Operating device

Abstract

The present invention provides an image forming apparatus that improves productivity while maintaining image quality when prioritizing image quality during image formation. [Solution] The image forming apparatus can form images on paper at multiple image forming speeds. The image forming apparatus stores information in RAM 203 for each type of paper, including a first image forming speed when performing image forming in productivity priority mode and a second image forming speed when performing image forming in image quality priority mode. The RAM 203 also stores a setting value for changing the image forming speed when operating in image quality priority mode. When operating in productivity priority mode, the image forming apparatus performs image forming at the first image forming speed corresponding to the type of paper, and when operating in image quality priority mode, it performs image forming at a speed that changes the second image forming speed according to the paper type and the setting value.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile apparatus, etc. that forms an image on a sheet of paper.

Background Art

[0002] Image forming apparatuses are required to have multimedia compatibility, which enables printing an image on various types of sheets of paper such as thin paper, thick paper, coated paper (gloss coated paper, matte coated paper, etc.), and high productivity. The heavier the basis weight of the paper, the more heat needs to be applied to the paper when fixing the image transferred onto the paper. Generally, in order to increase the amount of heat applied per unit area of the paper, the image forming speed is set to be slow. Therefore, the image forming apparatus can operate at a plurality of image forming speeds according to the basis weight and surface properties of the paper. Note that the image forming speed indicates the operating speed of an image forming unit such as a photosensitive drum, a developing device, an intermediate transfer belt, etc. described later, the conveyance speed of the paper when transferring an image onto the paper, the conveyance speed of the paper when fixing the toner on the paper, and the like.

[0003] Depending on the output product, the points that the user values may differ. For example, in the case of report printing of documents, etc., many users value maximizing productivity more than image quality, and in the case of image printing of photos, etc., many users value maximizing image quality more than productivity. The image forming apparatus of Patent Document 1 can select a productivity priority mode with a higher image forming speed while suppressing the image quality within a predetermined range, and an image quality priority mode with the image forming speed at which the image quality is maximized (Patent Document 1). An image is printed at an image forming speed corresponding to the operation mode selected by the user.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Image forming machines for commercial printing handle a wide variety of paper types. Therefore, even papers with the same basis weight can have significantly different characteristics. For example, one characteristic of paper is its stiffness. Stiffness, also known as paper rigidity, is an indicator of the paper's resistance to bending. High stiffness results in a greater impact on the transfer section when the paper enters it during transport. This can cause unevenness in the transferred image. In this case, slowing down the speed at which the paper enters the transfer section (image formation speed) reduces the impact and suppresses the cause of image unevenness.

[0006] The image quality priority mode is designed to produce images with the highest possible image quality, regardless of the paper's characteristics, as long as the paper weight is the same. Therefore, the image formation speed is set to match the speed of the paper with the highest stiffness. The image formation speed of the paper with the highest stiffness is slower than that of other papers. This means that even if a faster image formation speed is possible for other papers with lower stiffness, a slower speed will be set. Consequently, in image quality priority mode, images are formed at a slow speed regardless of the paper's characteristics, making it difficult to increase productivity.

[0007] In view of the above-mentioned problems, the primary objective of the present invention is to provide an image forming apparatus that improves productivity while maintaining image quality when forming images with image quality as the priority. [Means for solving the problem]

[0008] The present invention relates to an image forming apparatus capable of forming an image on paper at multiple image forming speeds, comprising: a holding means for holding information of a first image forming speed when performing image forming in a first operation mode and a second image forming speed when performing image forming in a second operation mode for each type of paper; a storage means for storing a setting value for changing the image forming speed when operating in the second operation mode; and a control means that, when operating in the first operation mode, performs image forming at the first image forming speed corresponding to the type of paper, and when operating in the second operation mode, performs image forming at a speed that changes the second image forming speed according to the setting value corresponding to the type of paper. [Effects of the Invention]

[0009] According to the present invention, when forming an image with image quality as the priority, it is possible to perform an image forming operation that improves productivity while maintaining image quality. [Brief explanation of the drawing]

[0010] [Figure 1] A diagram illustrating the configuration of an image forming apparatus. [Figure 2] Diagram illustrating the control unit. [Figure 3] (a) and (b) are explanatory diagrams of the control panel. [Figure 4] A diagram illustrating the rate of image formation. [Figure 5] A diagram illustrating the image formation speed for each paper type. [Figure 6] An example diagram of the operating mode selection screen. [Figure 7] An example diagram of the form registration screen. [Figure 8] An example diagram of the paper type selection screen. [Figure 9] An example diagram of the paper type selection screen when a new paper type is added. [Figure 10] An example diagram of the screen for changing paper settings. [Figure 11] An example diagram of the basis weight setting screen. [Figure 12] An example diagram of the image formation speed setting screen when prioritizing image quality. [Figure 13] Flowchart representing image forming processing. [Figure 14] Flowchart representing image forming processing. [Figure 15] Flowchart representing image forming speed limiting processing. [Figure 16] Exemplary diagram of a table showing the limitation range of image forming speed. [Figure 17] Exemplary diagram of a setting screen for setting upper and lower limit values. [Figure 18] Flowchart representing the process of determining upper and lower limit values. [Figure 19] Flowchart representing the display setting process of a paper setting change screen. [Figure 20] Flowchart representing the display process of a paper setting change screen. [Figure 21] Exemplary diagram of a paper setting change screen A.

Mode for Carrying Out the Invention

[0011] Hereinafter, exemplary preferred embodiments of this invention will be described in detail with reference to the drawings.

[0012] (First Embodiment) Fig. 1 is a configuration diagram of the image forming apparatus of this embodiment. This image forming apparatus is an electrophotographic full-color image forming apparatus. The image forming apparatus includes a reader 1 and a printer 5. The reader 1 is provided on the housing of the printer 5. The reader 1 of this embodiment is an image reading device that reads a color image from a document. The printer 5 of this embodiment is a color printer that prints a color image on a paper P. Such an image forming apparatus is, for example, a copying machine, a multifunction machine, etc.

[0013] The reader 1 comprises a document glass 2, a full-color sensor 3, and an image processing unit 4. The document glass 2 is on which the document to be scanned, with the image printed on it, is placed. The full-color sensor 3 is, for example, a CCD (Charge Coupled Device) image sensor. The full-color sensor 3 receives reflected light from light irradiated onto the document and converts the received reflected light into an electrical signal (color separation image signal). The color separation image signal is processed by the image processing unit 4 and transmitted to the printer 5.

[0014] Printer 5 has a configuration in which four image forming units (first to fourth image forming units UY, UM, UC, and UK) are arranged in tandem. Each of the first to fourth image forming units UY, UM, UC, and UK is a laser exposure electrophotographic process mechanism, and performs image formation based on a color separation image signal sent from reader 1, for example, during the copying process. Printer 5 includes a primary transfer unit 6, an intermediate transfer belt 7, a secondary transfer unit 8, a fuser 12, a cassette paper feeding mechanism 9, and a manual paper feed unit 11. A deck paper feed unit 10 is connected to printer 5.

[0015] The first to fourth image forming units UY, UM, UC, and UK each comprise a photosensitive drum, a charger, an exposure unit, and a developer, respectively. The photosensitive drum is a drum-shaped photoreceptor having a photosensitive layer on its surface. The charger uniformly charges the surface of the photosensitive drum. The exposure unit irradiates the charged surface of the photosensitive drum with laser light modulated according to the corresponding color separation image signal, thereby forming an electrostatic latent image on the surface of the photosensitive drum. The developer unit develops the electrostatic latent image with toner of the corresponding color, thereby forming a toner image on the photosensitive drum.

[0016] The first image forming unit UY forms a yellow toner image on the surface of the photosensitive drum. The second image forming unit UM forms a magenta toner image on the surface of the photosensitive drum. The third image forming unit UC forms a cyan toner image on the surface of the photosensitive drum. The fourth image forming unit UK forms a black toner image on the surface of the photosensitive drum. The first to fourth image forming units UY, UM, UC, and UK form toner images at their respective timings.

[0017] The toner images formed on the photosensitive drums of the first to fourth image forming units UY, UM, UC, and UK are sequentially superimposed and transferred onto the intermediate transfer belt 7 by the primary transfer unit 6. This creates a full-color toner image on the intermediate transfer belt 7 by superimposing the four toner images. The intermediate transfer belt 7 rotates to transport the full-color toner image to the secondary transfer unit 8.

[0018] Paper P can be fed from the cassette feeding mechanism 9, the manual feed section 11, and the deck feeding section 10. Paper P is fed from the cassette feeding mechanism 9, the manual feed section 11, and the deck feeding section 10 to the secondary transfer section 8 according to the timing of image formation by the first to fourth image forming sections UY, UM, UC, and UK. The secondary transfer section 8 transfers the full-color toner image carried by the intermediate transfer belt 7 onto the fed paper P in one go. Paper P with the transferred toner image is transported from the secondary transfer section 8 to the fuser 12.

[0019] The fuser 12 grips and transports the paper P onto which the toner image has been transferred using the fuser nip. During this gripping and transporting process, the unfixed toner image is melted and mixed by heat and pressure, fixing to the paper P as a fixed image. The paper P with the fixed image is then discharged as a finished product into either the face-up output tray 14 or the face-down output tray 15. A flapper 13 is located behind the fuser 12. The paper P is discharged by the flapper 13 into either the face-up output tray 14 or the face-down output tray 15.

[0020] When performing double-sided printing, the paper P, on which an image has been formed on one side (the first side), is first transported from the fuser 12 to the transport path on the face-down output tray 15 side, and then switched back and transported to the re-transport sheet path 16. This reverses the printed side of the paper P. The paper P is then transported to the secondary transfer unit 8 via the re-transport sheet path 16. Thereafter, similar to printing an image on the first side, the toner image is transferred to the second side of the paper P, which is different from the first side, and the image is fixed by the fuser 12. In this way, an image is printed on the second side. The paper P, with images printed on both sides, is discharged to the face-up output tray 14 or the face-down output tray 15.

[0021] Figure 2 is an explanatory diagram of the control unit that controls the operation of the image forming apparatus. The control unit 200 is an information processing device that includes a CPU (Central Processing Unit) 204, a ROM (Read Only Memory) 205, and a RAM (Random Access Memory) 203. The CPU 204 controls the overall operation of the image forming apparatus by executing a computer program stored in the ROM 205. The RAM 203 provides a workspace for the CPU 204 when it is performing processing. In addition to the reader 1 and printer 5 mentioned above, an operation unit 300 is connected to the control unit 200. The control unit 200 is installed, for example, inside the housing of the printer 5.

[0022] Reader 1 transmits a color separation image signal to control unit 200. Control unit 200 controls the operation of printer 5 as described above in accordance with the color separation image signal and prints the image on paper P. Printer 5 operates the first to fourth image forming units UY, UM, UC, UK, secondary transfer unit 8, and fuser 12, etc., in accordance with instructions from control unit 200 to perform the image forming process (printing process) as described above. As described above, printer 5 includes a cassette paper feeding mechanism 9, a deck paper feeding unit 10, and a manual paper feeding unit 11. Printer 5 feeds paper P used for printing from either the cassette paper feeding mechanism 9, the deck paper feeding unit 10, or the manual paper feeding unit 11 in accordance with instructions from control unit 200. Printer 5 controls the transport speed of paper P during feeding in accordance with instructions from control unit 200.

[0023] Figure 3 is an explanatory diagram of the operation unit 300. The user can input and set various image formation conditions and information to the image forming apparatus using the operation unit 300. The operation unit 300 is a user interface equipped with an input interface and an output interface. The input interface includes various key buttons, a touch panel, etc. The output interface includes a display 301, a speaker, etc. The operation unit 300 is used to display print information, print progress information, etc., and to make various settings for the printer 5.

[0024] Figure 3(a) is a plan view of the control unit 300. The control unit 300 includes a display 301, a reset key 302, a start key 303, a stop key 304, a clear key 305, a numeric keypad 306, a color mode selection key 307, and a user mode key 308. Figure 3(b) shows an example of the settings screen displayed on the display 301 during copying. On the settings screen during copying, it is possible to set the number of copies, the selected paper size, the magnification, the copy density, etc.

[0025] The reset key 302 is used to reset settings, for example, returning the copy mode to standard mode. The start key 303 is used, for example, to instruct the start of a copy operation. The stop key 304 is used, for example, to instruct the interruption of a copy operation. The clear key 305 is used, for example, to return the operation mode from copy mode to standard mode. The numeric keypad 306 is used for numerical settings, for example, the number of copies. When the user mode key 308 is pressed, it displays the selection screen described later on the display 301.

[0026] The color mode selection key 307 includes an ACS key, a Color key, and a Black key. The ACS key is used to instruct the reader 1 to automatically determine whether the image of the document to be scanned is in color or black and white, and to output a color image signal if it is in color, and a black and white image signal if it is in black and white. The Color key is used to instruct the reader 1 to output a color image signal regardless of the image of the document. The Black key is used to instruct the reader 1 to output a black and white image signal regardless of the image of the document. In this embodiment, the color mode selection key 307 is configured so that one of the selected keys lights up.

[0027] (Image quality priority mode, Productivity priority mode) When fixing a toner image transferred onto paper P using a fuser 12, the amount of heat supplied to paper P per unit time differs depending on the basis weight of paper P. Therefore, the optimal image formation speed is set according to the basis weight of paper P. Setting the basis weight for each sheet of paper P is cumbersome for the user. For this reason, the image forming apparatus has the same transfer conditions, fixing conditions, and paper transport speed (image formation speed) set for each predetermined range of basis weights. The aforementioned range of basis weights is called a paper category. In the following example, paper P with a basis weight of 64 to 150 [gsm] is called "plain paper," paper P with a basis weight of 151 to 250 [gsm] is called "thick paper 1," and paper P with a basis weight of 251 to 350 [gsm] is called "thick paper 2."

[0028] Figure 4 is an explanatory diagram of the image forming speed of the image forming apparatus. When the image forming speed is changed, the rotation speed of the photosensitive drum and the rotation speed of the intermediate transfer belt 7 are controlled to match the rotation speed based on the image forming speed. The image forming apparatus can operate at three image forming speeds: first, second, and third. In this embodiment, the first speed is the fastest image forming speed and is 400 mm / s. The second speed is a slower image forming speed than the first speed and is 300 mm / s. The third speed is the slowest image forming speed and is 200 mm / s.

[0029] In productivity-priority mode, which prioritizes the productivity of the deliverables, the image formation speed is set to the fastest possible speed for image formation. In image quality-priority mode, which prioritizes the image quality of the deliverables, the image formation speed is set slower than in productivity-priority mode. In image quality-priority mode, the image of the deliverable is printed with higher image quality than in productivity-priority mode. Productivity-priority mode and image quality-priority mode will be explained separately.

[0030] The productivity priority mode is an operating mode in which image formation is performed at the maximum possible image formation speed. In productivity priority mode, image quality is kept within a predetermined range, and productivity is maximized. The image quality priority mode is an operating mode in which image formation is performed at a slower image formation speed than in productivity priority mode in order to maximize the image quality of the image printed on the output. In image quality priority mode, for example, the transport speed of the paper P when the paper P enters the secondary transfer unit 8 is slowed down to reduce the shock when the paper P enters the secondary transfer unit 8, thereby improving the transfer quality. In addition, in image quality priority mode, the transport speed of the paper P in the fuser 12 is slowed down to supply more heat to the paper P from the fuser 12, improving glossiness.

[0031] Figure 5 is an explanatory diagram of the image formation speed for each paper type in each operating mode (productivity priority mode, image quality priority mode). In Figure 5, the paper types are plain paper, thick paper 1, and thick paper 2. The image formation speed is determined by the operating mode and the paper type. For example, the image formation speed for plain paper is the first speed (400 [mm / s]) in productivity priority mode and the second speed (300 [mm / s]) in image quality priority mode. Both thick paper 1 and thick paper 2 have a larger basis weight, so it is necessary to further suppress the shock when they enter the secondary transfer section 8. For this reason, the image formation speed for thick paper 1 and thick paper 2 in image quality priority mode is the slowest third speed (200 [mm / s]). The image formation speed for thick paper 1 in productivity priority mode is the first speed (400 [mm / s]). In the productivity priority mode for cardboard 2, the image forming speed is set to the second speed (300 [mm / s]) because more heat needs to be supplied to the paper P from the fuser 12 than for cardboard 1.

[0032] In this embodiment, the description applies to plain paper / cardboard with a high-quality surface, but the image formation speed can be similarly determined for paper with a coated surface, such as coated paper. Furthermore, while the image formation speed for plain paper is set to the second speed in image quality priority mode, it does not have to be the second speed as long as it is slower than the first speed. For example, it could be the third speed, or a fourth speed different from the second and third speeds. In other words, the image formation speed can be set to more speeds than the first, second, and third speeds. The image formation speed in image quality priority mode is set to a slower speed than the image formation speed in productivity priority mode, but depending on the paper weight, they may be the same speed. For example, for plain paper, the image formation speed in image quality priority mode and the image formation speed in productivity priority mode may both be the same first speed.

[0033] The image formation speed information (table) for each paper type in each operating mode, as shown in Figure 5, is stored in advance in RAM 203 or ROM 205. Based on this information, the CPU 204 determines the image formation speed during image formation and prints the image onto paper P.

[0034] (Select operating mode) Figure 6 is an example of the operating mode selection screen. The selection screen is displayed on the display 301 of the operation unit 300. The user can select an operating mode (productivity priority mode, image quality priority mode) from the selection screen using the input interface of the operation unit 300. Information representing the operating mode selection result is stored in the RAM 203.

[0035] The selection screen shown in Figure 6 is displayed on the display 301 when the user mode key 308 is pressed. Before executing a print job, the user selects either the productivity priority mode selection button 601 or the image quality priority mode selection button 602 from the selection screen using the operation unit 300. The control unit 200 obtains the selection from the operation unit 300 and sets the image forming apparatus to the selected operating mode. The information of the set operating mode is stored in the RAM 203.

[0036] When the productivity priority mode selection button 601 is selected, the image forming apparatus can perform image forming with maximum productivity for all paper stored in all paper feed stages (cassette paper feed mechanism 9, manual feed section 11, and deck paper feed section 10). When the image quality priority mode selection button 602 is selected, the image forming apparatus can perform image forming with maximum image quality for all paper stored in all paper feed stages.

[0037] (Registering paper type for each paper feed tray) The paper type and category of the paper P stored in each paper feed stage of the cassette paper feeding mechanism 9, manual feed section 11, and deck paper feeding section 10 are registered in the image forming apparatus. Figure 7 is an example of the paper registration screen. The user selects the paper feed stage to which to register the paper from the registration screen shown in Figure 7 on the display 301 using the operation unit 300. The cassette paper feeding mechanism 9 includes cassettes 1 to 4. Once a paper feed stage is selected, the type of paper to be stored in the selected paper feed stage can be selected.

[0038] Figure 8 is an example of the paper type selection screen that appears when a paper feed stage is selected. The control unit 200 stores a list of paper types usable by the image forming apparatus in the RAM 203. Multiple lists of paper types are stored for each paper category predetermined by the image forming apparatus. The user selects the type of paper P stored in the cassette paper feed mechanism 9, deck paper feed section 10, and manual paper feed section 11 from this list and presses the OK button. This completes the registration of the paper for the paper feed stage selected in Figure 7. The registered information is stored in the RAM 203.

[0039] When using typical paper types, the paper is registered as described above. However, in the case of image forming machines for commercial printing, there are many types of paper that can be handled, so the pre-created paper settings may need to be changed. For this reason, it is important that the system is configured to allow users to change the paper settings.

[0040] When a user wants to change paper settings, they select the desired paper type from the paper type selection screen shown in Figure 8 and press the duplicate button. This creates new paper type information that duplicates the settings of the selected paper. Figure 9 is an example of the paper type selection screen when a new paper type has been added. Here, "Thick Paper 1_Modified," which is a copy of "Thick Paper 1," has been added. Paper settings are then applied to the newly added paper type.

[0041] Figure 10 is an example of the paper settings change screen. Paper settings for newly added paper types are made using this change screen. The paper settings change screen is displayed on the display 301 when the paper to be changed is selected from the selection screen in Figure 9 using the operation unit 300. Paper settings include, for example, "basis weight," "transfer voltage," "fixing temperature," and "image formation speed when prioritizing image quality," but other paper-related settings may also be made available.

[0042] The "Basis Weight" button is used to change the basis weight setting of the paper. When the "Basis Weight" button is pressed, the basis weight setting screen shown in Figure 11 is displayed on the display 301. The user can input the paper basis weight in gsm units using the numeric keypad 306. After entering the basis weight, the user presses the OK button to set the paper's basis weight.

[0043] The "Transfer Voltage" button is used to change the voltage value used when the secondary transfer unit 8 transfers the image (toner image) to the paper. Since the resistance value differs depending on the type (brand) of paper, the transfer voltage needs to be adjusted for each brand. When the "Transfer" button is pressed, the transfer voltage setting screen (not shown) is displayed on the display 301. The user can change the transfer voltage according to the characteristics of the paper. The transfer voltage is one of the parameters included in the image formation conditions.

[0044] The "Fusing Temperature" button is used to change the temperature of the fuser 12 when fixing the toner image to the paper. Because paper has different thicknesses depending on the type (brand), the amount of heat required to fix the image differs depending on the type of paper. For this reason, the fixing temperature can be adjusted. When the "Fusing" button is pressed, the fixing temperature setting screen (not shown) is displayed on the display 301. The user can change the fixing temperature according to the characteristics of the paper. The fixing temperature is one of the parameters included in the image formation conditions.

[0045] The "Image Formation Speed ​​in Image Quality Priority Mode" button is used to change the image formation speed in image quality priority mode. When the "Image Formation Speed ​​in Image Quality Priority Mode" button is pressed, the image formation speed setting screen in image quality priority mode, as illustrated in Figure 12, is displayed on the display 301. The user can change the image formation speed in image quality priority mode from the preset default speed by pressing the "+" or "-" button using the numeric keypad 306. When the "+" button is pressed, the image formation speed in image quality priority mode is changed to a faster speed than the default speed. When the "-" button is pressed, the image formation speed in image quality priority mode is changed to a slower speed than the default speed.

[0046] The result of changing the image formation speed when prioritizing image quality by pressing the "+" or "-" button is displayed on the screen in Figure 12 as the set value (-2 / -1 / 0 / +1 / +2). The user confirms the displayed set value and presses the OK button to set the image formation speed when prioritizing image quality.

[0047] For example, if the basis weight of paper P is 180 [gsm], the control unit 200 sets the default image formation speed to 200 [mm / s] in image quality priority mode, based on Figure 5. Therefore, if "0" is displayed as the setting value on the screen in Figure 12, the image formation speed in image quality priority mode will be 200 [mm / s]. Also, if the "+" button is pressed once in Figure 12 (setting value is +1), the image formation speed in image quality priority mode will be 300 [mm / s], one step faster than the default speed, based on Figure 4. If the "+" button is pressed twice in Figure 12 (setting value is +2), the image formation speed in image quality priority mode will be 400 [mm / s], two steps faster than the default speed, based on Figure 4.

[0048] As described above, each item is changed using the paper settings change screen in Figure 10. The user presses the OK button after changing each item. When the OK button is pressed, the control unit 200 saves the settings of each entered item as the paper settings for the duplicated paper type in RAM 203. In this way, the duplicated paper type is added to the list of paper types.

[0049] (Image formation speed determination process) Figure 13 is a flowchart representing the image formation process, including the process of determining the image formation speed. In this process, the image formation speed for productivity priority mode and the image formation speed for image quality priority mode are determined. Image formation is then performed according to the determined image formation speed.

[0050] The user instructs the control unit 200 (CPU 204) to start a job by pressing the start key 303 on the operation unit 300. To this end, the control unit 200 waits for the start of the job until the start key 303 is pressed (S101:N). When the user presses the start key 303 on the operation unit 300, the control unit 200 starts the job (S101:Y). The control unit 200 obtains the paper settings set in the paper feed stage that stores the paper P used for the image forming operation (S102). Based on the paper settings, the control unit 200 checks the "basis weight" of the paper P and determines the paper classification shown in Figure 5 according to the basis weight (S103).

[0051] The control unit 200 refers to the operating mode stored in the RAM 203 and determines whether the operating mode is productivity priority mode (S104). If the operating mode is productivity priority mode (S104:Y), the control unit 200 determines the image formation speed in productivity priority mode based on the paper classification determined in the process of S103, using the table shown in Figure 5 (S105).

[0052] If the operating mode is image quality priority mode (S104:N), the control unit 200 checks the setting value of "image formation speed when image quality is prioritized" included in the paper settings obtained in the process of S102 (S111). The control unit 200 determines whether the obtained setting value is "0" or not (S112). If the setting value is "0" (S112:Y), the control unit 200 determines the image formation speed in image quality priority mode based on the paper classification determined in the process of S103, using the table shown in Figure 5 (S113).

[0053] If the set value is not "0" (S112:N), the control unit 200 selects a default image formation speed, similar to the process in S113 (S121). The control unit 200 then determines the image formation speed in image quality priority mode by offsetting the selected image formation speed according to the set value (S122).

[0054] The control unit 200, which has determined the image forming speed through processing S105, S113, or S122, starts the image forming operation based on the transfer voltage and fixing temperature obtained in processing S102, and the determined image forming speed (S106). As a result, the image forming apparatus forms an image on the paper P and produces a finished product.

[0055] The control unit 200 repeatedly performs the processes from S102 to S106 until it reaches the last page specified in the job (S107:N). The control unit 200 performs the processes from S102 to S106 until it reaches the last page specified in the job, and when it outputs the output for the last page, it terminates the process (S107).

[0056] In the above process, the operating mode is determined for each page, but it is also possible to save the operating mode in RAM203 at the start of the job and perform the processing by referring to that saved content.

[0057] The image forming apparatus of this embodiment can operate in a productivity-priority mode and an image quality-priority mode, and the image forming speed is determined by the type of paper and the operating mode. The image forming speed in image quality-priority mode can be changed (adjusted). Therefore, even in image quality priority mode, image forming can be performed at an image forming speed suitable for the paper, enabling image forming that improves productivity while maintaining image quality.

[0058] (Second Embodiment) The image forming apparatus and control unit of the second embodiment have the same configuration as the image forming apparatus and control unit 200 of the first embodiment, so their description will be omitted. The differences from the image forming apparatus of the first embodiment will be described below.

[0059] In the first embodiment, the image formation speed in image quality priority mode can be changed by the user. This allows the user to achieve their desired image formation speed, but depending on the setting, an image formation speed that does not guarantee image quality may be set. Therefore, in the second embodiment, the following operation is performed.

[0060] Figure 14 is a flowchart showing the image forming process, including the process for determining the image forming speed, in the second embodiment. The control unit 200 (CPU 204) determines the image forming speed by the same process as S101-S105, S111-S113, S121, and S122 in Figure 13 (S901-S905, S911-S913, S921, S922). Furthermore, if the operating mode is set to image quality priority mode and the image formation speed is offset according to the set value (S922), the control unit 200 performs the image formation speed limiting process described later to set the offset image formation speed to a speed within a predetermined limit range (S923).

[0061] The control unit 200, having determined the image formation speed, starts the image formation operation based on the transfer voltage and fixing temperature obtained in the paper settings in the S902 process, and the determined image formation speed (S906). As a result, the image forming apparatus forms an image on the paper P and produces a finished product.

[0062] The control unit 200 repeatedly performs the processes from S902 to S906 until it reaches the last page specified in the job (S907:N). The control unit 200 performs the processes from S902 to S906 until it reaches the last page specified in the job, and when it outputs the output for the last page, it terminates the process (S907).

[0063] In the above process, the operating mode is determined for each page, but it is also possible to save the operating mode in RAM203 at the start of the job and perform the processing by referring to that saved content.

[0064] Figure 15 is a flowchart representing the image formation speed limiting process of S923. Figure 16 is an example of a table showing the image formation speed limit range according to the basis weight (paper category). The image formation speed limit range is set by the upper and lower speed limits for each paper category. The table in Figure 16 is stored in RAM203.

[0065] When the control unit 200 starts the image formation speed limiting process, it checks the type of paper P used for image formation. The control unit 200 determines whether the type of paper P is set to plain paper (basis weight 64-150 [gsm]) or not (S1201). If plain paper is set (S1201:Y), the control unit 200 sets the upper limit speed X of the image formation speed to upper limit speed 1 (Figure 16) and the lower limit speed Y to lower limit speed 1 (Figure 16) (S1202).

[0066] If plain paper is not set (S1201:N), the control unit 200 determines whether the type of paper P is set to thick paper 1 (basis weight 151-250 [gsm]) (S1203). If thick paper 1 is set (S1203:Y), the control unit 200 sets the upper limit speed X of the image forming speed to upper limit speed 2 (Figure 16) and the lower limit speed Y to lower limit speed 2 (Figure 16) (S1204).

[0067] If cardboard 1 is not set (S1203:N), the control unit 200 determines that the paper P is cardboard 2 (basis weight 251-350 [gsm]). In this case, the control unit 200 sets the upper limit speed X of the image forming speed to upper limit speed 3 (Figure 16) and the lower limit speed Y to lower limit speed 3 (Figure 16) (S1205).

[0068] Here, as shown in Figure 16, upper and lower limits for image formation speed are set for each paper weight to ensure that the image forming apparatus performs image formation within an appropriate range of image formation speeds. For example, if image formation is performed at an image formation speed exceeding the upper limit speed 1 for plain paper, the photosensitive drum may not be able to be uniformly charged, potentially resulting in a decrease in image quality. Also, if image formation is performed at an image formation speed below the lower limit speed 1, excessive heat may be applied to the paper P as it passes through the fuser 12, potentially resulting in a decrease in image quality. Therefore, a table in Figure 16, which includes the maximum image formation speed (upper limit speed) that can guarantee image quality for each paper weight and the minimum image formation speed (lower limit speed) that can guarantee image quality for each paper weight, is pre-stored in the RAM 203.

[0069] In this embodiment, the upper limit speed is set so as not to exceed the image forming speed in productivity priority mode. This is because the image forming speed in "productivity priority mode" is usually the maximum speed at which the image forming apparatus can form an image while guaranteeing image quality.

[0070] The control unit 200 obtains the image forming speed determined in the process S922 in Figure 14 (S1206). The control unit 200 determines whether this image forming speed exceeds the upper limit speed X set in any of the processes S1202, S1204, or S1205 (S1207). If the image forming speed exceeds the upper limit speed X (S1207:Y), the control unit 200 changes the image forming speed to the upper limit speed X (S1208). The control unit 200 changes the image forming speed and terminates the image forming speed limiting process.

[0071] If the image formation speed does not exceed the upper limit speed X (S1207:N), the control unit 200 determines whether the image formation speed is below the lower limit speed Y set in any of the processes S1202, S1204, or S1205 (S1209). If the image formation speed is below the lower limit speed Y (S1209:Y), the control unit 200 changes the image formation speed to the lower limit speed Y (S1210). The control unit 200 changes the image formation speed and terminates the image formation speed limiting process. If the image formation speed is not below the lower limit speed Y (S1209:N), the control unit 200 terminates the image formation speed limiting process without changing the image formation speed.

[0072] For example, if the basis weight of paper P is set to 180 [gsm] on the screen shown in Figure 11, the default image forming speed in image quality priority mode is determined to be 200 [mm / s] according to Figure 5. If the image forming speed is then set to "-1" or "-2" on the screen shown in Figure 12, the image forming speed will be changed to 200 [mm / s] or less. However, due to the image forming speed limiting process, the changed image forming speed will be changed back to 200 [mm / s]. As a result, the image forming apparatus can form an image on paper P at an image forming speed that guarantees image quality.

[0073] Figure 17 is an example of a settings screen for setting the upper and lower limits of the adjustable range for image formation speed. This screen is displayed on display 301. The upper limit 1802 and lower limit 1801 change according to the basis weight of the paper. Figure 18 is a flowchart showing the process for determining the upper limit 1802 and lower limit 1801. This process is started when the user selects "Image formation speed with image quality priority" from the paper settings change screen in Figure 10 and presses the OK button.

[0074] The control unit 200 refers to the operating mode stored in the RAM 203 to determine whether or not the image quality priority mode is set (S1301). If the operating mode is the image quality priority mode (S1301:Y), the control unit 200 obtains the paper type selected on the selection screen in Figure 8 (S1302). The control unit 200 determines the paper category according to the basis weight of the obtained paper type using the table shown in Figure 5 (S1303).

[0075] The control unit 200 determines the upper limit value 1802 after determining the paper type, and then determines the lower limit value 1801. Note that the order in which the upper limit value 1802 and the lower limit value 1801 are determined may be reversed. Here, we will explain using the case where the basis weight of the paper is set to 180 [gsm] on the basis weight setting screen in Figure 11 as an example.

[0076] Based on the determined paper classification, the control unit 200 selects the image formation speed for image quality priority mode using the table shown in Figure 5. The control unit 200 sets the selected image formation speed as the speed for image quality priority mode and sets it to variable Z, which is stored in RAM 203 (S1304). In the case of a basis weight of 180 [gsm], the paper classification is "thick paper 1", and the image formation speed (=variable Z) for image quality priority mode is 200 [mm / s]. After setting variable Z, the control unit 200 clears the upper limit setting value stored in RAM 203 to "0" (S1305).

[0077] The control unit 200 selects the image formation speed for productivity priority mode based on the determined paper type, using the table shown in Figure 5. The control unit 200 compares the selected image formation speed for productivity priority mode with the image formation speed set in variable Z (S1306). For a basis weight of 180 [gsm], the image formation speed for productivity priority mode is 400 [mm / s]. The image formation speed set in variable Z is 200 [mm / s].

[0078] If the image forming speed in productivity priority mode is faster than the image forming speed set in variable Z (S1306:Y), the control unit 200 increments the upper limit setting by 1 (S1307). The control unit 200 changes the image forming speed set in variable Z to one step faster, according to the speed that can be set in the image forming apparatus shown in Figure 4 (S1308). In the case of a basis weight of 180 [gsm], the image forming speed of variable Z is changed from 200 [mm / s] to 300 [mm / s], which is one step faster.

[0079] The control unit 200 repeatedly performs the processes S1306 to S1308 as long as the image formation speed in productivity priority mode is faster than the image formation speed set in variable Z. When the image formation speed in productivity priority mode becomes less than or equal to the image formation speed set in variable Z (S1306:N), the control unit 200 determines the upper limit setting value, which has been updated by repeating the processes S1306 to S1308, to the upper limit value 1802 (S1310).

[0080] For a basis weight of 180 gsm, the speed in productivity priority mode is 400 mm / s, and the image formation speed set in variable Z is 200 mm / s. By incrementing the upper limit setting by 1 and changing the image formation speed of variable Z to one step faster, the image formation speed set in variable Z is changed to 300 mm / s. By repeating the processes in S1306 to S1308 again, the image formation speed in productivity priority mode becomes the same as the image formation speed set in variable Z, which is 400 mm / s. The upper limit setting is "+2". At this point, the process proceeds to S1310, and the upper limit setting value of "+2" is determined for the upper limit value 1802.

[0081] Having determined the upper limit value of 1802, the control unit 200 sets the image formation speed for image quality priority mode in variable Z, similar to the process in S1304 (S1311). After setting variable Z, the control unit 200 clears the lower limit setting value held in RAM 203 to "0" (S1311). The control unit 200 selects the lowest image formation speed (200 [mm / s]) from the speeds that can be set in the image forming apparatus shown in Figure 4. The control unit 200 compares the selected lowest image formation speed with the image formation speed set in variable Z (S1313).

[0082] If the minimum image forming speed is greater than or equal to the image forming speed set for variable Z (S1313:Y), the control unit 200 determines the lower limit setting value to the lower limit value 1801 (S1321). In the case of a basis weight of 180 [gsm], the minimum speed is 200 [mm / s], and the image forming speed of variable Z is 200 [mm / s]. Therefore, the lower limit value 1801 is determined to be the lower limit setting value "0".

[0083] If the minimum image forming speed is slower than the image forming speed set in variable Z (S1313:N), the control unit 200 decrements the lower limit setting by 1 (S1314). The control unit 200 changes the image forming speed set in variable Z to a speed one step lower, according to the speed that can be set in the image forming apparatus shown in Figure 4 (S1315). The control unit 200 repeats the process from S1313 to S1315 as long as the minimum image forming speed is slower than the image forming speed set in variable Z.

[0084] If the minimum image forming speed becomes greater than or equal to the image forming speed set in variable Z (S1313:N), the control unit 200 repeats the processes S1313 to S1315 to update the lower limit setting value to a lower limit value of 1801 (S1321). In the case of a basis weight of 180 [gsm], the minimum speed is 200 [mm / s] and the image forming speed set in variable Z is 200 [mm / s]. Therefore, in this case, the processes S1313 to S1315 are not performed.

[0085] The control unit 200, having determined the upper limit 1802 and the lower limit 1801, displays the determined upper limit 1802 and lower limit 1801 on the display 301 (S1322). In the case of a basis weight of 180 [gsm], as illustrated in Figure 17, "+2" is displayed as the upper limit 1802 and "0" is displayed as the lower limit 1801.

[0086] When the operating mode is productivity priority mode (S1301:N), the control unit 200 determines both the upper limit 1802 and the lower limit 1801 to "0" (S1331, S1332). The determined upper limit 1802 and lower limit 1801 are displayed on the display 301 (S1322). Note that while the upper limit 1802 and lower limit 1801 are displayed as "0" in productivity priority mode, any display method is acceptable as long as it indicates that pressing the "+" and "-" buttons in Figure 18 is not effective in productivity priority mode.

[0087] By setting an upper limit of 1802 and a lower limit of 1801 as described above, it is possible to prevent users from setting an image formation speed that does not guarantee image quality when they change the image formation speed.

[0088] (Third embodiment) The image forming apparatus and control unit of the third embodiment have the same configuration as the image forming apparatus and control unit 200 of the first embodiment, so their description will be omitted. The differences from the image forming apparatus of the first and second embodiments will be described below.

[0089] In the first embodiment, regardless of whether the operating mode is set to image quality priority mode or productivity priority mode, "Image formation speed in image quality priority mode" is displayed in the configurable items on the paper settings change screen in Figure 10. However, in productivity priority mode, the "Image formation speed setting in image quality priority mode" is not used during image formation. Therefore, in productivity priority mode, even if the user sets the image formation speed for image quality priority mode, it may lead to results different from what the user expects. This results in a decrease in usability.

[0090] In the third embodiment, when in productivity priority mode, the "image formation speed when prioritizing image quality" is excluded from the configurable items on the paper settings change screen. Figure 19 is a flowchart showing the display setting process for the paper settings change screen.

[0091] The control unit 200 determines whether the productivity priority mode has been selected by the user mode key 308 from the operation mode selection screen in Figure 6 (S650). If the productivity priority mode is selected (S650:Y), the control unit 200 sets the status of the flag that disables the image formation speed setting for image quality priority mode, which is held in RAM 203, to ON (S651). If the image quality priority mode is selected (S650:N), the control unit 200 sets the status of the flag that disables the image formation speed setting for image quality priority mode to OFF (S652). The status of the flag that disables the image formation speed setting for image quality priority mode is held in RAM 203.

[0092] Figure 20 is a flowchart illustrating the display process for the paper settings change screen.

[0093] The control unit 200 waits until the paper type to be changed is selected by the operation unit 300 from the selection screen in Figure 9 and the display of the paper setting change screen is instructed (S700:N). When the display of the paper setting change screen is instructed (S700:Y), the control unit 200 checks the status of the flag that disables the image formation speed setting in image quality priority mode, which is stored in the RAM 203 (S701).

[0094] If the setting disable flag is ON (S701:Y), the control unit 200 displays the paper setting change screen A on the display 301 (S702). Figure 21 is an example of the paper setting change screen A. The paper setting change screen A is the same as the paper setting change screen in Figure 10, but with the "Image formation speed when prioritizing image quality" item removed. If the setting disable flag is OFF (S701:N), the control unit 200 displays the paper setting change screen B on the display 301 (S703). The paper setting change screen B is the same as the paper setting change screen in Figure 10.

[0095] As a result of the above processing, in productivity priority mode, the "Image Formation Speed ​​when Image Quality is Prioritized" item will not be displayed on the paper settings change screen, and it will be impossible to input a setting value to change the image formation speed. This prevents a decrease in usability.

Claims

1. An operating device for inputting user instruction information to an image forming apparatus that forms an image on a sheet based on a mode selected from a plurality of modes having different image forming speeds, A display means that displays a selection screen for selecting a sheet type from among several types of sheets, and a change screen for changing the first image formation speed of the image quality priority mode among the multiple modes in accordance with the sheet type, The system is characterized by comprising a control means that, after the type of sheet is selected on the selection screen, causes a button for displaying the change screen to be displayed on the display means. Operating device.

2. The control means is characterized in that it displays a mode selection screen on the display means for selecting a mode to operate the image forming apparatus from the plurality of modes, The operating device according to claim 1.

3. When the image quality priority mode is selected from the plurality of modes on the mode selection screen, the control means displays the button on the display means after the type of sheet is selected on the selection screen. The operating device according to claim 2.

4. When a productivity priority mode different from the image quality priority mode is selected from the plurality of modes on the mode selection screen, the change screen is not displayed on the display means, characterized in that The operating device according to claim 3.

5. The change screen is characterized in that it includes a button for increasing the first image forming speed and a button for decreasing the first image forming speed. The operating device according to claim 1.

6. The change screen is characterized in that it includes information regarding the range in which the first image forming speed can be changed. The operating device according to claim 1.

7. The image forming apparatus is Photoreceptor and A light source that irradiates the photosensitive material with light to form an electrostatic latent image on the photosensitive material, A developing device that develops the electrostatic latent image on the photoreceptor to form an image on the photoreceptor, An intermediate transfer body on which the image on the photoreceptor is transferred, A transfer nip formed between the intermediate transfer body and the transfer nip comprises a transfer section configured to transfer the image from the intermediate transfer body onto a sheet, The rotation speed of the photoreceptor is controlled based on the image forming speed, The operating device according to claim 1.

8. The image forming apparatus is Photoreceptor and A light source that irradiates the photosensitive material with light to form an electrostatic latent image on the photosensitive material, A developing device that develops the electrostatic latent image on the photoreceptor to form an image on the photoreceptor, An intermediate transfer body on which the image on the photoreceptor is transferred, A transfer nip formed between the intermediate transfer body and the transfer nip comprises a transfer section configured to transfer the image from the intermediate transfer body onto a sheet, The transport speed at which the sheet passes through the transfer nip is controlled based on the image forming speed, The operating device according to claim 1.

9. The image forming apparatus is Photoreceptor and A light source that irradiates the photosensitive material with light to form an electrostatic latent image on the photosensitive material, A developing device that develops the electrostatic latent image on the photoreceptor to form an image on the photoreceptor, An intermediate transfer body on which the image on the photoreceptor is transferred, A transfer nip formed between the intermediate transfer body and the transfer nip includes a transfer section configured to transfer the image from the intermediate transfer body onto the sheet, The system includes a fuser that fixes the image onto the sheet while transporting the sheet, The sheet transport speed by the fuser is controlled based on the image forming speed, The operating device according to claim 1.

10. The first image forming speed corresponding to the first type of sheet in the image quality priority mode is faster than the second image forming speed corresponding to the first type of sheet in a productivity priority mode different from the image quality priority mode, The first image forming speed corresponding to the first type of sheet in the image quality priority mode is characterized in that it is different from the first image forming speed corresponding to a second type of sheet different from the first type in the image quality priority mode. The operating device according to claim 1.

11. The basis weight of the first type of sheet is smaller than the basis weight of the second type of sheet, The operating device according to claim 10.

12. The first image forming speed corresponding to the first type of sheet is faster than the second image forming speed corresponding to the first type of sheet. The first image forming speed corresponding to the first type of sheet is faster than the first image forming speed corresponding to the second type of sheet. The operating device according to claim 11.

13. The first image forming speed corresponding to a third type of sheet that is different from both the first type of sheet and the second type of sheet is equal to the second image forming speed corresponding to the third type of sheet, The second image forming speed corresponding to the third type of sheet is characterized by being faster than the second image forming speed corresponding to the first type of sheet. The operating device according to claim 12.

14. The image forming apparatus is characterized in that the production capacity of the image quality priority mode is higher than the production capacity of the productivity priority mode. The operating device according to claim 11.

15. The first image forming speed corresponding to a third type of sheet that is different from both the first type of sheet and the second type of sheet in the image quality priority mode is equal to the second image forming speed corresponding to the third type of sheet, The second image forming speed corresponding to the third type of sheet is characterized by being faster than the second image forming speed corresponding to the first type of sheet. The operating device according to claim 10.

16. The basis weight of the third type of sheet is smaller than the basis weight of the first type of sheet. The operating device according to claim 15.

Images