Image forming device and image forming method

Abstract

To provide an image forming device and an image forming method which can achieve improvement in productivity and stabilization of an image quality in the image forming device, with good balance.SOLUTION: In an image forming device (100), when a printing type of a printing process that is executed by a printing processing part (50) is changed from either of monochrome printing and color printing to the other, an adjustment processing part (52) can execute a condition adjustment process for adjusting an image formation condition in the image forming part (3), before the monochrome printing or the color printing is executed after the printing type is changed. The printing processing part (50) can change a linear velocity in the image forming part (3) in accordance with a combination of a linear velocity preset to correspond to a sheer type of a sheet and the printing type. Further, the adjustment processing part (52) can restrict execution of the condition adjustment process, when the linear velocity mode is same before and after the printing type is changed and when a preset restriction condition is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus and an image forming method. [Background technology]

[0002] An electrophotographic image forming apparatus includes an image forming unit that forms an image on a sheet based on input image data (see, for example, Patent Document 1). In this type of image forming apparatus, a condition adjustment process is executed at a preset timing to adjust various image formation conditions, such as the amount of laser light and the developing bias voltage, in the image forming unit. For example, when the linear speed of a transfer medium, such as an intermediate transfer belt, in the image forming unit is changed, the condition adjustment process may be executed before the execution of a printing process after the change in linear speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-135305 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the condition adjustment process is performed before the execution of the printing process after the linear speed in the image forming unit is changed, the start of the printing process is delayed, which reduces the productivity (printing efficiency) of the image forming device.On the other hand, if the condition adjustment process is not performed before the execution of the printing process after the linear speed in the image forming unit is changed, there is a risk that the stabilization of image quality in the image forming device will be hindered.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus and an image forming method that can achieve a good balance between improving productivity in the image forming apparatus and stabilizing image quality. [Means for solving the problem]

[0006] According to one aspect of the present invention, an image forming apparatus includes a print processing unit and an adjustment processing unit. The print processing unit controls an image forming unit having image forming units corresponding to multiple colors, and performs monochrome printing to form a monochrome image on a sheet or color printing to form a color image on the sheet based on input image data. When the print type of the printing process performed by the print processing unit is changed from monochrome printing or color printing to the other, the adjustment processing unit is capable of performing a condition adjustment process to adjust image formation conditions in the image forming unit before performing the monochrome printing or color printing after the print type change. The print processing unit is capable of changing the linear speed in the image forming unit in accordance with a combination of a linear speed mode preset in association with the sheet type of the sheet and the print type. The adjustment processing unit is capable of restricting the execution of the condition adjustment process when the linear speed mode is the same before and after the print type change and when a preset restriction condition is satisfied.

[0007] According to another aspect of the present invention, an image forming method includes a printing step and an adjustment step, in which one or more processors execute a printing step and an adjustment step. In the printing step, an image forming unit having image forming units corresponding to multiple colors is controlled to perform monochrome printing, which forms a monochrome image on a sheet, or color printing, which forms a color image on the sheet, based on input image data. In the adjustment step, when the printing type of the printing process executed in the printing step is changed from monochrome printing or color printing to the other, a condition adjustment process can be executed to adjust image formation conditions in the image forming unit before executing the monochrome printing or color printing after the change in printing type. In the printing step, the linear speed in the image forming unit can be changed according to a combination of a linear speed mode preset in association with the sheet type of the sheet and the printing type. In the adjustment step, execution of the condition adjustment process can be restricted when the linear speed mode is the same before and after the change in printing type and a preset restriction condition is satisfied. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an image forming apparatus and an image forming method that can achieve a good balance between improving productivity in the image forming apparatus and stabilizing image quality. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view showing the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing the system configuration of the image forming apparatus according to the embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram showing the configuration of the image forming unit of the image forming apparatus according to the embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing an example of linear velocity correspondence information used in the image forming apparatus according to the embodiment of the present invention. [Figure 5] FIG. 5 is a flowchart showing an example of adjustment control processing executed in the image forming apparatus according to the embodiment of the present invention. [Figure 6] FIG. 6 is a flowchart showing an example of adjustment control processing executed in the image forming apparatus according to the embodiment of the present invention. [Figure 7] FIG. 7 is a flowchart showing an example of the adjustment control process executed in the image forming apparatus according to the embodiment of the present invention. [Figure 8] FIG. 8 is a flowchart showing an example of adjustment control processing executed in the image forming apparatus according to the embodiment of the present invention. [Figure 9] FIG. 9 is a flowchart showing an example of the adjustment control process executed in the image forming apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Note that the following embodiment is an example of a specific embodiment of the present invention and does not limit the technical scope of the present invention.

[0011] First, the configuration of an image forming apparatus 100 according to an embodiment of the present invention will be described with reference to FIGS.

[0012] For ease of explanation, the vertical direction in the installation state where image forming apparatus 100 is usable (the state shown in FIG. 1) is defined as the up-down direction D1. Also, the front-to-back direction D2 is defined with the left side of image forming apparatus 100 on the paper surface shown in FIG. 1 as the front (front face). Also, the left-to-right direction D3 is defined with the front face of image forming apparatus 100 in the installation state as the reference point.

[0013] Image forming apparatus 100 is a multifunction peripheral that has multiple functions, such as a scanning function for reading an image from an original document, a printing function for forming an image based on image data, a fax function, and a copy function. Note that the present invention may also be applied to image forming apparatuses such as printers, fax machines, and copy machines that are capable of forming images using an electrophotographic method.

[0014] As shown in FIGS. 1 and 2, the image forming apparatus 100 includes an ADF (Auto Document Feeder) 1, an image reading unit 2, an image forming unit 3, a paper feeding unit 4, an operation display unit 5, a storage unit 6, and a control unit .

[0015] The ADF 1 transports documents to be scanned by the scanning function, and includes a document setting section, a plurality of transport rollers, a document holder, and a paper ejection section.

[0016] The image reading unit 2 realizes the scanning function and includes a document table, a light source, a plurality of mirrors, an optical lens, and a CCD (Charge Coupled Device).

[0017] The image forming unit 3 realizes the printing function. Specifically, the image forming unit 3 forms a color image or a monochrome image on a sheet fed from the paper feed unit 4 according to an electrophotographic method.

[0018] The paper feed unit 4 supplies sheets to the image forming unit 3. The paper feed unit 4 includes multiple paper feed cassettes 4A, a manual feed tray, and multiple transport rollers. The control unit 7 can preset the sheet type of the sheets stored in each paper feed cassette 4A in response to a user operation. Specifically, the sheet types include multiple types of sheet types such as plain paper, medium-weight paper, and thick paper. The control unit 7 may automatically detect the sheet type of the sheets stored in each paper feed cassette 4A based on the detection results of a detection unit such as an optical sensor or weight sensor (not shown).

[0019] The operation display unit 5 is a user interface of the image forming apparatus 100. The operation display unit 5 has a display unit such as a liquid crystal display that displays various information in response to control instructions from the control unit 7, and an operation unit such as operation keys or a touch panel that inputs various information to the control unit 7 in response to user operations.

[0020] The storage unit 6 is a nonvolatile storage device. For example, the storage unit 6 is a nonvolatile memory such as a flash memory. The storage unit 6 may be an SSD (Solid State Drive) or an HDD (Hard Disk Drive).

[0021] The control unit 7 performs overall control of the image forming apparatus 100. As shown in FIG. 2, the control unit 7 includes a CPU 11, a ROM 12, and a RAM 13. The CPU 11 includes one or more processors that execute various types of arithmetic processing. The ROM 12 is a non-volatile storage device that stores in advance information such as control programs for causing the CPU 11 to execute various types of processing. The RAM 13 is a volatile or non-volatile storage device that is used as a temporary storage memory (work area) for the various types of processing executed by the CPU 11. The CPU 11 performs overall control of the image forming apparatus 100 by executing the various control programs that are stored in advance in the ROM 12.

[0022] The control unit 7 may be a control unit provided separately from a main control unit that performs overall control of the image forming apparatus 100. The control unit 7 may also be configured with an electronic circuit such as an integrated circuit (ASIC).

[0023] [Configuration of image forming unit 3] Next, the configuration of the image forming section 3 will be described with reference to Figures 1 to 3. Here, Figure 3 is a schematic diagram showing the configurations of the image forming unit 20, intermediate transfer belt 26, and secondary transfer roller 27. Figure 3 is also a bottom view showing the configurations of the photosensitive drum 31, intermediate transfer belt 26, drive roller 26A, and secondary transfer roller 27 of the image forming unit 24.

[0024] 1, the image forming section 3 includes four image forming units 20, an optical scanning device 25, an intermediate transfer belt 26, a secondary transfer roller 27, a fixing device 28, and a paper discharge tray 29. Also, as shown in FIGS. 2 and 3, the image forming section 3 includes four first power sources 40, a second power source 45, and a detection section 46.

[0025] The four image forming units 20 include image forming units 21 to 24 corresponding to multiple colors. Image forming unit 21 (see FIG. 3) forms a Y (yellow) toner image. Image forming unit 22 (see FIG. 3) forms a C (cyan) toner image. Image forming unit 23 (see FIG. 3) forms an M (magenta) toner image. Image forming unit 24 (see FIG. 3) forms a K (black) toner image. As shown in FIGS. 1 and 3, the four image forming units 20 are arranged side by side in the order of yellow, cyan, magenta, and black from the front side of image forming apparatus 100 along the front-rear direction D2. Of the image forming units 20, image forming unit 24 is used for monochrome printing, and image forming units 21 to 24 are used for color printing.

[0026] 3, each image forming unit 20 includes a photosensitive drum 31, a charging roller 32, a developing device 33, a primary transfer roller 34, and a drum cleaning unit 35. Each image forming unit 20 also includes a toner container 36 shown in FIG.

[0027] An electrostatic latent image is formed on the surface of the photosensitive drum 31. For example, the photosensitive drum 31 has a photosensitive layer made of amorphous silicon. The photosensitive drum 31 receives a rotational driving force supplied from a motor (not shown) and rotates in a drum rotation direction D4 shown in FIG. 3. As a result, the photosensitive drum 31 transports the electrostatic latent image formed on its surface.

[0028] A preset charging voltage is applied to the charging roller 32, which charges the surface of the photosensitive drum 31. For example, the charging roller 32 charges the surface of the photosensitive drum 31 to a positive polarity. The surface of the photosensitive drum 31 charged by the charging roller 32 is irradiated with light based on image data emitted from the optical scanning device 25. As a result, an electrostatic latent image is formed on the surface of the photosensitive drum 31.

[0029] The developing device 33 develops the electrostatic latent image formed on the surface of the photosensitive drum 31. The developing device 33 includes a pair of stirring members, a magnet roller, and a developing roller. The pair of stirring members stir the developer, which contains toner and a carrier, contained within the developing device 33. For example, the toner contained in the developer is positively charged due to friction with the carrier contained in the developer. The magnet roller draws up the developer stirred by the pair of stirring members and supplies the toner contained in the developer to the developing roller. The developing roller transports the toner supplied from the magnet roller to a position facing the photosensitive drum 31. Furthermore, the developing roller receives a preset development bias voltage and supplies the toner transported to the facing position to the photosensitive drum 31. As a result, toner is selectively supplied to an exposure area of ​​the photosensitive drum 31 irradiated with light emitted from the optical scanning device 25, thereby developing the electrostatic latent image formed on the surface of the photosensitive drum 31. The developing device 33 is supplied with toner from a toner container 36 .

[0030] The primary transfer roller 34 receives a supply of a preset primary transfer current and transfers the toner image formed on the surface of the photosensitive drum 31 onto the outer circumferential surface of the intermediate transfer belt 26. As shown in Fig. 3, the primary transfer roller 34 is disposed opposite the photosensitive drum 31 with the intermediate transfer belt 26 sandwiched therebetween.

[0031] The drum cleaning unit 35 removes the toner remaining on the surface of the photosensitive drum 31 after the toner image has been transferred by the primary transfer roller 34 .

[0032] The optical scanning device 25 emits light based on image data toward the surface of the photosensitive drum 31 of each image forming unit 20.

[0033] The intermediate transfer belt 26 is an endless belt member onto which the toner images formed on the surfaces of the photosensitive drums 31 of each image forming unit 20 are transferred. For example, the intermediate transfer belt 26 is made of a resin material such as polyimide. The intermediate transfer belt 26 is stretched with a predetermined tension by a drive roller 26A (see FIG. 3) and a tension roller 26B (see FIG. 3). The intermediate transfer belt 26 rotates in a belt rotation direction D5 shown in FIG. 3 when the drive roller 26A rotates due to a rotational driving force supplied from a motor (not shown). As a result, the intermediate transfer belt 26 transports the toner images transferred from each photosensitive drum 31 to a transfer position onto a sheet by a secondary transfer roller 27. After the toner images are transferred by the secondary transfer roller 27, the outer peripheral surface of the intermediate transfer belt 26 is cleaned by a belt cleaning unit 26C (see FIG. 3).

[0034] The secondary transfer roller 27 receives a preset secondary transfer current and transfers the toner image transferred onto the outer peripheral surface of the intermediate transfer belt 26 onto a sheet supplied from the paper feed unit 4. As shown in FIG. 3, the secondary transfer roller 27 is disposed opposite the drive roller 26A with the intermediate transfer belt 26 sandwiched therebetween.

[0035] The fixing device 28 fixes the toner image transferred onto the sheet by the secondary transfer roller 27 onto the sheet.

[0036] The sheet on which the toner image has been fixed by the fixing device 28 is discharged onto the paper discharge tray 29.

[0037] Of the four first power sources 40, first power source 41 (see FIG. 2) is a constant current power source that supplies the primary transfer current to the primary transfer roller 34 of the image forming unit 21. Of the four first power sources 40, first power source 42 (see FIG. 2) is a constant current power source that supplies the primary transfer current to the primary transfer roller 34 of the image forming unit 22. Of the four first power sources 40, first power source 43 (see FIG. 2) is a constant current power source that supplies the primary transfer current to the primary transfer roller 34 of the image forming unit 23. Of the four first power sources 40, first power source 44 (see FIG. 2) is a constant current power source that supplies the primary transfer current to the primary transfer roller 34 of the image forming unit 24. Each of the first power sources 40 supplies the primary transfer current set by the control unit 7 to the primary transfer roller 34. For example, the primary transfer current is a negative current.

[0038] The second power supply 45 is a constant current power supply that supplies the secondary transfer current to the secondary transfer roller 27. The second power supply 45 supplies the secondary transfer current set by the control unit 7 to the secondary transfer roller 27. For example, the secondary transfer current is a negative current.

[0039] The detection unit 46 is used to detect the density and position of the toner image transferred onto the outer peripheral surface of the intermediate transfer belt 26. For example, the detection unit 46 is a reflective photosensor that includes a light-emitting unit that emits light toward the intermediate transfer belt 26 and a light-receiving unit that receives the light emitted from the light-emitting unit and reflected by the intermediate transfer belt 26. The detection unit 46 then inputs an electrical signal to the control unit 7 that corresponds to the density of the toner image to be detected.

[0040] 3, the detection unit 46 is disposed downstream in the belt rotation direction D5 of the photosensitive drum 31 of the image forming unit 24 and upstream in the belt rotation direction D5 of the position where the toner image is transferred by the secondary transfer roller 27. Furthermore, when a detection toner image, which will be described later, is formed on the intermediate transfer belt 26 outside the area where a print image based on the image data of the print target is formed, the detection unit 46 may be disposed downstream in the belt rotation direction D5 of the position where the toner image is transferred by the secondary transfer roller 27 and upstream in the belt rotation direction D5 of the position where the belt cleaning unit 26C cleans the outer circumferential surface of the intermediate transfer belt 26.

[0041] [Configuration of control unit 7] Next, the configuration of the control unit 7 will be described with reference to FIG.

[0042] 2, the control unit 7 includes a print processing unit 50, a count processing unit 51, and an adjustment processing unit 52. Specifically, a condition adjustment program for causing the CPU 11 to function as each of the above-mentioned processing units is stored in advance in the ROM 12 of the control unit 7. The CPU 11 then executes the condition adjustment program stored in the ROM 12 to function as each of the above-mentioned processing units.

[0043] The condition adjustment program may be recorded on a computer-readable recording medium such as a CD, DVD, or flash memory, and may be read from the recording medium and stored in a storage device such as the memory unit 6. In addition, some or all of the print processing unit 50, count processing unit 51, and adjustment processing unit 52 may be configured with electronic circuits such as an application specific integrated circuit (ASIC).

[0044] The print processing unit 50 controls the image forming unit 3, which has image forming units 21-24 corresponding to multiple colors, and performs printing processes such as monochrome printing, which forms a monochrome image on a sheet, or color printing, which forms a color image on the sheet, based on input image data. Specifically, the print processing unit 50 controls the optical scanning device 25 based on the image data of the print target, and forms electrostatic latent images corresponding to each color on the photosensitive drum 31 of each image forming unit 20 at a predetermined timing. As a result, in each image forming unit 20, the electrostatic latent image formed on the photosensitive drum 31 is developed into a toner image, and the toner images are sequentially transferred to the intermediate transfer belt 26. Thereafter, the color image or monochrome image formed on the intermediate transfer belt 26 is transferred to a sheet by the secondary transfer roller 27, and the intermediate transfer belt 26 is cleaned by the belt cleaning unit 26C.

[0045] During the printing process, the print processing unit 50 controls the amount of laser light emitted by the optical scanning device 25 based on the image data and input / output characteristics that indicate the relationship between input image data and the amount of light emitted by the optical scanning device 25. During the printing process, the print processing unit 50 also controls the development bias voltage in each image forming unit 20 to a value that is set in advance for that image forming unit 20. During the printing process, the print processing unit 50 also controls the charging voltage, the primary transfer current, the secondary transfer current of the secondary transfer roller 27, and the like in each image forming unit 20.

[0046] Furthermore, the print processing unit 50 can change the linear speed in the image forming unit 3 depending on the type of sheet used in the printing process (plain paper, medium-weight paper, thick paper, etc.) and the type of printing process (monochrome printing, color printing). The linear speed is the running speed (surface movement speed) of a transfer medium such as the intermediate transfer belt 26, and the print processing unit 50 changes the linear speed by adjusting the rotation speed of the drive roller 26A that drives the intermediate transfer belt 26. Note that, for example, if the image forming unit 3 does not have an intermediate transfer belt 26 and a toner image is transferred from each photosensitive drum 31 to a sheet, the linear speed may be the sheet transport speed.

[0047] The print processing unit 50 can determine the sheet type (plain paper, medium thickness paper, thick paper, etc.) of the sheets used in the print process according to the paper feed cassette 4A used in the print process. The print processing unit 50 may also determine the sheet type of the sheets used in the print process based on the image data to be printed based on the print conditions set by a user operation for the print process of the image data.

[0048] The print processing unit 50 can automatically determine whether the print type of the print process is monochrome printing or color printing based on the image data. The print processing unit 50 may also determine whether the print type of the print process is monochrome printing or color printing based on printing conditions set by a user operation for the print process of the image data.

[0049] Specifically, in this embodiment, linear speed correspondence information (see FIG. 5 ) in which correspondences between a plurality of preset linear speed modes and a plurality of sheet types are predetermined is stored in the storage unit 6. Specifically, as shown in FIG. 5 , the linear speed correspondence information used in this embodiment includes full speed mode, medium speed mode, and half speed mode as the linear speed modes. The full speed mode is associated with the sheet type "plain paper," the medium speed mode is associated with the sheet type "medium-thick paper," and the half speed mode is associated with the sheet type "thick paper." Note that each of the linear speed modes may be associated with a plurality of sheet types. For example, the full speed mode may be associated with two sheet types: "plain paper" and "color paper." Note that each of the sheet types is associated in advance with one of the linear speed modes depending on the basis weight of the sheet.

[0050] 5, the linear speed correspondence information defines a correspondence relationship between a plurality of linear speed modes and a plurality of printing types. Specifically, in the linear speed correspondence information, for the full speed mode, the printing type is "monochrome printing" and the linear speed is "C1" when the printing type is "color printing." For the medium speed mode, the printing type is "monochrome printing" and the linear speed is "M2" when the printing type is "color printing." Furthermore, for the half speed mode, the printing type is "monochrome printing" and the linear speed is "M3" when the printing type is "color printing," and the linear speed is "C3" when the printing type is "color printing."

[0051] In this way, the linear speed correspondence information stores the linear speed associated with each combination of the linear speed mode and the print type. The print processing unit 50 changes the linear speed of the image forming unit 3 in the print process based on the linear speed correspondence information, the sheet type of the sheet used in the print process, and the print type in the print process.

[0052] The linear velocities "M1" to "M3" have a relationship of M1>M2>M3, and the linear velocities "C1" to "C3" have a relationship of C1>C2>C3. The linear velocities "M1" to "M3" and the linear velocities "C1" to "C3" have a relationship of M1>C1, M2>C2, and M3>C3. The difference in linear speed between monochrome printing and color printing in the same linear speed mode is considered to be smaller than the difference in linear speed between monochrome printing in different linear speed modes. Similarly, the difference in linear speed between monochrome printing and color printing in the same linear speed mode is considered to be smaller than the difference in linear speed between color printing in different linear speed modes. That is, the change in linear speed due to a change in the printing type is smaller than the change in linear speed due to a change in the linear speed mode.

[0053] The count processing unit 51 starts counting a count value indicating elapsed time when a preset start condition is satisfied. Specifically, when the print processing unit 50 starts a series of printing processes in which images are formed on multiple sheets based on image data corresponding to one print job, the count processing unit 51 starts counting a print count value indicating elapsed time in the printing processes. When the print processing unit 50 continuously executes print processes for multiple sheets in multiple jobs, the print count value may be the elapsed time in the series of printing processes continuously executed. Note that the count processing unit 51 resets the print count value to 0 each time the series of printing processes starts or when the image forming apparatus 100 does not execute a printing process for a preset period of time. Furthermore, when the adjustment processing unit 52 executes a color adjustment process (described below), the count processing unit 51 starts counting an interval count value indicating the elapsed time from the time the color adjustment process (the start or end of execution) was executed to the present time.

[0054] Furthermore, the count processing unit 51 may count a count value indicating the number of printed sheets instead of or together with the elapsed time. Specifically, when the print processing unit 50 starts the print processing in which images are formed on one or more sheets based on image data corresponding to one print job, the count processing unit 51 may start counting a print count value indicating the number of printed sheets in the print processing. Furthermore, when the adjustment processing unit 52 executes a color adjustment processing described below, the count processing unit 51 may start counting an interval count value indicating the number of printed sheets from the time the color adjustment processing was executed (the time the execution started or the time the execution ended) to the present time.

[0055] The adjustment processing unit 52 can execute a condition adjustment process to adjust the image formation conditions in the image forming unit 3 when the linear speed of the image forming unit 3 is changed by changing the linear speed mode or the print type in the printing process executed by the print processing unit 50. Specifically, when the linear speed is changed by changing the print type of the printing process executed by the print processing unit 50 from one of monochrome printing and color printing to the other, the adjustment processing unit 52 executes the condition adjustment process before (between sheets of paper) monochrome printing or color printing is executed after the print type is changed. In another embodiment, the condition adjustment process may be executed in parallel with the printing process.

[0056] If the printing process executed after the change in linear speed is monochrome printing, the condition adjustment process is executed only for the image forming units 24 used for monochrome printing. If the printing process executed after the change in linear speed is color printing, the condition adjustment process is executed for the image forming units 21 to 24 used for color printing. Furthermore, as another embodiment, if the printing process executed after the change in linear speed is either monochrome printing or color printing, the condition adjustment process may be executed for the image forming units 21 to 24 used for color printing.

[0057] In the condition adjustment process, the adjustment processing unit 52 controls the image forming unit 3 to form one or more detection toner images based on preset detection image data on the intermediate transfer belt 26 by each of the image forming units 20 to be adjusted at the linear speed in the printing process executed after the print type change. The adjustment processing unit 52 then uses the detection unit 46 to detect the density and position of each of the detection toner images formed on the intermediate transfer belt 26. Based on the detection results of the density and position of the detection toner images, the adjustment processing unit 52 adjusts the image formation conditions in the image forming unit 3 to adjust the density and position of the toner images formed by each of the image forming units 20. For example, the image formation conditions include the development bias voltage, the amount of laser light in the optical scanning device 25, the image formation position (image write start timing) by the optical scanning device 25, and input / output characteristics (gamma characteristics). The image formation conditions may also include the charging voltage, the primary transfer current, and the secondary transfer current.

[0058] However, if the condition adjustment process is executed before the execution of the printing process after the linear speed has been changed in the image forming unit 3, the start of the printing process will be delayed, resulting in a decrease in productivity (printing efficiency) in the image forming apparatus. On the other hand, if the condition adjustment process is not executed before the execution of the printing process after the linear speed has been changed in the image forming unit 3, there is a risk that the stabilization of image quality in the image forming apparatus 100 will be hindered. In contrast, the image forming apparatus 100 according to this embodiment can achieve a good balance between improved productivity and stabilization of image quality in the image forming apparatus 100, as will be described below.

[0059] Specifically, in the image forming apparatus 100, the control unit 7 can select one of a plurality of operation modes having different execution conditions for the condition adjustment process in response to a user operation, for example, during initial setup of the image forming apparatus 100. In this embodiment, the operation modes include a first operation mode to a fifth operation mode. Then, in the condition adjustment control process described below, the control unit 7 determines whether or not to execute the condition adjustment process according to the pre-selected operation mode.

[0060] In particular, in the image forming apparatus 100 according to this embodiment, even when the print type is changed, if the linear speed mode is the same before and after the change of print type and if the restriction conditions set in advance for each operation mode are satisfied, the control unit 7 can restrict the execution of the condition adjustment process. Specifically, restricting the execution of the condition adjustment process includes not executing the condition adjustment process, or executing only a part of the condition adjustment process.

[0061] In other embodiments, it is sufficient if one or more of the first to fifth operation modes can be executed in the image forming apparatus 100. In addition to the first to fifth operation modes, the image forming apparatus 100 may be able to select an operation mode that has different criteria for determining whether or not to execute the condition adjustment process.

[0062] [Condition adjustment control processing] 5 to 9, an example of the procedure of the condition adjustment control process (image forming method) executed by the adjustment processing unit 52 of the control unit 7 when the first to fifth operation modes are selected in the image forming apparatus 100 will be described. The present invention may also be understood as an image forming method in which the control unit 7 executes each step in the condition adjustment control process corresponding to one or more of the first to fifth operation modes. Steps S11, S12, etc. represent the numbers of the processing procedures (steps) executed by the control unit 7.

[0063] The condition adjustment control process is executed by the control unit 7 each time an image forming operation on the intermediate transfer belt 26 corresponding to one sheet is completed when the print processing unit 50 is continuously executing printing processes for multiple sheets in one job. When a series of printing processes for multiple sheets in one job is continuously executed, the series of printing processes may include a mixture of monochrome printing and color printing, and the series of printing processes may switch between monochrome printing and color printing. The condition adjustment control process may also be executed by the control unit 7 each time an image forming operation on the intermediate transfer belt 26 corresponding to each sheet is completed when the print processing unit 50 is continuously executing printing processes for multiple sheets in multiple jobs. In this case, too, when a series of printing processes for multiple sheets in the multiple jobs is continuously executed, the series of printing processes may include a mixture of monochrome printing and color printing, and the series of printing processes may switch between monochrome printing and color printing. After that, when the condition adjustment control process is completed, the print processing unit 50 starts an image forming operation on the intermediate transfer belt 26 in the printing process for the next sheet. In addition, when the condition adjustment process is executed in the condition adjustment control process, the print processing unit 50 starts the image formation operation on the intermediate transfer belt 26 in the print process corresponding to the next sheet after the condition adjustment process is executed.

[0064] [Condition adjustment control process in first operation mode] First, with reference to FIG. 5, the condition adjustment process when the operation mode of the image forming apparatus 100 is the first operation mode will be described.

[0065] The restrictive condition in the first operation mode is that the printing type is changed from color printing to monochrome printing.

[0066] <Step S11> In step S11, the adjustment processing unit 52 of the control unit 7 determines whether the print type of the print process executed by the print processing unit 50 will be changed from color printing to monochrome printing. Specifically, if the print type of the previous print process was color printing and the print type of the next print process is monochrome printing, the adjustment processing unit 52 determines that the print type will be changed from color printing to monochrome printing. Here, if it is determined that the print type will be changed from color printing to monochrome printing (S11: Yes), the process proceeds to step S12. On the other hand, if it is determined that the print type will not be changed from color printing to monochrome printing (S11: No), the process proceeds to step S111.

[0067] <Step S12> In step S12, the adjustment processing unit 52 of the control unit 7 determines whether the linear speed mode will be changed. Specifically, the adjustment processing unit 52 determines that the linear speed mode will be changed if the linear speed mode in the previous printing process differs from the linear speed mode in the next printing process. For example, if the sheets used in the previous printing process were plain paper corresponding to the full speed mode and the sheets used in the next printing process are thick paper corresponding to the half speed mode, the adjustment processing unit 52 determines that the linear speed mode will be changed. Here, if it is determined that the linear speed mode will be changed (S12: Yes), the process proceeds to step S13. If it is determined that the linear speed mode will not be changed (S12: No), the condition adjustment control process ends.

[0068] <Step S111> Furthermore, in step S111, the adjustment processing unit 52 of the control unit 7 determines whether the printing type will be changed from monochrome printing to color printing. Specifically, if the printing type of the previous printing process was monochrome printing and the printing type of the next printing process is color printing, the adjustment processing unit 52 determines that the printing type will be changed from monochrome printing to color printing. Here, if it is determined that the printing type will be changed from monochrome printing to color printing (S111: Yes), the process proceeds to step S13. On the other hand, if it is determined that the printing type will not be changed from monochrome printing to color printing (S111: No), the process proceeds to step S12.

[0069] <Step S13> In step S13, the adjustment processing unit 52 of the control unit 7 executes the condition adjustment processing, and after the condition adjustment processing is completed, terminates the condition adjustment control processing. Specifically, if the printing type in the next printing processing is monochrome printing, the adjustment processing unit 52 executes monochrome adjustment processing corresponding to the monochrome printing as the condition adjustment processing. Here, if the printing type in the next printing processing is color printing, the adjustment processing unit 52 executes color adjustment processing corresponding to the color printing as the condition adjustment processing. In the color adjustment processing, the image formation conditions are adjusted for all of the image forming units 20. On the other hand, if the printing type in the next printing processing is monochrome printing, the adjustment processing unit 52 executes monochrome adjustment processing corresponding to the monochrome printing as the condition adjustment processing. In the monochrome adjustment processing, the image formation conditions are adjusted for only the K (black) image forming unit 24 among the image forming units 20.

[0070] In this way, in the first operating mode, the adjustment processing unit 52 executes the condition adjustment process when the printing type is changed from color printing to monochrome printing and the linear speed mode is changed. Also, in the first operating mode, the adjustment processing unit 52 executes the condition adjustment process when the printing type is changed from monochrome printing to color printing. Furthermore, in the first operating mode, the adjustment processing unit 52 executes the condition adjustment process when the linear speed mode is changed even if the printing type is not changed from monochrome printing to color printing.

[0071] On the other hand, in the first operation mode, the adjustment processing unit 52 does not execute the condition adjustment process when the linear speed mode is not changed, even when the printing type is changed from color printing to monochrome printing. Therefore, in the first operation mode, it is possible to improve productivity in the image forming apparatus 100 compared to when the condition adjustment process is executed when the printing type is changed from color printing to monochrome printing but the linear speed mode is not changed. Furthermore, in the first operation mode, when the printing type is changed from monochrome printing to color printing or when the linear speed mode is changed, the condition adjustment process is executed, thereby stabilizing image quality.

[0072] In the first operation mode of this embodiment, when the printing type is changed from monochrome printing to color printing (S111: Yes), the adjustment processing unit 52 of the control unit 7 executes the condition adjustment process (S13). On the other hand, in other embodiments, when the printing type is changed from monochrome printing to color printing (S111: Yes) in the first operation mode, the condition adjustment process does not have to be executed.

[0073] [Condition adjustment control process in second operation mode] Next, the condition adjustment process when the operation mode of the image forming apparatus 100 is the second operation mode will be described with reference to Fig. 6. In Fig. 6, the same processes as those in the condition adjustment process in Fig. 5 are denoted by the same reference numerals, and the description thereof will be omitted.

[0074] The restrictive condition in the second operation mode is that the printing type is changed from monochrome printing to color printing.

[0075] <Step S21> In step S21, the adjustment processing unit 52 of the control unit 7 determines whether the printing type will be changed from monochrome printing to color printing, similar to step S111. If it is determined that the printing type will be changed from monochrome printing to color printing (S21: Yes), the process proceeds to step S12. On the other hand, if it is determined that the printing type will not be changed from monochrome printing to color printing (S21: No), the process proceeds to step S211.

[0076] <Step S211> In step S211, the adjustment processing unit 52 of the control unit 7 determines whether the printing type will be changed from color printing to monochrome printing, similar to step S11. If it is determined that the printing type will be changed from monochrome printing to color printing (S211: Yes), the process proceeds to step S13. On the other hand, if it is determined that the printing type will not be changed from monochrome printing to color printing (S211: No), the process proceeds to step S12.

[0077] In this way, in the second operating mode, the adjustment processing unit 52 executes the condition adjustment process when the printing type is changed from monochrome printing to color printing and the linear speed mode is changed. Also, in the second operating mode, the adjustment processing unit 52 executes the condition adjustment process when the printing type is changed from color printing to monochrome printing. Furthermore, in the second operating mode, the adjustment processing unit 52 executes the condition adjustment process when the linear speed mode is changed even if the printing type is not changed from color printing to monochrome printing.

[0078] On the other hand, in the second operation mode, the adjustment processing unit 52 does not execute the condition adjustment process when the print type is changed from monochrome printing to color printing but the linear speed mode is not changed. Therefore, in the second operation mode, it is possible to improve productivity in the image forming apparatus 100 compared to when the condition adjustment process is executed even when the print type is changed from monochrome printing to color printing but the linear speed mode is not changed. Also, in the second operation mode, when the print type is changed from color printing to monochrome printing or when the linear speed mode is changed, the condition adjustment process is executed, thereby stabilizing image quality.

[0079] In the second operation mode of this embodiment, when the printing type is changed from color printing to monochrome printing (S211: Yes), the adjustment processing unit 52 of the control unit 7 executes the condition adjustment process (S13). On the other hand, in other embodiments, when the printing type is changed from color printing to monochrome printing (S211: Yes) in the second operation mode, the condition adjustment process does not have to be executed.

[0080] [Condition adjustment control process in the third operation mode] Next, the condition adjustment process when the operation mode of the image forming apparatus 100 is the third operation mode will be described with reference to Fig. 7. In Fig. 7, the same processes as those in the condition adjustment process in Fig. 5 are denoted by the same reference numerals, and the description thereof will be omitted.

[0081] The limiting condition in the third operating mode is that the printing type is changed from color printing to monochrome printing, and the execution time of monochrome printing executed before the change of printing type does not reach a first preset value, for example, 2 minutes or 5 minutes.

[0082] <Step S112> 7, in the condition adjustment control process corresponding to the third operation mode, if it is determined in step S111 that the print type will be changed from monochrome printing to color printing (S111: Yes), the process proceeds to step S13, and if it is determined that the print type will not be changed from monochrome printing to color printing (S111: No), the process proceeds to step S112. Then, in step S112, the adjustment processing unit 52 of the control unit 7 determines whether the linear velocity mode will be changed, as in step S12. Here, if it is determined that the linear velocity mode will be changed (S112: Yes), the process proceeds to step S13, and if it is determined that the linear velocity mode will not be changed (S112: No), the condition adjustment control process ends.

[0083] <Step S31> 7, in the condition adjustment control process corresponding to the third operation mode, if it is determined in step S12 that the linear speed mode will not be changed (S12: No), the process proceeds to step S31. Then, in step S31, the adjustment processing unit 52 of the control unit 7 determines whether the print count value counted by the count processing unit 51 has reached a preset first set value. The first set value is a value that is preset as a condition for restricting the execution of the condition adjustment process when the print type is changed from color printing to monochrome printing and the linear speed mode is not changed.

[0084] As described above, the print count value is a value that the counting unit 51 starts counting when the print process starts, and indicates the print time for the print process. If it is determined that the print count value has reached the first set value (S31: Yes), the process proceeds to step S13. On the other hand, if it is determined that the print count value has not reached the first set value (S31: No), the condition adjustment control process ends.

[0085] Thus, in operation mode 3, when the print type is changed from color printing to monochrome printing and the linear speed mode is not changed, the adjustment processing unit 52 does not execute the condition adjustment process until the period corresponding to the first set value has elapsed. As a result, when the total required time for the printing process is short, the condition adjustment process is not executed, and a noticeable decrease in productivity is suppressed. On the other hand, in operation mode 3, when the print type is changed from color printing to monochrome printing and the linear speed mode is not changed, the adjustment processing unit 52 executes the condition adjustment process if the period corresponding to the first set value has elapsed. As a result, when the total required time for the printing process is long, the condition adjustment process is executed, and image quality is stabilized.

[0086] The count processing unit 51 may start counting a print count value indicating the number of prints in the printing process when the printing process is started. Then, in step S31, the adjustment processing unit 52 may determine whether the print count value indicating the number of prints has reached a preset number. That is, the limiting condition in the third operating mode may be that the printing type is changed from color printing to monochrome printing, and the number of monochrome prints performed before the change in printing type has not reached a preset first set value. The first set value is, for example, the number of prints, such as 100 or 200.

[0087] Furthermore, the count processing unit 51 may start counting both a first print count value and a second print count value, which indicate the elapsed time and the number of printed sheets in the printing process, when the printing process is started. It is also possible that a first time setting value is pre-set as the first setting value corresponding to the first print count value, and a first number-of-sheets setting value is pre-set as the first setting value corresponding to the second print count value. In this case, in step S31, the adjustment processing unit 52 may proceed to step S13 if at least one of the following conditions is met: the first print count value has reached the first time setting value; or the second print count value has reached the first number-of-sheets setting value.

[0088] [Condition adjustment control process in the fourth operation mode] Next, the condition adjustment process when the operation mode of the image forming apparatus 100 is the fourth operation mode will be described with reference to Fig. 8. In Fig. 8, the same processes as those in the condition adjustment process in Fig. 6 are denoted by the same reference numerals, and the description thereof will be omitted.

[0089] The limiting condition in the fourth operating mode is that the printing type is changed from monochrome printing to color printing, and the elapsed time since the previous execution of the color adjustment process has not reached a second preset value, which is a preset time such as 2 minutes or 5 minutes.

[0090] <Step S212> 8, in the condition adjustment control process corresponding to the fourth operation mode, if it is determined in step S211 that the printing type will be changed from color printing to monochrome printing (S211: Yes), the process proceeds to step S13, and if it is determined that the printing type will not be changed from color printing to monochrome printing (S211: No), the process proceeds to step S212. Then, in step S212, the adjustment processing unit 52 of the control unit 7 determines whether the linear velocity mode will be changed, as in step S12. Here, if it is determined that the linear velocity mode will be changed (S212: Yes), the process proceeds to step S13, and if it is determined that the linear velocity mode will not be changed (S212: No), the condition adjustment control process ends.

[0091] <Step S41> 8, in the condition adjustment control process corresponding to the fourth operation mode, when the condition adjustment process is executed in step S13, the process proceeds to step S41. Then, in step S41, the adjustment processing unit 52 of the control unit 7 determines whether the condition adjustment process executed in step S13 is the color adjustment process. If it is determined that the condition adjustment process is the color adjustment process (S41: Yes), the process proceeds to step S42, and if it is determined that the condition adjustment process is not the color adjustment process (S41: No), the condition adjustment control process ends.

[0092] <Step S42> In step S42, the count processing unit 51 of the control unit 7 starts counting an interval count value indicating the time elapsed since the previous color adjustment process was executed in step S13. That is, the elapsed time is the time elapsed since the color adjustment process was executed for the image forming units 21 to 24 used in color printing. If the count processing unit 51 has started counting the interval count value, it resets the count value to 0 and restarts counting the count value.

[0093] <Step S43> 8, in the condition adjustment control process corresponding to the fourth operating mode, if it is determined in step S12 that the linear velocity mode will not be changed (S12: No), the process proceeds to step S43. Then, in step S43, the adjustment processing unit 52 of the control unit 7 determines whether the interval count value counted in step S42 has reached a preset second set value. The second set value is a value preset as a condition for restricting execution of the condition adjustment process when the print type is changed from color printing to monochrome printing and the linear velocity mode is not changed. If it is determined that the interval count value has reached the second set value (S43: Yes), the process proceeds to step S13. On the other hand, if it is determined that the interval count value has not reached the second set value (S43: No), the condition adjustment control process ends.

[0094] As described above, in operation mode 4, when the printing type is changed from monochrome printing to color printing and the linear speed mode is not changed, the adjustment processing unit 52 does not execute the condition adjustment processing until the period corresponding to the second setting value has elapsed. This prevents the color adjustment processing from being executed frequently even if monochrome printing and color printing are frequently switched between. Also, in operation mode 4, when the printing type is changed from monochrome printing to color printing and the linear speed mode is not changed, the adjustment processing unit 52 executes the condition adjustment processing if the period corresponding to the second setting value has elapsed. This stabilizes image quality by executing the color adjustment processing if the period corresponding to the second setting value has elapsed since the color adjustment processing was executed.

[0095] When the color adjustment process is executed, the count processing unit 51 may start counting an interval count value indicating the number of printed sheets after the color adjustment process is executed. Then, in step S43, the adjustment processing unit 52 may determine whether the interval count value indicating the number of printed sheets has reached a preset number. That is, the limiting condition in the third operating mode is that the printing type has been changed from monochrome printing to color printing, and the number of printed sheets after the previous execution of the color adjustment process has not reached a preset second set value. The second set value is, for example, the number of printed sheets, such as 100 or 200.

[0096] Furthermore, the count processing unit 51 may start counting both a first interval count value and a second interval count value, which indicate the elapsed time and the number of printed sheets in the printing process, when the printing process is started. It is also possible that a second time setting value is pre-set as the second setting value corresponding to the first interval count value, and a second number-of-sheets setting value is pre-set as the second setting value corresponding to the second interval count value. In this case, in step S43, the adjustment processing unit 52 may proceed to step S13 if at least one of the following conditions is met: the first interval count value has reached the second time setting value; or the second interval counter value has reached the second number-of-sheets setting value.

[0097] [Condition adjustment control process in the fifth operation mode] Next, the condition adjustment process when the operation mode of the image forming apparatus 100 is the fifth operation mode will be described with reference to Fig. 9. In Fig. 9, the same processes as those in the condition adjustment process in Fig. 8 are denoted by the same reference numerals, and the description thereof will be omitted.

[0098] <Step S51> 9, if it is determined in step S211 that the printing type will be changed from color printing to monochrome printing (S12: Yes), the process proceeds to step S51. Then, in step S51, the adjustment processing unit 52 of the control unit 7 determines whether the linear speed mode will be changed, as in step S12. Here, if it is determined that the linear speed mode will be changed (S51: Yes), the process proceeds to step S13, and if it is determined that the linear speed mode will not be changed (S51: No), the process proceeds to step S52.

[0099] <Step S52> In step S52, the adjustment processing unit 52 of the control unit 7 determines whether the print count value counted by the count processing unit 51 has reached a preset first set value, similar to step S31 (see FIG. 7). If it is determined that the print count value has reached the first set value (S52: Yes), the process proceeds to step S13. On the other hand, if it is determined that the print count value has not reached the first set value (S52: No), the condition adjustment control process ends.

[0100] Thus, in operation mode 5, when the print type is changed from color printing to monochrome printing and the linear speed mode is not changed, the adjustment processing unit 52 does not execute the condition adjustment process until the period corresponding to the first set value has elapsed. As a result, when the total required time for the print process is short, the condition adjustment process is not executed, and a noticeable decrease in productivity is suppressed. On the other hand, in operation mode 5, when the print type is changed from color printing to monochrome printing and the linear speed mode is not changed, the adjustment processing unit 52 executes the condition adjustment process if the period corresponding to the first set value has elapsed. As a result, when the total required time for the print process is long, the condition adjustment process is executed, and image quality is stabilized.

[0101] Furthermore, in operation mode 5, when the printing type is changed from monochrome printing to color printing but the linear speed mode is not changed, the adjustment processing unit 52 does not execute the condition adjustment processing until the period corresponding to the second setting value has elapsed. This prevents the color adjustment processing from being executed frequently even if monochrome printing and color printing are frequently switched between. Furthermore, in operation mode 5, when the printing type is changed from monochrome printing to color printing but the linear speed mode is not changed, the adjustment processing unit 52 executes the condition adjustment processing if the period corresponding to the second setting value has elapsed. This stabilizes image quality by executing the color adjustment processing if the period corresponding to the second setting value has elapsed since the color adjustment processing was executed.

[0102] [Notes on the Invention] The following is a summary of the invention extracted from the above-described embodiment. Note that the configurations and processing functions described in the following supplementary notes can be selected and combined as desired.

[0103] <Appendix 1> a print processing unit that controls an image forming unit having image forming units corresponding to a plurality of colors, and performs monochrome printing to form a monochrome image on a sheet or color printing to form a color image on the sheet based on input image data; an adjustment processing unit that is capable of executing a condition adjustment process to adjust image formation conditions in the image forming unit before execution of the monochrome printing or the color printing after the change in print type when the print type of the print process executed by the print processing unit is changed from one of the monochrome printing and the color printing to the other; Equipped with the print processing unit is capable of changing a linear speed in the image forming unit in accordance with a combination of a linear speed mode that is set in advance in association with a sheet type of the sheet and the print type; the adjustment processing unit is capable of restricting the execution of the condition adjustment process when the linear speed mode is the same before and after the change of the print type and when a preset restriction condition is satisfied. Image forming device.

[0104] <Appendix 2> the restricting condition is that the printing type is changed from color printing to monochrome printing; 2. The image forming apparatus according to claim 1.

[0105] <Appendix 3> The limiting condition is that the printing type is changed from the color printing to the monochrome printing, and the execution time of the monochrome printing executed before the change of the printing type has not reached a first set value that is set in advance. 3. The image forming apparatus according to claim 1 or 2.

[0106] <Appendix 4> The limiting condition is that the printing type is changed from the color printing to the monochrome printing, and the number of sheets printed in the color printing executed before the change of the printing type has not reached a first set value that is set in advance. 4. The image forming apparatus according to claim 1.

[0107] <Appendix 5> the restricting condition is that the printing type is changed from the monochrome printing to the color printing; 2. The image forming apparatus according to claim 1.

[0108] <Appendix 6> The limiting condition is that the printing type is changed from the monochrome printing to the color printing, and the elapsed time since the previous execution of the condition adjustment process has not reached a second set value that is set in advance. 6. The image forming apparatus according to any one of claims 1 and 3 to 5.

[0109] <Appendix 7> the elapsed time is the time elapsed since the condition adjustment process was performed on the image forming unit used in the color printing; 7. The image forming apparatus according to claim 6.

[0110] <Appendix 8> The limiting condition is that the printing type is changed from the monochrome printing to the color printing, and the number of printed sheets after the previous execution of the condition adjustment process has not reached a second set value that is set in advance. An image forming apparatus according to any one of appendixes 1 and 3 to 7.

[0111] <Appendix 9> the number of prints is the number of prints after the condition adjustment process is performed on the image forming unit used in the color printing; 9. The image forming apparatus according to claim 8.

[0112] <Appendix 10> one or more processors, a printing step of controlling an image forming section having image forming units corresponding to a plurality of colors, and performing monochrome printing to form a monochrome image on a sheet or color printing to form a color image on the sheet based on input image data; an adjustment step capable of executing a condition adjustment process for adjusting image formation conditions in the image forming unit before execution of the monochrome printing or the color printing after the change of the print type when the print type of the print process executed by the printing step is changed from one of the monochrome printing and the color printing to the other; An image forming method that performs the above steps, In the printing step, a linear speed in the image forming unit can be changed in accordance with a combination of a linear speed mode that is set in advance in association with a sheet type of the sheet and the printing type, In the adjusting step, when the linear speed mode is the same before and after the change of the printing type and a preset restriction condition is satisfied, the execution of the condition adjustment process can be restricted. Image forming method. [Explanation of symbols]

[0113] 1 ADF 2 Image reading unit 3 Image forming unit 4 Paper feed section 5 Operation display section 6 Memory section 7 Control Unit 20 Image forming unit 25 Optical scanning device 26 Intermediate transfer belt 27 Secondary transfer roller 28 Fixing device 31 Photosensitive drum 32 Charging roller 33 Developing device 34 Primary transfer roller 35 Drum Cleaning Department 36 Toner container 40 1st power supply 45 2nd power supply 46 Detector 100 Image forming device

Claims

1. a print processing unit that controls an image forming unit having image forming units corresponding to a plurality of colors, and performs monochrome printing to form a monochrome image on a sheet or color printing to form a color image on the sheet based on input image data; an adjustment processing unit that is capable of executing a condition adjustment process to adjust image formation conditions in the image forming unit before execution of the monochrome printing or the color printing after the change in print type when the print type of the print process executed by the print processing unit is changed from one of the monochrome printing and the color printing to the other; Equipped with the print processing unit is capable of changing a linear speed in the image forming unit in accordance with a combination of a linear speed mode that is set in advance in association with a sheet type of the sheet and the print type; the adjustment processing unit is capable of restricting the execution of the condition adjustment process when the linear speed mode is the same before and after the change of the print type and when a preset restriction condition is satisfied. Image forming device.

2. the restricting condition is that the printing type is changed from color printing to monochrome printing; The image forming apparatus according to claim 1 .

3. The limiting condition is that the printing type is changed from the color printing to the monochrome printing, and the execution time of the monochrome printing executed before the change of the printing type has not reached a first set value that is set in advance. The image forming apparatus according to claim 1 .

4. The limiting condition is that the printing type is changed from the color printing to the monochrome printing, and the number of sheets printed in the color printing executed before the change of the printing type has not reached a first set value that is set in advance. The image forming apparatus according to claim 1 .

5. the restricting condition is that the printing type is changed from the monochrome printing to the color printing; The image forming apparatus according to claim 1 .

6. The limiting condition is that the printing type is changed from the monochrome printing to the color printing, and the elapsed time since the previous execution of the condition adjustment process has not reached a second set value that is set in advance. The image forming apparatus according to claim 1 .

7. the elapsed time is the time elapsed since the condition adjustment process was performed on the image forming unit used in the color printing; The image forming apparatus according to claim 6 .

8. The limiting condition is that the printing type is changed from the monochrome printing to the color printing, and the number of printed sheets after the previous execution of the condition adjustment process has not reached a second set value that is set in advance. The image forming apparatus according to claim 1 .

9. the number of prints is the number of prints after the condition adjustment process is performed on the image forming unit used in the color printing; The image forming apparatus according to claim 8 .

10. one or more processors, a printing step of controlling an image forming section having image forming units corresponding to a plurality of colors, and performing monochrome printing to form a monochrome image on a sheet or color printing to form a color image on the sheet based on input image data; an adjustment step capable of executing a condition adjustment process for adjusting image formation conditions in the image forming unit before execution of the monochrome printing or the color printing after the change of the print type when the print type of the print process executed by the printing step is changed from one of the monochrome printing and the color printing to the other; An image forming method that performs the above steps, In the printing step, a linear speed in the image forming unit can be changed in accordance with a combination of a linear speed mode that is set in advance in association with a sheet type of the sheet and the printing type, In the adjusting step, when the linear speed mode is the same before and after the change of the printing type and a preset restriction condition is satisfied, the execution of the condition adjustment process can be restricted. Image forming method.

Images