on the belt based on the behavior of the belt for each phase; a paper feed unit that transports paper to the determined placement position, determining a paper placement position on the belt based on the behavior of the belt for each phase includes determining a paper placement position so that the behavior of the belt is minimized or equal to or less than a predetermined threshold during a period in which the paper passes through the one or more printing units; An image forming apparatus, wherein determining the paper placement position so that the behavior of the belt is minimized or below a predetermined threshold during the period in which the paper passes through the one or more printing units includes determining the paper placement position so that the change in the amount of meandering of the belt is minimized or below the predetermined threshold during the period in which the paper passes through the one or more printing units.

3. One or more printing units that print on paper; a loop-shaped belt that transports the paper to a printing position; a roller for feeding the belt; a phase detector that detects the phase of the belt; a behavior detection unit that detects the behavior of the belt; a control unit that determines a paper placement position on the belt based on the behavior of the belt for each phase; a paper feed unit that transports paper to the determined placement position; An input unit and a communication unit are provided, determining a paper placement position on the belt based on the behavior of the belt for each phase includes determining a paper placement position so that the behavior of the belt is minimized or equal to or less than a predetermined threshold during a period in which the paper passes through the one or more printing units; the one or more printing units include printing units of a plurality of colors, the control unit selects one or more printing units to be used for printing processing from among the printing units of the plurality of colors, the period during which the paper passes through the one or more printing units is a period during which the paper passes through the selected one or more printing units, An image forming device, wherein selecting one or more printing units to be used for the printing process from among the printing units of the plurality of colors includes selecting one or more printing units to be used for the printing process from among the printing units of the plurality of colors based on color specification input received via the input unit or the communication unit.

4. One or more printing units for printing on paper; a loop-shaped belt that transports the paper to a printing position; a roller for feeding the belt; a phase detector that detects the phase of the belt; a behavior detection unit that detects the behavior of the belt; a control unit that determines a paper placement position on the belt based on the behavior of the belt for each phase; a paper feed unit that transports paper to the determined placement position, determining a paper placement position on the belt based on the behavior of the belt for each phase includes determining a paper placement position so that the behavior of the belt is minimized or equal to or less than a predetermined threshold during a period in which the paper passes through the one or more printing units; the one or more printing units include printing units for each of a plurality of colors, the control unit selects one or more printing units to be used for printing processing from among the printing units of the plurality of colors, the period during which the paper passes through the one or more printing units is a period during which the paper passes through the selected one or more printing units, The control unit analyzes image data to be printed on the paper, An image forming device, wherein selecting one or more printing units to be used for the printing process from among the printing units of the plurality of colors includes selecting one or more printing units to be used for the printing process from among the printing units of the plurality of colors based on the analysis results of the image data.

5. One or more printing units for printing on paper; a loop-shaped belt that transports the paper to a printing position; a roller for feeding the belt; a phase detector that detects the phase of the belt; a behavior detection unit that detects the behavior of the belt; a control unit that determines a paper placement position on the belt based on the behavior of the belt for each phase; a paper feed unit that transports paper to the determined placement position, determining a paper placement position on the belt based on the behavior of the belt for each phase includes determining a paper placement position so that the behavior of the belt is minimized or equal to or less than a predetermined threshold during a period in which the paper passes through the one or more printing units; the one or more printing units include printing units for each of a plurality of colors, the control unit selects one or more printing units to be used for printing processing from among the printing units of the plurality of colors, the period during which the paper passes through the one or more printing units is a period during which the paper passes through the selected one or more printing units, the behavior detection unit includes a plurality of behavior detection units, Each of the plurality of behavior detection units provided near the printing units of the plurality of colors, The image forming apparatus detects the behavior of the belt in the vicinity of each of the printing units of the plurality of colors.

6. One or more printing units for printing on paper; a loop-shaped belt that transports the paper to a printing position; a roller for feeding the belt; a phase detector that detects the phase of the belt; a behavior detection unit that detects the behavior of the belt; a control unit that determines a paper placement position on the belt based on the behavior of the belt for each phase; a paper feed unit that transports paper to the determined placement position, The control unit estimates deterioration of the belt based on a detection result of the behavior of the belt.

7. An image forming apparatus as described in any one of claims 1 to 5, wherein determining the loading position of the paper so that the behavior of the belt is minimized or below a predetermined threshold during the period in which the paper passes through the one or more printing units includes determining the loading position of the paper so that the change in the speed of the belt in the feed direction is minimized or below the predetermined threshold during the period in which the paper passes through the one or more printing units.

8. An image forming apparatus as described in any one of claims 1 to 5, wherein determining the loading position of the paper so that the behavior of the belt is minimized or below a predetermined threshold during the period in which the paper passes through the one or more printing units includes determining the loading position of the paper so that the cumulative change in the speed of the belt in the feed direction during the period in which the paper passes through the one or more printing units is minimized or below the predetermined threshold.

9. the one or more printing units include printing units for each of a plurality of colors, 9. The image forming apparatus according to claim 2, wherein the period during which the paper passes through the one or more printing units is a period during which the paper passes through all of the printing units for each of the plurality of colors.

10. The image forming apparatus according to claim 4 , wherein the analysis result of the image data includes coverage in the image data for each of the plurality of colors.

11. An image forming apparatus as described in any one of claims 1 to 10, wherein determining the paper placement position on the belt based on the behavior of the belt for each phase includes selecting multiple sections on the belt as paper placement positions on the belt based on the behavior of the belt for each phase.

12. The image forming apparatus according to claim 6 , wherein the control unit outputs a notification based on an estimation result of the deterioration of the belt.

Images