JP4529536B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a technique for efficiently performing a fixing process in an image forming apparatus.

  In an electrophotographic image forming apparatus such as a printer or a copying machine, it is necessary to fix a toner image (unfixed image) transferred to a sheet to the sheet. As such a fixing device, for example, a thermal fixing device including a fixing roller heated by a heat source (heater) and a pressure roller pressed against the fixing roller is widely used. When this heat fixing device performs the fixing process, the surface temperature of the fixing roller is maintained at a constant temperature by controlling the heat generation amount per unit time of the heat source, and the sheet is sandwiched between the fixing roller and the pressure roller, Heat the toner image on the paper. At this time, if the heating amount for the toner image is larger than an appropriate value, the toner particles are melted by heat, so that spot-off (missing) easily occurs or the paper is wrinkled. On the other hand, when the heating amount is smaller than the appropriate value, the toner particles are not sufficiently softened, and fixing failure is likely to occur.

  The appropriate value of the heating amount varies depending on the type of paper. The types of paper referred to here include weight per unit area (basis weight) of paper, distinction between paper and OHP film, distinction between coated paper and uncoated paper, and the like. For example, a thin (light) paper is likely to be warmed, so that the heating amount at the time of fixing is small. However, a thick (heavy) paper is difficult to warm, so a larger heating amount is required. In view of such a point, Patent Document 1 proposes a technique for adjusting the heating amount by the fixing device in accordance with whether the paper is thick paper or thin paper.

  Recently, an image forming apparatus capable of executing a series of image forming jobs while using different types of paper has been put into practical use. According to this type of image forming apparatus, for example, thick paper can be used for the front cover and the back cover, and thin paper can be used for the main body portion sandwiched between the covers. It is also possible to scan a plurality of document groups at once with a scanner, copy the first scanned document group with thin paper, and then scan the scanned document group with thick paper. Similarly to this, it is possible to easily realize printing by changing the paper type for each of a plurality of image data supplied from a client device such as a personal computer.

  Thus, in order to use a plurality of types of paper properly, it is necessary to adjust the surface temperature of the fixing device according to the paper. Therefore, immediately after the paper type is changed, the image forming job must be interrupted until the surface temperature of the fixing device reaches a predetermined temperature, and it takes a very long time to complete the job. There is a problem. Of course, if the quality of the image formed on the paper is important, the job will take a considerable amount of time, but depending on the user, the processing speed and productivity may be more important than the image quality. It can be enough. However, the conventional technology cannot flexibly meet such user demands.

JP 2001-154533 A

  The present invention has been made in view of such a background, and an object of the present invention is to provide a mechanism that can flexibly cope with both cases where importance is attached to image quality and cases where importance is attached to the speed of image forming processing. It is in.

In order to solve the above-mentioned problems, the present invention provides an image forming means for forming an image on an image carrier and transferring the image onto a transfer material, and heating the image transferred onto the transfer material to the transfer material. Fixing means for fixing, switching means for switching between the first operation mode and the second operation mode, storage means for storing an appropriate range of the heating amount determined for each type of transfer material, and the first operation In the mode, when the image forming unit transfers an image to a plurality of types of transfer materials, the heating amount determined for each type of the transfer material stored in the storage unit according to the type of the transfer material A first heat quantity control unit that instructs the fixing unit to heat the image within a suitable range of the image, and the image forming unit transfers the image to a plurality of types of transfer materials in the second operation mode. to, among stored in said storage means Based on the instruction on the fixing means such that the image by the image forming means heats the image in a specific amount of heating of the proper range overlap each other portion of the heating amount to the plurality of types of transfer materials to be transferred And an image forming apparatus including a second heat quantity control unit.
The present invention also includes an image forming unit that forms an image on an image carrier and transfers the image to a transfer material, and a fixing unit that heats and fixes the image transferred to the transfer material to the transfer material; Switching means for switching between the first operation mode and the second operation mode, a target value of the heating amount determined for each type of transfer material, and range information indicating an appropriate range based on the target value are stored. In the storage unit and in the first operation mode, when the image forming unit transfers an image to a plurality of types of transfer materials, the transfer material stored in the storage unit according to the type of the transfer material A first heat amount control unit that instructs the fixing unit to heat the image with a heating amount of a target value determined for each type, and in the second operation mode, the image forming unit includes a plurality of types. When transferring an image to a transfer material, Based on the contents stored in the storage means, the image is heated with a specific heating amount in a portion where the appropriate ranges of the heating amounts for the plurality of types of transfer materials onto which the image is transferred by the image forming means overlap. Thus, an image forming apparatus is provided that includes a second heat quantity control unit that instructs the fixing unit.

  In another preferred embodiment, the apparatus further comprises a designation unit for a user to designate one of the first operation mode and the second operation mode, and the switching unit includes: Switch to the specified operation mode. In this way, the user can switch the operation mode depending on whether, for example, the image quality is important or the processing speed and productivity are important.

  In another preferred embodiment, the reversing conveyance path for reversing the front surface and the back surface of the transfer material, and in the second operation mode, the transfer material having the front surface as a transfer surface, and the reversing conveyance path are provided. A transfer control unit configured to alternately transfer a transfer material having a back surface as a transfer surface to the image forming unit. In this way, in the second operation mode, the time required to transport the transfer material to the image forming unit is shortened, and the processing speed or productivity per unit time can be further improved. Become.

  The conveyance control unit alternately conveys a transfer material having a transfer surface as a transfer surface and a transfer material of a different type from the transfer material and having a back surface as a transfer surface to the image forming unit. May be. In this way, regardless of the type of transfer material, the time required to transport these transfer materials to the image forming means can be shortened.

  Further, the conveyance control unit alternately forms the transfer material used in a certain image forming job with the transfer surface as a transfer surface and the transfer material used as a transfer image with the back surface as a transfer surface in another image forming job. You may make it convey to a means. In this way, even when shifting from one image forming job to another, it is possible to reduce the time required to transport the transfer material used for these jobs to the image forming means.

An embodiment of the present invention will be described.
FIG. 1 is a diagram illustrating a configuration example of an image forming system 100 according to the embodiment. As shown in FIG. 1, in this image forming system 100, a plurality of client terminals 1a and 1b such as personal computers are connected via a network 2 and a print server 10 (hereinafter referred to simply as DFE 10). It is connected to an image forming apparatus (Image Output Terminal: hereinafter simply referred to as IOT) 3. Further, the IOT 3 includes a paper feeding device (High Capacity Feeder: hereinafter simply referred to as HCF) 4, a paper discharging device (High Capacity Stacker: hereinafter simply referred to as HCS) 5, and a paper discharging device (High Capacity Staple). Stacker (hereinafter simply referred to as HCSS) 6 is connected in cascade. Although not shown in FIG. 1, an image input device (Image Input Terminal: hereinafter simply referred to as IIT) such as a scanner may be connected to the IOT 3.

  The DFE 10 is a server machine provided in front of the device group (IOT3, HCF4, HCS5, HCSS6) surrounded by a dotted line a. For example, the DFE 10 decomposes image data received from the client terminals 1a and 1b via the network 2. And a function for validating data relating to an image forming job. The IOT 3 is, for example, an electrophotographic printer or copier, and forms an image on a sheet based on image data received from the client terminals 1a and 1b via the network 2, or based on image data read by the IIT. To form an image on the paper. The HCF 4 stores a large number of sheets and supplies them one by one to the IOT 3. The HCF 4 is connected to the upstream side in the sheet transport direction as viewed from the IOT 3. The HCS 5 is connected to the downstream side of the IOT 3 and accumulates a large amount of sheets on which images are formed by the IOT 3. The HCSS 6 is also connected to the downstream side of the IOT 3 and accumulates after performing a stapling process or the like on a sheet on which an image is formed by the IOT 3.

  Next, FIG. 2 is a diagram showing an external configuration of a device group (IOT3, HCF4, HCS5, HCSS6) surrounded by a dotted line a in FIG. As illustrated in FIG. 2, the IOT 3 includes a user interface unit 30 configured as a touch panel for a user to perform various operations and settings. Similarly, HCF4, HCS5, and HCSS6 also include user interface units 40, 50, and 60 configured as touch panels. The HCS 5 includes a paper discharge tray 501 (hereinafter referred to as a “top tray 501”) provided at the top of the housing, a large capacity paper discharge tray 502 (hereinafter referred to as a “stack tray 502”) housed inside the housing, and the like. And a bypass discharge path (not shown) for discharging the paper as it is to the outside of the housing (here, HCSS 6). The HCSS 6 includes a paper discharge tray 601 (hereinafter referred to as a “top tray 601”) provided at the upper part of the housing, a paper discharge tray 602 (hereinafter referred to as a “stack tray 602”) provided on the side of the housing, and these paper discharges. A mechanism (not shown) for discharging the paper to the tray is provided, and a stapler device (not shown) for holding the paper with staples.

Next, FIG. 3 is a diagram showing an internal configuration of the device group (IOT3, HCF4, HCS5, HCSS6) shown in FIG. The HCF 4 includes large capacity paper feed trays 401 and 402. The IOT 3 itself also includes large capacity paper feed trays 301 and 302. These paper feed trays 301, 302, 401, and 402 contain different types of paper (weight per unit area). A two-dot chain line S in FIG. 3 indicates a sheet conveyance path, and the sheet is conveyed along the conveyance path S from the left side (upstream side) to the right side (downstream side).
Here, FIG. 4 is an enlarged view of the internal configuration of the IOT 3 shown in FIG. The IOT 3 includes image forming engines 310Y, 310M, 310C, and 310K that respectively form yellow (Y), magenta (M), cyan (C), and black (K) toner images, and a plurality of rolls. To the intermediate transfer belt 320 that is wound around and rotated counterclockwise, a primary transfer roll 321 for primary transfer of toner images from the image forming engines 310Y, 310M, 310C, and 310K, and the intermediate transfer belt 320 A secondary transfer roll 322 for secondary transfer of the primary transferred toner image onto the paper and a fixing device 330 for fixing the toner image transferred onto the paper by heating and pressurizing are provided.

  Each of the image forming engines 310Y, 310M, 310C, and 310K corresponds to each of Y, M, C, and K colors on the photosensitive drum that is an image carrier, a charging device that charges the photosensitive drum, and the charged photosensitive drum. An exposure device that irradiates light modulated based on the image signal thus formed to form an electrostatic latent image on the drum surface, and supplies toners of colors Y, M, C, and K to the electrostatic latent image. The image forming apparatus includes a developing device that forms an image and a cleaning device that cleans toner remaining on the photosensitive drum K after primary transfer of the toner image. Toner units 311Y, 311M, 311C, and 311K are connected to the developing device via pipes with built-in augers, and an appropriate amount of toner is supplied from the toner boxes 311Y, 311M, 311C, and 311K to the developing device. It has become so.

  The toner image primarily transferred to the intermediate transfer belt 320 is subjected to the action of an electric field formed by the secondary transfer roll 322 and its opposing roll, and is sent out from any of the paper feed trays 301, 302, 401, 402. Secondary transferred onto incoming paper. The sheet on which the toner image is transferred is sent to the fixing device 330 by the conveyor belts 341, 342, and 343. The fixing device 330 includes a fixing roller heated by a heat source (heater), and a pressure roller pressed against the fixing roller. The fixing roller 330 and the pressure roller sandwich and convey the sheet to apply pressure. However, the toner image on the paper is heated with an appropriate amount of heat. The sheet subjected to such a fixing process is discharged to one of the discharge trays 501, 502, 601, and 602 of HCS5 and HCS6.

  Further, when images are formed on both the front and back sides of the paper, the paper whose surface is fixed is transported to the reverse transport path Sb, where it is switched back and the front and back surfaces are reversed. Then, it is conveyed clockwise along the conveyance path Sd. Then, at the secondary transfer position (a nip region formed by the secondary transfer roll and the opposing roll), the image is transferred to the back surface, and a fixing process is performed by the fixing device 330. The paper on which images are formed on both sides in this manner is discharged to one of the paper discharge trays 501, 502, 601, and 602 of HCS5 and HSS6.

  Next, FIG. 5 is a diagram showing a functional configuration of the IOT 3, HCF 4, HCS 5, and HCSS 6 shown in FIG. As shown in FIG. 5, the IOT 3, HCF 4, HCS 5, HCSS 6 includes communication units 31, 41, 51, 61 that communicate with other devices in addition to the user interface units 30, 40, 50, 60 described above, And control units 32, 42, 52, 62 constituted by a microprocessor and various memories. The control units 42, 52, and 62 control the respective units of HCF4, HCS5, and HCSS6, but the control unit 32 comprehensively controls the operations of HCF4, HCS5, and HCSS6 in addition to the respective units of IOT3. ing. Further, the IOT 3 forms an image on the image carrier and transfers the image to a sheet, an image forming unit 33, a fixing unit 34 for fixing the image transferred on the sheet to the sheet, and a sheet A paper feeding / conveying section 35 for paper / conveying is provided. The memory of the control unit 32 has a procedure for feeding and transporting as described later using the paper feeding and transporting unit 35 and a procedure for controlling the fixing temperature in the fixing unit 34 as described later. The described computer program is stored. The HCF 4 includes a paper feed unit 43 for sequentially feeding the accumulated paper. The HCS 5 includes a post-processing unit 53 that discharges the paper supplied from the IOT 3 to the paper discharge trays 501 and 502 or bypasses and supplies the paper to another apparatus. The HCSS 6 includes a post-processing unit 63 that performs a stapling process or the like on a sheet on which an image is formed, and then discharges the sheet to the discharge trays 601 and 602.

  The IOT 3 has two operation modes. One is a mode in which when the image forming unit 33 performs an image forming job using a plurality of types of recording paper, the fixing temperature in the fixing device 330 is changed for each paper type. This is called “single paper type productivity priority mode”. In the single paper type priority mode, when the paper type changes, the image forming job is suspended until the surface temperature of the fixing device 330 reaches a fixing temperature suitable for another type of paper. The other operation mode is a mode in which the fixing temperature is fixed and operated even when the image forming unit 33 performs an image forming job using a plurality of types of recording paper. This is called “mixed paper type productivity priority mode”. In this mixed paper type productivity priority mode, it is not necessary to change the fixing temperature, so that the overall processing speed can be improved. However, fixing is not always performed at the most suitable fixing temperature for each type of paper. There is a possibility that the image quality is slightly deteriorated as compared with the single paper type productivity priority mode. Since two operation modes are prepared in this way, if the user places importance on the quality of the image formed on the paper, the IOT 3 may be operated in the single paper type productivity priority mode. If the user places more importance on the processing speed and productivity per unit time than the image quality, the IOT 3 may be operated in the mixed paper type productivity priority mode.

  In the mixed paper type productivity priority mode, there are two methods for determining the heating amount commonly used for a plurality of types of paper. First, the first method (hereinafter, method a) has a certain limit on the types of paper that can be used by the IOT 3. Therefore, a fixing temperature common to all or most of the types of paper that can be used by the IOT 3 is set. In this method, only one is specified in advance, and the fixing process is performed at this fixing temperature. Next, the second method (hereinafter, method b) has a certain allowable range of fixing temperatures suitable for the type of paper, so depending on the type of paper used for the image forming process, A common fixing temperature is specified each time, and fixing processing is performed at the specified fixing temperature. The user or customer engineer can refer to the setting screen displayed on the user interface unit 30 and specify which operation mode to select on the screen.

  Here, FIG. 6 is a diagram showing the relationship between the weight per unit area (basis weight) of the sheet, the optimum fixing temperature for the sheet, and the appropriate range of the allowable fixing temperature. Note that “gsm” which is a unit of weight means the number of grams per square meter. In FIG. 6, when fixing an image on a sheet having a weight per unit area of, for example, “60 to 80 (gsm)”, the fixing temperature is about 148 (° C.) to 172 (° C.). Fixing processing is possible, and it is shown that the optimum fixing temperature in these ranges is 160 (° C.). Accordingly, in the single paper type productivity priority mode, when an image is fixed on a sheet having a weight per unit area of “60 to 80 (gsm)”, the fixing temperature 160 (° C.) is a target value. That is, the control unit 32 of the IOT 3 may instruct the heat source of the fixing device 330 to heat at the fixing temperature 160 (° C.).

  On the other hand, when the method a described above is employed in the mixed paper type productivity priority mode, assuming that the weight of all sheets that can be used by the IOT 3 falls within the range of 60 to 300 (gsm), this FIG. According to the contents, the fixing temperature common to the sheets belonging to this range is a temperature (approximately 168 ° C.) indicated by a dotted line in FIG. Therefore, the control unit 32 of the IOT 3 stores 168 (° C.) in advance as the fixing temperature in the mixed paper type productivity priority mode, and always sets the fixing temperature in the mixed paper type productivity priority mode to 168 (° C.). The heat source of the fixing device 330 may be indicated as follows.

  When the method b described above is employed in the mixed paper type productivity priority mode, the fixing temperature is determined as follows. The control unit 32 of the IOT 3 stores information related to the fixing temperature as shown in FIG. 6 in a table format in advance. When the image forming unit 33 of the IOT 3 performs image forming processing using, for example, 70 (gsm) and 130 (gsm) sheets, the fixing temperature ranges suitable for these sheets are “148 to 172 (° C.), respectively. ) ”And“ 155 to 178 (° C.) ”, the fixing temperature common to these sheets is 155 to 172 (° C.). Accordingly, the control unit 32 calculates an intermediate value (= 163.5 ° C.) of 155 to 172 (° C.), and the fixing temperature in the mixed paper type productivity priority mode becomes 163.5 (° C.). Thus, the heat source of the fixing device 330 may be indicated.

  Furthermore, in order to advance the process quickly and efficiently in the mixed paper type productivity priority mode, when forming images on both sides of the paper (when performing so-called double-sided printing), the paper with the front side as the transfer side and the back side The sheet as the transfer surface is alternately conveyed to the secondary transfer position. Here, with reference to FIG. 7 to FIG. 16, how the paper is conveyed in the mixed paper type productivity priority mode will be described. 7 to 16 assume a case where two image forming jobs are continuously performed. The first image forming job is a job for five sheets of paper for one front cover, one back cover and three main bodies, and the next image forming job is for four sheets of paper for one front cover and three main bodies. Job. In any image forming job, 150 (gsm) paper (thick paper) stored in the paper feed tray 301 is used as the paper for the front cover and the back cover, and the paper for the main body portion is supplied. Assume that 70 (gsm) paper (thin paper) stored in the paper tray 302 is used.

  First, the control unit 32 determines the fixing temperature according to the content of the first image forming job instructed by the user. Here, since image forming processing is performed using 70 (gsm) and 130 (gsm) sheets, the fixing temperature of the fixing device 330 is set to 163.5 (° C.) according to the method b described above. When the fixing temperature of the fixing device 330 reaches 163.5 (° C.), the control unit 32 starts an image forming process. FIG. 7 shows a state in which an image is transferred from the intermediate transfer belt 320 to the first sheet P1 of the first image forming job at the secondary transfer position. The paper P1 is a paper (thick paper) supplied from the paper feed tray 301.

  Next, FIG. 8 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 8, the paper P <b> 1 is subjected to fixing processing by the fixing device 330, and the paper P <b> 2 is about to be sent out from the paper feed tray 302 to the transport path S. Next, FIG. 9 shows a state when 1 second has elapsed from the state of FIG. As can be seen from FIG. 9, the sheet P1 is switched back in the reverse conveyance path Sb and is conveyed in the left direction in the drawing with its transfer surface facing downward in the drawing, and at the secondary transfer position. The image is transferred from the intermediate transfer belt 320 to the paper P2.

  Next, FIG. 10 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 10, the sheet P <b> 1 is conveyed leftward in the drawing, and the sheet P <b> 2 is subjected to fixing processing by the fixing device 330, and the third sheet P <b> 3 is removed from the sheet feed tray 302. It is about to be sent out to the conveyance path S. Next, FIG. 11 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 11, the sheet P1 is conveyed in the upward direction in the drawing, and the sheet P2 is switched back by the reverse conveying path Sb, and the transfer surface is directed downward in the drawing. The image is transferred leftward, and an image is transferred from the intermediate transfer belt 320 to the paper P3 at the secondary transfer position.

  Next, FIG. 12 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 12, the image is transferred from the intermediate transfer belt 320 to the back surface of the paper P1 at the secondary transfer position, and the paper P2 is conveyed in the left direction in the figure. The fixing process is performed by 330, and the fourth sheet P4 is about to be sent out from the sheet feed tray 302 to the transport path S. Next, FIG. 13 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 13, the fixing process 330 is applied to the paper P1, the paper P2 is transported upward in the figure, and the paper P3 is switched back by the reverse transport path Sb. The sheet is conveyed leftward in the figure with its transfer surface facing downward in the figure, and the image is transferred from the intermediate transfer belt 320 to the fourth sheet P4 at the secondary transfer position.

  Next, FIG. 14 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 14, the sheet P1 is going to be discharged to the outside (HCS5) from the IOT3, and the image is transferred from the intermediate transfer belt 320 to the back surface of the sheet P2 at the secondary transfer position. The sheet P4 is conveyed in the left direction, and the fixing process 330 is applied to the sheet P4. The fifth sheet P5 is about to be sent out from the sheet feeding tray 301 to the conveying path S. Next, FIG. 15 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 15, the fixing process 330 is applied to the paper P2, the paper P3 is transported upward in the figure, and the paper P4 is switched back by the reverse transport path Sb. The sheet is conveyed leftward in the drawing with the transfer surface facing downward in the drawing, and the image is transferred from the intermediate transfer belt 320 to the paper P5 at the secondary transfer position.

  Next, FIG. 16 shows a state when one second has elapsed from the state of FIG. As can be seen from FIG. 16, the sheet P2 is going to be discharged from the IOT 3 to the outside (HCS5), and the image is transferred from the intermediate transfer belt 320 to the sheet P3 at the secondary transfer position. The sheet P5 is conveyed leftward, and the fixing process 330 is applied to the sheet P5. Then, the first sheet P <b> 1 ′ used for the next image forming job is about to be sent out from the sheet feed tray 301 to the transport path S. Thereafter, paper feeding / conveying and image forming processing are performed in the same manner as described above.

  In the above operation example, the order of the sheets reaching the secondary transfer position is represented in time series as shown in FIG. In FIG. 17A, the back side paper is indicated by diagonal lines so that the case of transferring the image to the front side of the paper and the case of transferring the image to the back side can be distinguished. Further, the front cover and the back cover (thick paper) and the main body (thin paper) are indicated by thick lines so that the main cover (thin paper) can be distinguished. As shown in FIG. 17A, after the transfer process on the front surface of the paper P3, the paper having the front surface as the transfer surface and the paper having the back surface as the transfer surface are alternately conveyed to the secondary transfer position. It has become so. In addition, after the transfer process on the back side of the paper P3, the back side paper used for the first image forming job and the front side paper used for the next image forming job are alternately conveyed to the secondary transfer position. It has become.

  Here, in FIG. 17B, the image is first transferred to the front surface of the first sheet P1, the image is transferred to the back surface, and then the image is transferred to the front surface of the second sheet P2. Later, an image is transferred to the back surface of the sheet, and so on. As can be seen from a comparison between FIG. 17B and FIG. 17A described above, as shown in FIG. 17A, the sheet having the front surface as the transfer surface and the sheet having the back surface as the transfer surface are alternately 2 If it is conveyed to the next transfer position, the time until all the processes are completed can be very short.

  Furthermore, in the prior art, since it takes time to change the fixing temperature each time the type of paper changes, as shown in FIG. 17C, the transfer process for the back surface of the paper P1 and the surface of the paper P2 are performed. Further processing time is required between the transfer process and the transfer process. Therefore, by feeding and transporting the sheet by the method shown in FIG. 17A, the time until all the processes are completed can be significantly reduced.

Next, a procedure for switching the operation mode of the IOT 3 will be described in detail.
As described above, the user / customer engineer can refer to the setting screen displayed on the user interface unit 30 and specify which operation mode to select on the screen. More specifically, when the user performs a predetermined operation using the user interface unit 30, a setting screen is displayed on the user interface unit 30 for the image forming job. On this setting screen, the single paper type productivity priority mode is set, the mixed paper type productivity priority mode is set, or the default operation mode (single paper type production) initially set in the IOT 3 is set. The first priority mode or the mixed paper type productivity priority mode) can be selected.

When the user inputs various conditions of the image forming job on this setting screen and further selects a desired operation mode, the user interface unit 30 outputs a request having a format as shown in FIG. 18 to the control unit 32 of the IOT 3. In the field “Productivity Mode” indicated by the slanted line f1 in FIG. 18, information specifying the operation mode described above is described. For example, when “01” is described in this field “Productivity Mode”, it means “single paper type productivity priority mode”, and when “10” is described, “mixed paper”. "Species productivity priority mode" means that "00" is described as the default operation mode that was initially set in IOT3. The control unit 32 switches the operation mode according to the contents described in this field “Productivity Mode”.
Further, similarly, the user can switch the operation mode of the IOT 3 using the DFE 10. That is, since the DFE 10 includes an operation unit and a display unit as shown in FIG. 3, the user selects an operation mode using the operation unit while displaying the above setting screen on the display unit. It is only necessary to perform an operation. In response to this operation, the DFE 10 transmits a request having a format as shown in FIG. 18 to the control unit 32 of the IOT, and the control unit 32 switches the operation mode according to the content of the received request.

  According to the embodiment described above, as the operation mode of the IOT 3, the operation mode (single paper type productivity priority mode) in which the fixing temperature of the fixing device 330 is changed for each paper type, and the fixing regardless of the paper type. An operation mode (mixed paper type productivity priority mode) for fixing the temperature constant is prepared. If the user attaches importance to the quality of the image formed on the paper, the single paper type productivity priority mode may be designated, and the user attaches more importance to the processing speed and productivity per unit time than the image quality. In this case, the mixed paper type productivity priority mode may be designated. Therefore, it can respond flexibly to the user's needs.

  Further, in the mixed paper type productivity priority mode, when the reverse surface of the paper is reversed using the reverse conveyance path Sb and the image is transferred to both surfaces, the transfer material having the front surface as the transfer surface and the back surface as the transfer surface are used. The transferred material is fed and transported according to a transport schedule that minimizes the time required to transport these transfer materials. More specifically, the transfer material having the front surface as the transfer surface and the transfer material having the back surface as the transfer surface are alternately conveyed to the secondary transfer position. Thereby, in the mixed paper type productivity priority mode, the processing speed or the productivity per unit time can be further improved.

The embodiment described above can be modified as follows.
FIG. 6 shows the relationship between the weight (basis weight) per unit area of the sheet, the optimum fixing temperature for the sheet, and the appropriate range of the allowable fixing temperature. The control unit 32 of the IOT 3 stores the relationship. The information to be performed is not limited to the content shown in FIG. In the mixed paper type productivity priority mode, the control unit 32 only needs to be able to specify a common fixing temperature that is considered appropriate for a plurality of types of paper, and therefore stores information indicating only the appropriate range of the fixing temperature for each paper type. Alternatively, an optimum fixing temperature (target value) for the sheet and information indicating an appropriate range based on the fixing temperature (target value) (for example, target value ± 30 ° C.) are stored. Also good. Further, a common fixing temperature may be stored in advance for each possible combination of different types of paper. For example, when the IOT 3 can use three types of papers of types A, B, and C, the fixing temperature common to the papers of types A and B, the fixing temperature common to the papers of types B and C, and the type C For example, the common fixing temperature of type A can be specified easily and stored in the control unit 32. In the embodiment, the intermediate value of the portion where the appropriate range of the fixing temperature overlaps is determined as the fixing temperature of the fixing device 330. However, in addition to this intermediate value, the portion of the portion where the appropriate range of the fixing temperature overlaps is specified. Any fixing temperature can be used.

  Further, although the configuration of the IOT 3 of the present embodiment has been described using an image forming apparatus having a tandem configuration using the intermediate transfer belt 320, an intermediate transfer drum may be used instead of the intermediate transfer belt 320. Furthermore, the method is not limited to the intermediate transfer method, and may be a method of transferring directly to a transfer material conveyed by a conveyance belt or a transfer material conveyed by a conveyance drum.

  1, 2, 3, and 5 show the case where the HCF 4 is connected to the upstream side of the IOT 3, and the HCS 5 and the HCSS 6 are connected to the downstream side. There is a form. For example, only HCS5 may be connected to the downstream side of IOT3, only HCS6 may be connected to the downstream side of IOT3, HCF4 may be connected to the upstream side of IOT3, and HCSS6 may be connected to the downstream side. Alternatively, the HCF 4 may be connected to the upstream side of the IOT 3 and the HCSS 6 may be connected to the downstream side. Further, the present invention is not only applied to the image forming system configured by a plurality of apparatus groups as described above, but can be applied to a single image forming apparatus.

  In the embodiment, the paper is described as an example of the transfer material to which the image formed on the image carrier is transferred. However, in addition to this, various transfer such as a plastic such as an OHP film and a cloth can be used. Materials can be used. The computer program executed by the control unit 32 described in the embodiment includes a magnetic tape, a magnetic disk, a floppy (registered trademark) disk, an optical recording medium, a magneto-optical recording medium, a CD (Compact Disk) -ROM, a DVD ( Digital Versatile Disk) and a recording medium such as a RAM can be provided.

1 is a diagram illustrating a configuration of an image forming system according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an external configuration of each device (IOT, HCF, HCS, HCSS) in a portion surrounded by a dotted line in the image forming system. It is a figure which shows the internal structure of IOT, HCF, HCS, and HCSS. It is sectional drawing which shows the internal structure of IOT. It is a block diagram which shows the function structure of IOT, HCF, HCS, and HCSS. FIG. 5 is a diagram illustrating a relationship between a weight per unit area (basis weight) of a sheet, an optimum fixing temperature for the sheet, and an appropriate range of an allowable fixing temperature. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure for demonstrating a mode that a sheet | seat is conveyed in mixed paper type productivity priority mode. It is a figure showing the order of the paper which reaches this embodiment and the conventional secondary transfer position in time series. It is a figure which shows the format of the request output to the control part of IOT from a user interface part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Image forming system, 1a, 1b ... Client terminal, 2 ... Network, 3 ... Image forming apparatus (IOT), 4 ... Paper feed device (HCF), 5 ... Paper discharge device (HCS), 6 ... Paper discharge device ( HCCS), 10 ... print server (DFE), 30, 40, 50, 60 ... user interface unit, 32, 42, 52, 62 ... control unit, 33 ... image forming unit, 34 ... fixing unit , 35 ... paper feeding / conveying unit, 330 ... fixing device, S ... conveying path.

Claims (6)

An image forming means for forming an image on an image carrier and transferring the image to a transfer material;
Fixing means for heating and fixing the image transferred to the transfer material to the transfer material;
Switching means for switching between the first operation mode and the second operation mode;
Storage means for storing an appropriate range of heating amount determined for each type of transfer material;
In the first operation mode, when the image forming unit transfers an image to a plurality of types of transfer materials, depending on the type of the transfer material, for each type of the transfer material stored in the storage unit First heat amount control means for instructing the fixing means to heat the image within a suitable range of heating amounts determined ;
In the second operation mode, when the image forming unit transfers an image to a plurality of types of transfer materials, a plurality of images are transferred by the image forming unit based on the contents stored in the storage unit. An image forming apparatus comprising: a second heat amount control unit that instructs the fixing unit to heat the image with a specific heating amount in a portion where appropriate ranges of heating amounts of the types of transfer materials overlap each other . An image forming means for forming an image on an image carrier and transferring the image to a transfer material;
Fixing means for heating and fixing the image transferred to the transfer material to the transfer material;
Switching means for switching between the first operation mode and the second operation mode;
A storage means for storing a target value of the heating amount determined for each type of transfer material and range information indicating an appropriate range based on the target value;
In the first operation mode, when the image forming unit transfers an image to a plurality of types of transfer materials, depending on the type of the transfer material, for each type of the transfer material stored in the storage unit First heat quantity control means for instructing the fixing means to heat the image with a heating amount of a determined target value;
In the second operation mode, when the image forming unit transfers an image to a plurality of types of transfer materials, a plurality of images are transferred by the image forming unit based on the contents stored in the storage unit. A second heat quantity control means for instructing the fixing means to heat the image with a specific heating amount in a portion where the appropriate ranges of the heating amounts for the types of transfer materials overlap with each other;
An image forming apparatus comprising: Comprising a specifying means for a user to specify one of the previous SL first operation mode and the second operation mode,
The image forming apparatus according to claim 1, wherein the switching unit switches to an operation mode designated by the designation unit. A reverse conveying path for reversing a front surface and a back surface of the front Symbol transfer material,
In the second operation mode, a conveyance control unit that alternately conveys a transfer material whose front surface is a transfer surface and a transfer material whose rear surface is a transfer surface via the reverse conveyance path to the image forming unit. The image forming apparatus according to claim 1, further comprising: The conveyance control unit conveys a transfer material having a transfer surface as a transfer surface and a transfer material of a type different from the transfer material and having a back surface as a transfer surface to the image forming unit alternately. 5. The image forming apparatus according to 4 . The transport control unit alternately uses a transfer material having a transfer surface as a transfer surface used in a certain image forming job and a transfer material having a transfer surface as a transfer surface used in another image forming job to the image forming unit. The image forming apparatus according to claim 4 , wherein the image forming apparatus is conveyed.

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