JP2010217296A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which can shorten a wait time for printing as the whole image forming apparatus without deteriorating productivity. <P>SOLUTION: An image forming apparatus 100 includes printing parts 110Y, 110M, 110C, and 110K for forming images on a sheet 90 and a fixing part 130 for fixing the image formed on the sheet 90, and when the fixing part 130 reaches a prescribed printing permission temperature, starts operations of printing parts 110Y, 110M, 110C, and 110K. The image forming apparatus is provided with a delay factor detection part 201 which detects a printing delay factor which delays the operation of the image forming apparatus before the fixing part 130 reaches the printing permission temperature after the start of warm-up. The image forming apparatus is provided with a printing delay control part 202 which sets a printing permission temperature variably in accordance with a delay time resulting from the detected printing delay factor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus that performs print delay control in accordance with a print delay factor.

  In a general electrophotographic image forming apparatus, for example, the surface temperature of a fixing roller is detected, and when the temperature reaches a predetermined temperature (printing permission temperature), printing is permitted (a printing permission signal is generated). An image forming operation has started. The print permission temperature is set higher than the image quality guarantee temperature so that the image quality can be guaranteed even if the heat is taken away by the paper and starts to drop at the start of printing.

  In recent years, there has been a demand for shortening the printing waiting time from the start until printing is permitted. Therefore, recently, a proposal has been made to shorten the print waiting time by setting a plurality of print permission temperatures according to conditions and lowering the print permission temperature to allow printing depending on the conditions (for example, Patent Document 1). (See JP 2003-186346 A).) For example, the temperature at which only monochrome printing is permitted, the temperature at which only a small number of jobs are permitted to print, and the temperature at which only A4 size printing is permitted may be set lower than the original permitted temperature.

JP 2003-186346 A

  However, as described above, multiple print permission temperatures can be set according to the conditions, and depending on the conditions, even if the print wait time is shortened by lowering the print permission temperature to allow printing, In some cases, in order to maintain the fixing property, the productivity (the number of printed sheets per unit time) must be reduced for printing. In addition to the warm-up of the fixing device such as image adjustment and cleaning control, the image forming apparatus as a whole has other factors that delay printing. There are times when you have to wait for a factor.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that can shorten the printing waiting time of the entire image forming apparatus without reducing productivity.

In order to solve the above problems, an image forming apparatus according to the present invention provides:
An image having a printing unit for forming an image on a sheet and a fixing unit for fixing the image formed on the sheet, and starting the operation of the printing unit when the fixing unit reaches a predetermined print permission temperature. In the forming device,
A delay factor detection unit that detects a printing delay factor that delays the operation of the image forming apparatus before the fixing unit reaches the print permission temperature from the start of warm-up;
And a print delay control unit that variably sets the print permission temperature in accordance with the detected delay time caused by the print delay factor.

  In the image forming apparatus of the present invention, the delay factor detection unit detects a printing delay factor that delays the operation of the image forming device before the fixing unit reaches the print permission temperature. The print delay control unit variably sets the print permission temperature according to the detected delay time caused by the print delay factor. Therefore, even if there are various print delay factors that delay the operation of the image forming apparatus, the print permission temperature can be set appropriately. As a result, it is possible to shorten the printing waiting time of the entire image forming apparatus without reducing productivity.

  In the image forming apparatus according to an embodiment, the print delay factor detected by the delay factor detection unit includes a factor related to a job accepted by a print reservation operation during warm-up of the fixing unit.

  In the image forming apparatus of this embodiment, even if a print delay factor related to a job accepted by a print reservation operation occurs during warm-up of the fixing unit, the print permission temperature can be set appropriately.

  In the image forming apparatus according to an embodiment, when the delay factor detection unit detects a plurality of print delay factors, the print delay control unit can execute controls corresponding to the plurality of print delay factors in parallel with each other. In order to set the print permission temperature, a delay time corresponding to the control that makes the print waiting time the longest among the controls that can be executed in parallel with each other is used. .

  In the image forming apparatus according to this embodiment, the print permission temperature can be appropriately set when control individually corresponding to a plurality of print delay factors can be executed in parallel with each other.

  It is desirable to provide a parallel execution determination table that indicates whether or not the controls individually corresponding to a plurality of print delay factors can be executed in parallel with each other. If the delay factor detection unit refers to the parallel execution possibility determination table, it can be easily determined whether or not the controls individually corresponding to the plurality of print delay factors can be executed in parallel.

  In an image forming apparatus according to an embodiment, the print delay factor detected by the delay factor detection unit includes a factor related to an environment in which the image forming device is placed during warm-up of the fixing unit.

  In the image forming apparatus according to this embodiment, the printing permission temperature can be appropriately set when a printing delay factor related to the environment in which the image forming apparatus is placed occurs during warming up of the fixing unit.

  In the image forming apparatus according to the embodiment, the print delay factor detected by the delay factor detection unit includes a factor related to a paper type designated by the job accepted in the print reservation operation.

  In the image forming apparatus of this embodiment, when the job received in the print reservation operation includes a print delay factor related to the paper type specified, the print permission temperature can be set appropriately.

  In the image forming apparatus according to the embodiment, the print delay factor detected by the delay factor detection unit includes a factor related to a paper size designated by a job received in the print reservation operation.

  In the image forming apparatus of this embodiment, when the job accepted in the print reservation operation includes a print delay factor related to the paper size specified, the print permission temperature can be set appropriately.

In the image forming apparatus of one embodiment,
The delay factor detection unit sequentially detects print delay factors that occur between the start of warm-up of the fixing unit and the arrival of the print permission temperature,
When a new print delay factor is detected between the start of warm-up of the fixing unit and the arrival of the print permission temperature, the print delay control unit permits printing as a candidate for change according to the new print delay factor. When the temperature is obtained sequentially, and when the print permission temperature as the change candidate is equal to or lower than the set print permission temperature, the already set print permission temperature is set as the change candidate temperature. It is characterized by updating with the value of.

  In the image forming apparatus according to this embodiment, the print permission temperature can be set appropriately and successively, no matter how many times the various print delay factors that delay the operation of the image forming apparatus occur during the warm-up of the fixing unit. . As a result, it is possible to shorten the printing waiting time of the entire image forming apparatus without reducing productivity.

  In the image forming apparatus according to an embodiment, when the updated print permission temperature becomes equal to or lower than the temperature of the fixing unit at the time of the update, the operation of the printing unit is started immediately.

  According to the image forming apparatus of this embodiment, the operation of the printing unit can be started immediately when the conditions for permitting printing are satisfied, and productivity can be improved.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a basic print delay control flow in the image forming apparatus. It is a figure which shows various printing delay factors and the timing which detects those printing delay factors as a correspondence table. It is a figure which shows the control time and attribute about control for every printing delay factor. It is a figure which shows the parallel execution possibility table which memorize | stored whether the printing delay factors can be executed in parallel. FIG. 6 is a diagram illustrating a print delay control flow when there are a plurality of print delay factors in the image forming apparatus. (A) is a diagram schematically illustrating the concept of control when two printing delay factors can be executed in parallel, and (b) schematically illustrates the concept of control when two printing delay factors are not executable in parallel. It is. (A) is a diagram illustrating the contents of the delay control according to the environment, (b) is the contents of the delay control according to the paper type, and (c) is a diagram illustrating the contents of the delay control according to the paper size. FIG. 6 is a diagram illustrating a print delay control flow for changing the print permission temperature in real time during warm-up in the image forming apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a color tandem image forming apparatus (MFP;) 100 according to an embodiment of the present invention. This image forming apparatus is a multifunction machine having functions such as a scanner, copying, and printing, and is called an MFP (Multi Function Peripheral).

  The image forming apparatus 100 includes an intermediate transfer belt 108 as an annular image carrier that moves in the circumferential direction and is wound around two rollers 102 and 106 at a substantially central position in a main body casing 101. Of the two rollers 102 and 104, one roller 102 is arranged on the left side in the figure, and the other roller 106 is arranged on the right side in the figure. The intermediate transfer belt 108 is supported by these rollers 102 and 106 and is driven to rotate in the arrow X direction.

  Below the intermediate transfer belt 108, in order from the left in the figure, image forming units 110Y and 110M as printing units corresponding to yellow (Y), magenta (M), cyan (C), and black (K) toners. 110C and 110K are arranged side by side.

  The image forming units 110Y, 110M, 110C, and 110K are configured in exactly the same manner except for the difference in the toner colors that they handle. Specifically, for example, the yellow image forming unit 110Y includes a photosensitive drum 190, a charging device 191, an exposure device 192, a developing device 193 that performs development using toner, and a cleaner device 195. It is configured. A primary transfer roller 194 is provided at a position facing the photosensitive drum 190 with the intermediate transfer belt 108 interposed therebetween. At the time of image formation, the surface of the photosensitive drum 190 is first uniformly charged by the charging device 191. Subsequently, the surface of the photosensitive drum 190 is output by the exposure device 192 in accordance with an image signal input from an external device (not shown), for example. Are exposed to form a latent image there. Next, the latent image on the surface of the photosensitive drum 190 is developed by the developing device 193 to become a toner image. This toner image is transferred to the intermediate transfer belt 108 by applying a voltage between the photosensitive drum 190 and the primary transfer roller 194. The transfer residual toner on the surface of the photosensitive drum 190 is cleaned by a cleaner device 195.

  As the intermediate transfer belt 108 moves in the arrow X direction, four color toner images are superimposed on the intermediate transfer belt 108 by the image forming units 110Y, 110M, 110C, and 110K.

  On the left side of the intermediate transfer belt 108, a cleaning device 125 that removes residual toner from the surface of the intermediate transfer belt 108 and a toner collection box 126 that collects toner removed by the cleaning device 125 are provided. On the right side of the intermediate transfer belt 108, a secondary transfer roller 112 as a secondary transfer member is provided with a conveyance path 124 for paper interposed therebetween. Conveying rollers 120 and 119 are provided in positions corresponding to the upstream and downstream sides of the secondary transfer roller 112 in the conveying path 124, respectively. An optical sensor (toner density sensor) for detecting a toner pattern on the intermediate transfer belt 108 is provided integrally with the conveying roller 120.

  A fixing device 130 serving as a fixing unit that fixes toner on a sheet is provided in the upper right portion of the main body casing 101. The fixing device 130 includes a pair of left and right rollers 133 and 134 extending perpendicularly to the paper surface in FIG. 1, a fixing belt 132 as a heating member wound around the rollers 133 and 134, and a fixing belt 132. A pressure roller 131 is provided as a pressure member extending in a direction perpendicular to the paper surface of FIG. The fixing belt 132 is heated to a predetermined print permission temperature by a heating source (not shown). The pressure roller 131 is urged toward the fixing belt 132 by a spring (not shown). Thus, the pressure roller 131 and the fixing belt 132 form a nip portion for fixing. The sheet 90 on which the toner image has been transferred passes through the nip portion, whereby the toner image is fixed on the sheet 90. In this example, the temperatures of the pressure roller 131 and the fixing belt 132 are detected by temperature sensors 135 and 136 made of thermistors, respectively.

  Further, at the lower part of the main body casing 101, paper feed cassettes 116A and 116B serving as paper feed ports accommodating paper 90 as a sheet on which an image is to be formed are provided in two stages. Each of the paper feed cassettes 116A and 116B is provided with a paper feed roller 118 for feeding the paper and a paper feed sensor 117 for detecting the fed paper. For simplicity, a state in which the sheet 90 is stored only in the sheet feeding cassette 116A is shown.

  In the main body casing 101, a control unit 200 including a CPU (Central Processing Unit) that controls the operation of the entire image forming apparatus is provided. As will be described later, the control unit 200 functions as a delay factor detection unit 201 and a print delay control unit 202.

  At the time of image formation, the paper 90 is fed one sheet at a time from the paper feed cassette 116A to the transport path 124 by the paper feed roller 118 under the control of the control unit 200. The sheet 90 sent to the transport path 124 is sent to the toner transfer position between the intermediate transfer belt 108 and the secondary transfer roller 112 by the transport roller 120 at a timing by the registration sensor 114. On the other hand, as described above, four color toner images are formed on the intermediate transfer belt 108 by the image forming units 110Y, 110M, 110C, and 110K. The four-color toner images on the intermediate transfer belt 108 are transferred by the secondary transfer roller 112 to the sheet 90 sent to the toner transfer position described above. The sheet 90 on which the toner image has been transferred is conveyed through a nip formed by the pressure roller 131 and the fixing belt 132 of the fixing device 130 and is heated and pressurized. As a result, the toner image is fixed on the sheet 90. Then, the paper sheet 90 on which the toner image is fixed is discharged by a paper discharge roller 121 to a paper discharge tray section 122 provided on the upper surface of the main body casing 101 through a paper discharge path 127. In this example, a switchback conveyance path 128 is provided for feeding the paper sheet 90 to the toner transfer position again in the case of duplex printing.

  In the image forming apparatus 100, the control unit 200 detects the temperatures of the pressure roller 131 and the fixing belt 132 using the temperature sensors 135 and 136 described above. However, the pressure roller 131 as the pressure member has a larger heat capacity and the temperature rise is slower than the fixing belt 132 as the heating member. Therefore, in this example, the control unit 200 generates a print permission signal when the temperature of the pressure roller 131 reaches a predetermined print permission temperature, and starts the printing operation. The temperature rise rate of the pressure roller 131 is 1 ° C./sec.

  FIG. 3 shows print delay factors (identified by reference numerals Fa1, Fa2,..., Fa10) that are factors for variably setting the print permission temperature in the image forming apparatus 100.

  That is, as shown in the “print delay factor” column in FIG. 3, “secondary transfer member cleaning” Fa1, “ATVC” Fa2, “polygon mirror speed switching” Fa3, “color misregistration correction” Fa4, “sheet feeding port” "Switching" Fa5, "Photoconductor speed switching" Fa6, "Low temperature printing" Fa7, "High humidity printing" Fa8, "Thick paper printing" Fa9, "Large size paper printing" Fa10.

  “Secondary transfer member cleaning” Fa1 is a process of cleaning the secondary transfer roller 112 as a secondary transfer member. As shown in the “delay execution determination” column in FIG. 3, “secondary transfer member cleaning” Fa <b> 1 is determined according to whether or not a predetermined number of sheets are passed. For example, if there is a print request after the cumulative number of prints reaches a specified number, printing is delayed for a predetermined time before the start of printing, regardless of what the requested job is. Cleaning is always performed.

  "ATVC" (Active Transfer Voltage Control) Fa2 is a process for automatically controlling the transfer bias, and is performed when there is a change in humidity exceeding a specified value.

  “Polygon mirror speed switching” Fa3 is a process of switching the speed of the polygon mirror (a member that scans the light beam in the width direction of the paper) in the exposure device 192, and is performed as necessary during printing.

  “Color misregistration correction” Fa4 is a process for appropriately adjusting the position and magnification of each color toner of yellow (Y), magenta (M), cyan (C), and black (K). This is done when there is a color print request.

  “Paper feeding port switching” Fa5 is a process of switching the paper feeding cassettes 116A and 116B as the paper feeding port, and is performed when the paper is switched.

  “Photoconductor speed switching” Fa6 is a process of switching the process speed (the rotational speed of the photoconductor), and is performed according to the setting at the time of printing.

  “Printing at a low temperature” Fa7 is a process for printing in a low temperature environment, and is performed when a printing request is made in a low temperature environment when the fixing temperature is lower than a specified value.

  “Printing at high humidity” Fa8 is a process for printing in a high humidity environment, and is performed when there is a print request at high humidity in a situation where the fixing temperature is lower than a specified value.

  “Thick paper printing” Fa9 is a process for printing on thick paper, and is performed when there is a request to print on thick paper in a situation where the fixing temperature is lower than a specified value.

  “Large-size paper printing” Fa10 is a process for printing on a large-size paper (for example, A3 defined in Japanese Industrial Standards (JIS)). Implemented when requested to print.

  As shown in the “print delay factor determination possible timing” column in FIG. 3, “secondary transfer member cleaning” Fa1 and “ATVC” Fa2 can occur during warm-up, but other print delay factors Fa3, Fa4. ,..., Fa10 occurs after accepting a print reservation.

  The “control for each print delay factor” table in FIG. 4 stores each control performed corresponding to each print delay factor in FIG. 3, its control time, and an attribute in association with each other. The name of the printing delay factor and the name of each control are substantially the same. In particular, the names of the print delay factors Fa1,..., Fa5 are the same as the control names. Further, the control performed in response to the “low temperature printing” Fa7 is “low temperature printing weight”, and the control performed in response to the “high humidity printing” Fa8 is “high humidity weight”, “thick paper printing” Fa9. The control performed in response to "Thick paper printing weight" and the control performed in response to "Large size paper printing" Fa10 are referred to as "large size paper weight", respectively.

  The control time for each control is a value shown in the “control time (s)” column in FIG. For example, it takes 10 seconds for secondary transfer member cleaning and 6 seconds for ATVC.

  “Attribute” in FIG. 4 represents the priority of each control. In this example, the control group of “low temperature printing weight”, “high humidity weight”, “thick paper printing weight”, and “large paper weight” having the attribute “2” affects the fixability. Is the highest. The control group of “secondary transfer member cleaning” and “ATVC” having the attribute “1-1” does not affect the fixing property, but can be executed without receiving a print reservation. . The control group of “polygon mirror speed switching”, “color misregistration correction”, “paper feed port switching”, and “photosensitive body speed switching” having the attribute “1-2” has low priority. In the case of the same attribute, the higher priority in the table is higher.

  FIG. 2 illustrates a basic print delay control flow by the control unit 200 of the image forming apparatus 100. This example starts from the time when a print job is received during standby and the fixing device 130 starts to warm up. The warm-up is performed when the image forming apparatus 100 is turned on or when the image forming apparatus 100 returns from the standby state to the operating state.

  i) First, at the start of warm-up of the fixing device 130, in step S1, the print permission temperature (this is the temperature that should be reached by the pressure roller 131 as described above; the same shall apply hereinafter) Tend is set to a predetermined initial value. .

  As a specific example, when the paper 90 is A4 or B5 size plain paper at a room temperature of 23 ° C., first, the print permission temperature Tend is set to 100 ° C.

  ii) Next, before the temperature of the pressure roller 131 reaches the print permission temperature Tend from the start of warm-up, the control unit 200 works as the delay factor detection unit 201 in step S2 to operate the image forming apparatus 100. Detects a delay in printing delay.

  In this example, it is assumed that only “secondary transfer member cleaning” is detected as a print delay factor among the print delay factors shown in FIG. Therefore, it is determined that the print delay factor is “present” in step S2 ′ in FIG. If it is determined in step S2 ′ that the print delay factor is “none”, the process proceeds to step S4 described later without changing the print permission temperature.

  iii) Next, in step S3, the print permission temperature Tend is changed from the initial value to a new value (Tnew) according to the delay time generated by the print delay factor.

  As described above, the control time (delay time) for cleaning the secondary transfer member is 10 seconds, and the temperature rise rate of the pressure roller 131 is 1 ° C./second. Therefore, in this example, it can be expected that the temperature of the pressure roller 131 rises by 10 ° C. in 10 seconds after the print permission signal is generated and before the sheet 90 reaches the fixing device 130. Therefore, according to the 10 seconds, the print permission temperature Tend is changed to 90 ° C. (Tnew) by subtracting 10 ° C. from the initial set value 100 ° C.

  iv) Next, in step S4, it is determined whether or not the current temperature Tnow of the pressure roller 131 has reached or exceeded the print permission temperature Tend. If the current temperature Tnow of the pressure roller 131 has not reached the print permission temperature Tend or more (“F” in step S4 ′), the processes in steps S2 to S4 are repeated.

  On the other hand, if the current temperature Tnow of the pressure roller 131 has reached or exceeded the print permission temperature Tend (90 ° C. in this example) (“T” in step S4 ′), a print permission signal is generated. Thus, after the secondary transfer member cleaning is performed for 10 seconds, the toner image is transferred to the sheet 90 and is fixed by the fixing device 130. In this case, during the fixing operation, the pressure roller 131 has reached the original print permission temperature of 100 ° C., so that there is no problem in the fixing property.

  By performing the control as described above, it is possible to appropriately set the print permission temperature even if there are various print delay factors that delay the operation of the image forming apparatus 100. As a result, it is possible to shorten the printing waiting time of the entire image forming apparatus without reducing productivity. In the above example, the print waiting time can be reduced by 10 seconds.

  Next, referring to the print delay flow in FIG. 2 again, the case where “color misregistration correction” is the print delay factor among the print delay factors shown in FIG. 3 will be described.

  This print delay factor “color misregistration correction” can occur when a print reservation is accepted during warm-up. That is, it is assumed that, during the warm-up, a temperature change in the image forming apparatus 100 in the apparatus (environment) is detected in step S2 of FIG. Furthermore, it is assumed that there is a color print request in the print reservation and plain paper is designated as the paper. In such a case, it is necessary to perform color misregistration correction control for 8 seconds (see FIG. 4) before printing (color printing). Then, the control unit 200 operates as the delay factor detection unit 201 to detect “color misregistration correction” as a print delay factor among the print delay factors illustrated in FIG. 3. Therefore, it is determined that the print delay factor is “present” in step S2 ′ in FIG.

  Next, in step S3, the print permission temperature Tend is changed from the initial value to a new value (Tnew) according to the delay time generated by the print delay factor. In this example, the print permission temperature Tend is changed to 92 ° C. (Tnew) by subtracting 8 ° C. from the initial set value 100 ° C.

  In this case, in step S4, it is determined whether or not the current temperature Tnow of the pressure roller 131 has reached or exceeded the print permission temperature Tend, and the current temperature Tnow of the pressure roller 131 is determined to be the print permission temperature Tend (in this example). If the temperature reaches 92 ° C. or higher (“T” in step S4 ′), a print permission signal is generated. As a result, after color misregistration correction is performed for 8 seconds, a color toner image is transferred to the sheet 90 and is fixed by the fixing device 130. In this case, during the fixing operation, the pressure roller 131 has reached the original print permission temperature of 100 ° C., so that there is no problem in the fixing property. In this example, the print waiting time can be reduced by 8 seconds.

  As described above, according to this print delay flow, even if a print delay factor related to the job accepted by the print reservation operation occurs during the warm-up of the fixing device 130, the print permission temperature can be set appropriately. As a result, the printing waiting time of the entire image forming apparatus 100 can be shortened without reducing productivity.

  In the examples so far, the case where only one print delay factor is detected in step S2 of FIG. 2 has been described. In contrast, when a plurality of print delay factors are detected, whether or not the control individually corresponding to the plurality of print delay factors can be executed in parallel to reduce the delay time as a whole. Is a problem. 5 stores whether or not the control individually corresponding to the print delay factors Fa1, Fa2,..., Fa10 shown in FIG. 4 can be executed in parallel with each other.

  In the parallel execution feasibility determination table of FIG. 5, the frame specified by the control corresponding to the printing delay factors Fa1, Fa2,..., Fa10 in the left column and the control corresponding to the printing delay factors Fa1, Fa2,. In the figure, a circle mark is attached if parallel execution is possible, and a cross mark is attached if parallel execution is impossible. Referring to this parallel execution possibility determination table, it can be seen that, for example, the control corresponding to the print delay factor Fa1 and the control corresponding to the print delay factor Fa2 cannot be executed in parallel (x mark). In addition, it can be seen that the control corresponding to the print delay factor Fa1 and the control corresponding to the print delay factor Fa3 can be executed in parallel (circles).

  Next, control when there are a plurality of print delay factors will be described using the print delay flow of FIG.

  When the confirmation of the presence or absence of the print delay factor is started in step S100 in FIG. 6 (corresponding to the start of step S2 in FIG. 2), first, in step S101, it is determined whether or not there are two or more detected print delay factors. To do. If there are two or more print delay factors (“YES” in step S101 ′), the process proceeds to step S102, and the controls corresponding to these print delay factors are mutually connected with reference to the parallel execution possibility determination table of FIG. It is determined whether or not execution is possible in parallel. If the controls corresponding to these print delay factors can be executed in parallel with each other ("YES" in step S102 '), the process proceeds to step S103, and among these print delay factors, the delay time value is the largest. Determine the cause.

  For example, as shown in FIG. 7A, when the detected printing delay factors are the secondary transfer member cleaning Fa1 and the polygon mirror speed switching Fa3, referring to the parallel execution determination table in FIG. It can easily be seen that the corresponding controls can be executed in parallel with each other. Then, referring to the “control time” column in FIG. 4, it can be seen that the control times for canceling the print delay factors Fa1 and Fa3 are 10 seconds and 3 seconds, respectively. In this example, it is determined that the factor having the largest delay time (control time) value among the print delay factors Fa1 and Fa3 is the secondary transfer member cleaning Fa1.

  In step S105, the print permission temperature Tend is changed from the initial value to a new value (Tnew) according to the delay time generated by the determined print delay factor. In this example, since the delay time generated by the secondary transfer member cleaning Fa1 is 10 seconds, the print permission temperature Tend is changed from the initial value 100 ° C. to a new value (Tnew = 90 ° C.). Thereafter, the process proceeds to step S104 in FIG. In this example, the print waiting time can be reduced by 10 seconds.

  Thus, according to this print delay flow, the print permission temperature can be appropriately set when the control individually corresponding to a plurality of print delay factors can be executed in parallel with each other. As a result, the printing waiting time of the entire image forming apparatus 100 can be shortened without reducing productivity.

  On the other hand, if the controls corresponding to the detected printing delay factors cannot be executed in parallel with each other ("NO" in step S102 '), refer to the "attribute" column in FIG. The priority order between the controls corresponding to is determined.

  For example, as shown in FIG. 7B, when the detected printing delay factors are the secondary transfer member cleaning Fa1 and the color misregistration correction Fa4, referring to the “attribute” column in FIG. It can be easily understood that the member cleaning Fa1 has a higher priority than the color misregistration correction Fa4. Therefore, as shown in FIG. 7B, first, the control corresponding to the secondary transfer member cleaning Fa1 (10 seconds) is executed, and then the control corresponding to the color misregistration correction Fa4 (8 seconds) is executed. Become. In this case, the overall delay time is 18 seconds.

  Next, in step S105, the print permission temperature Tend is changed from the initial value to a new value (Tnew) according to the overall delay time caused by the print delay factor. In this example, since the overall delay time generated by the secondary transfer member cleaning Fa1 and the color misregistration correction Fa4 is 18 seconds, the print permission temperature Tend is changed from the initial value 100 ° C. to a new value (Tnew = 82 ° C.). Change to Thereafter, the process proceeds to step S104 in FIG. In this example, the print waiting time can be shortened for 18 seconds.

  Note that when only one print delay factor is detected in the print delay flow of FIG. 6 (in the case of “NO” in step S101 ′ and proceeding to steps S107 and S107 ′), it is substantially the same as FIG. This is the same control as the print delay flow.

  FIGS. 8A, 8B, and 8C show a case where the print permission temperature Tend should not be set low but set rather high for a job accepted in the reservation operation during warm-up. Yes.

  For example, in the upper example of “delay control by environment” in FIG. 8A (control corresponding to the print delay factor Fa7), for example, when a print reservation operation is accepted during warm-up, the image forming apparatus 100 at that time This shows that a printing delay operation for 5 seconds is generated when the temperature in the apparatus (environment) is equal to or lower than a predetermined temperature (for example, 10 ° C. or lower). The purpose of this print delay operation is to ensure the fixability by positively delaying for 5 seconds and raising the fixing temperature (target temperature). Therefore, instead of setting the print permission temperature low (if it is set low, an unfixed image may be generated), the print permission temperature is set higher by the amount that rises in 5 seconds. In this example, since the rate of temperature increase of the pressure roller 131 is 1 ° C./sec, the print permission temperature Tend is set to 105 ° C. By doing so, the fixing property can be maintained well. In addition, although the warm-up time is extended, there is no need to wait after the print permission signal is generated, so that it is possible to provide a consistent operation while keeping the waiting time of the image forming apparatus 100 as a whole.

  In the lower example of “delay control by environment” in FIG. 8A (control corresponding to the print delay factor Fa8), when a print reservation operation is accepted during warm-up, the image forming apparatus 100 at that time ( When the absolute humidity of the environment is equal to or higher than a predetermined value, the print delay operation is generated until the pressure roller 131 reaches 130 ° C.

  In the upper example of “delay control according to paper type” in FIG. 8B (control corresponding to the print delay factor Fa9), when a print reservation operation is accepted during warm-up, the print job designates the print job. When the paper type is thick paper, the printing delay operation for 3 seconds is generated.

  In the lower example of “delay control according to paper type” in FIG. 8B, when a print reservation operation is accepted during warm-up, the paper type designated by the print job is OHP (overhead projector) film. In this case, the print delay operation for 10 seconds is generated.

  In the example of “delay control according to paper size” in FIG. 8C (control corresponding to the print delay factor Fa10), the paper size designated by the print job when a print reservation operation is accepted during warm-up. Indicates that a printing delay operation of 5 seconds is generated when the paper width is 216 mm or more.

  Also in the case shown in FIGS. 8A to 8C, the print permission temperature Tend can be set appropriately by setting the print permission temperature Tend high, so that the fixing property can be maintained satisfactorily.

  FIG. 9 shows a print delay control flow in which the print permission temperature is changed in real time from the start of warm-up of the fixing device 130 until the print permission temperature is reached, that is, during the warm-up.

  i) First, at the start of warm-up of the fixing device 130, in step S401, the print permission temperature (the temperature that should be reached by the pressure roller 131 as described above; the same applies hereinafter) T1 is set to a predetermined initial value. .

  As a specific example, when the paper 90 is A4 or B5 size plain paper at a room temperature of 23 ° C., first, the print permission temperature T1 is set to 100 ° C.

  ii) Next, before the temperature of the pressure roller 131 reaches the print permission temperature T1 from the start of warm-up, in step S402, the control unit 200 operates as the delay factor detection unit 201 to operate the image forming apparatus 100. Detects a delay in printing delay.

  If any one of the print delay factors shown in FIG. 3 is detected, it is determined that the print delay factor is “present” in step S402 ′ in FIG. When it is determined in step S402 ′ that the print delay factor is “none”, the process proceeds to step S405 described later.

  iii) Next, in step S403, a print permission temperature T2 is obtained as a change candidate according to the delay time generated by the detected print delay factor. Further, it is confirmed whether the print permission temperature T2 as the change candidate is equal to or lower than the initial value T1, that is, whether T2 ≦ T1. If T2 ≦ T1 (“T” in step S403 ′), the process proceeds to step S404, and the print permission temperature T1 that has already been set is updated with the value of the print permission temperature T2 as a change candidate.

  For example, in this example, “ATVC” Fa2 is newly detected as a print delay factor among the print delay factors shown in FIG. 3 due to the occurrence of a humidity change that exceeds the specified value in step S402 described above. Suppose. As described above, the control time (delay time) for ATVC is 6 seconds, and the temperature rise rate of the pressure roller 131 is 1 ° C./second. Therefore, in this example, the print permission temperature T2 as a change candidate is 94 ° C. The print permission temperature T1 that has already been set is 100 ° C. Therefore, since T2 ≦ T1, in step S404, the print permission temperature T1 is updated with the value 94 ° C. of the print permission temperature T2 as a change candidate.

  On the other hand, if T2> T1 (“F” in step S403 ′), the process proceeds to step S405 described later.

  iv) Next, in step S405, it is determined whether or not the current temperature Tnow of the pressure roller 131 has reached or exceeded the print permission temperature T1 (94 ° C. in the above example). Here, if the current temperature Tnow of the pressure roller 131 does not reach the print permission temperature T1 or more (“F” in step S405 ′), the processes in steps S402 to S405 are repeated.

  For example, by accepting a print reservation while repeating the processes in steps S402 to S405, among the print delay factors shown in FIG. 3, “paper feed port switching” Fa5 is newly detected as the print delay factor. Suppose that it is determined that the “feed port switching” control is to be executed before the start of printing of a job by the print reservation. Referring to the parallel execution determination table of FIG. 5, it can be seen that the controls corresponding to “ATVC” and “paper feed switching” can be executed in parallel with each other. Then, referring to the “control time” column in FIG. 4, it can be seen that the control times for canceling the print delay factors Fa2 and Fa5 are 6 seconds and 1 second, respectively. Accordingly, the print permission temperature T2 as a change candidate in this case is 94 ° C. If T2> T1, the process proceeds to step S405 without updating the print permission temperature.

  v) While repeating the processes of steps S402 to S405 in this way, if the current temperature Tnow of the pressure roller 131 has reached the print permission temperature T1 or higher in steps S405 and S405 ′ (“ T "), a print permission signal is generated. As a result, the image forming operation can be started immediately when the conditions for permitting printing are satisfied, and the productivity of the image forming apparatus 100 can be improved.

  Thus, in this print delay control flow, when a new print delay factor is detected during the warm-up of the fixing device 130, the print permission temperature T2 as a change candidate corresponding to the new print delay factor is sequentially obtained. . When the print permission temperature T2 as the change candidate is equal to or lower than the set print permission temperature T1 at the time of the determination, the already set print permission temperature T1 is used as the change candidate. Update with the value of T2.

  By performing the control as described above, the print permission temperature can be appropriately set sequentially regardless of how many times the various print delay factors that delay the operation of the image forming apparatus 100 occur during the warm-up of the fixing device 130. As a result, it is possible to shorten the printing waiting time of the entire image forming apparatus without reducing productivity. In the above example, the print waiting time can be shortened by 6 seconds.

  4 may be included in the control unit 200, or may be stored in a storage unit different from the control unit 200. Also good.

  In the examples so far, the paper 90 is assumed to be A4 or B5 size plain paper, so that the initial setting value of the print permission temperature Tend is set to 100 ° C. When all paper types and sizes are targeted, it is desirable to set the initial setting value of the print permission temperature Tend to 130 ° C., for example.

  In the above-described embodiment, the image is mainly formed on the sheet 90 as a sheet. However, the image may be formed not only on the sheet but also on a resin such as an OHP (overhead projector) film.

  In the above-described embodiment, the heating member is the fixing belt 132 around which the pair of rollers 133 and 134 are wound. However, the present invention is not limited to this. The heating member may be a roller.

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 130 Fixing apparatus 200 Control part 201 Delay factor detection part 202 Print delay control part

Claims (8)

An image having a printing unit for forming an image on a sheet and a fixing unit for fixing the image formed on the sheet, and starting the operation of the printing unit when the fixing unit reaches a predetermined print permission temperature. In the forming device,
A delay factor detection unit that detects a printing delay factor that delays the operation of the image forming apparatus before the fixing unit reaches the print permission temperature from the start of warm-up;
An image forming apparatus comprising: a print delay control unit configured to variably set the print permission temperature according to a detected delay time caused by the print delay factor. The image forming apparatus according to claim 1,
The print delay factor detected by the delay factor detection unit includes a factor related to a job accepted by a print reservation operation during warm-up of the fixing unit. The image forming apparatus according to claim 1,
When the delay factor detection unit detects a plurality of print delay factors, the print delay control unit determines whether or not the controls corresponding to the plurality of print delay factors can be executed in parallel with each other. An image forming apparatus using a delay time corresponding to the control that makes the print waiting time the longest among the controls that can be executed in parallel with each other for setting the print permission temperature. The image forming apparatus according to claim 1,
The printing delay factor detected by the delay factor detection unit includes a factor relating to an environment in which the image forming device is placed during warm-up of the fixing unit. The image forming apparatus according to claim 1,
The print delay factor detected by the delay factor detection unit includes a factor related to a paper type specified by a job accepted in a print reservation operation. The image forming apparatus according to claim 1,
The print delay factor detected by the delay factor detection unit includes a factor related to a paper size designated by a job accepted in a print reservation operation. The image forming apparatus according to claim 1,
The delay factor detection unit sequentially detects print delay factors that occur between the start of warm-up of the fixing unit and the arrival of the print permission temperature,
When a new print delay factor is detected between the start of warm-up of the fixing unit and the arrival of the print permission temperature, the print delay control unit permits printing as a candidate for change according to the new print delay factor. When the temperature is obtained sequentially, and when the print permission temperature as the change candidate is equal to or lower than the set print permission temperature, the already set print permission temperature is set as the change candidate temperature. The image forming apparatus is updated with the value of. The image forming apparatus according to claim 7.
An image forming apparatus characterized in that when the updated print permission temperature becomes equal to or lower than the temperature of the fixing unit at the time of the update, the operation of the printing unit is started immediately.

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