JPH01100583A - Laser printer - Google Patents

Abstract

PURPOSE:To suppress unnecessary power consumption and to prolong the life of the heater of a fixation part by turning off the heater forcibly unless a printing request signal is inputted from a host system for a certain time. CONSTITUTION:When a next printing request signal is not inputted from the host system 19 before the prescribed time is elapsed, the heater 13d of the fixation part 13 is turned off forcibly. This prescribed time is set in consideration of the mean time required from the start of turning on the heater 13d to the point where temperature T reaches prescribed temperature Ts, the frequency of a printing request signal sent out of the host system 19, a required time for printing one form in response to one printing request signal, etc. Consequently, the printing throughput of the whole laser printer is not decreased greatly and the power consumption is reduced.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a laser printer, and in particular to a laser printer that forcibly shuts off a heater in a fixing unit when a print request signal is not input from a host system for a certain period of time. Regarding printers.

[Prior Art] Generally, in a laser printer, a charging unit that charges the photosensitive drum is turned on and off in response to externally input data, for example, along the circumference of the photosensitive drum that is rotating at a constant speed. an exposure section that scans a laser beam in the axial direction of the photosensitive drum; a development section that develops the image formed on the photosensitive drum; a transfer section that transfers the developed image to paper; and a static elimination section that erases the transferred image. etc. are arranged. Further, a paper feed cassette containing a large number of sheets of paper is provided on one side of the transfer section, and a fixing section consisting of a pair of fixing rollers that thermally fixes the transferred image onto the paper is provided on the other side. There is.

When the power switch of this laser printer is turned on, drive power is supplied to the control circuits of each component, and the heater provided in the fixing roller of the fixing section starts to be energized. When the density of the fixing roller rises to a specified temperature, the laser printer enters a printable state, that is, a standby state for inputting a print request signal from an external host system. When data to be printed is input from the host system following a print request signal, the photosensitive drum starts rotating, and a laser beam output from the exposure unit is applied to the photosensitive surface of the photosensitive drum from which the static electricity has been removed. A corresponding image is created, which is developed in the olfactory image section and directed to the transfer section. In the transfer section, the image is transferred onto the paper fed from the paper feed cassette. The paper onto which the image has been transferred is transported to a fixing section by a transport roller, and the transferred image is thermally fixed by a fixing roller heated to a specified temperature.

[Problems to be Solved by the Invention] However, even the laser printer configured as described above has the following problems. That is, the fixing roller of the fixing section needs to be maintained at a specified temperature of over 100 degrees Celsius at all times in order to thermally fix the image transferred to the paper. Therefore, the amount of power consumed by the heater built into the fixing roller of this fixing section is a value that cannot be ignored. In particular, the heater of this fixing section starts energizing immediately in response to the power-on operation of the laser printer, and once the specified temperature is reached, the temperature control circuit operates and controls the heater on and off.
The fixing roller of the fixing section is maintained at the specified temperature.

However, since this laser printer performs printing operations based on data input from an external host system,
Conversely, no printing operation is performed unless a print request signal and data are input from the host system. This period becomes a waiting period for input of a print request signal from the host system.

Even during the input period of this print request signal, the temperature of the fixing section is maintained at the above-mentioned specified temperature. Therefore, if a print request signal is not input from the host system for a long period of time, there is a problem in that power consumption for constantly maintaining the fixing section at a specified temperature is wasted.

To provide a laser printer that can suppress wasteful power consumption and extend the life of the heater by forcibly shutting off a heater in a fixing section when a print request signal is not input from a host system for a certain period of time. With the goal.

[Means for Solving the Problems J] The present invention, as shown in FIG. In response to the input print request signal E, an image is formed by scanning a laser beam from the exposure section B onto the photosensitive surface of the photoconductor A, and the formed image is transferred to paper at the transfer section C, and the image is In a laser printer that thermally fixes the paper onto which has been transferred by a fixing unit G controlled to a specified temperature by a heater F, there is an elapsed time counter H that measures the elapsed time from the input time of one print request message ME; A heater cut-off means J that cuts off the heater F in the fixing section G when the elapsed time counter H measures a predetermined time, and a heater energization means that turns on the heater F in response to input of a print request signal E. It is something that

[Function] With a laser printer configured in this way, for example, when the power is turned on, the heater in the fixing section is energized, and once it reaches a specified temperature, the laser is activated in response to a print request signal sent from the host system. The printer executes printing processing, but if the print request signal from the host system is interrupted for a predetermined period of time or more, the heater of the fixing section is forcibly shut off. Then, when the print request signal is input, the heater is energized again. Note that usually 1
Since one sheet of paper is printed in response to one print request signal, the time required for printing is approximately constant.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic cross-sectional view showing the general configuration of the laser printer of the embodiment. In the figure, reference numeral 1 denotes a case that covers the entire device, and a photosensitive drum 2 having a photosensitive surface formed on its outer peripheral surface is disposed at a central position within the case 1. Along the outer periphery of the photosensitive drum 2, a charging section 3. A laser beam I that turns on and off in response to data input from an external host system t! Exposure section 5 which outputs 4. a developing section 6 for developing the image formed on the photosensitive drum 2 in the exposing section 5; A transfer unit 9 consisting of a transfer charger that transfers the developed image onto the paper 8 fed from the paper feed cassette 7. Static elimination 8B10 consisting of a snow removal lamp for erasing transferred images
is installed.

Further, the sheets 8 stored in the paper feed cassette 7 are pulled out one by one from the paper feed cassette 7 by the CF roller 11.
The image is guided to the transfer section 9 via the conveyance roller 12. The image on the photosensitive drum 2 is transferred at this transfer section 9 . The paper 8 on which the image has been transferred is discharged to the outside of the case 1 from a paper discharge port 14 via a fixing section 13 consisting of a pair of fixing rollers 13a and 13b.

FIG. 3 is a block diagram showing a schematic configuration of the laser printer. CPU (Central Processing Unit) that performs various calculation processes
15 is a ROM 17.17 which stores fixed data such as a control program via a pass line 16. R that stores variable data such as various commands input from an external host system
AM18° An interface 20 to which data to be printed and various command signals are input from an external host system 19. It controls an input/output boat 21 that inputs and outputs various commands and data to various constituent members.

This input/output boat 21 includes a drum motor 22.0 that drives the photosensitive drum 2 at zero rotation. Charging part 3. Exposure section 5, transfer section 9.
Static eliminator 10. The drive motors for the PC roller 11 and the transport roller 12, the fixing section 13, etc. are connected. Note that this fixing section 13 includes a pair of fixing rollers 13a as shown in the figure.

A fixing roller motor 13c for rotating the fixing roller 13b, a heater 13C built into the fixing rollers 13a and 13b, a thermistor or the like for detecting the temperature T of the fixing rollers 13a and 13b, and a temperature sensor 13e. . Although not shown in the fixing section 13, there are
A temperature control circuit for controlling the temperature T of the fixing roller 13a, 1) to a specified temperature T8 is incorporated.

Further, a timer 23 is connected to the interrupt terminal of the CPU 15, and a timer interrupt signal is input from the timer 23 every time a minute time Δ elapses.

Additionally, within the RAM 18, as shown in FIG. 4, a working area 18a for processing various data and commands is provided.
In addition, a cutoff flag 18b1 indicates that the heater 13d of the fixing unit 13 is forcibly cut off not by a command from the temperature control circuit but by a command from the CPIJ 15. Print processing for one sheet of paper 8 from the host system 19 An elapsed time counter 18G is stored that measures the elapsed time from the time when one print request signal instructing the execution of is input. Note that the printing time for each sheet of paper is approximately constant.

Further, the print request signal is transmitted to one sheet of paper 8 as described above.
Therefore, when printing on a plurality of sheets of paper 8 in succession, the print request signal for the next sheet of paper 8 is input when the printing process for one sheet of paper is completed.

When a power switch (not shown) attached to the case 1 is turned on, the CPU 15 is programmed to execute a main routine according to the flowchart shown in FIG. That is, when the power switch is turned on, first, the interface 20. Initialization processing for the storage contents of the RAM 18 and the input/output board 21 is executed. Thereafter, power supply to the heater 13d of the fixing section 13 is started.

Then, the temperature T of the fixing rollers 13a and 13b is detected via the temperature sensor 13e at Pl, and when it is confirmed that the detected temperature T has reached the specified temperature Ts, the laser printer is determined to be ready for printing. Make a judgment and proceed to P2.

Then, at P2, timer interrupts from the timer 23 are permitted every minute time Δ.

At P3, it is confirmed that each component shown in FIG. 3 is operating normally. If some kind of failure occurs and an error state occurs, the operation of all components connected to the input/output board 21 is stopped, and the operation of this main routine is forcibly terminated.

If no error has occurred in each component at P3, it is checked whether a print request signal is input from the host system 19 to the interface 20. If the print request signal is not input, it is confirmed in P5 that printing of data input from the host system 19 is not currently being executed. After confirming in P6 that the shutoff flag 18b of the RAM 18 is not set to 1, the count value C of the elapsed time counter 18c of the RAM 18 is checked in P7.

This elapsed time counter 18c is operated according to the flowchart of FIG. That is, when a timer interrupt signal every minute time Δ is input from the timer 23 to the interrupt terminal of the CPU 15, if the count value C of the elapsed time counter 18C has not been decremented to 0, the count value C is decreased by 1. Subtract only.

Moreover, if the count value C has already been subtracted to O, the flowchart is ended without doing anything.

The count value C of the elapsed time counter 8C at P7 in FIG.
However, if it has not yet been subtracted from O, return to P3 and check whether an error has occurred in each component.

Then, when a print request signal is input from the host system 19 to the interface 20 at P4, the RA
It is confirmed that the 7 lag 18b during interruption of M18 is not set to 1, and the count value C of the elapsed time counter 8C is reset to the count value Cmax corresponding to the specified time in P9. Thereafter, the PIO starts normal printing processing for data input from the host system 19 following the print request signal. When the data printing process for one print request signal is started, the process returns to P3 and an error check for each component is executed again.

Also, when the print request signal is input, P8 indicates that the print request signal is being input.
If the lug 8b is already set to 1, the current fixing unit 13
Since the heater 13d is being forcibly shut off, this heater 1
3d is energized again. Then, the fixing roller 13a of the fixing unit 13 at Pll.

When it is confirmed that the temperature T of 13b has reached the specified temperature, the 7 lug 18b during shutoff is released to O. After that, Plo
Proceed to , and start normal printing processing for the input data.

Further, if no print request signal is input to the interface 20 at P4 and print processing is being executed at P5, this print processing is determined to be a print processing for the print request signal input earlier. Then, proceed to P8 and check the setting state of the 7 lugs 18b during shutoff.

Furthermore, if the interruption flag 18b has already been set to 1 at P6, the count value C of the elapsed time counter 18C is O, and the process returns to P3.

In a laser printer configured in this way, when the power switch is turned on, the heater 13d of the fixing section 13 starts to be energized, and after a predetermined time, the temperature T of the fixing section 13 reaches the specified temperature Ts.Then, this laser printer enters a standby state for input of a print request signal from the host system 19.

Then, when a print request signal is input from the host system 19, the count value C of the elapsed time counter 18C is reset to the count value Cl1ax corresponding to a predetermined specified time. Then, printing processing for the data input from the host system 19 is started.

When the count value C reaches O after a predetermined time has elapsed from the input time of the mark m request signal, the heater 13d is forcibly cut off regardless of the on/off control by the temperature control circuit described above.

Then, when the print request signal is input again from the host system 19, the heater 13d is energized and after reaching the specified temperature T8, printing processing for the data input from the host system 19 is started.

Note that if the next print request signal is input before the specified time has elapsed from the input time of one print request signal, the count value C of the elapsed time counter 18C is reset to the initial value CIaX, so the heater 13d is shut off. It never happens.

In this way, if the next print request signal is not input from the host system 19 before the specified time elapses,
Since the heater 13d of the fixing unit 13 is forcibly shut off, unnecessary power consumption can be suppressed.

Note that this specified time depends on the average time required for the temperature T to reach the specified temperature T8 after the heater 13d starts being energized, the frequency of print request signals sent from the host system 19, and the response time to one print request signal. 1 executed with
If it is set in consideration of the time required to print a sheet of paper 8, etc., it is possible to reduce power consumption without significantly reducing the print processing efficiency of the entire laser printer.

Further, since the entire energizing time in the heater 13d is shortened, it is possible to extend the life of the heater 13d.

[Effects of the Invention] As explained above, according to the laser printer of the present invention,
When no print request signal is input from the host system for a certain period of time, the heater of the fixing unit is forcibly shut off. Therefore, it is possible to suppress wasteful power consumption and extend the life of the heater.

[Brief explanation of the drawing]

Figure 1 is a functional block diagram showing the present invention, Figures 2 to 6
The figures show a laser printer according to an embodiment of the present invention. Fig. 2 is a cross-sectional schematic diagram showing the entire device, Fig. 3 is a block diagram showing the entire device, and Fig. 4 shows the main parts of the storage section. The memory diagrams, FIGS. 5 and 6, are flowcharts illustrating the operation. DESCRIPTION OF SYMBOLS 1... Case, 2... Photosensitive drum, 3... Charging section, 5... Exposure section, 6... Developing section, 7... Paper feed cassette, 8... Paper, 9... ... Transfer section, 10... Static elimination section, 13... Fixing section, 13a, 13b... Fixing roller, 13d... Heater, 13e... Temperature sensor, 1
5...CPU. 18...RAM, 18b...Shutdown flag, 18c
...Elapsed time counter. Applicant's agent Patent attorney Takehiko Suzue Figure 4

Claims (1)

[Claims] At least an exposure section and a transfer section are arranged along the moving direction of the photoconductor, and a laser beam is scanned from the exposure section onto the photosensitive surface of the photoconductor in response to a print request signal input from an external host system. In a laser printer, an image is formed, the formed image is transferred to paper in the transfer section, and the paper onto which the image has been transferred is thermally fixed by a fixing section whose temperature is controlled to a specified temperature by a heater. an elapsed time counter for measuring the elapsed time from the input time of the print request signal; a heater cutoff means for cutting off the heater in the fixing unit when the elapsed time counter measures a predetermined time; and the print request signal input. and a heater energizing means for energizing the heater in response to.