JP2002132086A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of some time always taken from a standby state to a printing feasible state, even in the case of printing a small number of sheets in an image forming device having an automatic preheat mode or an automatic shut-off mode. SOLUTION: Whether fixing temperature in normal printing, is required or output in a low-speed and low-temperature mode is possible, is calculated based on the scheduled number of printed sheets and the temperature of the fixing means at that time. In the case of outputting a small number of sheets, they are outputted in the low-speed and low-temperature mode, whereby the waiting time is made short and printing finish time is made early.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile, a printer, a copying machine, and more particularly to a device having a power saving mode (preheat mode) employing an electrophotographic system.

[0002]

2. Description of the Related Art A conventional electrophotographic image forming apparatus includes:
The toner image transferred to the paper is fixed by nipping and heating a nip between a heat roller having a heat source such as a halogen lamp therein and a pressure roller whose surface is covered with elastic rubber. With this method, the electric power supplied to the heat roller of the fixing unit becomes extremely large, so that in the standby state, the preheat mode in which the temperature is set lower than the fixing temperature at the time of copying, or the copying must be performed for a certain period of time. There is an auto-shut-off mode for cutting off the power supply to the fixing unit, and in each case, when the user performs an operation for making a copy, the temperature of the fixing unit is controlled to return to a predetermined temperature at the time of copying.

[0003]

However, in the case of the copier having the above-described preheat mode, the waiting time is shorter than when the apparatus is started up from the beginning because of waiting at the preheating temperature, but only a few sheets are copied. It felt like a long wait if you wanted to.

[0004]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a fixing unit for fixing a toner image transferred to a sheet by heat and pressure, and a first unit necessary for normal printing. A normal printing mode in which printing is performed at a fixing temperature, a low-speed low-temperature fixing mode in which printing is performed at a second fixing temperature lower than the first fixing temperature by lowering the transport speed than the normal printing, and a fixing temperature when not used. A mode control unit for switching between a power saving mode in which a standby is performed at a standby temperature lower than the two fixing temperatures; and the mode control unit is configured such that when the fixing unit receives a print command in the power saving mode, the fixing unit performs the second operation. 1 fixing temperature has not been reached,
When it is determined that the number of sheets to be printed is the number of sheets that can be printed in the low-speed fixing mode, there is provided an electrophotographic image forming apparatus having control means for performing printing in the low-speed low-temperature fixing mode.

In the second invention of the present invention, the determination of the number of printable sheets in the low-speed fixing mode by the control means is (printing time in the normal printing mode) + (transition time from the standby temperature to the first fixing temperature). > (Printing time in low-speed low-temperature fixing mode) + (Transition time from standby temperature to second fixing temperature)
The electrophotographic image forming apparatus according to the first aspect, wherein the number of sheets satisfies the above condition.

[0006]

The fixing temperature required for normal printing is a set temperature assuming continuous printing of a large number of sheets. If printing is to be performed on a small number of sheets of 4 to 5 sheets, the conveyance speed is reduced and the fixing is performed at a temperature lower than the set temperature. It is possible to In the first aspect of the present invention, it is determined in advance whether low-speed low-temperature fixing is possible from the number of printed sheets, and if possible, low-temperature low-temperature fixing is performed to reduce the waiting time.

In the second invention of the present invention, it is determined from the number of printed sheets whether low-speed low-temperature fixing is possible by determining (printing time in normal printing mode) + (transition time from standby temperature to first fixing temperature) and ( Printing time in low-speed low-temperature fixing mode) +
Comparing (the transition time from the standby temperature to the second fixing temperature), printing is performed in the low-speed low-temperature fixing mode when printing in the low-speed low-temperature fixing mode results in the end of printing sooner.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an image forming apparatus employing the first and second aspects of the present invention will be described with reference to FIG. In FIG. 1, the image forming apparatus includes a control unit 1, a scanner unit 2, a bitmap memory 3, a printer unit 4, a printer controller unit 5, a communication control unit 6, a CODEC 7, an image memory 8, an operation unit 9, and the like. ing.

More specifically, the control unit 1 controls each component of the image forming apparatus, and is connected to a ROM 11 storing various programs and a RAM 12 storing setting data and the like.

The scanner unit 2 includes an automatic document feeder 21
The original is illuminated one sheet at a time with a halogen lamp, the reflected light is read by a CCD sensor, this analog signal is converted to a digital signal by A / D conversion, and image processing is performed.
It is developed in the bitmap memory 2 at the subsequent stage. The document number counting means 21 required for the present invention can be determined from the counter of the document feeder. When a document is set manually, it can be determined that the number of documents is one.

The bit map memory 3 stores the image data from the scanner unit 3 and the coded image data transferred from the PC into the printer control unit 5, C
Image data transmitted via the ODEC 7; a public line from the facsimile of the other party;
This is a means for developing and holding the image data sent via the EC 7 as full bitmap image data.

The printer section 4 comprises a paper feeding and conveying means 41, an image forming means 42, a fixing means 43 and the like. The paper fed from the paper feeding cassette is transferred with a toner image by the image forming means 42. The toner image is fixed by being nipped and heated by the nip between the heat roller and the pressure roller of the fixing unit 43.

The surface temperature of the heat roller of the fixing means 43 is detected by a temperature sensor, and based on the result, when the temperature is lower than a set temperature, the halogen lamp 1 is used.
321 is turned on and warmed, and if the temperature is higher than the set temperature, the halogen lamp is turned off to maintain the set temperature. That is, when the set temperature (first fixing temperature) of the heat roller during the copy operation is 180 ° C., 180 ° C.
It changes before and after, and the set temperature during standby in the power saving mode is 13
If it is 5 ° C, the standby temperature that is not used is 135 ° C
The control is maintained before and after.

More specifically, a change in the temperature of the fixing means 43 when the image forming apparatus in the standby mode in the power saving mode starts printing will be described with reference to FIG. FIG. 2A shows the state of the temperature of the fixing unit 43 when printing is started in the normal printing mode while the apparatus is on standby in the power saving mode. Here, the standby temperature is 135 ° C., and the normal fixing temperature is 18
Since the temperature is about 0 ° C. (first fixing temperature), the temperature must be raised by 45 ° C. before printing starts, and a waiting time of about 30 seconds is required. On the other hand, FIG. 2B shows the state of the temperature of the fixing means 43 when printing is started in the low-speed low-temperature fixing mode while the apparatus is on standby in the power saving mode. Here, the fixing temperature (second fixing temperature) in the low-speed low-temperature fixing mode is 150.
Since it is set to ° C, a waiting time of about 10 seconds is sufficient.

In the low-speed low-temperature fixing mode, the heat capacity per unit area given to the sheet by lowering the transport speed is made equal to that at the normal transport speed at the normal print temperature. However, since the transport speed is reduced, the number of prints per unit time is reduced. That is, whether or not all printing is completed earlier in the low-speed low-temperature fixing mode is determined by the total number of printed sheets and the number of printed sheets per unit time of the image forming apparatus in each mode. For example, in the normal print mode, 12 sheets (1
When 5 sheets can be printed in 5 seconds) and 6 sheets (10 seconds per sheet) can be printed in 60 seconds in the low-temperature fixing mode, the number of sheets that can be printed in the low-speed fixing mode is A. Then
(5 × A) +30> (10 × A) +10, that is, 4> A
Becomes When the number of sheets is three or less (the time until completion is the same for four sheets), printing in the low-temperature fixing mode can be completed quickly, so that it is determined that the printing is possible.

The printer controller section 5 is for outputting image data transferred from a PC or a network line by the printer section 4 and has a function of expanding font data and coded data ( In the embodiment, a CODEC 7 is separately provided in the figure for the multifunction machine). Further, there is a print number counting means 51 for counting the number of prints required for the present invention.

The communication control means 6 receives image data sent from a destination facsimile via a public line, and performs a series of operations such as line connection and protocol exchange. Also here, there is the reception number counting means 61 necessary for the present invention, and the number can be known from the data of the communication procedure.

The CODEC 7 expands the compressed data since the image data is usually compressed and sent. Also, an image read by the scanner unit 2,
The processed data obtained by rotating or enlarging or reducing the data is compressed and stored in the image memory 8.

The image memory 8 is for storing image data when receiving a memory in a memory copy mode or a facsimile mode. As described above, the image data is stored as compressed image data to increase the memory efficiency.

The operation unit 9 is provided for the user to operate the image forming apparatus, and includes a print button, numeric keys, other exposure adjustment keys, a paper selection key, a mode setting key, and the like.

Next, the procedure for determining the print mode of the heat roller of the fixing means when the image forming apparatus is used as a copying machine will be described with reference to the flowchart of FIG.

First, the image forming apparatus waits in the power saving mode (S101), and determines whether the power saving mode has been released (S102). When the power saving mode is released, the fixing temperature required for normal printing is immediately set (S103), and the fixing temperature rises and proceeds to the next step, during which the user performs operations such as placing a document and setting the number of sheets. Is performed, and it is determined whether the print key has been pressed (S104). It is determined whether the fixing temperature required for normal printing has been reached when the print key is pressed (S105), and if so, the document is read (S106), and printing is sequentially started at the normal fixing temperature (S107). If the fixing temperature required for normal printing has not been reached in step S105, first, document reading is started (S108) and stored in the image memory 8, and at the same time, it is determined whether the fixing temperature required for normal printing has been reached. Judgment (S
109) If the fixing temperature has reached the temperature required for normal printing during the reading of the document, the process proceeds to S107, and if not, it is determined whether the reading of the document has been completed (S1).
10). Steps S109 and S110 are repeated until the fixing temperature reaches a temperature necessary for normal printing or the reading of the document is completed. If the reading of the document is completed without the fixing temperature reaching the temperature required for normal printing, the expected number of prints is calculated (S111). Since the number of originals can be counted by the original number counting means 21 provided in the scanner section 2, the expected number of prints can be calculated from the number of originals and the set number of copies.

Once the expected number of prints is determined, it is determined whether this is the number of prints that can be performed only in normal printing or the number of prints that can be performed in the low-speed low-temperature fixing mode (S112). Wait until (S1
13) Start normal printing. If it is determined in S112 that the number of printable sheets is in the low-speed low-temperature fixing mode, it is determined whether the fixing temperature is necessary for the low-speed low-temperature fixing mode (S1).
14) When it becomes possible, printing is started in the low-speed low-temperature fixing mode (S115).

After this, when printing is completed (S116),
After a lapse of a predetermined time, the apparatus waits again in the power saving mode (S11).
7), the process ends.

Since the image forming apparatus is a multifunction machine, the procedure for determining the print mode of the heat roller of the fixing means when used as a printer and a facsimile will be described with reference to the flowchart of FIG.

First, the image forming apparatus waits in the power saving mode (S201), determines whether there is a facsimile reception or printer output instruction (S202), and if so, cancels the power saving mode (S203). Immediately after the power saving mode is released, the fixing temperature required for normal printing is set (S204), the fixing temperature rises, and the number of prints included in facsimile transmission data and printer data is calculated (S205). This is obtained from the number-of-prints counting means 51 provided in the printer controller unit 5 or the number-of-received-sheets counting means 61 of the communication control means 6.

In the next step, it is determined whether the expected number of prints requires the fixing temperature for normal printing (S206). If necessary, it is determined whether the fixing temperature required for normal printing has been reached (S207). Printing is started, and if low-speed low-temperature fixing is possible, it is determined whether the fixing temperature required for the low-speed low-temperature fixing mode has been reached (S209), and printing is started in the low-speed low-temperature fixing mode when it becomes possible (S210).

After this, when printing is completed (S211),
After a lapse of a predetermined time, the apparatus waits again in the power saving mode (S21).
2), end the process.

[0029]

According to the present invention, when printing is performed on a small number of sheets of 3 to 4 sheets, the conveyance speed is reduced, and the fixing is performed at a temperature lower than the set temperature, thereby shortening the waiting time and shortening the printing end time. are doing.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image forming apparatus according to the present invention.

FIG. 2 is a time chart of a fixing temperature in normal printing and printing in a low-speed low-temperature fixing mode of the fixing unit of the present invention.

FIG. 3 is a flowchart for determining whether to print in a normal printing mode or a low-speed low-temperature fixing mode when the image forming apparatus of the present invention is used as a copying machine.

FIG. 4 is a flowchart for determining whether to print in a normal print mode or a low-speed low-temperature fixing mode when the image forming apparatus of the present invention is used as a printer or a facsimile. DESCRIPTION OF SYMBOLS 1; Control part 11; ROM 12; RAM 2; Scanner part 21; Number-of-documents counting means 3: Bitmap memory 4: Printer part 41; Feeding-and-conveying means 42; Image-forming means 43; 51; print number counting means 6; communication control means 61; reception number counting means 7; CODEC 8; image memory 9;

Claims (2)

[Claims] A fixing unit for fixing a toner image transferred onto a sheet by heat and pressure; a normal printing mode for printing at a first fixing temperature required for normal printing; and a conveyance speed lower than the normal printing. Mode control for switching between a low-speed low-temperature fixing mode in which printing is performed at a second fixing temperature lower than the first fixing temperature and a power saving mode in which the fixing temperature stands by at a standby temperature lower than the two fixing temperatures when not used. Means and the mode control means, when receiving a print command in the power saving mode, the fixing means has not reached the first fixing temperature, and the number of sheets to be printed can be printed in the low-speed fixing mode. A control unit for performing printing in the low-speed low-temperature fixing mode when the number of sheets is determined to be an appropriate number. 2. The method according to claim 1, wherein the determination of the number of printable sheets in the low-speed fixing mode is performed by (a printing time in a normal printing mode).
+ (Transition time from standby temperature to first fixing temperature)> (printing time in low-speed low-temperature fixing mode) + (transition time from standby temperature to second fixing temperature) The electrophotographic image forming apparatus according to claim 1.