JPH07107622B2 - Multiple image forming device - Google Patents

Description

Description: TECHNICAL FIELD The present invention is provided with a low temperature control means for maintaining the temperature of a fixing device at a temperature lower than the temperature at the time of fixing operation during standby, The present invention relates to a multiplex image forming apparatus that can store in an intermediate storage unit, guide it to an image forming unit again, and perform at least one of double-sided copying and composite copying.

<Outline of the Invention> In summary, the multiplex image forming apparatus according to the present invention is configured so that when the paper detection unit that detects the presence or absence of paper in the intermediate storage unit detects the paper, the low temperature control of the operator is performed. By providing the low temperature control prohibiting means for prohibiting the change to the low set temperature regardless of the instruction or the detection of the interrupted state of the copying work, the paper remains in the intermediate storage portion at the start of the multiple image forming work, It is intended to prevent the crowding.

<Prior Art and Its Deficiencies> In an image forming apparatus using an electrophotographic method, a transfer material on which a developer image is transferred is guided to a fixing device, and this is heated and pressed to melt and fix it. The melting temperature of the developer is generally 180 ℃
Before and after the image forming operation, the temperature of the transfer material contact portion of the fixing device is raised to about 180 ° C. as a fixing temperature at which the developer can be melted by a heating means such as a heater lamp.
A large amount of electric power is required to maintain the fixing device at such a high temperature, while it takes a long time to rise from the room temperature state to the fixing temperature. For these reasons, maintaining the temperature at which the developer can be melted constantly even when the apparatus main body is energized and waiting for execution of image forming work unnecessarily wastes electric power and causes an increase in running cost. . Further, if the driving of the heating means is stopped each time the image forming work is completed, the work cannot be started until the fixing device reaches the fixing temperature at the time of executing the next image forming work, and it takes a long time to start the work. Will turn into.

Therefore, in the conventional image forming apparatus, the temperature of the transfer material contact portion of the fixing device can be maintained at two temperatures, that is, the fixing temperature and a low set temperature slightly lower than this, and a switch and a timer are provided. There has been provided with a low temperature control means for maintaining the temperature of the fixing device at a low set temperature when the operator operates the switch or when the image forming work is stopped for a certain period of time. The low set temperature maintained by the low temperature control means is determined in consideration of the power consumption of the heating means and the time required for the temperature rise, so that the waste of the power is prevented and the time to rise to the fixing temperature is unreasonable. It won't be long. The low temperature control means as described above is generally used in most types of image forming apparatuses including a multiple image forming apparatus which has an intermediate reservoir and is capable of double-sided copying and composite copying.

However, there is no conventional image forming apparatus that determines whether or not the operation of the low temperature control means is possible. Therefore, during the multiple image forming operation, the images of the originals on the first side are formed on a larger number of transfer materials than the required number of sheets, and the images are stored in the intermediate storage section. When the image is formed only on the transfer material, the transfer material on which the image on the first surface is formed remains in the intermediate storage portion. In this state, if the operator does not notice the transfer material remaining in the intermediate storage and operates the low temperature control means, the transfer material remaining in the intermediate storage must be discharged before starting the next image forming operation. Therefore, there is a drawback that workability is deteriorated and work is prolonged.

Further, in the case where the continuous stop time of the image forming work is timed by the timer and the low temperature control means is enabled after the elapse of a certain time, if the image forming work on the first surface is left for a long time, Since the low temperature control means is automatically activated and the temperature of the fixing device is set to a low set temperature, the image forming work on the second side cannot be immediately started, and the image forming work is interrupted. Further, in general, when the low temperature control means operates, the copy data stored in the control unit is cleared, and therefore the copy data must be input again during the image forming operation for the second surface, and the copy operation must be performed again. There was a drawback that it was complicated.

<Objects of the Invention> In view of the above-mentioned conventional drawbacks, the object of the present invention is to detect an operator's instruction to execute low temperature control or detection of an interrupted state of copying work when paper remains in the intermediate storage unit. Despite this, it is an object of the present invention to provide a multiplex image forming apparatus capable of inhibiting the operation of the low temperature control means and preventing the multiplex image forming work from being interrupted and complicated.

<Structure and Effect of the Invention> The multiplex image forming apparatus of the present invention includes low temperature control means for selectively maintaining the temperature of the fixing device at a low set temperature lower than the fixing temperature at which the developer can be melted, and In the multiplex image forming apparatus, which stores the sheet for which the image forming process for one surface is completed, in the intermediate storing unit and guides it to the image forming unit again to execute the image forming process for the second surface, the low temperature control unit, It is a means for keeping the temperature of the fixing device at a low set temperature when the power saving key provided in the operation section is operated or when the time measuring means for measuring the duration of the interruption of the copying operation measures a predetermined time. A sheet detecting means for detecting the presence or absence of the sheet in the intermediate storage section,
After the image forming process is completed and while the paper detection means detects the paper, the low temperature control means maintains the low set temperature regardless of the operation of the power saving key or the time measurement of the predetermined time by the time measurement means. And a low temperature control prohibiting means for prohibiting.

According to the present invention having the above-described structure, after the image forming process is completed, the presence or absence of the paper in the intermediate storage unit is detected by the paper detection unit, and when the paper detection unit detects the paper, the operator saves power. Even when the execution of the low temperature control is instructed by the operation of the key, or when the interrupting state of the image forming work is detected by the time measuring means counting the interruption continuation for the predetermined time, the low temperature control prohibiting means keeps the low set temperature low. Retention can be prohibited. Therefore, even if the transfer material remains in the intermediate storage section when the image forming operation of the original on the first side is performed unattended for a long time after the operation is completed, the temperature of the fixing device is low. You won't be disappointed. Therefore, the next multiple image forming work can be prevented from becoming complicated and taking a long time, and the multiple image forming work can be prevented from being interrupted, so that the operation efficiency can be improved.

<Embodiment> FIG. 2 is a schematic front sectional view showing a configuration of a multiple image forming apparatus according to an embodiment of the present invention.

A photoconductor drum 18 is provided in the center of the inside of the copying machine main body 21, and constitutes a copying process section together with the charging charger 7, the developing device 6, the transfer / peel charger 9, the cleaner 8 and the charge eliminating lamp 20 in the outer peripheral portion. . A paper cassette 4 is mounted on the right side of the copying process unit, and a paper feeding unit having a paper feeding roller 4a is configured. A fixing device 22 including a conveyor belt 17, a heat roller 1 and a pressure roller 2 is provided on the left side of the copying process section. A thermistor 3 is provided near the heat roller 1 of the fixing device 22 and detects the surface temperature of the heat roller 1. Further, the heat roller 1 is formed in a hollow cylindrical shape,
A heater lamp 5 as a heating means is provided inside. Further, on the left side thereof, a paper discharge unit including a paper discharge roller 23 and a paper discharge tray 16 is configured. As described above, the paper transport path 24 is formed from the paper feed unit to the paper discharge unit via the copy process unit.

An intermediate tray 10, which is an intermediate storage section, is provided inside a cabinet 26 in which a copying machine main body 21 is placed. The intermediate tray 10 is provided with a paper feed roller 11 and a paper detection sensor 25. The paper detection sensor 25 is composed of a transmissive photo sensor. A sub-transport path 27 is formed between the paper discharge section and the intermediate tray 10. A flapper 15 is provided in the paper discharge section, and the transport path 24 is connected to either the paper discharge tray 16 or the sub transport path 27. The switchback transport path 12 is formed in the sub transport path 27. The switchback conveyance path 12 is provided with rollers 12a that rotate in both forward and reverse directions, and reverses the front and rear ends of the sheet in the conveyance direction. Sub transport path
Flapper 14 is provided at the joint between 27 and switchback transport path 12.
a and 14b are provided. These flappers 14a and 14b open the sub transport path 27 to either the intermediate tray 10 or the switchback transport path 12, and connect the switchback transport path 12 and the intermediate tray 10. further,
A passage 28 is formed between the intermediate tray 10 and the copying process section.

With the above-described configuration, during a normal single-sided copying operation, the paper fed from the paper feed unit advances in the paper transport path 24 via the copy process unit and the paper discharge unit, forms an image on one side, and discharges the image. The paper is ejected to the paper tray 16. During the double-sided copying work, the paper fed from the paper feeding section is not fed after the single-sided copying work.
Further, the sheet is guided to the switchback transport path 12, and the front and rear ends in the transport direction are reversed to be temporarily stored in the intermediate tray 10. The paper stored in the intermediate tray is guided again to the copying process section via the passage 28, an image is formed on the surface opposite to the surface on which the image was previously formed, and the paper is discharged to the paper discharge tray 16. At the time of the composite copying work, the paper for which the one-sided copying work is completed is guided directly from the sub-transport path 27 to the intermediate tray 10 and temporarily stored. After that, the paper is guided from the intermediate tray 10 to the copying process section again via the passage 28, an image is formed on the same surface as the surface on which the image was previously formed, and then the paper is discharged to the paper discharge tray 16.

FIG. 3 is a partial plan view of an operation panel provided in the copying machine.

The operation panel 31 includes a print switch 33, a numeric keypad 34, a clear key 35, a display section 36, and copy mode setting keys 37 to 39.
Is provided. The mode keys 37 to 39 are keys operated when selecting the single-sided copy mode, the double-sided copy mode, and the composite copy mode, respectively. The display unit 36 displays the set number of sheets, copy magnification, warning, and the like. Numeric keypad 34
Is a key for inputting numerical data such as the set number of sheets. The clear key 35 is used for clearing the data input by the numeric keypad 34, and for discharging the paper stored in the intermediate tray 10 to the paper discharge tray 16 without performing the copying process during the double-sided copying work or the composite copying work. To operate.
The print switch 33 is a key for starting the copying work.
A power saving key 32 is provided above the print switch 33. The power saving key 32 is a key for selecting the operation of the low temperature control means, and is a key for setting or canceling the control temperature of the heater lamp 5 to a low set temperature.

FIG. 4 is a block diagram of the control unit of the copying machine.

The resistivity of the thermistor 3 provided near the heat roller 1 decreases as the temperature rises. Therefore, as the temperature of the heat roller 1 rises, the resistance of the thermistor 3 and the resistance
The potential at the point P between R1 decreases. This potential is input to the comparators 63 and 64. The input voltage is compared with the voltages V ₁ and V ₂ , respectively. Comparator 63, 64
Outputs a voltage according to the comparison result to the heater lamp control unit 60 as a low temperature signal S1 and a high temperature signal S2, respectively. The voltage V ₂ is equal to the voltage at point P when the fixing temperature is 180 ° C., and the voltage V ₁ is equal to the voltage at point P when the temperature is 150 ° C.

On the other hand, the copy data by the key operation of the operation panel 31 is input to the CPU 50 via the encoder 53. Further, the detection data of the paper detection sensor 25 is input via the input circuit 51. When the power saving key 32 of the operation panel 31 is operated, the ON signal is input as data from the encoder 53. Also, a timer 55 for measuring the interruption time of the copying work is connected to the CPU 50. The copy data input to the CPU 50 is stored in the RAM 52. Further, the ROM 59 stores a program that defines the operation of each unit device, and the CPU 50 outputs control data to the copy process unit 57, the transport unit 58, etc. via the output interface 56 in accordance with this program.

The heater lamp control unit 60 sends the power saving mode signal S3 from the CPU 50.
Is entered. The power saving mode signal S3 is the power saving key on the operation unit 31.
It is set to “H” when the detection data from the paper detection sensor 25 is not input either when 32 is operated or when the copying operation is interrupted for a predetermined time and the timer 55 times up. When the power saving mode signal S3 is "H", the output signal S1 from the comparator 63 is validated to save the power saving mode signal.
When S3 is "L", the output signal S2 from the comparator 64 is validated. That is, the heater lamp control unit 60 selects either the low temperature signal S1 or the high temperature signal S2 according to the content of the power saving mode signal S3. The signal thus selected is output from the heater lamp control unit 60 to the triac control unit 61. The triac control unit 61 applies the gate trigger voltage to the triac Q1 when the input signal is negative, and stops the application of the gate trigger voltage when the signal is positive. As a result, when the power saving mode signal S3 is "L", the heater lamp 5 is driven so that the temperature of the heat roller becomes 180 ° C. On the other hand, when the power saving mode signal S3 is "H", the heater lamp 5 is driven so that the temperature of the heat roller becomes 150 ° C.

FIG. 1 is a flowchart showing the operation of the multiplex image forming apparatus.

While power is being supplied to the copier body 21, step n1 (hereinafter referred to as step ni
Is simply called ni. ), If any key provided on the operation panel 31 is operated, the process proceeds to n2, and the power saving mode signal S3 output from the CPU 50 to the heater lamp control unit 60 is set to “L”, and the set temperature T of the fixing device is set. Set to the fixing temperature Th.
When the current temperature Ta detected by the thermistor 3 reaches the fixing temperature Th in n3, the process proceeds to n4 and the ready lamp is turned on to display the startable state of the copying operation. When the copy data is input at n5 and the print switch 33 is operated at n6, the process proceeds to n7,
Perform the duplication process. When the copy process for the set number of sheets is completed in n8, the process proceeds to n9, and the timer 55 is turned on.

After this, it is judged at n10 whether or not the timer 55 has timed out. If the timer 55 has not timed out in n10, the process proceeds to n11, and it is determined whether or not the power saving key 32 has been operated. When the power saving key 32 is not operated in n11, the process proceeds to n12, and it is determined whether or not the print switch 33 is turned on. If neither the power save key 32 nor the print switch 33 is operated, n10 to n
When the timer 55 times out in n10 or the power save key 32 is operated in n11, the operation in n13 is repeated.
Proceed to. When the print switch 33 is operated in n12, the process proceeds to n7 and a predetermined copying process is performed.

At n13, it is determined whether the paper detection sensor 25 is on. When the paper detection sensor 25 is turned on in n13, that is, when there is no paper in the intermediate tray 10, n1
Proceeding to 4, the set temperature T is set to a low temperature Tr, the memory and the timer are cleared at n15 and n16, respectively, and the ready lamp is turned off and the process returns to n1. Paper detection sensor 2 at n13
When 5 is off, it is determined that the paper remains in the intermediate tray 10, and the process returns to n12. In the above, n10 to n13
Corresponds to the low temperature control inhibiting means of the present invention.

As described above, according to this embodiment, when the work is interrupted for a predetermined time while the sheet remains on the intermediate tray 10,
Repeat n10 → n13 → n12 → n10. Also, if the power save key 32 is operated with paper remaining on the intermediate tray 10,
By repeating n11 → n13 → n12 → n10 → n11, the set temperature of the fixing roller is maintained at the fixing temperature Th at which the developer can be melted, and the copy data stored in the memory is stored.

Therefore, the temperature of the fixing device does not become the low temperature Tr when the sheet remains on the intermediate tray 10. by this,
There is no need to wait for the temperature of the fixing device to rise or to re-input copy data when copying the image of the second-side original onto the paper stored in the intermediate tray 10.

When the power saving key 32 is operated after the completion of the multiple copying operation, if the intermediate tray 10 has paper remaining, the mode is not changed to the power saving mode and the operator forgets to remove the paper remaining in the intermediate tray 10. There is no. Therefore, it is not necessary to discharge the sheets remaining on the intermediate tray 10 at the start of the next multiplex copying operation, and the delay of the copying operation can be prevented.

[Brief description of drawings]

FIG. 1 is a flow chart showing the operation of a multiple image forming apparatus according to an embodiment of the present invention, FIG. 2 is a schematic front sectional view showing the construction of the copying machine, and FIG. 3 is a plan view of an operating section of the copying machine. 4 and 5 are block diagrams of the control unit of the copying machine. 3 ... Thermistor, 5 ... Heater lamp, 10 ... Intermediate tray, 22 ... Fixing device, 25 ... Paper detection sensor.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G03G 21/14

Claims (1)

[Claims] 1. A sheet having a low temperature control means for selectively holding the temperature of a fixing device at a low set temperature lower than a fixing temperature at which a developing agent can be melted, and which has completed an image forming process on a first side. In the multiplex image forming apparatus that stores the image in the intermediate storage unit and guides it to the image forming unit again to execute the image forming process for the second surface, the low temperature control unit is configured to operate a power saving key provided in the operation unit. In the intermediate storage section, the presence / absence of paper is detected when the temperature of the fixing device is kept at a low preset temperature when the time duration of the interruption of the copying operation is timed Paper detection means for
After the image forming process is completed and while the paper detection means detects the paper, the low temperature control means maintains the low set temperature regardless of the operation of the power saving key or the time measurement of the predetermined time by the time measurement means. And a low temperature control prohibiting means for prohibiting the multi-image forming apparatus.