Image forming apparatus or information processing apparatus

Abstract

To improve the productivity of a sheet width mixed job.SOLUTION: An image formation apparatus comprises: a heating rotor which has a first heating element and a second heating element having the shorter length in the longitudinal direction than the first heating element and heats an unfixed toner image carried by a recording material; a pressure rotor which forms a fixation nip part by compressing the heating rotor, causes the fixation nip part to hold and convey the recording material carrying the unfixed toner and fix the unfixed toner image to the recording material; and a control unit which rearranges the printing order. In a mixed job in which the recording material with the first width and the recording material with the second width having the shorter length in the longitudinal direction than the recording material with the first width exist, when the mixed job is the printing job which is performed first in the one or plurality of printing jobs, the control unit rearranges the printing order so as to perform printing of the recording material with the second width after performing printing of the recording material with the first width.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus that forms a toner image on a recording material. [Background technology]

[0002] The image forming apparatus has a fixing device that fixes the unfixed toner image on the recording material to the recording material.

[0003] The fixing device has a pair of rotors, including a heating rotor that applies heat to unfixed toner and is driven to rotate, and a pressure rotor that applies pressure to the heating rotor to form a fixing nip between the heating rotor and the pressure rotor, which is also driven to rotate. When a recording material with unfixed toner on it is conveyed to the fixing nip, the heat of the heating rotor and the pressure of the pressure rotor are applied to the recording material, and the unfixed toner is fixed to the recording material.

[0004] The heating rotor uses, for example, a film heating system (so-called ODF fixing system) in which the heating element is a ceramic heater. In the ODF fixing system that uses a ceramic heater as a heat source, the following phenomenon occurs.

[0005] When a recording material (small-size paper) with a paper width shorter than the length of the heating element is conveyed in the longitudinal direction of the heating element, the temperature in the heating area of ​​the heating element and the non-paper-passing area of ​​the recording material becomes higher than the paper-passing area. This phenomenon is called non-paper-passing area temperature rise. If the temperature in the non-paper-passing area becomes too high, the support member that supports the ceramic heater will deform and cause a malfunction.

[0006] Furthermore, the temperature of the pressure roller in the non-paper-passing area rises. This causes the area to expand, resulting in a difference in conveyance speed in the longitudinal direction and resulting in paper wrinkles. To prevent this temperature rise in the non-paper-passing area, the temperature of the non-paper-passing area is detected, and if it exceeds a predetermined temperature, control such as widening the gap between sheets is performed to lower the temperature in the non-paper-passing area. This raises the risk of reduced productivity.

[0007] Therefore, in order to suppress this decline in productivity, for example, Patent Document 1 discloses a configuration in which multiple heating elements with different lengths in the longitudinal direction are provided. A switching relay that switches between the multiple heating elements switches between the heating elements to supply power exclusively. This configuration allows for selective use of heating elements with lengths corresponding to the size of the recording material. By selectively using heating elements with lengths corresponding to the size of the recording material, the temperature of non-paper passing areas is increased, suppressing the decline in productivity when printing small-sized paper. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-100558 Summary of the Invention [Problem to be solved by the invention]

[0009] In a fixing device having multiple heating elements, when recording materials of different paper widths are mixed in a single print job (a mixed-paper-width job), it is necessary to switch the heating element used for fixing. Specifically, we will explain a case where a fixing device has a heating element for small-size paper (small heating element) and a heating element for large-size paper (large heating element), and printing is performed in order from small to large size paper. In the longitudinal direction of the heating element, the paper passage area for large-size paper is larger than the heating area of ​​the small heating element. Therefore, to ensure fixation at the edge of large-size paper, the heating element used is switched from the small heating element to the large heating element. A waiting time is required until the large heating element reaches the temperature required for fixing. Therefore, there is a risk of reduced productivity in a mixed-paper-width job.

[0010] SUMMARY OF THE INVENTION It is therefore an object of the present invention to improve productivity in jobs involving mixed paper widths. [Means for solving the problem]

[0011] The image forming apparatus according to the present invention comprises a heating rotor having a first heating element, a second heating element shorter in length than the first heating element in the longitudinal direction of the heating element, and configured to heat an unfixed toner image carried on a recording material, a pressure rotor that forms a fixing nip by applying pressure to the heating rotor, and nip-conveys the recording material carrying the unfixed toner through the fixing nip to fix the unfixed toner image on the recording material, and a control unit that controls the printing order of the recording material. Equipped with A mixed job in which recording materials of a first width and recording materials of a second width that are shorter in the longitudinal direction than the recording materials of the first width are mixed. a mixed job is executed in which printing is performed on the recording material of the second width as the first sheet of the mixed job and printing is performed on the recording material of the first width as the second sheet of the mixed job; In this case, the control unit performs printing on the recording material of the second width after printing on the recording material of the first width, Among the mixed jobs It is characterized by being able to rearrange the printing order. [Effects of the Invention]

[0012] According to the present invention, it is possible to improve productivity in a job involving mixed paper widths. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram according to an embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram of a fixing device and a heater according to the present embodiment. [Figure 4] 10 is a flowchart showing a flow when a print job is executed. [Figure 5] 10 is a flowchart showing a flow of rearrangement control. [Figure 6] This is an example in which the display unit displays a message to prompt the user to select whether or not to perform rearrangement control. [Figure 7] FIG. 2 is a diagram illustrating a printing operation performed by the image forming apparatus. [Figure 8] 10 is a flowchart showing the flow of rearrangement control in the second embodiment. [Figure 9] FIG. 10 is a block diagram according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Example 1 <Image forming device> Fig. 1 is a schematic diagram showing the configuration of an image forming apparatus 100. As shown in Fig. 1, image forming apparatus 100 has four image forming units for yellow, magenta, cyan, and black arranged along the direction of movement of intermediate transfer belt 130. First, the process of forming a toner image on intermediate transfer belt 130 will be described using the yellow image forming unit PY as an example.

[0015] The surface of the photosensitive drum, which is rotated by a charger, is uniformly charged (charging). Then, an exposure device irradiates the photosensitive drum surface with a laser in accordance with input image data, forming an electrostatic latent image on the photosensitive drum surface (exposure). Then, a development device forms a yellow toner image on the photosensitive drum (development). Primary transfer roller 123a applies a voltage of the opposite polarity to the potential polarity of the yellow toner image to intermediate transfer belt 130. This transfers the yellow toner on the photosensitive drum to intermediate transfer belt 130 (primary transfer). Any remaining yellow toner on the photosensitive drum surface is scraped off and removed by a toner cleaner. This series of processes is repeated for magenta PM, cyan PC, and black PK. As a result, a full-color toner image is formed on intermediate transfer belt 130.

[0016] The toner image on the intermediate transfer belt 130 is transported to a secondary transfer section formed by a pair of secondary transfer rollers 140. In synchronization with the transport of the toner image, recording materials (paper sheets) are taken out one by one from a recording material cassette 150 and fed to the secondary transfer section. Then, the toner image on the intermediate transfer belt 130 is transferred to the recording material (secondary transfer).

[0017] The recording material onto which the toner image has been transferred is transported to the fixing device 170, where it is fixed by heat and pressure (fixing). The recording material onto which the toner image has been fixed is discharged onto a paper discharge tray 196.

[0018] Image forming apparatus 100 can also form monochrome images. When forming monochrome images, only the black image forming station PK is driven among the multiple image forming stations.

[0019] This section explains double-sided printing, in which images are formed on both sides of a recording material. After the recording material with an image formed on one side is discharged from the fixing device 170, it is guided to the paper path 230 by the flapper 172. Once the recording material is transported to the paper path 230, it is guided to the reversing rollers 252 and 253. When the reversing sensor 251 detects that the trailing edge of the recording material has been transported to the reversing roller 252, the reversing flapper 250 is driven so that the recording material is transported toward the reversing pickup sensor 254. The recording material is then transported to the paper path 155. At this time, the recording material is in an inverted state. The recording material is then transported again to the secondary transfer section, where the toner image is transferred, and the unfixed toner image is fixed by the fixing device 170. The recording material on which double-sided printing has been performed is then discharged to the discharge tray 196.

[0020] This process, which starts with charging and ends with the recording material on which the toner image is fixed being discharged onto the discharge tray 196, is called image forming processing. The period during which image formation is being performed is called image forming processing.

[0021] <Block diagram> The control unit 300 in FIG. 2 is composed of a CPU 301, a ROM 302, and a RAM 303, which is a storage unit. A print operation start instruction is input to the CPU 301 from a display unit 340 or an external device I / F 330, such as a PC. In response to the operation start instruction, the CPU 301 drives and controls loads 312, including flappers such as the transport flapper 172 connected via an I / O 310, and motors such as a pre-fixing transport motor and a fixing unit transport motor (not shown). The control unit 300 can also detect input signals from sensors 311, including paper detection sensors such as the paper transport sensor 171, via the I / O 310. Furthermore, the control unit 300 can notify the display unit 340 or the external device I / F 330 of various information and display the information on the display unit of the display unit 340 or the external device I / F 330.

[0022] <Fixing device> Next, the fixing control unit 350 will be described with reference to FIG.

[0023] 3A is a cross-sectional view of the fixing device 170, FIG. 3B is a schematic diagram of the heater 54, and FIG. 3C is a schematic circuit diagram of the power control unit.

[0024] 3(a) is composed of a cylindrical fixing film 173, a pressure roller 174 that forms a fixing nip portion N together with the fixing film 173, a heater 54 for heating the paper P, and a fixing temperature sensor 59 that monitors the temperature of the heater 54. An unfixed toner image Tn held on the paper P is transported from right to left on the paper surface in FIG. 3, melted by the heater 54 heated in the fixing nip portion N, and fixed to the paper P.

[0025] The fixing film 173, which is the heating rotor 175, is an endless, rotatable film. The base layer is made of, for example, polyimide, and the outer periphery of the base layer is provided with an elastic layer made of silicone rubber and a release layer made of PFA. In this embodiment, grease is applied to the inner periphery of the fixing film 173 to reduce the frictional force between the fixing film 173 and the heater due to the rotation of the fixing film 173.

[0026] A heater 54 is provided in contact with the inner circumferential surface of the fixing film 173, with both longitudinal ends held therein. A pressure roller 174, which is a pressure rotating body, is provided facing the heater 54. A fixing nip N is formed between the heater 54 and the pressure roller 174 via the fixing film 173. The pressure roller 174 is made of a core metal, an elastic layer, and a release layer, and is rotatably held at both longitudinal ends. It is driven to rotate in the direction of arrow A by a drive motor (not shown). Because the fixing film 173 is sandwiched between the heater 54 and the pressure roller 174, it is rotated in response to the rotation of the pressure roller 174. This causes the fixing film 173 to rotate. A recording material carrying an unfixed toner image is sandwiched and conveyed through the fixing nip N. The pressure required for fixing and heat from the heater 54 are then applied to the recording material, and the toner image is fixed to the recording material.

[0027] <Heater> Here, the heater 54 will be described in detail with reference to FIG.

[0028] The heater 54 has a heater substrate 54a, and a first heating element 54b1 and a second heating element 54b2 for applying heat to the toner. The first heating element 54b1 and the second heating element 54b2 are protected by a protective glass 54e to ensure insulation from the fixing film 173. The heater 54 also has a fixing temperature sensor 59 for detecting the temperature of the heater 54. In this embodiment, a ceramic heater is used as the heating element.

[0029] The first heating element 54b1 and the second heating element 54b2 have different lengths in the longitudinal direction. Specifically, the length of the first heating element 54b1 is L1, and the length of the heating element 54b2 is L2, with the relationship between the lengths of the heating elements in the longitudinal direction being L1 > L2. The length L1 of the heating element 54b1 is set to a length that enables fixing of a recording material having the maximum width of the recording material that the image forming apparatus 100 can print on (hereinafter referred to as the maximum paper passing width).

[0030] The first heating element 54b1 is electrically connected to the first contact 54d1 and the contact 54d3 via the conductor 54c. The second heating element 54b2 is electrically connected to the second contact 54d2 and the contact 54d3 via the conductor 54c. In other words, the contact 54d3 is a contact that is commonly connected to the first heating elements 54b1 and 54b2. The fixing temperature sensor 59 is disposed at the center of the first heating element 54b1 and the second heating element 54b2 in the longitudinal direction, and periodically obtains the temperatures of the first heating element 54b1 and the second heating element 54b2 and notifies the CPU 301 of the temperatures.

[0031] The fixing temperature sensor 59 is located on the opposite side of the substrate 54a from the protective glass layer 54e, and is installed at the center position in the longitudinal direction of the heating elements 54b1 and 54b2, and is in contact with the substrate 54a. The fixing temperature sensor 59 is, for example, a thermistor, and detects the temperature of the heater 54 and outputs the detection result to the CPU 301. The CPU 301 controls the temperature during the fixing process based on the detection result of the fixing temperature sensor 59.

[0032] <Power control of heating elements> Next, the power control unit 353 will be described using (c).

[0033] The power control unit 353 is composed of a triac 351, an AC power supply 55, and a heating element switch 352. The triac 351 and the heating element switch 352 are connected to the heater 54. The triac 351 serves to supply power from the AC power supply 55 to the heater 54, specifically to the contact 54d3. The contact 54d3 is connected to the first heating element 54b1 and the second heating element 54b2, so that power is simultaneously supplied to or cut off from the first heating element 54b1 and the second heating element 54b2. When the triac 351 is turned ON, power from the AC power supply 55 is supplied to the first heating element 54b1 and the second heating element 54b2. When the triac 351 is turned OFF, the power supply from the AC power supply 55 to the first heating element 54b1 and the second heating element 54b2 is cut off.

[0034] The heating element switch 352 has contacts 352a, 352b1, and 352b2. Contact 352b1 is connected to the first heating element 54b1, and when contact 352a and contact 352b1 are connected, the first heating element 54b1 is connected to the AC power supply 55. Contact 352b2 is connected to the second heating element 54b2, and when contact 352a and contact 352c are connected, the second heating element 54b2 is connected to the AC power supply 55. In this manner, power is supplied exclusively to the heating elements 54b1 and 54b2 by the heating element switch 352. It is assumed that 200 ms is required from the time the CPU 301 issues a switching instruction to the heating element switch 352 until the actual completion of switching. Note that in this example, a configuration having multiple heating elements is used. While this embodiment uses two heating elements as shown in FIG. 3, the number is not limited to two, and three or more heating elements may be used.

[0035] <Selecting the Heating Element to be Used Depending on the Length in the Longitudinal Direction of the Recording Material> The length of the second heating element 54b2 in the longitudinal direction is shorter than that of the first heating element 54b1. In this embodiment, when a recording material (hereinafter, small-size paper) that is equal to or shorter than the second heating element 54b2 in the longitudinal direction is conveyed to the fixing nip N, power is supplied to the second heating element 54b2. Fixing is performed by the second heating element 54b2. On the other hand, when a recording material (hereinafter, large-size paper) that is longer than the second heating element 54b2 in the longitudinal direction is conveyed to the fixing nip N, attempting to perform fixing using the second heating element 54b2 may not provide the heat required for fixing to both ends of the recording material. Therefore, when fixing large-size paper, power is supplied to the first heating element 54b1. Since the paper passage area for large-size paper in the longitudinal direction is equal to or shorter than the first heating element 54b1, fixability of the toner image carried on the large-size paper is ensured.

[0036] Also, consider a case where small-sized paper is fixed using the first heating element 54b1. The paper-passing area for small-sized paper is below the first heating element 54b1, ensuring fixability. However, a non-paper-passing area is created within the area where the heating element generates heat, where no recording material passes. The non-paper-passing area has a higher temperature than the paper-passing area because no recording material passes through it and therefore heat is not absorbed. If continuous fixing of recording materials is performed under conditions that create a non-paper-passing area, the temperature of the non-paper-passing area will rise too much (hereinafter referred to as non-paper-passing area temperature rise). This could damage components around the non-paper-passing area, such as the component supporting the heater 54 and the fixing film 173. Therefore, when fixing small-sized paper, the second heating element 54b2 is used to reduce the non-paper-passing area and suppress temperature rise in the non-paper-passing area.

[0037] In this way, the fixing control section 353 performs control to change the type of heat generating element to be used depending on the length in the longitudinal direction of the recording material conveyed to the fixing nip portion N.

[0038] <Issues when printing from small to large size paper> In a fixing device having multiple heat generating elements, if recording materials of different paper widths are mixed in one print job (mixed paper width job), it is necessary to switch the heat generating element used for fixing during the job.

[0039] Specifically, when a job with mixed paper widths is performed in a fixing device having a heating element for large size paper and a heating element for small size paper, it is necessary to switch the heating element used for fixing. The heating element switching can be performed in two patterns: from the heating element for large size paper to the heating element for small size paper, or from the heating element for small size paper to the heating element for large size paper. In this embodiment, the heating element for large size paper is the first heating element 54b1, and the heating element for small size paper is the second heating element 54b2.

[0040] The following describes a case where small-sized paper is transported to the fixing nip in the printing order from large-sized paper to small-sized paper. In the longitudinal direction, the width of small-sized paper, which is the recording material to be fixed by the second heating element 54b2, is equal to or less than the width of the first heating element 54b1. Therefore, the paper passage area for small-sized paper is equal to or less than the width of the first heating element 54b1. In this embodiment, the first heating element 54b1 generates heat when fixing large-sized paper, and the second heating element 54b2 generates heat when fixing small-sized paper. In a mixed-paper-width job, if small-sized paper is transported to the fixing nip after large-sized paper, the rear edge of the large-sized paper passes through the fixing nip, and the heating element is switched (200 ms), and the small-sized paper is transported to the fixing nip. When the small-sized paper is transported to the fixing nip, the heating element is switched, and heating of the first heating element 54b1 is stopped. However, since the first heating element 54b1 is preheated, it is possible to fix the small size paper without waiting for the temperature of the second heating element 54b2 to rise to a temperature required for fixing.

[0041] On the other hand, let us consider a case where sheets are transported to the fixing nip in the printing order from small to large. The width of large-size sheets, which are recording materials to be fixed by the first heating element 54b1, is larger in the longitudinal direction than the width of the second heating element 54b2. In a mixed-size job, if large-size sheets are transported to the fixing nip after small-size sheets, the heating element must be changed from the second heating element 54b2 to the first heating element 54b1 to ensure fixability at the longitudinal edges of the large-size sheets. This requires a waiting time (hereinafter referred to as the "leveling time") until the temperature of the first heating element 54b1 rises to the temperature required for fixing. During this time, the center of the first heating element 54b1 may be hotter than the edges due to the influence of the temperature of the second heating element 54b2. Therefore, during the leveling time, it is necessary to eliminate the temperature difference between the center and edges of the first heating element 54b1 while raising the temperature of the first heating element 54b1 to the temperature required for fixing. Here, eliminating the temperature difference between the center and end of the first heating element 54b1 means that the temperature difference between the center and end becomes equal to or less than a predetermined value. In this embodiment, the equalization time is approximately 20 seconds. Then, after the small-size paper passes through the fixing nip, the heating element is switched (200 ms), and after the equalization time (20 seconds) has elapsed, the large-size paper is transported to the fixing nip. Therefore, in a mixed-paper-width job, if small-size paper is printed first, followed by large-size paper, there is a risk that productivity will decrease due to the equalization time.

[0042] Therefore, the purpose is to suppress the decrease in productivity in jobs with mixed paper widths by reducing the smoothing time, as described in detail below.

[0043] <Sorting control> The sorting control for reducing the smoothing time by changing the print order in the case of a job with mixed paper widths will be described with reference to Figs. 4 and 5. Fig. 4 is a flowchart for executing a job in the first embodiment. Fig. 5 is a flowchart showing the sorting control in the first embodiment. First, the description will be given with reference to Fig. 4.

[0044] S1000 CPU 301, which is a control unit of image forming apparatus 100, determines whether job data has been received from external I / F 330 or display unit 340, which are information processing devices. The job data received here is data input by the user via display unit 340 or external I / F 330. Job data includes information such as the type of recording material, job ID, printing order, recording material size (recording material width), basis weight, paper feed tray, and job content such as single-sided or double-sided printing. CPU 301 stores the received job data in a job table in FIG. 7, which will be described later, by linking it to a paper ID.

[0045] S1001 The job ID of the job to be executed is obtained from the job data table (c-2) and stored in the variable j representing the job ID (hereafter referred to as job ID j). If the job ID variable j has the same value, it indicates that it is the same print job. Then, 1 is stored in the variable p representing the print order (hereafter referred to as print order p). Then, the process proceeds to S1002.

[0046] S1002 CPU 301 determines whether the widths of the recording materials included in the print job to be executed are uniform. Specifically, CPU 301 references the width of the paper IDs for which the job ID variable j in the job data table (c-2) has the same value. If CPU 301 determines that the recording material widths match, the process proceeds to S1005; if it determines that they do not match, the process proceeds to S1003. "Matching" here refers to a case where the same heating element is used when fixing the recording materials included in the print job (this also applies when using a prior art document, as will be described later). On the other hand, it refers to a case where different heating elements are used when fixing the recording materials included in the print job. Note that if the number of sheets of recording material included in the print job is one, CPU 301 determines that the paper widths match.

[0047] S1003 The CPU 301 determines whether the user has given permission to rearrange the print order. A method for instructing permission to rearrange the print order is described below with reference to FIG. 6. FIG. 6 shows a screen that the CPU 301 displays on the display unit 340. The display screen that the CPU 301 displays on the display unit 340 displays information related to the print time of the image forming apparatus 100 and information related to the print order. Specifically, as shown in FIG. 6, a screen is displayed that prompts the user to select whether to select the time priority mode. The CPU 301 may display information indicating that the print time will be reduced if the time priority mode is selected. Alternatively, the CPU 301 may display information indicating that the print speed will be increased. In other words, the information may indicate that the print time per unit number of sheets will be reduced. This makes it easier for the user to recognize the benefits of selecting the time priority mode. Furthermore, by having the CPU 301 display information on the display unit that the print order may be changed, the CPU 301 can prevent the print order from being changed without the user's permission.

[0048] If the time priority mode is not selected, image formation is performed in the order priority mode. The order priority mode refers to a mode in which image formation is performed without changing the print order. Some users place importance on the print order. Therefore, the system is configured so that the user can select the order priority mode.

[0049] In this example, the instruction to allow rearrangement of the print order is received via the display unit 340 of the image forming apparatus 100, but this is not limited to this. For example, the rearrangement instruction may be received by displaying a support screen on a PC screen or a smartphone screen via the external I / F 330, which is a type of information processing apparatus (e.g., PC). Also, while the instruction to allow rearrangement of the print order is requested before a job is executed, the rearrangement permission setting may be saved in RAM 303 so that the setting continues to be used while the power is on. A configuration in which the setting is saved for each user may also be used. If rearrangement of the print order is allowed (in this embodiment, speed priority mode is selected), the process proceeds to S1004; if it is not allowed, the process proceeds to S1005.

[0050] S1004 The printing order is rearranged, as explained below with reference to the flowchart of rearrangement control in FIG.

[0051] S2000 The CPU 301 stores the number of paper IDs having the job ID j in a variable m representing the number of sheets in the job (hereinafter referred to as the job number m), stores 1 in a variable n representing the reservation order (hereinafter referred to as the reservation order n), and saves them in the RAM 303. For example, in the job data table (c-2) in FIG. 7 described later, if the job ID j to be executed is 1, there are three paper IDs (ID1, ID2, ID3) with the job ID 1, and therefore stores 3 in the job number m.

[0052] S2010 CPU 301 acquires the paper width of the paper ID whose job ID in job data table (c-2) matches job ID j and whose reservation order in job data table (c-2) matches reservation order n. CPU 301 determines from the acquired paper width whether the fixing of the recording material to be printed is to be performed by second heating element 54b2. In this embodiment, second heating element 54b2 has a width corresponding to the width of standard B5 size paper, and fixing of recording materials B5 or smaller is performed by second heating element 54b2. Therefore, if CPU 301 determines that the paper width is equal to or smaller than second heating element 54b2, the process proceeds to S2011, and if CPU 301 determines that the paper width exceeds second heating element 54b2, the process proceeds to S2012.

[0053] S2011 The CPU 301 adds "small group" to the group information of the target paper ID in the job data table (c-2). The "group" here refers to information about the width of the recording material in the longitudinal direction of the heating element. Then, the process proceeds to S2013. It should be noted that, as mentioned above, the recording material classified as a small group is fixed using the second heating element 54b2.

[0054] S2012 The CPU 301 adds "large group" to the group information of the target paper ID in the job data table (c-2). Then, the process proceeds to step S2013. Note that, as will be repeated, the recording materials classified into the large group are fixed using the first heating element 54b1.

[0055] S2013 The CPU 301 adds 1 to the reservation order n and proceeds to S2014.

[0056] S2014 The CPU 301 compares the reservation order n with the number of sheets in the job m, and if the reservation order n is equal to or greater than the number of sheets in the job m, it determines that grouping within the print job is complete and proceeds to step S2020. If the reservation order n is less than the number of sheets in the job m, it determines that grouping within the job is incomplete and returns to step S2010.

[0057] S2020 The CPU 301 checks whether the job for which grouping has been completed is the first job. Specifically, when the CPU 301 receives a print job in S1000, it checks whether the job is the first job by determining whether the image forming apparatus 100 is in standby mode. The image forming apparatus 100 enters standby mode when the last sheet of the print job has passed through the fixing nip N and been discharged to the paper output tray, and the CPU 301 has not received any subsequent print jobs. In this embodiment, the heating element is not generating heat in standby mode. If the CPU 301 receives job data in this standby mode, the CPU 301 determines that the print job is the first job. The process then proceeds to S2030. Note that if the image forming apparatus 100 is not in standby mode, i.e., the image forming apparatus 100 is in the middle of image formation processing, and the CPU 301 receives job data, the CPU 301 determines that the print job is a job subsequent to the first print job, i.e., a subsequent print job. The process then proceeds to S2024. The determination as to whether the target print job is the first may be made when the CPU 301 receives the print job in S1000.

[0058] S2024 CPU 301 obtains group information for the last sheet of the previously executed print job from the job data table (c-2). Specifically, it obtains group information for the sheet ID with the highest printing order among the sheet IDs having the previously executed job ID. If the group information for the last sheet of the previously executed print job is a "large group," the process proceeds to S2030. If the group information is a "small group," the process proceeds to S2040.

[0059] S2030 The CPU 301 refers to the job data table (c-3) and, among the paper IDs having the same job ID, sets the printing order of those with group information of "large group" to be earlier than those with group information of "small group." In this way, the CPU 301 rearranges the paper so that the large group is printed before the small group, and proceeds to S2031.

[0060] S2040 The CPU 301 then assigns the printing order of groups with "small" information to be earlier than those with "large" information, rearranging the groups so that small groups are printed before large groups, and proceeds to step S2031.

[0061] S2031 When a group contains multiple recording materials, the CPU 301 rearranges the printing order within the group. Specifically, the rearrangement is performed so that the recording material with the largest longitudinal width within the group is printed last. For example, if the last group is a small group and the small group contains B5 sheets with a paper width of 182 mm and business card sheets with a paper width of 55 mm, the printing order for the business card sheets is adjusted to precede the B5 sheets so that they are printed last. This reduces the non-paper passing area compared to when the business card sheets are printed last. The smaller non-paper passing area can suppress temperature increases in the non-paper passing area. Alternatively, the printing order may be rearranged so that the recording material with the smallest longitudinal width within the group is printed first. Once the rearrangement of the printing order is completed, the process proceeds to S1005.

[0062] S1005 In S1005, the CPU 301 acquires group information for a paper sheet ID whose job ID in the job data table (c-2) matches the execution job ID j and whose print order in the job data table (c-2) matches the print order p. If the group of the target paper sheet ID is a small group, the process proceeds to S1006, and if the group of the target paper sheet ID is a large group, the process proceeds to S1010.

[0063] S1006 The CPU 301 turns on the second heating element 54b2. Specifically, by connecting the contact 352a and the contact 352b2 of the heating element switching device 352, power is supplied to the second heating element 54b2 and power to the first heating element 54b1 is cut off. After completion, the process proceeds to S1007.

[0064] S1007 The process waits for the connection between contacts 352a and 352b2 of the heat element switching device 352 to be completed. This waiting time is the time required for the physical switching to be completed when CPU 301 issues a command to switch between 352a and 352b2 when contacts 352a and 352b1 of the heat element switching device are connected, and requires approximately 200 ms, for example. Note that if the connection between contacts 352a and 352b2 of the heat element switching device 352 has already been completed because the second heat element 54b2 was used in the previous print job or the default setting is the small heat element 54b2, this waiting time is 0 ms. If the heat element switching is completed and CPU 301 determines that the temperature in the small-size paper passage area of ​​the heat element has risen to the temperature required for fusing, the process proceeds to S1020. In this case, the heat element may be either the first heat element 54b1 or the second heat element 54b2. If the first heating element 54b1 was used in the previous job, the residual heat may have reached the fixing temperature even if power to the first heating element 54b1 is cut off for the current job. In this case, fixing can be performed without waiting for the temperature of the second heating element 54b2 to rise.

[0065] S1010 The CPU 301 turns on the first heating element 54b1. Specifically, by connecting the contact 352a and the contact 352b1 of the heating element switching device 352, power is supplied to the first heating element 54b1, and after power to the second heating element 54b2 is cut off, the process proceeds to S1011.

[0066] S1011 The process waits for the completion of connection between the contact 352a and the contact 352b1 of the heating element switcher 352. The time required to complete this heating element switching is the same as the time required for switching to the small heating element 54b2 described above. When the heating element switching is complete, the process proceeds to S1012.

[0067] S1012 The CPU 301 determines whether a temperature difference exists between the end and center of the first heating element 54b1 in the longitudinal direction. This determination may be made by placing temperature sensors at the end and center of the first heating element 54b1 in the longitudinal direction, and determining that a temperature difference exists if the temperature difference is equal to or greater than a predetermined value. If the CPU 301 determines that there is no temperature difference between the end and center of the first heating element 54b1, the process proceeds to S1020.

[0068] S1013 If it is determined that there is a temperature difference between the center and end portions of the first heating element 54b1, the process proceeds to S1013 and waits for the temperature difference to be resolved. This can be done by measuring the time required for the temperature difference to be resolved in advance and waiting for that time to pass, or by actually measuring the temperature difference between the end portions and center portion of the large heating element 54b1 and waiting for the temperature difference to become equal to or less than a predetermined value. In this example, the equalization time requires 20 seconds. If the CPU 301 determines that the temperature difference has been resolved after waiting for the equalization time in S1013 and that the temperature of the first heating element 54b1 has risen to a temperature required for fixing, the process proceeds to S1020.

[0069] S1020 The CPU 301 prints one page and proceeds to S1021.

[0070] S1021 The CPU 301 adds 1 to the printing order p, and proceeds to step S1022.

[0071] S1022 The CPU 301 determines whether the job has ended. Specifically, if the largest value among the print orders of the paper IDs whose job ID matches the execution job ID j in the job data table (c-2) is equal to or larger than the print order p, the CPU 301 determines that the job has not ended and returns to S1004. If the largest value among the print orders of the paper IDs whose job ID matches the execution job ID j is smaller than the print order p, the CPU 301 determines that the job has ended and proceeds to S1023.

[0072] S1023 Before the job is completed, the CPU 301 stores the group information of the width of the recording material on which printing was last performed in the RAM 303. Then, the flow chart returns to S1000. If a subsequent job has been received at this point, the flow proceeds to S1001, where the subsequent job is executed.

[0073] In this embodiment, an example is shown in which printing is performed in the order of large to small groups in a mixed job. However, printing may be performed in the order of small to large groups as long as the temperature rise in the non-sheet-passing area is within an acceptable range. For example, when fixing recording materials classified as small groups of a predetermined number of sheets or less using the first heating element 54b1, the temperature rise in the non-sheet-passing area must be within an acceptable range to prevent damage to the support member that supports the heater. In this embodiment, the predetermined number is set to two sheets, and when consecutively printing recording materials classified as small groups of two sheets or less, fixing is performed using the first heating element 54b1. Therefore, the printing order is not rearranged.

[0074] <Effects on productivity when implementing the present invention> Next, the effect of implementing the present invention will be described using FIG. 7. Here, the description will be made by comparing an example of productivity when the present invention is used with an example of productivity when the present invention is not used. In this example, the description will be made assuming use in a pharmacy. At the pharmacy, two medicine envelopes (B5 size) containing medicines and a medicine information sheet (A4 size) containing information about the medicines are printed as one job for each patient. FIG. 7(a) shows the reservation contents of a job received by the CPU 301 via the external I / F 330 or the display unit 340. FIG. 7(b) shows the print order, waiting time (b-1), and job data table (b-2) when the image forming apparatus performs printing without sorting control. FIG. 7(c) shows the print order, waiting time (c-1), and job data table (c-2) when the image forming apparatus performs printing with sorting control. As mentioned above, when there are two sheets of recording material classified into a small group, fixing may be performed using the first heating element 54b1, but for the sake of explanation, this embodiment shows a case where there are two small-sized recording materials.

[0075] In Figure 7(a), the CPU 301 receives three jobs: Job 1 (Patient 1), Job 2 (Patient 2), and Job 3 (Patient 3). The paper size and reservation order for all three jobs are the same: two B5 size medicine envelopes and one A4 size medicine information sheet, and the reservation order at the time of job reception is B5 number 1, B5 number 2, and A4 number 3. Note that the job data also includes printing order information, but the printing order and reservation order usually match.

[0076] <Without sorting control> First, using Figure 7(b), the printing order and waiting time when the job shown in Figure 7(a) is received without rearrangement control will be described. When CPU 301 receives job data, it saves the received job data in job data table (b-2) in RAM 303. Next, it obtains the paper size (B5) for ID1, which has job ID 1 and reservation order 1, from job data table (b-2). Because the recording material width is equal to or less than the width L2 of the second heating element 54b2, it switches the heating element to the second heating element 54b2 and prints ID1. After printing ID1 is completed, it obtains the paper size (B5) for ID2, which has job ID 1 and reservation order 2, and because the paper width is equal to or less than the width L2 of the second heating element 54b2, it continues to use the second heating element 54b2 and prints. After printing ID2 is complete, CPU 301 retrieves the paper size (A4) of ID3, which has a job ID of 1 and a reservation order within the job of 3, from job data table (b-2). Because the paper width exceeds the width L2 of the second heating element 54b2, CPU 301 switches the heating element to the first heating element 54b1. Before printing the paper for ID3, the previously mentioned heating element switching time (200 ms) is required. Furthermore, the CPU 301 waits for the temperature difference between the center and edges of the first heating element 54b1, which occurs while the second heating element 54b2 is being heated, to be eliminated, and for the first heating element 54b1 to reach the temperature required for fixing to elapse. Because the heating element switching time (200 ms) is very short compared to the elapsed ...

[0077] Next, job 2 is executed. First, the paper size (B5) of ID4, which has a job ID of 2 and a reservation order of 1, is obtained from the job data table (c-2). Since the paper width is less than the width L2 of the second heating element 54b2, the heating element is switched to the second heating element 54b2, and after the switching time has elapsed, ID4 is printed. Subsequent IDs 5 to 9 are processed in the same way as IDs 2 to 4 described above.

[0078] <With sorting control> Next, the printing order and productivity when rearrangement control is performed will be described with reference to FIG.

[0079] When the CPU 301 receives the job data, it saves the job data in the job data table (c-2) of the RAM 303. Next, it groups the job data of job 1 and adds the results to the job data table (c-2) as group information. The grouping is as follows: if the paper width is equal to or less than the width L2 of the second heating element 54b2, it is classified as "small"; if the paper width exceeds the width L2 of the second heating element 54b2, it is classified as "large." In this example, the B5-sized paper of ID1 and ID2 is classified as "small," and the A4-sized paper of ID3 is classified as "large." Next, the CPU 301 changes the print order information in the job data table (c-2). First, because job 1 is the top job, the print order within job 1 is rearranged so that the "small" paper is printed after the "large" paper. For job 1, the print order for ID3 is set to 1, the print order for ID1 to 2, and the print order for ID2 to 3, and these are saved in the job data table (c-2).

[0080] Once the grouping and printing order of job ID1 are complete, CPU 301 performs printing according to the printing order in job data table (c-2). In this example, ID3 is in printing order 1, so the first heating element 54b1 is used to print ID3, and once printing of ID3 is complete, the second heating element 54b2 is used to print jobs in printing order 2 to 3 (ID1, ID2).

[0081] Once job 1 is complete, job 2 is rearranged. First, as with job 1, each sheet is classified as "large" or "small." In job 2, ID4 and ID5 are assigned "small," and ID6 is assigned "large." Next, the print order information in the job data table (c-2) is changed. Because job 2 is a subsequent job, the method for rearranging the groups is determined based on the group information of the last sheet of the immediately preceding job. In job 2, because the last sheet (ID2) of the immediately preceding job, job 1, is "small," the print order is rearranged so that the "large" group is printed after the "small." The CPU 301 saves ID4 as 4, ID5 as 5, and ID6 as 6 in the job data table (c-2). Once the rearrangement of job 2 is complete, the CPU 301 performs printing according to the print order in the job data table (c-2). First, ID4, whose print order is 1, is printed. At this time, because ID2, the last sheet of the previous job, has been fixed by the second heating element 54b2, printing is carried out without switching heating elements. Once printing of ID4 is complete, ID5, which has the printing order of 2, is printed next. Because ID5 is fixed by the second heating element 54b2 like ID4, printing is carried out without switching heating elements. Once printing of ID5 is complete, printing of ID6, which has the printing order of 3, is carried out. Because ID6 needs to be switched to the first heating element 54b1, printing is carried out after waiting for the heating element switching time (200 ms) and the equalization time (20 s) to elapse.

[0082] Once job 2 is complete, job 3 is rearranged. As with jobs 1 and 2, the groups are classified into "large" or "small" for each sheet of paper. In job 3, ID7 and ID8 are "small," and ID9 is "large." Next, print order information is added to the job data table (c-2). Like job 2, job 3 is a subsequent job. However, because the final sheet of job 2 (ID6) is "large," the print order for job 3 is rearranged so that the "small" group is printed after the "large" group. As described for jobs 2 and 3, for subsequent jobs, rearranging the print order to prioritize printing the same group as the final sheet of the immediately preceding job reduces the waiting time (200 ms) associated with switching the heating elements. The print order is now ID7: 2, ID8: 3, and ID9: 1, and the CPU 301 saves this in the job data table (c-2). Once rearrangement for job 3 is complete, the CPU 301 prints according to the print order in the job data table (c-2). First, ID9, which has a printing order of 1, is printed. At this time, the final sheet of ID6 in the previous job has been printed using the first heating element 54b1, so printing is carried out without switching heating elements. Once printing of ID9 is complete, ID7, which has a printing order of 2, is printed next. Since ID7 uses the second heating element 54b2, the heating element is switched and printing begins after the heating element switching time (200 ms) has elapsed. Once printing of ID7 is complete, ID8, which has a printing order of 3, is printed. Since ID8 uses the second heating element 54b2, no heating element switching time occurs.

[0083] As described above, in the case of FIG. 7(b) without rearrangement control, the average time (20 s) occurs three times in total, and the heating element switching time (200 ms) occurs twice, resulting in a waiting time of 60,600 ms in total.

[0084] On the other hand, in the case of (c) with rearrangement control, there is one equalization time (20 s) and two heating element switching times (200 ms), resulting in a total waiting time of 20,200 ms.

[0085] The operation of the embodiment described above can improve productivity even for jobs that involve a mixture of multiple paper widths. Furthermore, when multiple jobs are executed, changing the sorting method for each job can shorten the time it takes to complete all jobs and improve productivity.

[0086] <Effect of printing from a large group for the first job> If the job being executed is a mixed paper width job and is the first job, the printing of the recording materials classified as the large group is performed first, followed by the printing of the recording materials classified as the small group. This eliminates the need for the leveling time required when switching the heating element used from the second heating element 54b2 to the first heating element 54b1. Therefore, by printing from the large group, the decrease in productivity due to the leveling time is suppressed. As a result, productivity is improved when the job is a mixed paper width job and is the first job.

[0087] <When subsequent jobs are received, they are sorted to fit the final paper width group> The following explanation assumes that the job being executed is a mixed paper width job and a subsequent job. In the job being executed this time, printing is first performed on the same group of recording materials as the final group of sheets of the previous job, and then printing is performed on a group of sheets different from the final group of sheets of the previous job.

[0088] When transitioning from the previous job to the job to be executed this time, the heating element is not switched. Therefore, the "heating element switching time" or "smoothing time" that occurred between the previous job and the job to be executed this time is suppressed. As a result, productivity is improved when the job is a subsequent job with mixed paper widths.

[0089] <The effect of displaying a screen that allows the user to select whether or not sorting control is performed> When using the present invention, there are cases where the user benefits from improved printing speed and productivity. However, there are cases where the print order is changed. Some users may not want the print order to be changed. For this reason, as shown in Figure 6, a screen is displayed on the display unit that allows the user to select whether to prioritize productivity even if the print order is changed, or to prioritize the print order even if productivity is reduced. As a result, the user can select the print mode according to the specifications that are most important to them.

[0090] <Example 2> 2, an example was shown in which the image forming apparatus 100 has an external I / F 330 and a CPU 301 that is a control unit that performs rearrangement control. In the second embodiment, a case will be described in which an external I / F that is an information processing device such as a PC has a processing unit 370, and the processing unit processes information on the print order. Note that explanations of parts that overlap with the first embodiment will be omitted.

[0091] Explained using Figure 4 S3000 The processing unit 301 included in the information processing apparatus determines whether job data has been received. Alternatively, the user creates job data to be executed by the image forming apparatus 100, and the created job data is acquired by the processing unit.

[0092] In S3001 to S3004, the processing unit 370 included in the external I / F performs the operations that were performed by the CPU 301 in S1001 to S1004 in the first embodiment. Therefore, the CPU 301 described in S1001 to S1004 in the embodiment is simply replaced by the processing unit 370, and therefore a description thereof will be omitted.

[0093] S3005 The processing unit 370 transmits the print job after the rearrangement of the printing order to the CPU 301 of the image forming apparatus 100. The image forming apparatus 100 that has received the print job performs printing from S1000 according to the flowchart shown in Fig. 4. Note that the control performed in S1001 to S1004 overlaps with that already performed in the information processing apparatus, and therefore may be omitted in the second embodiment only. [Explanation of symbols]

[0094] 54 Heater 54b1 First heating element 54b2 Second heating element 100 Image forming device 170 Fixing device 173 Fixing film 174 Pressurized Rotating Body 175 Heating Rotor 301 CPU 303 RAM (storage unit) 330 External I / F 340 Display section 370 Processing Section N Fixing nip P Recording material (paper)

Claims

1. a heating rotor having a first heating element and a second heating element shorter in length than the first heating element in the longitudinal direction of the heating element, for heating an unfixed toner image carried on a recording material; a pressure rotating body that applies pressure to the heating rotating body to form a fixing nip portion, and that nip-conveys a recording material carrying unfixed toner into the fixing nip portion, thereby fixing the unfixed toner image onto the recording material; a control unit that controls the printing order of the recording material, When the received job is a mixed job in which a first width recording material and a second width recording material that is shorter in the longitudinal direction than the first width recording material are mixed, and printing is to be performed on the second width recording material as the first sheet of the mixed job, and printing is to be performed on the first width recording material as the second sheet of the mixed job, The control unit rearranges the printing order within the mixed job so that printing of the recording material of the first width is performed after printing of the recording material of the second width before executing the printing process of the received mixed job.

2. The image forming apparatus according to claim 1, characterized in that when a recording material of the first width is transported to the fixing nip portion, fixing is performed by heating the first heating element, and when a recording material of the second width is transported to the fixing nip portion, fixing is performed by heating the second heating element.

3. In the longitudinal direction, the width of the first width recording material is equal to or less than the width of the first heat generating element, 3. An image forming apparatus according to claim 1, wherein the width of the second recording material is equal to or less than the width of the second heat generating element.

4. An image forming apparatus as described in any one of claims 1 to 3, characterized in that when the mixed job is the first print job among one or more print jobs, the control unit is capable of rearranging the printing order so that printing of the recording material of the first width is performed after printing of the recording material of the second width.

5. a storage unit that stores the width of the recording material printed last in the longitudinal direction of the print job; The image forming apparatus of claim 4, characterized in that when the current print job is a print job subsequent to the first job and the width of the recording material printed last in the previous print job is included in the recording material in the current job, the control unit is capable of rearranging the printing order of the current print job so that the width of the recording material printed first in the current job is the same as the width of the recording material printed last in the previous job.

6. In the mixed job, image formation can be performed in a sequence priority mode or a time priority mode, 6. The image forming apparatus according to claim 1, wherein in the order priority mode, image formation is performed without rearranging the print order, and in the time priority mode, image formation is performed with the print order rearranged.

7. 7. The image forming apparatus according to claim 1, wherein, in the mixed job, when a predetermined number of sheets or less of the second width recording material are printed continuously, the printing order is not rearranged.

8. An information processing device that transmits information to an image forming device that includes a heating rotor that includes a first heating element and a second heating element that is shorter in length in a longitudinal direction than the first heating element and that heats an unfixed toner image carried on a recording material, and a pressure rotor that forms a fixing nip by pressing the heating rotor and nip-conveys the recording material carrying the unfixed toner through the fixing nip to fix the unfixed toner image on the recording material, a processing unit that processes information about the printing order of the recording materials; When the received job is a mixed job in which a first width recording material and a second width recording material that is shorter in length in the longitudinal direction than the first width recording material are mixed, and when printing is to be performed on the second width recording material as the first sheet of the mixed job and on the first width recording material as the second sheet of the mixed job, The information processing device is characterized in that the processing unit rearranges the printing order within the mixed job so that printing of the recording material of the first width is performed after printing of the recording material of the second width before executing the printing process of the received mixed job.

9. a heating rotor having a first heating element and a second heating element shorter in length in the longitudinal direction than the first heating element, for heating an unfixed toner image carried on a recording material; a pressure rotating body that applies pressure to the heating rotating body to form a fixing nip portion, and that nip-conveys a recording material carrying unfixed toner into the fixing nip portion, thereby fixing the unfixed toner image onto the recording material; a control unit that controls the printing order of the recording material, In a mixed job in which a recording material of a first width and a recording material of a second width that is shorter in the longitudinal direction than the recording material of the first width are mixed, and printing is performed on the recording material of the second width as the first sheet of the mixed job, and printing is performed on the recording material of the first width as the second sheet of the mixed job, and a display unit that displays a screen on which a time priority mode can be selected, which allows prioritizing printing time by rearranging the printing order of recording materials.

10. When the time priority mode is selected, 10. The image forming apparatus according to claim 9, wherein the control unit is capable of rearranging the printing order so that printing on the recording material of the second width is performed after printing on the recording material of the first width.

11. An information processing device that transmits information to an image forming device that includes a heating rotor that includes a first heating element and a second heating element that is shorter in length in a longitudinal direction than the first heating element and that heats an unfixed toner image carried on a recording material, and a pressure rotor that forms a fixing nip by pressing the heating rotor and nip-conveys the recording material carrying the unfixed toner through the fixing nip to fix the unfixed toner image on the recording material, a processing unit that processes information about the printing order of the recording materials; In a mixed job in which a recording material of a first width and a recording material of a second width that is shorter in the longitudinal direction than the recording material of the first width are mixed, and printing is performed on the recording material of the second width as the first sheet of the mixed job, and printing is performed on the recording material of the first width as the second sheet of the mixed job, and a display unit that displays a screen on which a user can select a time priority mode that allows the user to prioritize printing time by rearranging the printing order of recording materials.

Images