Image forming apparatus and control method

Abstract

To provide an image forming apparatus capable of suppressing the occurrence of fixing failures while suppressing reduction in productivity.SOLUTION: An image forming apparatus 100 includes: a fixing device that thermally fixes an image on a sheet in accordance with a print job; and a control part that changes a temperature setting of the fixing device according to a type of a printer driver 300 that generated the print job.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus and a control method.

Background Art

[0002] Conventionally, an image forming apparatus that thermally fixes a toner image corresponding to a print job received from a client terminal onto a sheet is known. A heating device is required for thermally fixing the toner image onto the sheet. Therefore, technologies for suppressing the energy consumed for thermally fixing the toner image onto the sheet have been developed. For example, Japanese Patent Application Laid-Open No. 2011-186131 (Patent Document 1) discloses a technique for performing fixing at a temperature corresponding to the difference in dither used for drawing.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technique disclosed in Patent Document 1 focuses on the difference in dither and does not focus on the amount of toner placed on the sheet (hereinafter referred to as "toner loading amount"). In order to suppress the energy consumed for thermally fixing the toner image onto the sheet, it is conceivable to detect the maximum toner loading amount and set the fixing temperature so that fixing failure does not occur even at the detected maximum toner loading amount. However, in this case, image processing for detecting the maximum toner loading amount takes time and productivity decreases.

[0005] The present disclosure has been made in view of the above background, and an object thereof is to provide an image forming apparatus and a control method capable of suppressing the occurrence of fixing failure while suppressing a decrease in productivity.

Means for Solving the Problems

[0006] An image forming apparatus according to a certain aspect of this disclosure includes a fixing device that heat-fixes an image corresponding to a print job onto a sheet, and a control unit that changes the set temperature of the fixing device according to the type of printer driver that generated the print job.

[0007] Preferably, the control unit changes the set temperature when in color printing mode, but does not change the set temperature when in monochrome printing mode.

[0008] Preferably, the control unit changes the set temperature according to the type of printer driver as well as the image quality mode.

[0009] Preferably, the image forming apparatus further includes a correction unit that performs edge correction to adjust the density of edges in the image. The control unit changes the set temperature according to the type of printer driver and whether or not edge correction is performed by the correction unit.

[0010] Preferably, the control unit changes the set temperature according to at least one of the following, in addition to the type of printer driver: the type of sheet, the sheet transport speed, the external environment, and the operating state of the image forming apparatus.

[0011] According to one aspect of this disclosure, a method for controlling a fuser device that heat-fixes an image corresponding to a print job onto a sheet comprises the steps of: determining the type of printer driver that generated the print job; and changing the set temperature of the fuser device according to the determined type of printer driver. [Effects of the Invention]

[0012] According to this disclosure, it is possible to suppress the occurrence of poor adhesion while suppressing the decline in productivity. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows an example of the configuration of a system to which an image forming apparatus according to this embodiment is applied. [Figure 2] This figure shows an example of an image forming apparatus according to this embodiment. [Figure 3] This is a block diagram showing an example of the hardware configuration of an image forming apparatus. [Figure 4] This diagram shows the functional configuration of the main controller and engine controller. [Figure 5] This diagram shows how a toner image is formed on the surface of a photoreceptor. [Figure 6] This is a diagram explaining edge correction. [Figure 7] This figure shows an example of a set temperature table. [Figure 8] This is a flowchart showing part of the processing flow of an image forming apparatus. [Figure 9] This is a flowchart showing another part of the processing flow of an image forming apparatus. [Figure 10] This is a flowchart showing yet another part of the processing flow of an image forming apparatus. [Modes for carrying out the invention]

[0014] Embodiments and modifications according to this disclosure will be described below with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions of them will not be repeated. The embodiments and modifications described below may be combined selectively as appropriate.

[0015] (A. System Configuration) Figure 1 shows an example of the configuration of a system to which an image forming apparatus according to this embodiment is applied. The system includes an image forming apparatus 100 and client terminals 200. In the example shown in Figure 1, the system includes two client terminals 200A and 200B. This configuration is just one example, and the configuration of this system is not limited thereto. In some aspects, the system may include any number of image forming apparatuses 100 and any number of client terminals.

[0016] The client terminal 200 is any device such as a PC (Personal Computer), tablet, or smartphone used by the user. Various types of applications 400 are installed on the client terminal 200. The applications 400 are, for example, spreadsheet software, image editing software, and the like.

[0017] Furthermore, a printer driver 300 for sending a print job to the image forming apparatus 100 is installed on the client terminal 200. The user installs one or more desired printer drivers 300 on the client terminal 200 from among multiple types of printer drivers.

[0018] As types of the printer driver 300, for example, there are a PS (PostScript) printer driver, a PCL (Printer Control Language) printer driver, and the like. The PS printer driver is suitable for printing from applications compliant with PostScript used for graphics and DTP (Desktop Publishing). The PCL printer driver is suitable for printing from applications for creating general business documents. In the example shown in FIG. 1, a PCL printer driver is installed on the client terminal 200A, and a PS printer driver is installed on the client terminal 200B. Note that both a PCL printer driver and a PS printer driver may be installed on each of the client terminals 200A and 200B.

[0019] The printer driver 300 generates a print job including image data indicating an image to be printed in response to an operation from the user. The print job generated by the printer driver 300 is sent to the image forming apparatus 100. Driver type information indicating the type (such as PS or PCL) of the printer driver 300 that generated the print job and condition information indicating print conditions are added to the print job.

[0020] The image forming apparatus 100 performs printing processing according to the print job received from the client terminal 200.

[0021] (B. Hardware configuration of the image forming apparatus) Figure 2 shows an example of an image forming apparatus according to this embodiment. As shown in Figure 2, the image forming apparatus 100 includes a print engine 110 and an operation panel 130.

[0022] The print engine 110 has a monochrome printing mode and a color printing mode. When the monochrome printing mode is set, the print engine 110 performs monochrome printing. When the color printing mode is set, the print engine 110 performs color printing.

[0023] The print engine 110 comprises an imaging unit 112, an intermediate transfer belt 114, a fixing device 116, a paper feeding unit 118, a delivery roller 120, a transport roller 122, and a registration roller 124.

[0024] The print engine 110 performs printing on the sheet S in the paper feed unit 118. The delivery roller 120 transports the sheet S from the paper feed unit 118. Furthermore, the transport roller 122 transports the sheet S in the direction of the intermediate transfer belt 114.

[0025] The imaging unit 112 includes imaging units 10C, 10M, 10Y, and 10K that form toner images of cyan (C), magenta (M), yellow (Y), and key plate (K), respectively. Each imaging unit 10C, 10M, 10Y, and 10K includes a charging unit (not shown), a developing unit (not shown), a cleaning unit (not shown), and an intermediate transfer contact roller (not shown).

[0026] Furthermore, imaging unit 10C includes photoreceptor 11C. Imaging unit 10M includes photoreceptor 11M. Imaging unit 10Y includes photoreceptor 11Y. Imaging unit 10K includes photoreceptor 11K. Hereafter, photoreceptors 11C, 11M, 11Y, and 11K may be collectively referred to simply as "photoreceptors."

[0027] The exposure unit 12 is common to imaging units 10C, 10M, 10Y, and 10K. In some cases, each of the imaging units 10C, 10M, 10Y, and 10K may include its own separate exposure unit 12.

[0028] The imaging unit 112 and the intermediate transfer belt 114 form a toner image to be transferred to the sheet S. The charging unit uniformly charges the surface of the photoreceptor. The exposure unit 12 exposes the surface of the photoreceptor according to a specified image pattern by laser writing or the like, thereby forming an electrostatic latent image on its surface. The developing unit develops the electrostatic latent image formed on the photoreceptor as a toner image. The developing unit uses, for example, a two-component developer containing toner and a carrier.

[0029] The toner image formed on the surface of the photoreceptor is transferred to the intermediate transfer belt 114. In color printing mode, the toner images from each photoreceptor are sequentially transferred onto the intermediate transfer belt 114, and the four toner images are superimposed.

[0030] The registration roller 124 adjusts the transport timing of the sheet S before it reaches the intermediate transfer belt 114. The intermediate transfer belt 114 transfers the toner image onto the sheet S. The sheet S, on which the toner image has been transferred, is transported to the fuser unit 116.

[0031] The fuser unit 116 heat-fixes the toner image to the sheet S. The fuser unit 116 includes a heating roller 116a equipped with a halogen lamp or the like for heating the sheet S and the toner image, and a pressure roller 116b that holds the sheet S together with the heating roller 116a and pressurizes the sheet S. The heating roller 116a may be heated on its surface by generating eddy currents on its surface through electromagnetic induction. The sheet S on which the toner image has been fixed by the fuser unit 116 is discharged into the discharge tray.

[0032] The control panel 130 includes a display unit (not shown) and an operation unit (not shown). The display unit includes a liquid crystal monitor, an organic EL (Electro-Luminescence) monitor, etc. The liquid crystal monitor, organic EL monitor, etc., includes a touch sensor and can display an operation menu and accept touch input from the user. The operation unit includes multiple buttons and can accept input from the user in the same way as the touch panel.

[0033] Figure 3 is a block diagram showing an example of the hardware configuration of an image forming apparatus. In addition to the print engine 110 and operation panel 130 shown in Figure 2, the image forming apparatus 100 includes a main controller 150, a network interface 160, an engine controller 170, and a bus 180. The bus 180 connects the various components of the image forming apparatus 100 to each other.

[0034] The network interface 160 is connected to external devices such as client terminals 200 via a wired or wireless network. The network interface 160 may be implemented, for example, by a wired LAN (Local Area Network) port and a Wi-Fi® (Wireless Fidelity) module. The image forming apparatus 100 can acquire print jobs via the network interface 160. The image forming apparatus 100 may have multiple network interfaces 160.

[0035] The main controller 150 controls the overall operation of the image forming apparatus 100. The main controller 150 generates image forming instructions according to the print job received via the network interface 160 and outputs the generated image forming instructions to the engine controller 170.

[0036] The engine controller 170 controls the print engine 110 so that an image is formed on the sheet S in response to an image formation instruction from the main controller 150.

[0037] In the example shown in Figure 3, the main controller 150 includes a CPU (Central Processing Unit) 152, which is an example of a hardware processor, RAM (Random Access Memory) 154, and ROM (Read Only Memory) 156. The engine controller 170 includes a CPU 172, which is an example of a hardware processor, RAM 174, and ROM 176.

[0038] CPUs 152 and 172 execute various programs stored in ROMs 156 and 176.

[0039] RAM154 and 174 temporarily store the program being executed and the data being referenced. For example, SRAM (Static Random Access Memory) or DRAM (Dynamic Random Access Memory) may be used as RAM154 and 174.

[0040] ROMs 156 and 176 are non-volatile memories that store various data used by the image forming apparatus 100. ROMs 156 and 176 also store programs for controlling the image forming apparatus 100. For example, EPROM (Erasable Programmable ROM), EEPROM (Electrically Erasable Programmable ROM), or flash memory may be used as ROMs 156 and 176.

[0041] The main controller 150 may consist of at least one embedded CPU, at least one ASIC (Application Specific Integrated Circuit), or at least one FPGA (Field Programmable Gate Array), etc. Alternatively, the main controller 150 may consist of a combination of two or more of these. Similarly, the engine controller 170 may consist of at least one embedded CPU, at least one ASIC, or at least one FPGA, etc. Alternatively, the engine controller 170 may consist of a combination of two or more of these.

[0042] (C. Functional configuration of the image forming apparatus) Figure 4 shows the functional configuration of the main controller and the engine controller. As shown in Figure 4, the main controller 150 includes an image quality mode setting unit 51, a color conversion unit 52, and an edge correction unit 53.

[0043] The image quality mode setting unit 51 sets the image quality mode for print jobs generated using the PS printer driver in response to operations on the operation panel 130. In this embodiment, the user can select either normal mode or designer mode as the image quality mode. Designer mode provides higher image quality than normal mode. The image quality mode setting unit 51 sets normal mode as the image quality mode for print jobs generated using the PCL printer driver.

[0044] The color conversion unit 52 converts the image data included in the print job received from the client terminal 200 into image data that shows CMYK density.

[0045] Note that the colors shown by the image data included in the print job will vary depending on the type of printer driver 300 and the type of application 400 in which the image data was created.

[0046] For example, an image generated by Microsoft Excel®, a spreadsheet software, shows RGB densities. When this image is to be printed, the printer driver 300 generates a print job that includes the following image data. Specifically, the PCL printer driver generates image data showing RGB densities. The PS printer driver generates image data showing Lab densities, regardless of the image quality mode set in the image forming apparatus 100.

[0047] Images generated by Adobe Systems Inc.'s Photoshop®, an image editing software, exhibit YMCK density. When such images are to be printed, the printer driver 300 generates a print job containing the following image data: The PCL printer driver generates image data showing RGB density. The PS printer driver generates image data showing Lab density when the image forming apparatus 100 is set to normal mode. The PS printer driver generates image data showing YMCK density when the image forming apparatus 100 is set to designer mode.

[0048] The color conversion unit 52 should perform color conversion processing according to the colors indicated by the image data included in the print job. When designer mode is set, the image data generated by the PS printer driver indicates the density of YMCK. In this case, the color conversion unit 52 adjusts the density of YMCK so that the amount of toner is suitable for the print engine 110.

[0049] The edge correction unit 53 performs an edge correction process to adjust the density of edges in the image. The operation panel 130 accepts a request to enable or disable the edge correction function. The edge correction unit 53 performs edge correction only when the edge correction function is set to enabled.

[0050] Figure 5 shows how a toner image is formed on the surface of the photoreceptor. Figure 5 shows the counter development method. In the counter development method, the photoreceptor 11 and the development sleeve 13 rotate in opposite directions, causing the toner at the leading edge of the photoreceptor 11 in the direction of rotation to be swept to the rear by the carrier's bristles. As a result, the toner density at the leading edge of the photoreceptor 11 in the direction of rotation becomes lighter. On the other hand, the toner density at the trailing edge of the photoreceptor 11 in the direction of rotation becomes darker.

[0051] Furthermore, in toner development, the edge effect is known, where more toner adheres to the edges of an image, while less adheres to the center. The edge effect is particularly noticeable in large areas of solid color. This is because the electric field lines of the electrostatic latent image on the photoreceptor concentrate at the edges, causing toner to concentrate at the edges.

[0052] The edge correction unit 53 corrects the image data to resolve such defects in toner density at the edges.

[0053] Figure 6 illustrates edge correction. The left side of Figure 6 shows the change in density value indicated by the image data along the rotation direction of the photoreceptor. The right side of Figure 6 shows the change in toner amount along the rotation direction of the photoreceptor.

[0054] The dashed line 30 shows the change in density when the edge correction function is disabled. The dashed line 34 shows the change in toner amount when the edge correction function is disabled. As shown by the dashed line 30, the image data shows a constant density value in the region where the toner image is formed. However, as shown in Figure 5, toner sweeping occurs, so as shown by the dashed line 34, the amount of toner on the leading edge in the rotation direction of the photoreceptor decreases, and the amount of toner on the trailing edge in the rotation direction increases.

[0055] The edge correction unit 53 corrects the image data as shown by the solid line 32 so that the effect of toner sweeping is suppressed. Specifically, the edge correction unit 53 increases the density value of the leading edge in the rotation direction of the photoreceptor and decreases the density value of the trailing edge in the rotation direction of the photoreceptor. As a result, fluctuations in the amount of toner applied due to toner sweeping are suppressed, as shown by the solid line 36.

[0056] The sweeping of toner by the carrier bristles and the edge effect are less likely to occur when the length L of the region where the toner image is formed, along the rotation direction of the photoreceptor, is shorter. Therefore, the edge correction unit 53 may not perform edge correction when the length L is less than a reference value, and may perform edge correction when the length L is greater than or equal to the reference value. The edge correction unit 53 may also change the strength of edge correction according to the length L. The greater the strength of edge correction, the greater the change in the solid line 32 relative to the dashed line 30 shown in Figure 6. For example, if the strength of edge correction when the length L is 1.69 mm or more is set to 100, the edge correction unit 53 may set the strength of edge correction when the length L is 1.35 mm to 1.69 mm to 60, the strength of edge correction when the length L is 0.68 mm to 1.02 mm to 40, and the strength of edge correction when the length L is less than 0.68 mm to 0.

[0057] In the text (character) area of ​​an image, the length L of the area where the toner image is formed is short. Therefore, in the text area, toner sweeping by carrier particles and edge effects are less likely to occur. Accordingly, when the edge correction function is enabled, the edge correction unit 53 may decide whether or not to perform edge correction for each area in the image. Specifically, the edge correction unit 53 determines the attributes of each pixel in the image and classifies the image into text areas, graphic (chart) areas, and image (picture or photograph) areas. The edge correction unit 53 does not perform edge correction on the text area, but performs edge correction on the graphic area and the image area.

[0058] The main controller 150 outputs image data obtained by the processing of the color conversion unit 52 and the edge correction unit 53 to the engine controller 170. The main controller 150 also outputs driver type information and condition information included in the print job to the engine controller 170. Furthermore, the main controller 150 outputs first additional information indicating the image quality mode set by the image quality mode setting unit 51, and second additional information indicating whether the edge correction function is enabled or disabled to the engine controller 170.

[0059] The engine controller 170 controls the operation of the print engine 110 according to the image data received from the main controller 150. As shown in Figure 4, the engine controller 170 includes a temperature control unit 71 and a set temperature table 72.

[0060] The temperature control unit 71 changes the set temperature of the fuser unit 116 according to the type of printer driver 300 that generated the print job.

[0061] The PCL printer driver generates image data with fewer color gradation combinations. Therefore, when printing based on image data generated by the PCL printer driver, there is less overlap of YMCK toner. As a result, the amount of toner on the sheet S is also reduced.

[0062] The PS printer driver generates image data with many color gradation combinations. Therefore, when printing based on the image data generated by the PS printer driver, there is a lot of overlap in the YMCK toner. As a result, the amount of toner on the sheet S is also large. In particular, when Designer's Mode is set as the image quality mode, the amount of toner on the sheet S is increased even further in order to obtain a high-quality image.

[0063] The more toner is applied, the more heat is required to fix the toner image to the sheet S. Therefore, the temperature control unit 71 adjusts the temperature control unit 71 when the printer driver 300 that generated the print job is a PCL printer driver, compared to when the printer driver 300 that generated the print job is a PCL printer driver. PS If it is a printer driver, increase the set temperature of the fuser unit 116.

[0064] Furthermore, if the printer driver 300 that generated the print job is a PS printer driver, the temperature control unit 71 may change the set temperature of the fuser unit 116 according to the image quality mode. Specifically, the temperature control unit 71 raises the set temperature of the fuser unit 116 when the image quality mode is designer mode compared to when the image quality mode is normal mode.

[0065] When the edge correction function is disabled, as shown by the dashed line 34 in Figure 6, the amount of toner on the rear edge in the rotational direction of the photoreceptor increases due to the toner being swept up by the carrier bristles. Therefore, the temperature control unit 71 may set the fuser unit 116 to a higher temperature when edge correction is not performed compared to when edge correction is performed.

[0066] Furthermore, the temperature control unit 71 may change the set temperature of the fixing device 116 depending on the type of sheet S. The type of sheet S is defined by its basis weight, thickness, etc. For example, cardboard has a greater heat capacity than ordinary paper. Therefore, the temperature control unit 71 sets the set temperature of the fixing device 116 higher when the sheet S is cardboard compared to when the sheet S is ordinary paper.

[0067] Specifically, the temperature control unit 71 refers to the set temperature table 72 and changes the set temperature of the fixing device 116.

[0068] Figure 7 shows an example of a set temperature table. As shown in Figure 7, the set temperature table 72 associates the type of printer driver 300, the image quality mode, the status of the edge correction function, the type of sheet S, and the set temperature of the fuser 116. The set temperature table 72 shown in Figure 7 is created in advance according to the specifications of the print engine 110.

[0069] The temperature control unit 71 identifies the type of printer driver 300 that generated the print job based on the driver type information. Furthermore, if the type of printer driver 300 is a PS printer driver, the temperature control unit 71 identifies the image quality mode set by the image quality mode setting unit 51 based on the first additional information received from the main controller 150. The temperature control unit 71 identifies whether the edge correction function is enabled or disabled based on the second additional information received from the main controller 150. The temperature control unit 71 identifies the type of sheet S based on the condition information.

[0070] The temperature control unit 71 reads the set temperature corresponding to the identified printer driver 300 type, image quality mode, edge correction function status, and sheet S type from the set temperature table 72. The temperature control unit 71 controls the fuser 116 to achieve the read set temperature.

[0071] In monochrome printing mode, the amount of toner on the sheet S is small, regardless of the type of printer driver 300. Therefore, the temperature control unit 71 does not change the set temperature in monochrome printing mode, but changes the set temperature in color printing mode. Specifically, in monochrome printing mode, the temperature control unit 71 sets the set temperature of the fuser unit 116 to the default temperature (for example, a temperature of 160°C or lower). In color printing mode, the temperature control unit 71 changes the set temperature of the fuser unit 116 according to the set temperature table 72.

[0072] (D. Processing flow of the image forming apparatus) Referring to Figures 8 to 10, an example of the processing flow of the image forming apparatus 100 will be explained. Figure 8 is a flowchart showing a part of the processing flow of the image forming apparatus 100. Figure 9 is a flowchart showing another part of the processing flow of the image forming apparatus 100. Figure 10 is a flowchart showing yet another part of the processing flow of the image forming apparatus 100. The processing shown in Figures 8 to 10 is performed each time a print job is received from the client terminal 200.

[0073] As shown in Figure 8, the image forming apparatus 100 determines the print mode (color mode and monochrome mode) (step S1). The print mode is determined according to the print conditions included in the print job or the operation on the control panel 130.

[0074] When the print mode is monochrome print mode, the image forming apparatus 100 does not change the set temperature of the fuser 116 according to the type of printer driver (step S2). That is, the image forming apparatus 100 sets the set temperature of the fuser 116 to the default temperature (for example, a temperature of 160°C or lower). The image forming apparatus 100 may change this default temperature based on the type of sheet, such as plain paper or cardboard.

[0075] If the print mode is color print mode, the image forming apparatus 100 determines the type of printer driver 300 that generated the print job based on the driver type information included in the print job (step S3).

[0076] If the determination result in step S3 indicates a PLC printer driver, the image forming apparatus 100 determines whether the edge correction function is enabled or disabled (step S4).

[0077] If the determination result in step S4 indicates validity, the image forming apparatus 100 performs edge correction (step S5). In step S5, edge correction may be performed on all edges in the image, or it may be performed according to the attributes of the regions in the image. For example, edge correction may not be performed on the text region, but on the graphic region and the image region.

[0078] After step S5, the image forming apparatus 100 determines the type of sheet S on which the image will be formed based on the condition information included in the print job (step S6).

[0079] If the determination result in step S6 indicates plain paper, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 160°C according to the set temperature table 72 shown in Figure 7 (step S7).

[0080] If the determination result in step S6 indicates cardboard, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 165°C according to the set temperature table 72 shown in Figure 7 (step S8).

[0081] If the determination result in step S4 indicates invalidity, the image forming apparatus 100 determines the type of sheet S on which the image will be formed based on the condition information included in the print job (step S9).

[0082] If the determination result in step S9 indicates plain paper, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 165°C according to the set temperature table 72 shown in Figure 7 (step S10).

[0083] If the determination result in step S9 indicates cardboard, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 170°C according to the set temperature table 72 shown in Figure 7 (step S11).

[0084] If the determination result in step S3 indicates a PS printer driver, the image forming apparatus 100 determines the image quality mode, as shown in Figure 9 (step S12).

[0085] If the determination result in step S12 indicates designer mode, the image forming apparatus 100 determines whether the edge correction function is enabled or disabled (step S13).

[0086] If the determination result in step S13 indicates validity, the image forming apparatus 100 performs edge correction (step S14). The details of step S14 are the same as in step S5.

[0087] After step S14, the image forming apparatus 100 determines the type of sheet S on which the image will be formed based on the condition information included in the print job (step S15).

[0088] If the determination result in step S15 indicates plain paper, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 165°C according to the set temperature table 72 shown in Figure 7 (step S16).

[0089] If the determination result in step S15 indicates cardboard, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 170°C according to the set temperature table 72 shown in Figure 7 (step S17).

[0090] If the determination result in step S13 indicates invalidity, the image forming apparatus 100 determines the type of sheet S on which the image will be formed based on the condition information included in the print job (step S18).

[0091] If the determination result in step S18 indicates plain paper, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 170°C according to the set temperature table 72 shown in Figure 7 (step S19).

[0092] If the determination result in step S18 indicates cardboard, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 175°C according to the set temperature table 72 shown in Figure 7 (step S20).

[0093] If the determination result in step S12 indicates the normal mode, the image forming apparatus 100 determines whether the edge correction function is enabled or disabled, as shown in Figure 10 (step S21).

[0094] If the determination result in step S21 indicates validity, the image forming apparatus 100 performs edge correction (step S22). The details of step S22 are the same as in step S5.

[0095] After step S22, the image forming apparatus 100 determines the type of sheet S on which the image will be formed based on the condition information included in the print job (step S23).

[0096] If the determination result in step S23 indicates plain paper, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 162°C according to the set temperature table 72 shown in Figure 7 (step S24).

[0097] If the determination result in step S23 indicates cardboard, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 167°C according to the set temperature table 72 shown in Figure 7 (step S25).

[0098] If the determination result in step S21 indicates invalidity, the image forming apparatus 100 determines the type of sheet S on which the image will be formed based on the condition information included in the print job (step S26).

[0099] If the determination result in step S26 indicates plain paper, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 167°C according to the set temperature table 72 shown in Figure 7 (step S27).

[0100] If the determination result in step S26 indicates cardboard, the image forming apparatus 100 changes the set temperature of the fixing device 116 to 172°C according to the set temperature table 72 shown in Figure 7 (step S28).

[0101] (E. Variant) The temperature control unit 71 of the engine controller 170 may change the set temperature of the fuser 116 in accordance with at least one of the following, in addition to the type of printer driver: the transport speed of the sheet S, the external environment, and the operating state of the image forming apparatus 100.

[0102] The faster the sheet S is transported, the less heat is transferred from the fixing device 116 to the sheet S per unit time. Therefore, it is preferable for the temperature control unit 71 to increase the set temperature of the fixing device 116 as the transport speed of the sheet S increases.

[0103] As the ambient temperature, one of the external environmental factors, increases, the amount of heat required to fix the toner image onto the sheet S decreases. Therefore, it is preferable for the temperature control unit 71 to lower the set temperature of the fixing device 116 as the ambient temperature increases.

[0104] As the ambient humidity, one of the external environmental factors, increases, the moisture content of the sheet S increases, making the sheet S more prone to curling after passing through the fixing device 116. Therefore, it is preferable for the temperature control unit 71 to lower the set temperature of the fixing device 116 as the ambient humidity increases.

[0105] If the image forming apparatus 100 has a sleep mode that stops or minimizes the power supply to each part in order to save energy, the temperature control unit 71 may change the set temperature of the fixing device 116 depending on whether the operating state of the image forming apparatus 100 has just recovered from sleep mode. During sleep mode, the power supply to the fixing device 116 is suppressed, and the temperature of the fixing device 116 decreases. Therefore, if the operating state of the image forming apparatus 100 has just recovered from sleep mode, it is preferable for the temperature control unit 71 to raise the set temperature of the fixing device 116.

[0106] (F. Note) As described above, this embodiment includes the following disclosures.

[0107] (Composition 1) A fixing device that heat-fixes an image corresponding to a print job onto a sheet S, An image forming apparatus comprising a control unit (temperature control unit 71) that changes the set temperature of the fuser according to the type of printer driver that generated the print job.

[0108] (Configuration 2) The image forming apparatus according to configuration 1, wherein the control unit changes the set temperature when in color printing mode, but does not change the set temperature when in monochrome printing mode.

[0109] (Composition 3) The image forming apparatus according to claim 1 or 2, wherein the control unit changes the set temperature according to the image quality mode in addition to the type of printer driver.

[0110] (Composition 4) It further includes a correction unit that performs edge correction to adjust the density of edges in the image, The image forming apparatus according to any one of configurations 1 to 3, wherein the control unit changes the set temperature according to the type of printer driver and whether or not the correction unit performs the edge correction.

[0111] (Composition 5) The image forming apparatus according to any one of configurations 1 to 4, wherein the control unit changes the set temperature according to at least one of the following: the type of printer driver, the type of sheet, the sheet transport speed, the external environment, and the operating state of the image forming apparatus.

[0112] (Composition 6) A control method for a fixing device that heat-fixes an image onto a sheet according to a print job, The steps include determining the type of printer driver that generated the print job, A control method comprising the step of changing the set temperature of the fuser device according to the type of printer driver that has been identified.

[0113] (Composition 7) The control method described in configuration 6, wherein the aforementioned modification step is performed when in color printing mode but not when in monochrome printing mode.

[0114] (Composition 8) The control method according to configuration 6 or 7, wherein the step of making the change includes changing the set temperature according to the image quality mode in addition to the type of printer driver.

[0115] (Composition 9) The process further includes a step to perform edge correction, which adjusts the density of edges in the image. The control method according to any one of configurations 6 to 8, wherein the step of making the change includes changing the set temperature depending on whether or not edge correction is performed, in addition to the type of printer driver.

[0116] (Composition 10) The control method according to any one of configurations 6 to 10, wherein the step of making the change includes changing the set temperature in accordance with at least one of the type of printer driver, the type of sheet, the sheet transport speed, the external environment, and the operating state of the image forming apparatus.

[0117] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0118] 10C, 10K, 10M, 10Y, 112 Imaging Unit, 11, 11C, 11K, 11M, 11Y Photoreceptor, 12 Exposure Unit, 13 Developing Sleeve, 51 Image Quality Mode Setting Unit, 52 Color Conversion Unit, 53 Edge Correction Unit, 71 Temperature Control Unit, 72 Setting Temperature Table, 100 Image Forming Apparatus, 110 Print Engine, 114 Intermediate Transfer Belt, 116 Fixing Unit, 116a Heating Roller, 116b Pressure Roller, 118 Paper Feeding Unit, 120 Feed Roller, 122 Transport Roller, 124 Resist Roller, 130 Operation Panel, 150 Main Controller, 152, 172 CPU, 154, 174 RAM, 156, 176 ROM, 160 Network Interface, 170 Engine Controller, 180 Bus, 200, 200A, 200B Client terminals, 300 printer drivers, 400 applications

Claims

1. A fixing device that heat-fixes images onto a sheet according to the print job, An edge correction unit that adjusts the density of edges in the image, An image forming apparatus comprising: a control unit that changes the set temperature of the fixing device according to the type of printer driver that generated the print job, as well as whether or not the edge correction is performed by the correction unit.

2. The image forming apparatus according to claim 1, wherein the control unit changes the set temperature when in color printing mode, and does not change the set temperature when in monochrome printing mode.

3. The image forming apparatus according to claim 1 or 2, wherein the control unit changes the set temperature according to the image quality mode in addition to the type of printer driver.

4. The image forming apparatus according to claim 1 or 2, wherein the control unit changes the set temperature in accordance with at least one of the following: the type of printer driver, the type of sheet, the sheet transport speed, the external environment, and the operating state of the image forming apparatus.

5. A control method for a fixing device that heat-fixes an image onto a sheet according to a print job, The steps include determining the type of printer driver that generated the print job, The steps include: determining whether the edge correction function is enabled or disabled, and performing edge correction to adjust the density of edges in the image depending on whether the edge correction function is enabled; A control method comprising the step of changing the set temperature of the fuser device according to whether or not the edge correction is performed, in addition to the type of printer driver that has been identified.

Images