JP2005196070A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow printing even when any one of image forming parts is not attached to an image forming apparatus in which a plurality of image forming units can be mounted. <P>SOLUTION: The image forming apparatus has the plurality of image forming units that form images of different colors and can separately be attached or detached. When none of the image forming units is attached, the image forming apparatus inhibits an image forming operation. The image forming apparatus includes: a plurality of unit sensors 36K, 36Y, 36M, and 36C for detecting whether the corresponding image forming units have been attached or not; an operation part 43 which, when at least one of the image forming unit is not attached, instructs to perform the image forming operation with the other image forming units attached; and a control part 40 which performs the image forming operation when the instruction to perform the image forming operation is given by the operation part 43. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus having a plurality of detachable image forming units such as a printer and a copying machine and capable of forming an image.

2. Description of the Related Art Conventionally, there are two types of electrophotographic printers as image forming apparatuses: a single color printer that can print only a single color and a color printer that enables color printing. In recent years, there has been a demand from users that they want to use a color printer, but the price is high, or they want color printing, but they do not need all the colors yellow, magenta, cyan, and black. As for the image forming units of yellow, magenta, cyan, and black, there are apparatuses that can be individually mounted on the apparatus main body as disclosed in, for example, Japanese Patent Laid-Open No. 10-187002. However, the apparatus disclosed in Japanese Patent Laid-Open No. 10-187002 is in an incomplete state as a color printer when at least one image forming unit is not installed. Can not.
In addition, some copiers and color printers are purchased as monochrome printers with black image forming units installed, and other three color combined image forming units are purchased separately and installed in the apparatus. There are printers that can be used as color printers. In this case as well, even if one of the combined three-color image forming units is missing, an error occurs and printing cannot be performed.

JP-A-10-187002

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which a plurality of image forming units can be mounted, and printing is possible even if there is an image forming unit that is not mounted.

In order to solve the above-described problems, the present invention provides an image forming apparatus capable of mounting a plurality of image forming units, a detection unit that detects whether or not the plurality of image forming units are mounted, and a detection result of the detection unit. A display unit that displays information indicating that the image forming unit is not mounted, and when at least one of the plurality of image forming units is not mounted, image formation is performed by the mounted image forming operation. An instructing unit for instructing and a control unit for performing an image forming operation when an instruction for an image forming operation is instructed by the instructing unit are provided.
According to another aspect of the invention, in an image forming apparatus capable of mounting a plurality of image forming units, a detecting unit that detects whether or not the plurality of image forming units are mounted, and an invalidating unit that invalidates the detection of the detecting unit And a control unit for performing an image forming operation by the mounted image forming unit based on the detection result of the detecting unit and the invalidating unit.

  According to the present invention, it is possible to easily print even if not all image forming units are mounted only by instructing an image forming operation by an instruction unit.

  Embodiments of the present invention will be described below with reference to the drawings. In each embodiment described below, an electrophotographic color printer will be described as an image forming apparatus. FIG. 1 is a schematic side view showing a color printer according to the first embodiment. In FIG. 1, a sheet feeding roller 11 and a sheet feeding sub-roller 12 driven by a conveyance roller (not shown) are stored in a sheet feeding cassette 14 by a sheet feeding force obtained by a sheet receiver 13 pushed up by a pushing spring (not shown). Feed the paper. The fed paper is transported to the transport belt unit 19 while being guided by the paper travel guide by the registration rollers 15 and 16 and the accompanying pressure rollers 17 and 18 that generate pressure and contact with the registration rollers 15 and 16.

  The conveying belt unit 19 includes a driving roller 20 driven by a belt motor (not shown), an idle roller 21 disposed on the opposite side, a conveying belt 22 stretched between the driving roller 20 and the idle roller 21, black, yellow, It includes transfer rollers 23K, 23Y, 23M, and 23C that are arranged to face the magenta and cyan image forming units. Black, yellow, magenta, and cyan image forming units 24K, 24Y, 24M, and 24C are detachably mounted on the upper portion of the conveyance belt unit 19, respectively. Each image forming unit 24 has the same configuration and is different only in the color of the toner accommodated therein. Each of the image forming units 24K, 24Y, 24M, and 24C has photosensitive drums 25K, 25Y, 25M, and 25C. After forming an electrostatic latent image, each of the image forming units 24K, 24Y, 24M, and 24C forms a toner image. The image is transferred to the paper on the conveyance belt 22 by 23Y, 23M, and 23C.

  The conveyance belt 22 conveys the sheet on which the toner image is transferred to the fixing device 26. The fixing device 26 includes a fixing roller 27 that is heated by a halogen lamp (not shown) and is driven to rotate, and a pressure roller 28 that rotates while being pressed against the fixing roller 27, and fixes the toner on the paper to the paper. A discharge roller 29 and a discharge roller 30 are provided on the left side of the fixing device 26, and the discharge roller 29 and the discharge roller 30 discharge the paper onto the face-up stacker 31 or the face-up stacker 31 is closed. In this case, it is discharged onto the top cover 32.

  An inner plate 33 is attached to the top cover 32. The inner plate 33 holds head holders 34K, 34Y, 34M, and 34C for the respective colors. The LED head portions 35K, 35Y, 35M, and 35C for the respective colors are attached to the lower end portions of the head holders 34K, 34Y, 34M, and 34C. The LED head portions 35K, 35Y, 35M, and 35C irradiate light to the opposing photosensitive drums 25K, 25Y, 25M, and 25C, and form electrostatic latent images on the photosensitive drums 25K, 25Y, 25M, and 25C.

  The top cover 32 can be opened and closed. When the top cover 32 is opened in the direction of arrow A, the inner plate 33 is lifted, and the head holders 34K, 34Y, 34M, 34C are also lifted, and the image forming units 24K, 24Y, 24M, 24C are lifted. The image forming units 24K, 24Y, 24M, and 24C can be attached and detached. FIG. 2 shows a state where the top cover is opened. The state shown in FIG. 2 is a state in which the top cover 32 is being opened, and the top cover 32 can be further opened to the extent that it does not interfere with the attachment / detachment of each image forming unit.

  In FIG. 2, unit sensors 36K, 36Y, 36M, and 36C are provided in the apparatus housings facing the image forming units 24K, 24Y, 24M, and 24C, respectively. The unit sensors 36K, 36Y, 36M, and 36C are configured by reflection type optical sensors, and detect the presence / absence of mounting of the image forming units 24K, 24Y, 24M, and 24C.

  FIG. 3 is a block diagram showing a main part of the first embodiment. In FIG. 3, a control unit 40 controls the operation of the entire apparatus, and each unit sensor 36K, 36Y, 36M, 36C is connected. The control unit 40 determines whether or not to perform a printing operation based on the output result from each of these unit sensors, and receives a detection result that any one of the image forming units is not installed. Outputs control for prohibiting the printing operation to the operation mode setting unit 41. When the control unit 40 receives a detection result that any one of the image forming units is not attached, the control unit 40 outputs a command to display an error to the display unit 42. The operation unit 43 has a number of buttons for setting device information such as a toner fixing temperature and a network.

  Next, the operation of the first embodiment will be described. Here, as shown in FIG. 4, it is assumed that only the black image forming unit 24K is mounted and the other image forming units are not mounted. Accordingly, a signal indicating attachment is output from the unit sensor 36K corresponding to the black image forming unit 24K to the control unit 40, but signals indicating non-installation are output from the other unit sensors 36Y, 36M, and 36C to the control unit 40. Are output.

  When a print command is transmitted from the user to the apparatus, the control unit 40 receives a signal indicating that the image forming unit is not mounted, and therefore outputs a command for prohibiting the print operation to the operation mode setting unit 41. The control unit 40 also outputs a command for displaying an error and a command for displaying an inquiry for allowing the user to select whether or not to perform a printing operation to the display unit 42. The user can select to perform a printing operation by operating the operation unit 43. When the user selects execution of the printing operation, a signal to that effect is sent from the operation unit 43 to the control unit 40, and the control unit 40 outputs a command for canceling the error and a command for performing the printing operation to the operation mode setting unit 41. . This enables a printing operation.

  The printing operation is performed as follows. In FIG. 4, the paper is transported to the transport belt unit 19 by the registration rollers 15 and 16 by rotating the paper feed roller 11 and the sub paper feed roller 12 counterclockwise. Thereafter, the sheet is adsorbed to the conveyance belt 22 and conveyed. On the other hand, in the black image forming unit 24K, an image forming operation is performed based on the print command and the print data. That is, the print data is sent to the black LED head part 35K, and the LED head part 35K turns on the LED corresponding to the sent print data, and the surface of the charged photosensitive drum 25K is set to 1 according to the print data. An electrostatic latent image for a line is formed. Black toner is stored in the image forming unit 24K, and charged black toner is attached to the electrostatic latent image on the surface of the photosensitive drum 25K. Then, the photosensitive drum 25K continues to rotate, and the electrostatic latent image is developed with black toner.

  When the leading edge of the paper reaches between the photosensitive drum 25K and the transfer roller 23K, the transfer power is turned on, and the toner image on the surface of the photosensitive drum 25K is transferred onto the paper. The toner images are successively transferred onto the sheet by the rotation of the photosensitive drum 25K, and a black image for one page is transferred onto the sheet. Thus, the transfer of the black image onto the sheet by the black image forming unit 24K is completed.

  The sheet continues to move with the conveyor belt 22. However, since the image forming units of other colors (yellow, magenta, cyan) are not mounted, image formation is not performed, and the paper passes through the lower part of the mounting position of these units and leaves the conveyance belt 22. Further, it is sent to the fixing device 26. In the fixing device 26, the toner image is fixed on the sheet by the fixing roller 27 that has already reached a fixing temperature and the pressure roller 28 that presses the fixing roller 27. When the fixing is completed, the sheet is discharged onto the face-up stacker 31. If there is more print data, the above operation is repeated to perform the print operation. If there is no print data to be printed next, the printing operation is terminated.

  When the user operates the operation unit 43 and selects to prohibit the printing operation, the control unit 40 outputs a command for canceling the error to the operation mode setting unit 41. The control unit 40 cancels the print command.

  As described above, according to the first embodiment, the printing operation is prohibited when not all image forming units are mounted, that is, when there is even one unformed image forming unit. Even a color printer that performs printing can be easily printed by pressing a button for canceling the prohibition of the printing operation. Further, since a button provided in advance on the operation unit is pressed, it is not necessary to add a dedicated button for canceling the prohibition of printing operation.

  In the first embodiment, the case where there is only one black image forming unit that has not been mounted has been described. However, it is needless to say that printing is also possible when there are two to three unmounted units. Absent. In the above embodiment, a display unit is provided as means for notifying that printing is possible even if there is an unmounted unit. However, if a specific button is pressed, printing is possible. Even if there is no copy, printing is possible.

  Next, a second embodiment will be described. In the second embodiment, FIG. 5 is a block diagram showing a main part of the second embodiment. In FIG. 5, the control unit 50 performs the first embodiment when the mounting of the image forming unit is not detected from any one of the unit sensors 36K, 36Y, 36M, and 36C that detect the mounting state of each image forming unit. As in the embodiment, a command for prohibiting the printing operation is output to the operation mode setting unit 51 and an output for displaying an error on the display unit 52 is performed. The operation unit 53 includes a plurality of buttons. By pressing a combination of buttons simultaneously with pressing a switch to turn on the power, it is possible to select detection of an error due to the mounting state of the image forming unit.

  In addition, the control unit 50 can issue an instruction to display on the display unit 52 for selecting an error detection state. The user operates the buttons on the operation unit 53 while viewing the display on the display unit 52. The sensor trigger 54 transmits a signal for invalidating the designated sensor output of the unit sensors 36K, 36Y, 36M, and 36C to the control unit 50 according to the error detection state selected by the operation unit 53. Other configurations are the same as those of the first embodiment.

  Next, the operation of the second embodiment will be described. Here, as in the case of the first embodiment, it is assumed that only the black image forming unit 24K is attached and the other color image forming units are not attached as shown in FIG. In the initial state or in the normal state of use as a full-color printer, when receiving a print command from the user, the control unit 50 receives a mounting signal from the unit sensor 36K and not from the unit sensors 36Y, 36M, and 36C. Receives a wearing signal. Since not all the image forming units are mounted, the control unit 50 outputs a command for prohibiting the print command to the operation mode setting unit 51 and outputs to display an error on the display unit 52. .

  Next, a switch for turning on the power is turned on, and at the same time, some of the buttons on the operation unit 53 are pressed in combination. At the same time when the apparatus is activated, the display unit 52 displays a screen for the user to select for each image forming unit whether or not to detect an error depending on the mounting state of the image forming unit. In order to detect only the mounting of the black image forming unit 24K by operating the operation unit 53 while viewing the displayed screen, the user detects unit sensors 36Y, 36M, Select the setting to disable the 36C output. The selection signal is sent to the sensor trigger 54. The sensor trigger 54 transmits a signal for invalidating the output of the unit sensors 36Y, 36M, and 36C to the control unit 50 in accordance with the transmitted selection signal, and ends the setting.

  When a print command is transmitted from the user, the black unit sensor 36K outputs a mounting signal to the control unit 50 because the black image forming unit 24K is mounted. The other unit sensors 36Y, 36M, and 36C output unmounted signals, but since these outputs are set to be invalid, the control unit 50 outputs a command to perform printing to the operation mode setting unit 51. At the same time, an output for displaying the print on the display unit 52 is performed. Next, a printing operation is performed. The printing operation is the same as that described in the first embodiment, and a description thereof will be omitted.

  As described above, according to the second embodiment, since the validity and invalidity of a plurality of unit sensor outputs are set in advance, even when the user transmits a large number of print commands, the print command is transmitted. The printing operation can be performed without releasing the printing prohibition operation. In the second embodiment, the case where only one image forming unit is not mounted has been described. However, it is needless to say that printing can be similarly performed when there are two to three unmounted units. Absent. Further, when the error detection selection screen is displayed, a plurality of buttons of the operation unit 53 are combined and pressed. However, a single button may be pressed and operated. Further, even if there is no display unit, a printable operation may be performed by pressing a specific button.

  Next, a third embodiment will be described. In a color printer that operates with all image forming units mounted, a temperature difference (T1 <T2) is generated between the toner fixing temperature T1 for monochrome printing of end colors and the toner fixing temperature T2 for full-color printing. Provided. This is because there is a difference in the thickness of the toner layer transferred onto the paper between monochrome printing and color printing, so the amount of heat applied by the fixing device is changed in order to reliably melt and fix the toner according to each case. This is because of doing so. However, for example, when only two-color image forming units are mounted, the fixing temperature is set to the same (T2) as that during color printing, and as a result, a printing failure called hot offset may occur. The third embodiment has been made in view of such circumstances.

  FIG. 6 is a block diagram showing the main part of the third embodiment. In FIG. 6, the control unit 60 receives output signals from the unit sensors 36K, 36Y, 36M, and 36C, and receives an invalid command for a specific image forming unit transmitted from the sensor trigger 64, and performs printing. The number of effective image forming units can be recognized. The fixing temperature when a single color image forming unit is attached is T1, the fixing temperature when a two color image forming unit is attached is T2, and the fixing temperature when a three color image forming unit is attached is T3. When the fixing temperature when all the image forming units are mounted is T4, a fixing temperature relation table 65 satisfying T1 <T2 <T3 <T4 is provided. In the table 65, a fixing temperature (standby temperature) Tw at the end of the printing operation or when waiting is set. The standby temperature Tw is normally set to be substantially the same as or slightly lower than T1.

  Similar to the second embodiment, the operation mode setting unit 61 performs a single color operation mode, a two-color operation mode, and a three-color operation according to the number of mounted image forming units in addition to the operation mode for prohibiting the printing operation. The operation mode and the full color operation mode can be switched. Other configurations are the same as those of the second embodiment.

  Next, the operation of the third embodiment will be described. First, it is assumed that only one image forming unit (for example, only a black image forming unit) is mounted, and the control unit 60 recognizes that only one image forming unit is mounted by the sensor trigger 64. . In this case, the control unit 60 sets T1 as the fixing temperature from the table 65. When a print command is received from the user in this state, as described in the second embodiment, the output of the unit sensor at the position where the image forming unit is not mounted is invalidated and the image forming unit is mounted. Only the unit sensor is valid, and the printing operation is performed only with the mounted image forming unit.

  At this time, the fixing temperature of the fixing device 26 is increased from the standby temperature Tw to the monochrome fixing temperature T1, and then the printing operation is performed. Since the toner layer on the paper is fixed at the monochrome fixing temperature T1, the toner layer can be fixed satisfactorily.

  Next, when printing is performed using the two-color image forming units, for example, when the black image forming unit 24K and the yellow image forming unit 24Y are mounted, the user temporarily turns on the power switch. The power switch is turned on while pressing a plurality of buttons of the operation unit 63 in combination. The apparatus is activated and displays on the display unit 62 a screen for the user to select whether to detect an error depending on the mounting state of the image forming unit for each image forming unit.

  While viewing the displayed screen, the user operates the operation unit 63 to detect only the mounting of two image forming units (for example, 24K and 24Y). 24C) is selected to disable the output of the unit sensor (for example, 36M, 36C) corresponding to 24C). The selection signal is sent to the sensor trigger 64. The sensor trigger 64 transmits a signal for invalidating the outputs of the two unit sensors (for example, 36M and 36C) to the control unit 60 according to the transmitted selection signal, and ends the setting.

  The control unit 60 receives a signal for invalidating the outputs of two unit sensors (for example, 36M and 36C), and simultaneously sets the fixing temperature to T2. When a two-color printing command is transmitted from the user, the control unit 60 determines whether printing is possible. If it is determined that the printing is possible, the fixing temperature of the fixing device 26 is increased from the standby temperature Tw to the two-color fixing temperature T2. Let Thereafter, the printing operation is started. Although the printing operation is as described above, since the two-color toner layer on the paper is fixed at the two-color fixing temperature T2, the toner layer can be fixed satisfactorily.

  Printing using a three-color image forming unit can be performed in the same manner as in the case of two colors. In this case, the fixing temperature is set to the fixing temperature T3 for three colors. In the case of full-color printing, printing is performed by setting the full-color fixing temperature T4.

  As described above, according to the third embodiment, the fixing temperature is set to an appropriate value according to the number of mounted image forming units, so that an appropriate amount of heat is supplied to the toner layer transferred onto the sheet. Thus, the user can always obtain a good print result. In the above embodiment, the temperature difference is provided in all cases so that the fixing temperature in each of single color, two colors, three colors, and full color is T1 <T2 <T3 <T4. For example, a fixing temperature table such as T1 <T2 ≦ T3 ≦ T4, T1 ≦ T2 <T3 ≦ T4, T1 <T2 ≦ T3 ≦ T4, T1 <T2 <T3 ≦ T4, T1 <T2 ≦ T3 < A table such as T4 may be set. As described above, if there is a fixing temperature table corresponding to the number of mounted image forming units and there is a temperature difference that does not match between the case of a single color and the case of a full color, it deviates from the third embodiment. Not what you want.

  The following fourth embodiment will be described. In the fourth embodiment, the time from when a print command is transmitted until the printing operation is completed is shortened. When the printing operation is completed or in a standby state, as described in the third embodiment, Tw is set as the standby temperature. The standby temperature Tw is a fixing temperature T1 during monochromatic printing. It is set to the same or slightly lower temperature. Although it is conceivable to set the standby temperature Tw to a temperature close to the fixing temperature T4 at the time of full-color printing, the reason for keeping it close to the fixing temperature T1 at the time of monochrome printing is that the temperature decrease rate per unit time is compared with the temperature increase rate. It is small. However, if the standby temperature Tw is set close to the fixing temperature T1 for monochrome printing, monochrome printing can start printing immediately, but in the case of full-color printing, it takes time until the fixing temperature reaches T4. Similarly, in the case of three-color printing and two-color printing, although not as much as in the case of full-color printing, it takes more time than monochrome printing.

  FIG. 7 is a block diagram showing the main part of the fourth embodiment. The control unit 70 receives output signals from the unit sensors 36K, 36Y, 36M, and 36C, and also receives an invalid command for a specific image forming unit transmitted from the sensor trigger 74, and forms an image that is effective for printing. Recognize the number of units. As in the third embodiment, the fixing temperature when the single color image forming unit is mounted is T1, the fixing temperature when the two color image forming unit is mounted is T2, and the three color image forming unit. A fixing temperature relationship table 75 that satisfies T1 <T2 <T3 <T4 is provided, where T3 is a fixing temperature when T is attached and T4 is a fixing temperature when all image forming units are attached.

  The table 75 has a standby temperature Tw when a single-color image forming unit is mounted, a standby temperature Tw2 when a single-color image forming unit is mounted, and a standby temperature when a three-color image forming unit is mounted. Tw3 and standby temperature Tw4 when all image forming units are mounted are also set, and these standby temperatures are set to satisfy Tw1 <Tw2 <Tw3 <Tw4. Similar to the second embodiment, the operation mode setting unit 71 performs a single color operation mode, a two-color operation mode, and a three-color operation according to the number of mounted image forming units in addition to the operation mode for prohibiting the printing operation. The operation mode and the full color operation mode can be switched. Other configurations are the same as those of the second embodiment.

  Next, the operation of the fourth embodiment will be described. First, it is assumed that only one image forming unit (for example, only a black image forming unit) is mounted, and the control unit 70 recognizes that only one image forming unit is mounted by the sensor trigger 74. . In this case, the control unit 70 sets T1 as the fixing temperature from the table 75 and sets Tw1 as the standby temperature. When a print command is received from the user in this state, as described in the second embodiment, the output of the unit sensor at the position where the image forming unit is not mounted is invalidated and the image forming unit is mounted. Only the unit sensor is valid, and the printing operation is performed only with the mounted image forming unit.

  At this time, the fixing temperature of the fixing device 26 is raised from the standby temperature Tw1 to the monochrome fixing temperature T1, and then the printing operation is performed. Since the toner layer on the paper is fixed at the monochrome fixing temperature T1, the toner layer can be fixed satisfactorily.

  Next, when printing is performed using the two-color image forming units, for example, when the black image forming unit 24K and the yellow image forming unit 24Y are mounted, the user temporarily turns on the power switch. The power switch is turned on while pressing a plurality of buttons of the operation unit 73 in combination. The apparatus is activated and displays on the display unit 72 a screen for the user to select whether to detect an error depending on the mounting state of the image forming unit for each image forming unit.

  While viewing the displayed screen, the user operates the operation unit 73 to detect only the mounting of two image forming units (for example, 24K and 24Y), so that other image forming units (for example, 24M, 24C) is selected to disable the output of the unit sensor (for example, 36M, 36C) corresponding to 24C). The selection signal is sent to the sensor trigger 74. The sensor trigger 74 transmits a signal for invalidating the outputs of the two unit sensors (for example, 36M and 36C) to the control unit 70 according to the transmitted selection signal, and ends the setting.

  The control unit 70 receives a signal for invalidating the outputs of the two unit sensors (for example, 36M and 36C), and simultaneously sets the fixing temperature to T2 and sets the standby temperature to Tw2. When a two-color printing command is transmitted from the user, the control unit 70 determines whether printing is possible. If it is determined that the printing is possible, the fixing temperature of the fixing device 26 is increased from the standby temperature Tw2 to the two-color fixing temperature T2. Let Thereafter, the printing operation is started. Although the printing operation is as described above, since it takes no time to raise the temperature from the standby temperature Tw2 to the fixing temperature T2 for two colors, the toner layer can be satisfactorily fixed in a shorter time.

  Printing using a three-color image forming unit can be performed in the same manner as in the case of two colors. In this case, the fixing temperature is set to the fixing temperature T3 for the three colors, and the standby temperature is set to Tw3. In the case of full-color printing, printing is performed with the full-color fixing temperature T4 set and the standby temperature set to Tw4. As a result, printing can be performed in a shorter time in both three-color printing and full-color printing.

  As described above, according to the fourth embodiment, not only the fixing temperature but also the standby temperature is changed according to the number of mounted image forming units, so that an appropriate amount of heat is supplied to the toner, which is good. Not only can a print result be obtained, but also printing can be completed in a shorter time.

  In the fourth embodiment, the temperature difference is provided in all cases so that the standby temperature in each of single color, two colors, three colors, and full color is Tw1 <Tw2 <Tw3 <Tw4. For example, a standby temperature table such as Tw1 <Tw2 ≦ Tw3 ≦ Tw4, Tw1 ≦ Tw2 <Tw3 ≦ Tw4, Tw1 <Tw2 ≦ Tw3 ≦ Tw4, Tw1 <Tw2 <Tw3 ≦ Tw4, Tw1 <Tw2 ≦ A table such as Tw3 <Tw4 may be set. As described above, if there is a fixing temperature table corresponding to the number of mounted image forming units and there is a temperature difference that does not match between the case of a single color and the case of a full color, it deviates from the fourth embodiment. Not what you want.

  In addition, the relationship between the fixing temperature and the standby temperature is the same or close temperature relationship table in each case. For example, Tn≈Twn (n = 1, 2, 3, 4), 0.9Tn ≦ Twn ≦ 1.1Tn (n = 1, 2, 3, 4) may be set.

1 is a schematic side view showing a color printer of a first embodiment. 1 is a schematic side view showing a color printer of a first embodiment. It is a block diagram which shows the principal part of 1st Embodiment. It is a schematic side view showing a state where only one image forming unit is mounted. It is a block diagram which shows the principal part of 2nd Embodiment. It is a block diagram which shows the principal part of 3rd Embodiment. It is a block diagram which shows the principal part of 4th Embodiment.

Explanation of symbols

24K, 24Y, 24M, 24C Image forming unit 36K, 36Y, 36M, 36C Unit sensor 40, 50, 60, 70 Control unit 41, 51, 61, 71 Operation mode setting unit 42, 52, 62, 72 Display unit 43, 53, 63, 73 Operation part 54, 64, 74 Sensor trigger

Claims (9)

In an image forming apparatus capable of mounting a plurality of image forming units,
Detecting means for detecting presence / absence of mounting of the plurality of image forming units;
A display unit that displays information indicating that the image forming unit is not mounted based on a detection result of the detection unit;
An instruction means for instructing image formation by an attached image forming operation when at least one of the plurality of image forming units is not attached;
An image forming apparatus comprising: a control unit that performs an image forming operation when an instruction for an image forming operation is given by the instruction unit. 2. The image forming apparatus according to claim 1, further comprising notification means for notifying an operator that an image forming operation is possible in a state where at least one image forming unit is not attached. The image forming apparatus according to claim 2, wherein the notification unit is a display unit. The image forming apparatus according to claim 1, wherein the instruction unit is an operation unit that presses a button. In an image forming apparatus capable of mounting a plurality of image forming units,
Detecting means for detecting presence / absence of mounting of the plurality of image forming units;
Invalidating means for invalidating detection of the detecting means;
An image forming apparatus comprising: a control unit configured to perform an image forming operation by a mounted image forming unit based on a detection result of the detecting unit and the invalidating unit. The image forming apparatus according to claim 5, wherein the fixing temperature is changed according to the number of image forming units that are mounted and perform an image forming operation. The image forming apparatus according to claim 6, wherein the standby temperature of the fixing unit is changed according to the number of image forming units that are mounted and perform an image forming operation. In an image forming apparatus capable of mounting a plurality of image forming units,
A storage section for storing fixing temperature information set based on the mounted image forming section;
Determining means for determining whether or not each of the plurality of image forming units is mounted;
An image forming apparatus that performs an image forming operation by a mounted image forming unit based on the presence or absence of mounting of the image forming unit determined by the determining unit and the fixing temperature information stored in the storage unit. 9. The image forming apparatus according to claim 8, further comprising a standby temperature table set according to the number of mounted image forming units.

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