JPH05107850A - Image forming device - Google Patents

Abstract

PURPOSE:To provide the image forming device where desired copying can be finished in a short period of time without carrying out exessive resetting of fixing temperature for each type of an original by not carrying out copying of the original at the fixing temperature which is different from that set temperature and ejecting the original if the fixing temperature is once set to match the type of original, such as black and white or color. CONSTITUTION:In the image forming device provided with fixing means 26 and 27 heat fixing a toner developed image to a specified member, their heating means, their heating temperature detection means, image reading means 1 to 7 which carry out automatic recognition of the black and white original and the color original, a control means controlling the fixing temperature according to the fixing mode, and an original carrying means, a mixed placed original instruction inputting means is provided ejecting one type of the original of the black and white original or the color original by the original carrying means without carrying out the copying operation after the image is read by the image reading means 1 to 7 when the originals where the black and white original and the color original are mixedly placed is set to the original carrying means and copying is executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus such as a copying machine, and more particularly to an image forming apparatus having fixing temperature control means.

[0002]

2. Description of the Related Art An electrostatic latent image is formed by exposing a light image corresponding to a document onto a uniformly charged electrostatic latent image carrier such as a photoconductor. An electrophotographic image obtained by developing with two or more color toners to form a toner development image, transferring the toner development image to a supporting member such as transfer paper, and then heating and fixing it to obtain a copy image corresponding to the original. Forming devices are well known. In such an image forming apparatus, in order to obtain a better image quality under various conditions such as a mode such as a single color mode or a multicolor mode, the color of the toner of the developer, the difference in the glossiness of the image, etc. Various examples in which a plurality of preset temperatures of the fixing roller are provided have been proposed, for example, 1. JP-A-58-120283, 2. JP-A-61-70571,
3. JP-A-61-126585, 4. JP-A-63-85764, 5.
JP-A-63-231474, 6. It is disclosed in JP-A-64-29887. It is also known that the set temperature of the fixing roller is different between the standby state and the fixing state. JP 6
3-231474, 7. JP-A-61-94080, 8. JP 62-20
No. 6580, 9. It is disclosed in JP-A-62-206581.

[0003]

By the way, in each of the above-mentioned prior arts, there is provided a means for controlling the fixing temperature depending on the mode, the color of the toner of the developer, the difference in image quality, etc., and the waiting time and the fixing time. Although a technique for changing the set temperature of the fixing roller is disclosed, it does not describe the case where an automatic document feeder conveys and copies a mixed original document in which black and white original documents, color original documents, and the like are mixed. Further, among the above-mentioned prior arts, those described in 1 to 6 may have a difference in fixing roller temperature between (copying) fixing and standby in the same manner as in 7 to 9, and therefore, the standby state. It is not always the case that copying is possible immediately from. That is, in an image forming apparatus having a different fixing temperature depending on a copy original such as a black-and-white original or a color original, when a mixed original including a black-and-white original and a color original is mixed and conveyed by an original feeder,
If the fixing temperature is reset depending on whether the original is a black-and-white original or a color original after reading the original, multiple resetting times are added to the copy time, which causes a problem that it takes too much time for copying. ..

The present invention has been made in view of the above circumstances, and once the fixing temperature is set according to the type of original such as a black-and-white original or a color original, an original having a fixing temperature different from the set temperature is set. An object of the present invention is to provide an image forming apparatus capable of ejecting a document without executing copying and ending desired copying without requiring an extra resetting time of fixing temperature.

[0005]

In order to achieve the above object, in the present invention, a fixing means for heating and fixing by passing a supporting member carrying an unfixed toner development image between one or a pair of heated fixing rollers and a fixing means. A heating means for heating the fixing roller; a temperature detecting means for detecting the temperature of the fixing roller; an image reading means for automatically recognizing a black-and-white original and a color original; and a first different first and second fixing modes at the time of fixing. , Second
Control means for controlling the temperature of the roller to a set temperature of,
In an image forming apparatus having an original conveying means for conveying a set original to an exposure position on a contact glass and discharging after exposure, an original on which a black and white original and a color original are mixed is set on the original conveying means to execute copying. At this time, one of the black-and-white original and the color original has a mixed original instruction inputting means for discharging the original by the original conveying means without performing a subsequent copying operation after the image is read by the image reading means. To do.

[0006]

In the image forming apparatus of the present invention, when the original on which the black and white original and the color original are mixed is set on the original conveying means and copying is executed, the mixed original instruction input means is used.
Either one of the black and white original and the color original is controlled so that the original is discharged by the original conveying means without performing the subsequent copying operation after the image is read by the image reading means. Copying work is carried out,
Since it is not necessary to change the setting of the fixing temperature each time the document type is changed, the time required for changing the setting of the fixing temperature can be saved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments. First, an outline of the image forming apparatus of the present invention will be described with reference to the embodiment of FIG. In FIG. 1, the image forming apparatus includes an image reading unit, a writing unit, a developing unit, a fixing unit, a sheet feeding unit, and a transfer sheet conveying unit. The image reading means includes a contact glass 1 on which a document is placed, an illumination lamp 2 for illuminating the document, a first mirror 3 that moves integrally with the illumination lamp 2 in the scanning direction, and the first mirror 3 is interlocked and is the same. Second and third mirrors 4, 5 that move in the scanning direction, an imaging lens 6 that forms a reflected light image from a document, and an image is read for each pixel at the imaging position of the imaging lens 6 and photoelectric conversion is performed. The color image sensor 7 and the like are used. In the image reading unit having the above configuration,
When the document is illuminated and scanned, the document image is captured by the color image sensor 7.
Is subjected to color separation for each pixel and then converted into a digital signal.

Next, the writing means for the photosensitive member 8 converts the digitized original information into a driving current for the laser diode (LD) 9 for each color (not shown), and substantially matches the original image density. An optical output is output from the LD 9, and this output light is converted into an image forming optical system 11 including a rotating mirror 10 and an fθ lens.
And the mirror 12 form an image on the photoconductor 8 and scan it. Here, the normal image and the mirror image can be written on the photoconductor 8 by temporarily storing and changing the order of writing to the photoconductor 8 in a storage unit (not shown).

Next, the image forming means including the developing means and the transfer means is means for visualizing the latent image written by the writing means on the photoconductor 8 as a toner image and transferring it to the transfer paper. The developing means 13 is composed of four developing devices, each of which is housed in a region divided into four parts in the rotary cylinder 14, and these four developing devices are the developing device 13Y for yellow (Y) toner development and the magenta ( M) Developing device 13M for developing toner,
It includes a developing device 13C for developing cyan (C) toner and a developing device 13B for developing black (B) toner. In each of these developing devices, in accordance with the arrival of the latent image of the color to be visualized, the developing device containing the toner of that color stops at the position facing the photoconductor 8 and the development is performed. The latent image formed on the photoconductor 8 before the development is a mirror image in the case of a black-and-white document and a normal image in the case of a color document.

In the case of a color original, a normal color toner image is transferred by a charger 16 to a belt intermediate transfer member 15 arranged opposite to the photoconductor 8. Then, this operation is repeated for each color to form a color image on the belt intermediate transfer member 15. At this time, the paper feed cassette 17 (or
18) The transfer paper stocked on top is sequentially fed from the transfer paper on the upper surface side by a paper feed roller 19 (or 20), and is fed to a registration roller 22 by a feed roller 21 and is on standby.

Next, the registration roller 22 is driven so that the head of the black toner image on the photoconductor 8 or the head of the color toner image on the belt intermediate transfer body 15 coincides with the head of the transfer paper, and the black on the photoconductor 8 is driven. The toner image is transferred onto the transfer paper by the charger 16, and the color toner image on the belt intermediate transfer body 15 is transferred onto the transfer paper by the chargers 23 and 24, and finally transferred onto the belt intermediate transfer body 15 by the charger 25. The paper is separated and conveyed to the fixing means. The fixing means is composed of fixing rollers 26 and 27 arranged opposite to each other, and the unfixed toner image on the transfer paper separated from the belt intermediate transfer member 15 is fixed by passing between these fixing rollers 26 and 27. To be done.

Next, the transfer paper conveying means will be shown. The path of the transfer sheet after passing through the fixing means is changed by the first switching claw 28. First, when the first switching claw 28 is in the A position, the transfer paper is discharged to the paper discharge tray 30 via the paper discharge roller 29. Next, when the first switching claw 28 is in the B position, the transfer sheet is once conveyed downward. At this time, the second switching pawl 35 is in the A position, the transfer rollers 31 to 34 are temporarily stopped after the trailing edge of the transfer paper passes through the paper detection element 36, and the first switching pawl 28 is returned to the position A and then reversed. The transfer paper is rotated and is reversed and discharged onto the discharge tray 30 by the discharge roller 29.
Next, when the first switching claw 28 is in the B position and the second switching claw 35 is changed to the B position after the rear end of the transfer paper has passed the paper detection element 37, the transport rollers 31 to 34 are temporarily stopped and then reversed. By the rotation, the transfer paper is stacked on the intermediate tray 38 which is an intermediate stacking means, and then the transfer paper is conveyed to the registration roller 22 by the re-feeding roller 39 by the copy command again.

Next, auxiliary means on the periphery of the photosensitive member 8 and the belt intermediate transfer member 15 will be described. The charger 40 is a charger for lowering the potential of the photoconductor 8 under the toner image, and has an effect of increasing the transfer efficiency of the toner image. The charger 41 lowers the potential of the photoconductor 8 under the residual toner after transfer, and the cleaning unit 42 removes all the residual toner from the photoconductor 8. The charge eliminating lamp 43 is the photoconductor 8
The charger 44 is a lamp for erasing the residual potential, and the charger 44 is a charging unit for the photoconductor 8. The dustproof glass 45 prevents the writing means from being contaminated by the toner, paper dust or the like around the photoconductor 8. The charger 46 is a belt intermediate transfer member 15
Charger 47 for changing the polarity of the surface.
Is a charge removal charger for changing polarity after cleaning the surface of the belt intermediate transfer member 15. The cleaning unit 48 is a cleaning unit for removing the residual toner after the transfer on the belt intermediate transfer body 15, and is released when the toner image is held on the belt intermediate transfer body 15.

Next, an example of the image data processing system implemented by the image forming apparatus of the present invention is shown in the block diagram of FIG. 2, and the image data processing will be described. The configuration of this image data processing system includes an image reading unit, an image processing unit, a writing unit, and a storage unit. In the image reading unit, a CCD (image pickup device) 102 photoelectrically converts document image data. Also C
The CD drive unit 101 is CC-dependent according to the resolution (dots / mm).
Drive D. Each color component (R (red) .G (green) .B (blue)) converted into electric signal by CCD 102
Is subjected to amplification, dark current correction, shading correction, and A / D conversion in the analog processing unit 103. A / D
The digital image processing unit 104 corrects the positional deviation of each color component of the read line in the converted image data. In this way, each color component signal is sent to the image processing unit 106 without positional deviation.

The clock generator 105 generates a basic image frequency and transfers it to the CCD driver 101. The image processing unit 106
Color processing (RGB → YMC, etc.), magnification processing, etc. are performed, and it is determined here whether the original is a monochrome original or a color original.
Then, the image data converted into YMCB (yellow, magenta, cyan, black) is sent to the writing unit. The writing control unit 108 performs writing speed correction, writing position deviation correction, and the like, and the LD driving unit 109 converts the digital signal indicating the image density into an LD driving current (PWM, power modulation) and sends it to the LD 110. Next, the storage unit stores each color component data after color processing for one maximum original in YMCB format in the frame memory 107.

Next, the configuration of the entire control system of the image forming apparatus according to the present invention will be described with reference to the block diagram of FIG. In FIG. 3, fixing heaters 201 and 202 are roller heating heaters incorporated in the fixing rollers 26 and 27 shown in FIG. 1, respectively. The system controller comprises a main control unit and a key input control unit (not shown) in the operation unit. Various input copy modes are processed by the key input control unit,
Outputs data to the image processing unit. The image processing unit performs processing such as magnification change based on the input data. In addition, the input copy mode is controlled by the motor controller through the main controller.
Data is output to the process control unit and the like. The motor control unit controls various motors (scanner, conveyance, developing, belt intermediate transfer body, etc.) by a predetermined operation. The process control unit controls ON / OFF and output values of a lighting lamp, a high voltage power supply, and the like. The various sensors are composed of elements for detecting the presence or absence of transfer paper and the surface temperature of the fixing roller, and the output values are input to the system controller. The other DC loads are composed of an electromagnetic clutch such as a paper feed roller and an electromagnetic solenoid such as a switching claw, and the operation is controlled by the main control unit in the system controller. The option includes an automatic document feeder, etc., and the DC power supply supplies power to various loads.

Next, an example of the structure of the fixing means implemented in the image forming apparatus of the present invention will be described with reference to FIG. FIG. 4A is a diagram showing a schematic configuration of the fixing rollers 26 and 27 which constitute the fixing means, and passes between the fixing rollers 26 and 27 through a supporting member such as a transfer paper carrying an unfixed toner development image. As a result, the unfixed toner developed image is heated and fixed by the fixing rollers 26 and 27 and fixed on the supporting member. In addition, in FIG.
26 is a first fixing roller, 201 is a first heating means for heating the first fixing roller 26, and 203 is a first temperature detecting element for detecting the temperature of the first fixing roller 26. Similarly, 27 is a second fixing roller, and 202 is a second fixing roller 27 for heating the second fixing roller 27.
Heating means 204 is a second temperature detecting element for detecting the temperature of the second fixing roller 27. Here, the temperature sensing element is 20
3, 204 are thermistors and the like, and heating means 201, 202
Is a halogen heater or the like.

Next, FIG. 4B is a block diagram of the temperature control system of the fixing rollers 26 and 27, and the temperature control of the fixing rollers is as follows. For example, in the case of the temperature detecting elements 203 and 204 which are thermistors, their resistance values uniquely correspond to the fixing roller temperature. When a voltage value corresponding to this resistance value is input to the AD terminal of the CPU in the system controller shown in FIG. 3, this voltage value (analog input) is converted into a digital value by the A / D converter built in the CPU. .. Next, the digital value and the reference value are compared, and the SSR is turned on / off through the I / O driver based on the comparison result, whereby the halogen heaters of the first and second heating means 201, 202 are turned on respectively. / OFF, both fixing rollers 26,
27 are controlled to arbitrary temperatures, respectively. The ROM in the system controller is a read-only memory that stores a control program, the RAM is a rewritable memory for recording data, and the RAM is a non-volatile memory that is energized even when the main SW shown in FIG. 3 is disconnected. RAM.

Next, FIG. 5 is a flow chart showing the flow of temperature control of the fixing roller at the time of (copy) fixing which is carried out by the image forming apparatus of the present invention. As shown in FIGS. 4 and 5, for temperature control, first, the first and second temperature detecting elements 20
At 3, 204, the temperatures (resistance value → voltage value (analog) → digital value) D ₁ and D ₂ of the fixing rollers 26 and 27 are detected. Next, from the fixing mode determined by the type of document, set temperature data D ₀₁ ,
D ₀₂ (first and second fixing roller set temperature data) has first fixing mode (or second fixing mode) temperature data D _{11 respectively.}
(Or D ₂₁ ) and D ₁₂ (or D ₂₂ ) are set. Next, the detected temperature data D ₁ and D ₂ are respectively set temperature data D ₀₁ ,
Compared with D ₀₂ , turn on or off SSR 211, 212,
The first and second heating means 201, 202 are turned on or off.

Next, FIG. 14 is an explanatory view of the setting operation and display of the fixing roller temperature during standby, which is carried out by the image forming apparatus of the present invention. Further, FIG. 12 shows a configuration example of an operation unit (operation panel) of the image forming apparatus, and FIG. 13 shows a block diagram of a display control system of the operation unit. To set the fixing roller temperature during standby, the keys in the operation unit shown in FIG. 12 are depressed in the following order. First, mode clear key 513 and enter key 507
Press, then use the numeric keypad 502 to select [1] [0] [1] (or
When [1] [0] [2]) is pushed down, the display shown in FIG. 14 is displayed on the display section 5-A in the operation section. Where the numeric keypad 502
By pressing [1] or [0], the temperatures of the first and second fixing rollers can be arbitrarily set. Then, the set data is stored in the nonvolatile RAM in the system controller shown in FIGS.

Next, with reference to FIGS. 6, 7 and 8, a waiting time calculating means for waiting, which is implemented in the image forming apparatus of the present invention, will be described. FIGS. 6 (a) and 6 (b) show the time taken for the first fixing roller to reach the first and second fixing temperatures, respectively. In the example, when the standby temperature is 170 ° C. The time to reach 2 fixing mode is 1.5 minutes and 4 minutes, respectively. Here, in FIGS. 6A and 6B, the temperature of the first fixing roller is 150 ° C., respectively.
FIG. 3 is a diagram showing the time required for cooling and heating to 180 ° C. First, as shown in the flowchart of FIG. 7, the temperature detection data D ₁ of the first fixing roller and the set temperature data D ₁₀₀ (180 ° C.) and D ₂₀₀ (150 ° C.) in the first and second fixing modes are set.
Differences D ₁₀₁ and D ₁₀₂ are obtained, and then the time data T ₁₀₁ and T ₁₀₂ obtained from FIGS. 6A and 6B are multiplied. Next, FIG.
As shown in the flowchart in FIG.
Also for the fixing roller, the difference from the set temperature data D ₂₀₁ ,
The result of calculating D ₂₀₂ is compared, and the time data T ₁ and T ₂ required for a long time are taken as the time to reach the first and second fixing modes, respectively. Finally, T ₁ and T ₂ are compared and the mixed document support input is turned on.
At this time, the first and second fixing modes are set to the short time fixing mode.

Next, FIG. 9 shows a flowchart for discharging an original, which is executed by the image forming apparatus of the present invention, and the control operation for discharging the original will be described. The original set on the original conveying means is conveyed on the contact glass. Next, the original is read by the image reading means, and the fixing mode selected from the original is set to the desired fixing mode. Finally, Figure 8
It is confirmed that the fixing mode set in step 1 and the desired fixing mode match, but when they do not match, the original is ejected. That is, in the image forming apparatus of the present invention, in the case of mixed originals, originals in a fixing mode different from the set fixing mode are ejected without executing copying.

FIG. 10 shows an example of the automatic document feeder implemented in the image forming apparatus of the present invention, and the operation thereof will be described below with reference to FIG. The document set table 50 is a table for placing a document before copying. The original set on the original setting table 50 is fed by the calling roller 51 from the lower surface (the image surface of the first page of the original). At this time, the original is called by the entrance guide mylar 52.
It is pressed against 51. With respect to the plurality of fed originals, the separation roller 53 and the separation blade 54 further convey the first page (lowermost surface) of the originals to the pullout rollers 55 and 56. At this time, since the calling roller 51 and the separation roller 53 are stopped, the document is conveyed to the document conveying belt 57 by the pullout rollers 55 and 56. The document transport belt 57 is
It is driven by the press roller 58 and conveys the document to a predetermined position on the contact glass 1. Then, the document after the exposure is conveyed again by the document conveyance belt 57, and is further ejected to the document ejection tray 61 by the intermediate conveyance roller 59 and the ejection roller 60. At this time, the switching claw 62 is lifted and is in a horizontal state, and is not on the document conveyance path. The document set sensor 63 and the document sensors 64 and 65 are sensors for confirming the presence or absence of a document.

Next, the document reversing operation will be described. The original after the exposure on the contact glass 1 is conveyed by the original conveying belt 57. At this time, the switching claw 62 is in a state in which the leading end side is lowered as shown in the figure. Therefore, the document is conveyed vertically upward and is rotated once by the reversing drive roller 66 and the turn roller 67 to be fed onto the contact glass 1. .. Here, the document is transported to a predetermined position on the contact glass 1 by the document transport belt 57 that moves in the direction opposite to the document discharge direction.

Next, the original after the exposure of the second side of the original is completed is conveyed by the original conveying belt 57. At this time, the switching claw 62
As shown in the figure, since the leading end side is lowered, the document is conveyed in the vertical upward direction again. After the trailing edge of the document passes through the reversal entrance sensor 68, the drive motors (not shown) of the reversing drive roller 66 and the turn roller 67 reversely rotate, so that the document is ejected to the document ejection tray 61. At this time, the original on the next page is read from the original setting table 50 on the contact glass 1
It has been transported to a predetermined position above. By the operation described above, the originals are ejected onto the original ejection tray 61 in page order.

Next, the image forming mode of the image forming apparatus according to the present invention will be described with reference to FIG. Figure 11 (a)
Is a normal image forming mode for black and white originals. In this mode, after a mirror image latent image is formed on the photoconductor 8, the black image development unit 13B visualizes the mirror image latent image on the photoconductor 8 with black toner. After that, the toner image is transferred to the surface of the transfer paper. Figure 11 (b)
Is a normal image forming mode for color originals. In this mode, a normal image latent image is formed on the photoconductor 8 for each color component, and then each color development unit (not shown) is used to print on the photoconductor 8. The latent image of the normal image is developed, and the developed images are successively transferred and transferred onto the belt intermediate transfer member 15. And finally the belt intermediate transfer body
The color developed image on 15 is transferred to the back side of the transfer paper. Figure 1
Reference numeral 1 (c) shows an image forming mode of a black and white original and a black and white original when the transfer paper page alignment mode is selected when a color original is mixed. However, the color original is the same as the image forming mode shown in FIG. In this mode, when a black-and-white original is used, a positive latent image is formed on the photoconductor 8 and then the photoconductor 8 is formed by the black developing section 13B (not shown).
After visualizing the upper normal image latent image, the toner image is transferred onto the belt intermediate transfer member 15, and then the toner image is transferred onto the back surface of the transfer paper.

Next, FIG. 12 is an explanatory view schematically showing an operating section used in the image forming apparatus of the present invention. In FIG. 12, when the copy key 501 is ready for the copy operation, pressing this key starts the copy operation. Numeric keypad: 502 is a key for setting a desired number of copies. It can also be combined with other keys to perform other functions. Paper selection key: 503 is a desired paper feeding unit (see FIG. 1) arranged in the image forming apparatus.
This is the key for selecting (17, 18). Also, density adjustment key: 504
Is a key for adjusting the density of the copied image. Interrupt key: 5
Reference numeral 05 is a key that temporarily interrupts the current copy operation and enables other copy mode settings and copy operations. By pressing this key again, the interrupted copy mode can be restored.

A stop / clear key: 506 is a key for interrupting the copying operation and for clearing the number of copies, etc. Enter key: 507 is used in combination with mode clear key: 513 to adjust each setting value of the copying process. Fixed magnification /
Same size key: 508 is a key for setting a copy ratio. Further, the special variable magnification key: 509 can be combined with the numeric keypad: 502 to set an arbitrary copy magnification. Double-sided key: 510 is a key for switching between double-sided copying and single-sided copying. The image shift key: 511 can be combined with the ten key: 502 to shift the image front end and the image support member by a desired size. Editing key: 512
Is a key that enables masking / trimming of a desired area in combination with the numeric keypad: 502. Mode clear key: 513 is a key that enables to clear the copy mode. Display areas: 5-A and 5-B are display portions for performing graphic display (full dot) and fixed pattern display, respectively, by liquid crystal or the like.

Next, FIG. 13 is a block diagram showing a schematic configuration of a display control system in the case where the display of the display section is performed by liquid crystal. In FIG. 13, the signals from the above-mentioned keys: 525 are sent to the key display controller: 526, and the signals from the key display controller: 526 are sent to the liquid crystal display control unit: 521 via the interface: 517.
Liquid crystal display: Displayed by 522. Further, a signal from the system controller shown in FIG. 3 is also transmitted to the liquid crystal display control unit: 521 to display various information.

[0030]

As described above, according to the present invention, the fixing means for heating and fixing the toner development image on the indicating member, the heating means for the fixing means, the temperature detecting means for the heating temperature, the black and white original and the color original. In an image forming apparatus having an image reading unit for automatically recognizing a document, a control unit for controlling a fixing temperature according to a fixing mode, and a document conveying unit for feeding and discharging a document, a black-and-white document and a color document are mixedly mounted. When the original is set on the original conveying means and copying is performed, either one of the black and white original and the color original is read by the image reading means and then the original is conveyed by the original conveying means without performing the subsequent copying operation. The image forming apparatus according to the present invention is characterized in that it has a mixed document instruction inputting means for ejecting, and since each part is configured as described based on the illustrated embodiment, UNA is an effect. That is, when an original in which a black-and-white original and a color original are mixed is set on the original conveying means to perform copying, one of the black-and-white original and the color original is read without copying after the image is read. The original is discharged by the conveying means, and the copying operation of only one of the originals is performed, thereby saving the time required to change the set temperature of the fixing temperature when the fixing mode is changed due to the change of the original type, Since the fixing temperature is set only once when the mode is set or when the first original is read, the time from the start of copying to the end of copying can be performed in a short time, and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention.

FIG. 2 is a block diagram showing an example of an image data processing system implemented by the image forming apparatus of the present invention.

FIG. 3 is a block diagram showing an overall configuration of a control system implemented in the image forming apparatus of the present invention.

FIG. 4A is a diagram showing a schematic configuration of a fixing roller of a fixing unit implemented in the image forming apparatus of the present invention, and FIG. 4B is a block diagram of a temperature control system of the fixing roller heating unit.

FIG. 5 is a flowchart showing a flow of temperature control of a fixing roller at the time of fixing, which is carried out by the image forming apparatus of the present invention.

FIG. 6A is a diagram showing a time taken for the first fixing roller to reach a first fixing mode, and FIG. 6B is a diagram showing a time taken for the first fixing roller to reach a second fixing mode.

FIG. 7 is a flowchart illustrating a waiting time waiting time calculation method executed by the image forming apparatus of the present invention.

FIG. 8 is a flowchart showing a waiting time calculation method during standby, which is carried out by the image forming apparatus of the present invention, similar to FIG.

FIG. 9 is a flowchart showing a flow at the time of ejecting a document, which is executed by the image forming apparatus of the present invention.

FIG. 10 is a schematic configuration diagram showing an example of an automatic document feeder that is implemented by the image forming apparatus of the present invention.

11A, 11B, and 11C are explanatory diagrams for explaining the operation of the image forming apparatus of the present invention in each image forming mode.

FIG. 12 is an explanatory view schematically showing an example of an operation unit used in the image forming apparatus of the present invention.

13 is a block diagram showing a schematic configuration of a display control system in the case where liquid crystal is used to display the display unit shown in FIG.

FIG. 14 is an explanatory diagram showing an example of a setting operation and display of the temperature of the fixing roller during standby, which is carried out by the image forming apparatus of the present invention.

[Explanation of symbols]

 1 Contact Glass 2 Original Illumination Lamp 7 Color Imaging Element 8 Photosensitive Body 9 Exposure Light Source 10 Rotating Mirror 11 Imaging Optical System 15 Belt Intermediate Transfer Body 13 Developing Means 26, 27 Fixing Roller 42 Cleaning Device 201, 202 Heating Heater 203, 204 Temperature Sensing element

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location G03G 15/20 109 6830-2H H04N 1/29 E 9186-5C

Claims (1)

[Claims] 1. A fixing unit for heating and fixing a supporting member carrying an unfixed toner development image by passing it between one or a pair of heated fixing rollers, a heating unit for heating the fixing roller, and a temperature thereof. Temperature detecting means, image reading means for automatically recognizing black and white originals and color originals, and control for controlling the temperature of the rollers to different first and second set temperatures in the first and second fixing modes during fixing. In an image forming apparatus having means for conveying a set document to an exposure position on a contact glass and discharging it after exposure, a document on which a black-and-white document and a color document are mixed is set on the document conveying means and copied. When executing, either one of the black and white original and the original of the color is read by the original feeding means without performing the subsequent copying operation after the image is read by the image reading means. An image forming apparatus characterized by having a mixed original instruction input means for discharging.