JPH1039674A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the working efficiency in the image formation by permitting the fixing operation when the temperature reaches the lower temperature between the first temperature suitable for the fixing operation, and the second temperature necessary for fixing an image for the total area of the image to be formed. SOLUTION: A central control means CPU 1 calcualtes the total area of an image to be formed as the number of sheets of copy by conversion of standard paper, on the basis of the data input from an operation panel OP by an operator (number of sheets of copy, paper size), and a number of sheets of documents detected by the document size detecting sensors SE50-52. The minimum temperature necessary for fixing the image of the number of sheets of copy by conversion of standard paper, is calculated by utilizing the data stored in a read only memory ROM on the basis of the calcualted number of sheets of copy by conversion of standard paper. The start of the fixing operation can be permitted, when the temperature of a fixing member reaches the minimum temperature necessary for fixing the total image of the image to be formed corresponding to the using condition by the operator, so that the stand-by time of the operator can be made minimum, and the working efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer having a fixing device for thermally fixing a toner image on a recording medium by a fixing member.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as an electrophotographic copying machine having a heat fixing device, a normal mode in which a fixing member such as a fixing roller is maintained at a temperature (fixing temperature) suitable for fixing a toner image is used. And a power saving mode called a power saving mode such as a low power mode in which the fixing member is maintained at a temperature lower than the fixing temperature (standby temperature) or an off mode in which power supply to the thermal fixing device is stopped. Have been. Hereinafter, an electrophotographic copying machine having a heat fixing device will be described as an example.

Generally, the fixing temperature is set to a temperature at which a sufficient amount of heat can be given to the fixing member without causing a fixing defect even when a large number of copies are made.

A power saving mode such as the low power mode or the off mode is usually automatically selected when a predetermined time has elapsed while the copying machine is in a standby state. And
The low power mode is released by, for example, a key input on the operation panel by the operator. The off mode is released by, for example, the operator turning on the main switch again. After these modes are released, warming up of the fixing member at a temperature lower than the fixing temperature is started. When the fixing member reaches the fixing temperature, the copying (fixing) operation is permitted.

[0005] While such a power saving mechanism can obtain the effect of power saving, the warm-up time is a waiting time until the start of copying for the operator. For this reason, the warm-up time is set to a length within an allowable range of the operator so as not to be too long.

[0006]

However, in the above-described conventional copying machine, copying performed after returning from the low power mode or the off mode to the normal mode does not require a large amount of heat for fixing the toner image. Even in the case of a large number of copies, it is necessary to wait for the same warm-up time as in the case of copying a large number of copies, which is inferior in work efficiency.

In particular, in a high-speed copying machine using a home power supply or the like whose power capacity is limited, the fixing roller has a large heat capacity to cope with a power shortage during continuous copying. Uptime must be set relatively long. For this reason, the work efficiency was significantly reduced.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and it is an object of the present invention to provide an image forming apparatus in which the standby time until the start of image formation is minimized, thereby improving work efficiency. .

[0009]

The present invention for achieving the above object is constituted as follows for each claim.

According to the first aspect of the present invention, there is provided an image forming means for forming a toner image on a recording medium, a fixing member for thermally fixing the toner image, and a first temperature suitable for fixing the fixing member. Heating means for heating the image to be formed, a total area calculating means for calculating the total area of the image to be formed, and the fixing member for fixing the image of the total area calculated by the total area calculating means. Temperature calculating means for calculating a second temperature, and control means for controlling the fixing member to permit the fixing operation when the fixing member reaches the second temperature when the second temperature is lower than the first temperature. An image forming apparatus comprising:

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the total area calculating means includes:
The total area is calculated based on at least the size of the recording medium or the number of images formed.

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, the fixing member is connected to the first fixing member.
A normal mode for maintaining the temperature; and a power saving mode for keeping the fixing member at a temperature lower than the first temperature, wherein the control unit performs the control when returning from the power saving mode to the normal mode. It is characterized by.

According to a fourth aspect of the present invention, in the image forming apparatus according to the first aspect, the control unit performs the control when power is turned on.

[0014]

According to the invention specified as described above, the following effects can be obtained by the configurations described in the respective claims.

According to the first aspect of the present invention, when the temperature of the fixing member for thermally fixing the toner image reaches the minimum temperature (second temperature) required for fixing the image to be formed, the fixing is performed. The fixing operation is permitted even if the temperature (first temperature) suitable for (1) has not been reached.

According to the second aspect of the present invention, the total area is calculated based on at least the size of the recording medium or the number of images formed.

According to the third aspect of the invention, when returning from the power saving mode to the normal mode, the temperature of the fixing member is set to the second level.
If the temperature has been reached, the fixing operation is permitted even if the temperature has not been reached.

According to the present invention, when the temperature of the fixing member reaches the second temperature when the power is turned on, the fixing operation is permitted even if the temperature does not reach the first temperature.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view showing the overall configuration of a copying machine according to an embodiment of the image forming apparatus of the present invention, and FIG.
FIG. 3 is a block diagram for explaining an image signal processing unit and a memory unit shown in FIG. 3, FIG. 3 is an explanatory diagram showing a configuration of a code memory of the memory unit, and FIG. 4 is a plan view showing an operation panel of the copying machine. 5 is a schematic block diagram for explaining a control system of the copying machine, and FIG. 6 is a graph and a diagram showing a relationship between the number of copies of reference paper and the temperature of a fixing roller required for fixing the copied image. 7 is an explanatory diagram showing the configuration of a management table for managing the code memory of the memory unit, FIGS. 8 to 11 are flowcharts for explaining the processing of the central control means, and FIG. FIG. 13 is an explanatory diagram for explaining a standby time when returning from the power saving mode in the copying machine, and FIG. 13 is an explanatory diagram for explaining a standby time when returning from the power saving mode in the conventional apparatus.

The image forming apparatus shown in FIG. 1 is a so-called digital copying machine. The present embodiment is a copying machine having a low power mode, and when returning from the low power mode to the normal mode for performing copying, an image to be formed based on the number of copies, the sheet size, the number of documents, etc. Is calculated, and when the fixing member reaches a temporary fixing temperature (second temperature) which is a temperature that gives a heat amount necessary for fixing the image of the total area, the normal mode is set. This shows a copying machine in which a fixing (copying) operation is permitted even if the fixing temperature (first temperature), which is a temperature suitable for copying a large number of copies, has not been reached.

The copying machine 1 includes, in order from the top, a document transport section 500 having document size detecting means for feeding a document, an image reading section 10 for converting reflected light from the document into a photoelectric conversion signal,
An image signal processing unit 20 that converts a photoelectric conversion signal into a digital signal (image data) to perform image quality correction; a memory unit unit 30 that stores image data; a print processing unit 40 that generates an exposure control signal from the image data; A print head unit 60 that generates a laser beam in response to a signal, a developing / transfer unit 70A that is an image forming unit that forms a toner image on paper (recording medium), a fixing member that thermally fixes the toner image, and a fixing member that is fixed A fixing / discharging unit 70B that has a heating unit that heats the toner image to a temperature (first temperature) and that fixes and discharges the toner image onto the sheet, and a sheet conveying unit 70C that sends the sheet toward the developing / transferring unit 70A are arranged. ing. An operation panel (input / output means) described later is provided on the upper surface of the copying machine 1.
An OP is provided.

Further, a central control means C of the copying machine 1 described later.
PU1 constitutes a total area calculating means for calculating a total area of an image to be formed together with the input / output means and the document size detecting means, while a temperature calculating means for calculating a provisional fixing temperature;
When the provisional fixing temperature is lower than the fixing temperature, when the fixing member reaches the provisional fixing temperature, the fixing member also serves as control means for controlling so as to permit the fixing operation of the fixing member.

Next, the configuration of each section will be described.

Document transport unit 5 located at the top of copying machine 1
Reference numeral 00 denotes an automatic document feeder ADFR, which includes a document tray 510 on which documents are stacked, a feed roller 501 for sequentially feeding the documents on the document tray 510 from the bottom, and a feed roller 5.
Separating roller 50 for separating the document sent from the sheet feeding device 01
2, a separation pad 503, an intermediate roller 504 and a registration roller 505 for assisting the feeding of the document, and a transport belt 50 for closely transporting the document onto the platen glass 18.
6. Original scale 512 for positioning the original,
A reversing roller 507 for changing the document feeding direction;
, A discharge roller 509 for discharging the document to the document discharge table 511, and a document size detection sensor (detection means) SE50 to SE52.
have.

The image reading section 10 located below the document transport section 500 has a platen glass 18 on which a document is placed, an exposure lamp 11 and a mirror 12, and moves along the platen glass 18 at a predetermined speed. A scanner 19 for exposing and scanning, mirrors 13a and 13b and a condenser lens 14 for forming an optical path of reflected light (original image) from the original,
A line sensor 16 that converts an original image into a photoelectric conversion signal and outputs the photoelectric conversion signal to an image signal processing unit 20;
Document detection sensor SE for detecting the presence or absence of a document on
It has ten. Reference numeral "SW" in FIG. 1 is a main switch for turning on and off the power of the copying machine.

The image signal processing unit 20, which is located below the image reading unit 10 and receives a photoelectric conversion signal via the line sensor 16, has an image reading unit 10 as shown in detail in FIG.
A / D converter 21 that converts a photoelectric conversion signal of a document input from a digital camera into a digital signal, performs image quality correction (shading correction, gamma correction, scaling processing, and the like) of the digital signal, and outputs the processed signal to memory unit 30. Image processing unit 23,
A timing control unit 22 for outputting an image reading synchronization signal (image control signal); and an image monitor memory 24 for storing image data after image quality correction for each line in the main scanning direction.
have.

As shown in detail in FIG. 2, a memory unit section 30 located on the right side of the image signal processing section 20 in the drawing includes a bus switching section 31 connected to the image processing section 23 and the print processing section 40, Binarization processing unit 32 for converting the image data into binary image data; image memory 33 for storing binary image data; and compression for generating compressed code data (compressed data) from binary image data. , A code memory 37 for storing code data, a decompressor 36 for expanding data to be printed from the code data and reproducing binary image data, and inverting the reproduced image data as necessary. A processing unit 38 and a multi-value processing unit 39 for restoring multi-value image data are provided. Note that the compressor 35 and the decompressor 36 are collectively referred to as a code processing unit 34.

The compressor 35 and the decompressor 36 are configured to operate independently of each other and to operate in parallel to improve the copying speed. The DMA transfer is performed by a DMA controller that does not use it.

The code memory 37 stores, as shown in FIG.
Compressed data for each page is stored in each area in consideration of enabling simultaneous control of writing (at the time of reading) and reading (at the time of printing). Is done.

A print processing section 40 located below the memory unit section 30 in the figure has an exposure control signal for forming an electrostatic latent image by the print head section 60 based on the image data output from the memory unit section 30. And an exposure control signal generator (not shown).

A print head unit 60 located on the left side of the print processing unit 40 in the figure has a laser diode 62 which emits light under the control of an exposure control signal output from the print processing unit 40, and a laser beam of the developing / transfer unit 70A. Polygon mirror 65 and main lens 69 forming an optical path leading to the exposure position
And mirrors 67a, 67b, 67c.

The developing / transferring section 70A, which is located below the print head section 60 in the figure, has a photosensitive drum 71, which is exposed to a laser beam to form an electrostatic latent image on its surface, and has a photosensitive drum 71 in advance. Charger 72 of variable output, a developing unit 73 for developing an electrostatic latent image to form a toner image, a transfer charger 74 for transferring the toner image to a sheet, and a separation charger 75 for separating the sheet from the photosensitive drum 71 And a cleaner 76 for cleaning the photosensitive drum 71 to which the toner image has been transferred.

A fixing / discharging section 70B adjacent to the developing / transferring section 70A includes a sheet conveying belt 83 for conveying the sheet on which the toner image has been transferred, a heat roller 84b having a built-in heater (heating means) 87, and a heat roller 84b. A fixing roller (fixing member) 84 composed of opposed pressure rollers 84 a for fixing the toner image, a discharge roller 85 for discharging the fixed paper, and discharging the discharged paper to the discharge tray 621 or re-feeding the paper to the re-feeding path 86. It has a re-feeding unit 600 for feeding in, a heater driving unit and a thermistor (not shown).

The paper transporting section 70C adjacent to the fixing / discharging section 70B includes paper cassettes 80a and 80b for storing copying paper and feeding them one by one into the copying machine.
It has a timing roller 82 for feeding a sheet so as to coincide with the toner image on the photosensitive drum 71.

As shown in FIG. 4, an operation panel OP arranged on the upper surface of the copying machine 1 includes a liquid crystal display panel 91 for displaying an operation state and a message, a numeric keypad 92 for inputting numerical values such as the number of copies, and the like. Basic key 9 for instructing basic operation
3a-93d, paper selection keys 94a, 94b, magnification selection keys 95a-95d, and density selection keys 96a-9.
6c.

The basic keys include a clear key 93a for clearing data such as the number of copies input, a reset key 93b for canceling the set copy conditions and returning to an initial state, a stop key 93c for interrupting the copy operation, and a copy start. And a copy key 93d for instructing.

A paper selection key is an automatic paper selection mode key 94a for automatically setting a copy paper of an optimum size from the original size and the selected copy magnification, and a paper selection mode key for manually selecting the paper size. 94b.

A magnification selection key is an automatic magnification selection mode key 95a for automatically selecting an optimum copying magnification from the original size and the selected paper size, and a predetermined magnification / reduction ratio from a preset enlargement / reduction ratio. It is composed of an enlargement magnification selection key 95b and a reduction magnification selection key 95c for selecting a magnification, and an equal magnification key 95d for selecting an equal magnification.

A density selection key 96a is an automatic density mode key 96a for automatically adjusting the density so that the background of the document does not appear.
And a density down key 96b for manually inputting and adjusting the density to increase or decrease the copy density.
And a density up key 96c.

Next, the operation of each section will be described.

The transport of the original and the reading of the image are performed as follows.

First, the original set on the original feed tray 510 with the surface to be read facing upward is conveyed by the feed roller 501 in order from the bottom, and
The sheets are separated by the separation pad 503 and fed one by one.

The fed document passes through the intermediate roller 504 and the skew is corrected by the registration roller 505.
Immediately after the trailing edge of the document passes the left edge of the document scale 512, the transport belt 506 slightly reverses and stops.
As a result, the right end of the document comes into contact with the edge of the document scale 512, and the document is accurately positioned on the platen glass 18. On the other hand, original size detection sensors SE50 to SE52
Thus, the size of the document is detected based on the passage timing of the document, and the result is described in
Used to create The number of documents is detected simultaneously with the detection of the document size, and is recorded in the management table MT1 as the page number PN.

When the original is set at the reading position on the platen glass 18, the original is read and scanned by the scanner 19, and the photoelectric conversion signal is transmitted to the image signal processing unit 20 via the line sensor 16. When the reading of the document is completed, the document is transported to the left in FIG. 1 by the transport belt 506, the transport direction is changed by the reversing roller 507, passes over the switching claw 508, and
09 with the original reading surface facing upward,
It is discharged on 1.

The data processing of the original image is performed as follows.

First, the photoelectric conversion signal of the original image input from the image reading unit 10 is converted into a digital signal by the A / D conversion unit 21 while maintaining synchronization. Then, after performing shading correction, gamma correction, scaling processing, and the like in the image processing unit 23, the corrected image signal is
It is output to the memory unit 30.

The corrected image signal, which is 8-bit image data, is input to the binarization processing unit 32 via the bus switching unit 31, and the multi-color image data can be restored by, for example, the dither method. Is converted to binary image data within a certain range. The binarized image data is temporarily written to the image memory 33. Next, the image data is read from the image memory 33, compressed by the compressor 35, and stored in the code memory 37.

When outputting image data, the code data to be printed is read from the code memory 37 by the reverse operation, decompressed by the decompressor 36, and the image data for one page is written to the image memory 33. .

Next, the image data is read out from the image memory 33, subjected to image inversion processing as required by the inversion processing section 38, and then restored to multi-valued image data by the multi-value processing section 39. . Then, via the bus switching unit 31,
The restored image data is output to the print processing unit 40.

Image formation and paper discharge are performed as follows.

First, image data of a document is output from the memory unit 30 to the print processing unit 40, and an exposure control signal is generated.

The print head unit 60 controls the laser diode 62 to generate a laser beam based on the exposure control signal, and develops the laser beam via the polygon mirror 65, the main lens 69 and the mirrors 67a to 67c. /
It is led to the exposure position of the transfer section 70A.

The photosensitive drum 71 rotates in the direction of the arrow in FIG. 1 and the surface thereof is uniformly charged by the charging charger 72. The photosensitive drum 71 is exposed to laser light to form an electrostatic latent image on the surface thereof, and this electrostatic latent image is visualized by the developing device 73 to become a toner image.

On the other hand, the paper is fed from the paper cassette 80a or 80b toward the inside of the copying machine, and temporarily stops at the timing roller 82. Then, in synchronization with the formation of the toner image on the photosensitive drum 71, the toner image is transferred to the opposing portion of the transfer charger 74 and the photosensitive drum 71, and the toner image is transferred.

Thereafter, the sheet is separated from the photosensitive drum 71 by the separation charger 75, and is conveyed to the fixing roller 84 by the conveying belt 83 so that the toner image on the sheet is fixed. The transferred photosensitive drum 7
1 is cleaned by the cleaner 76 in preparation for the next image formation.

Then, the fixed paper is discharged from the discharge roller 8.
5 is sent to the sheet re-feed unit 600. The paper re-feeding unit 600 discharges the paper as it is onto the discharge tray 621, or sends the paper again to the paper re-feeding path 86 provided in the copying machine as necessary.

Next, a control system of the copying machine 1 according to the embodiment of the present invention will be described with reference to FIG.

The central control means CPU1 for centrally controlling the copying machine 1 has a read-only storage means ROM for storing data, programs and the like, and a random access storage means RAM serving as a work area for program execution. A signal processing unit 20, a memory unit unit 30, a document transport unit 500 in which document size detection sensors SE50 to SE52 are arranged, an image reading unit 10 in which a document detection sensor SE10 is arranged, a print head unit 60, a print processing unit 40,
A developing / transferring unit 70A having a photosensitive drum 71, a sheet transporting unit 70C, an operation panel OP, a fixing / discharging unit 70B having a heater drive unit for controlling a heater 87 built in the fixing roller 84 and a thermistor, and , And other input / output means. Note that, in the figure, the symbol
Reference numeral 2 ”denotes control means of the document feeder 500.

The read-only storage means ROM stores the temperature of the fixing roller set in the normal mode, that is, the temperature of the fixing roller (fixing temperature) capable of giving a heat amount necessary for fixing a large area image (fixing temperature). The minimum required temperature of the fixing roller is stored corresponding to the total area of the image to be copied.

FIG. 6 shows an example of data stored in the read-only storage means ROM. As shown in FIG. 6, the total area of the image to be copied is converted into the number of reference papers having a predetermined size (area) such as A4 size, and the number of sheets of reference paper corresponding to the number of reference papers is fixed. The minimum required temperature of the fixing roller is stored.

In order to dynamically manage the code memory 37 in the memory unit 30, the central control means CPU1
The management table MT1 shown in FIG. 7 is stored in the random access storage means RAM. As shown in the figure, the management table MT1 is linked with a number indicating an area of the code memory 37, a page number (document image number) PN of image data added in a writing order (document scanning order). Various types of additional information required for compression / decompression processing, such as an area number, a compression method, and a data length, are stored.

Note that the term "previous link" described in FIG. 7 indicates a forward link of an area of every 32 Kbytes in each page, and when this is "00", it corresponds to one page. Indicates the first storage area of the data, and other than “00”, indicates the number of the preceding connected area. Similarly, the term “post-connection” indicates the last area when “FF” is set, and indicates the number of the area connected after other than “FF”. The information in the management table MT1 is read when the information of the corresponding page is normally read and the copy of the number of copies specified by the operator is completed.
Will be erased.

Further, the central control means CPU1 receives data (number of copies, paper size) input by a key from the operation panel OP by the operator and the original size detection sensors SE50 to SE50.
Based on the number of documents detected by 52, an operation is performed to calculate the total area of the image to be formed as the reference paper reduced copy number by the following equation.

[0065]

(Equation 1)

([Paper area] / [reference paper area])
Is, for example, when the A4 size is used as the reference paper, the paper size used for copying is “2” when the paper size is A3, “1.5” when the paper size is B4, “1” when the paper size is used for A4, and A5 Is 0.5.

Further, the central control means CPU1 uses the data stored in the read-only storage means ROM on the basis of the calculated number of copies of the reference paper, and uses the data stored in the read-only storage means ROM as a minimum for fixing the image of the number of copies of the reference paper. In addition, while performing the calculation for calculating the appropriate temperature (temporary fixing temperature), the heater 87 incorporated in the fixing roller 84 is controlled to warm up the fixing device. Then, when the temperature of the fixing roller 84 reaches the provisional fixing temperature, control is performed to permit the copying operation and the fixing operation of the fixing roller.

That is, the central control means CPU1 constitutes a total area calculating means for calculating the total area of the image to be formed together with the operation panel OP and the original size detecting sensors SE50 to SE52, while the temperature calculating means for calculating the second temperature. Means,
It also serves as control means for controlling the fixing operation of the fixing member to be permitted.

Next, the overall control flow will be described with reference to FIG.

When the main switch SW is turned on, initialization such as initialization of the random access storage means RAM is performed (step S1).

Next, the internal timer is started (step S2).

Subsequently, key input processing for determining the presence or absence of key input (step S3), temperature control processing for adjusting the temperature of the fixing roller (step S4), and print processing for controlling a series of copying operations (step S4) S5) After passing through the other processes (step S6), the process waits for the end of the internal timer (step S7), returns to step S2, and repeats this operation.

Next, a detailed flow of the temperature control process (step S4 in FIG. 8) will be described with reference to FIG.

First, it is determined whether or not the return mode set when returning from the low power mode is currently set (step S10). If the return mode is set, the process proceeds to step S20 to execute the return process, and ends the temperature control process.

If the return mode is not set in step S10, it is determined whether the low power mode is set (step S11). If the low power mode has been set, the process proceeds to step S16. If the low power mode is not set, it is determined that the mode is the normal mode, and the process proceeds to step S12.

In step S16, it is determined whether or not there is a key input on the operation panel. If key input is detected,
The return mode is set (step S17), "1", which is a value indicating immediately after returning from the low power mode, is set in the return flag (step S18), and the temperature control process ends. If no key input is detected, low power mode temperature adjustment control for keeping the temperature of the fixing roller low is executed (step S19), and the temperature adjustment process ends.

In step S12, it is determined whether or not a state without any key input has continued for a predetermined time. If the key input is detected within the predetermined time, the normal mode is continued, and the normal mode temperature control is performed to maintain the temperature of the fixing roller at a fixing temperature at which a large number of copies can be made (S15). If the key input is not detected within the predetermined time, the low power mode is set (S13), the printing operation is prohibited (S14), and the temperature control process ends.

Next, a detailed flow of the return process (step S20 in FIG. 9) will be described with reference to FIG.

First, it is determined whether the return flag is set to "1" (step S30). If the return flag is set to “1”, it is determined that the return from the low power mode has just been completed, the warm-up of the fixing roller is started, and the return flag is reset to “0”.
(Step S31), and the process proceeds to step S32.
If “1” is not set in the return flag, the process immediately proceeds to step S32.

In step S32, the provisional fixing temperature (second
It is determined whether (temperature) T2 has not been calculated. If the provisional fixing temperature T2 has not been calculated, the process proceeds to step S33. If the provisional fixing temperature T2 has been calculated, the process proceeds to step S41.

In step S33, it is determined whether "0" is set in the copy key flag. If "0" is not set in the copy key flag, it is determined that the copy key has already been turned on, and the process proceeds to step S36. If "0" is set in the copy key flag, it is determined in step S34 whether the copy key is turned on.

If it is determined in step S34 that the copy key has been turned on, "1" is set in the copy key flag, and the flow advances to step S36. If the ON of the copy key is not detected, the process proceeds to step S38.

In step S36, a process for calculating the provisional fixing temperature T2 is performed, and the flow advances to step S37.

In step S37, it is determined whether the provisional fixing temperature T2 has been calculated. If the provisional fixing temperature T2 has been calculated, the return process ends, and the provisional fixing temperature T2 is calculated.
If 2 has not been calculated, the process proceeds to step S38.

In step S38, the magnitude of the fixing temperature (first temperature) T1 that can withstand a large number of copies and the current temperature T of the fixing roller are compared. If the temperature T of the fixing roller is lower than the fixing temperature T1, the return process ends.
If the temperature T of the fixing roller is equal to or higher than the fixing temperature T1, the warm-up of the fixing roller is ended, the copy key flag is reset to "0" (step S39), and the normal mode is set. At the same time, the prohibition of printing is released (step S40), and the return process ends.

In step S41, the magnitude of the calculated provisional fixing temperature T2 and the current fixing roller temperature T are compared. Fixing roller temperature T is provisional fixing temperature T
If it is smaller than 2, the return process ends. If the temperature T of the fixing roller is equal to or greater than the provisional fixing temperature T2, the above-described steps S39 and S40 are executed, and the return processing ends.

Next, a detailed flow of the process of calculating the provisional fixing temperature T2 (step S36 in FIG. 10) will be described with reference to FIG.

First, it is determined whether there is a document on the automatic document feeder ADFR (step S50). If a document exists, the process proceeds to step S51. If no document exists, the process proceeds to step S62.

In step S62, it is determined whether there is a document on the platen glass. If there is no original, it is determined that the original is not set in the copying machine, a warning is displayed on the liquid crystal display panel of the operation panel (step S65), and the process of calculating the provisional fixing temperature T2 is terminated. If a document is present, the document size is detected (step S63) and the paper size is detected (step S64), and then the process proceeds to step S57 described below.

In step S51, the automatic document feeder A
The presence or absence of DFR operation (during document feeding) is determined from the document flag. If the document flag is set to "0", the automatic document feeder ADFR is instructed to start document feeding, and the document flag is set to "1" (step S52), and the process proceeds to step S53. If "1" is set in the document flag, the automatic document feeder ADFR determines that the document is being fed, and the process immediately proceeds to step S53.

In step S53, the document size is detected. In step S54, the paper size is detected, and the flow advances to step S55.

In step S55, automatic document feeder A
It is determined whether the document feed by the DFR is completed. If the document feeding is not completed and the code memory has a free space, the calculation process of the provisional fixing temperature T2 is ended. If the document feeding has been completed or if the code memory has run out of free space and the document feeding cannot be performed, it is determined that the document feeding has been completed, and the process proceeds to step S56.

In step S56, the document flag is reset and set to "0". In step S57, the number of documents is detected.
Next, in step S59, the provisional fixing temperature T2 is calculated, and the process proceeds to step S60.

In step S60, the magnitudes of the provisional fixing temperature T2 and the fixing temperature T1 are compared. If the provisional fixing temperature T2 is lower than the fixing temperature T1, the process of calculating the provisional fixing temperature is terminated. If the provisional fixing temperature T2 is equal to or higher than the fixing temperature T1, the provisional fixing temperature T2 is changed to the fixing temperature T2.
The value of 1 is substituted (step S61), and the provisional fixing temperature calculation process ends.

Hereinafter, a specific example will be described.

In the copying machine of this embodiment, the fixing temperature T
1 is set to 200 ° C. as a temperature required for fixing an image having a total area equivalent to 500 sheets of A4 size paper, and a set temperature T of a low power mode of the fixing roller.
A description will be given of a case where a document having an image having a total area equivalent to 50 sheets of A4 size paper is copied under the condition that L is set to 170 ° C.

FIG. 12 is a diagram showing the relationship between the fixing roller temperature and the elapsed time in the process of returning from the low power mode to the normal mode under the above set conditions.

In a copying machine in which the set temperature TL of the low power mode of the fixing roller is adjusted to 170 ° C.
At time t1, key input is performed by the operator, and warm-up is started. The temperature required to copy a document having an image of a total area equivalent to 50 sheets of A4 size paper, that is, the provisional fixing temperature T2 is calculated as 182 ° C. from FIG. 6 described above. Therefore, the warm-up is continued until time t2 when the temperature T of the fixing roller rises to 182 ° C. That is, the elapsed time from the time t1 to the time t2 is the standby time A1.

When the temperature T of the fixing roller reaches 182 ° C., copying is started. Then, at time t3, the copying ends. That is, the elapsed time from time t2 to time t3 is the copy time B1. Thereafter, the warm-up is started again, and the warm-up is continued until the temperature T of the fixing roller reaches 200 ° C., which is the fixing temperature T1.

The work time C1 of the operator is equal to the standby time A
It is expressed by the sum of 1 and the copying time B1, but when returning from the low power mode, the copying process can be performed before the temperature rises to the fixing temperature T1, so that the waiting time can be shortened. When copying a small number of copies, the work time can be reduced.

FIG. 13 shows, for comparison with the above specific example,
In a conventional copying machine, under the same setting conditions as in the above specific example,
In the process of returning from low power mode to normal mode,
4 shows a relationship between a fixing roller temperature and an elapsed time.

As is clear from FIG. 13, the standby time is
Regardless of the number of copies performed after the completion of warm-up, the fixing roller temperature is always increased from 170 ° C., which is the set temperature TL of the low power mode, to 500 A4 size paper.
The temperature required for fixing the image of the total area corresponding to the sheet, that is, the time A2 required to increase to 200 ° C., which is the fixing temperature T1, is inevitable, and the standby time is inevitably increased.

In the present embodiment, the return processing from the low power mode has been described. However, the present invention is not limited to this, and the temperature control may be performed when returning from the off mode or when the power is turned off and then turned on again. The present invention can be similarly applied to

The number of originals is determined by the automatic original feeder AD.
The detection is performed when the document is fed by the FR and when the image is read by the image reading unit 10. However, the detection is not limited to this. If the number of documents is known in advance, the operator can input the document from the operation panel. Alternatively, the number of documents may be calculated from the thickness of the loaded documents, the weight of the documents, or the like. Therefore, the present invention is applicable to an analog copying machine.

Furthermore, in the present embodiment, in the low power mode, if any key input on the operation panel is performed, the return processing is performed. In order to continue as long as possible, the warm-up of the fixing roller may be started only after the copy key is turned on.

Further, a two-in-one (2 in 1) mode for obtaining one composite copy from two originals and a four-in-one (4i) for obtaining one composite copy from four originals
It is also possible to provide an n1) mode. In this case, for example, the following equation can be used as the equation for calculating the reference sheet-equivalent copy number.

[0107]

(Equation 2)

However, the mode coefficient is normally “1”, “0.5” in the two-in-one mode, and “0.25” in the four-in-one mode.

[0109]

As described above, according to the present invention, the following effects can be obtained by the structures described in the respective claims.

According to the first aspect of the present invention, the temperature of the fixing member for thermally fixing the toner image is the minimum necessary for fixing the total area of the image to be formed, which corresponds to the use condition of the operator. When the temperature (second temperature) is reached, the fixing operation is permitted to start, so that the waiting time of the operator can be minimized and the working efficiency can be improved.

According to the second aspect of the present invention, the total area is calculated based on at least the size of the recording medium or the number of images formed, so that the total area can be calculated easily and with high accuracy. .

According to the third aspect of the present invention, when returning from the power saving mode to the normal mode, the temperature of the fixing member is set to the second level.
When the temperature reaches the first temperature, the fixing operation is permitted even if the temperature does not reach the first temperature, so that the warm-up time from the power saving mode to the start of the fixing operation can be shortened, and the operator needs to wait for the time. It is possible to minimize and improve the work efficiency.

According to the fourth aspect of the present invention, when the temperature of the fixing member reaches the second temperature when the power is turned on, the fixing operation is permitted even if the temperature does not reach the first temperature. The warm-up time until the fixing operation is started can be reduced, the waiting time of the operator can be minimized, and the working efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of a copying machine according to an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a block diagram for explaining an image signal processing unit and a memory unit unit shown in FIG.

FIG. 3 is an explanatory diagram showing a configuration of a code memory of a memory unit.

FIG. 4 is a plan view showing an operation panel of the copying machine.

FIG. 5 is a schematic block diagram for explaining a control system of the copying machine.

FIG. 6 is a graph showing the relationship between the number of copies of a reference sheet and the temperature of a fixing roller required for fixing the reference sheet.

FIG. 7 is an explanatory diagram showing a configuration of a management table of a memory unit.

FIG. 8 is a flowchart of the overall control.

FIG. 9 is a detailed flowchart of a temperature control process.

FIG. 10 is a detailed flowchart of a return process.

FIG. 11 is a detailed flowchart of a process of calculating a temporary fixing temperature.

FIG. 12 is an explanatory diagram for explaining a standby time of a copying machine to which the present invention has been applied.

FIG. 13 is an explanatory diagram for explaining a standby time of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Image reading part, 16 ... Line sensor, 18 ... Platen glass, 20 ... Image signal processing part, 23 ... Image processing part, 30 ... Memory unit part, 40 ... Print processing part, 60 ... Print head part, 70A ... Development / Transfer section (image forming means), 70B: fixing / discharging section, 70C: paper transport section, 71: photosensitive drum, 84: fixing roller (fixing member), 87: heater (heating means), 500: document transport section (Automatic document feeder), CPU1: central control means, OP: operation panel, ROM: read-only storage means, RAM: random access storage means, SE10: document detection sensor, SE50-52: document size detection sensor, T: fixing Roller temperature, T1: fixing temperature (first temperature), T2: provisional fixing temperature (second temperature).

Claims (4)

[Claims] An image forming means for forming a toner image on a recording medium; a fixing member for thermally fixing the toner image; a heating means for heating the fixing member to a first temperature suitable for fixing; Total area calculating means for calculating the total area of the image to be processed, and temperature calculating means for calculating a second temperature required for the fixing member to fix the image of the total area calculated by the total area calculating means. And a control unit for controlling the fixing member to permit the fixing operation when the fixing member reaches the second temperature when the second temperature is lower than the first temperature. Forming equipment. 2. The image forming apparatus according to claim 1, wherein the total area calculation unit calculates the total area based on at least a size of a recording medium or the number of images formed. 3. The image forming apparatus has a normal mode in which the fixing member is maintained at the first temperature, and a power saving mode in which the fixing member is maintained at a temperature lower than the first temperature. The image forming apparatus according to claim 1, wherein the control is performed when returning from the power saving mode to the normal mode. 4. The image forming apparatus according to claim 1, wherein the control unit performs the control when power is turned on.