JP4086402B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus that forms images on both sides of a sheet, such as a copying machine, a printer, and a composite device thereof.
[0002]
[Prior art]
Conventionally, when an image is formed on both sides of a sheet in an image forming apparatus, the conveyance path for conveying the sheet conveys a sheet on which an image is formed on one side, directly below a control unit that controls each part of the image forming apparatus. However, it does not have a function for changing the double-sided image forming speed or a function for changing the cooling amount of the cooling means.
[0003]
[Problems to be solved by the invention]
However, in the conventional image forming apparatus, since the conveyance path for double-sided image processing is disposed immediately below the control means, heat from the sheet immediately after passing through the fixing means is accumulated in the conveyance path, and the control means In some cases, the temperature of the electrical components may increase, and it is necessary to provide some cooling means to form images on both sides of the sheet. Therefore, the image forming apparatus becomes large and the cost is increased.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus in which the temperature of electric parts of a control unit is prevented from being increased by heat from a sheet after passing through a fixing unit.
[0005]
[Means for Solving the Problems]
An image forming apparatus according to the present invention forms an image on a sheet transport path that guides a sheet transported by a pair of sheet transport rotators and the sheet transported through the sheet transport path. An image forming unit, a fixing unit disposed in the sheet conveyance path, for fixing the image formed on the sheet by the image forming unit to the sheet, and a conveyance guide for the sheet on which the image is formed by the fixing unit; An image forming sheet conveyance path to be operated, a control unit that is disposed in the vicinity of the image forming sheet conveyance path and that controls operation of each unit in the apparatus main body such as the sheet conveyance rotating body pair, and the current image formation from the end of the previous image formation comprising a time measuring means for measuring the elapsed time until the image formation is started in the sheet counting means for counting the transport number of the sheets, and said control means, before The elapsed time measured by the time measuring means is compared with a predetermined time, and when the elapsed time exceeds the predetermined time, continuous images counted by the sheet counting means When the number of sheets formed exceeds the first number, the control unit slows down the sheet conveyance speed on the sheet conveyance path, and the elapsed time is equal to or less than the predetermined time, the sheet When the number of consecutively formed images counted by the counting means exceeds the second number, the control means slows down the sheet conveying speed on the sheet conveying path, and the first number is the second number. It is characterized in that the number is set to be larger than the number of sheets .
[0006]
The image forming apparatus transports a sheet on a sheet transport path by a pair of sheet transport rotators, and forms an image on one surface of the sheet by an image forming unit. Thereafter, the fixing unit fixes the image on the sheet. Then, the sheet is conveyed and guided by the image forming sheet conveying path, and the sheet is sent again to the image forming unit, and an image is formed on the other surface of the sheet. As a result, images can be formed on both sides of the sheet. These controls are performed by the control means.
[0007]
Sheets heated by the fixing unit are successively conveyed through the image forming sheet conveyance path, and the temperature in the apparatus main body, particularly, the image forming sheet conveyance path rises, and is disposed near the image forming sheet conveyance path. Means may be adversely affected by heat.
[0008]
However, if the number of sheets conveyed exceeds a predetermined number, heat accumulates in the apparatus main body, particularly in the image forming sheet conveyance path, and the temperature rises above a predetermined temperature. When the number of conveyed sheets exceeds a predetermined number, the control means slows the sheet conveying speed, reduces the number of conveyed sheets, and lowers the temperature in the apparatus main body.
[0009]
As a result, the control means can avoid the adverse effects of heat.
[0015]
In the image forming apparatus of the present invention, the image forming sheet conveying path is reversed by the image forming means so as to form a sheet on which an image is formed on one side and an image on the other side. It is a reverse sheet conveyance path for conveying and guiding the means.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a printer 1 that is an example of an image forming apparatus according to an embodiment of the present invention, a first reference example, a second reference example , and a third reference example will be described with reference to FIGS.
[0024]
The embodiment, the printer of the reference example, since the different in the engine control unit, describes the overall structure only printer embodiments, the first reference example, the second reference example, the printer of the third reference example Only the engine control unit will be described, and illustration and description of other parts will be omitted.
[0025]
In addition to the printer, the image forming apparatus includes a copying machine, a combined device of the printer and the copying machine, and the image forming apparatus is not limited to the printer.
[0026]
(First embodiment)
FIG. 1 is a schematic front sectional view of a printer 11 according to a first embodiment of the present invention.
[0027]
FIG. 2 is a flowchart showing a printing (hereinafter referred to as “printing”) operation for forming images on both sides of a sheet.
[0028]
In FIG. 1, reference numeral 10 denotes a printer main body, reference numeral 23 denotes a sheet rotating body pair, reference numeral 24 denotes a sheet conveyance path, reference numeral 11 denotes a process cartridge including a photosensitive drum 11a, and reference numeral 12 includes a semiconductor laser and a polygon motor. Reference numeral 13 denotes an optical unit, reference numeral 13 denotes a fan, reference numeral 14 denotes fixing means for fixing the toner image on the sheet, reference numeral 115 denotes an engine control unit for controlling the electrophotographic process, and reference numeral 21 denotes a transfer charger. Yes. The photosensitive drum 11 a and the transfer charger 21 constitute an image forming unit 22.
[0029]
The engine control unit 115 includes a time measuring unit 115a that measures an elapsed time from the end of the previous double-sided printing to the start of the next double-sided printing, and a counting unit (temperature information unit) 115c that counts the conveyed sheets. And a sheet number storage means (temperature information means) 115d. The sheet number storage means 115d is a part for storing the number of sheets obtained experimentally beforehand to determine how many sheets are continuously printed to increase the temperature of the electric component of the engine control unit 115.
[0030]
Reference numeral 16 denotes a conveyance path (image forming sheet conveyance path) for double-sided printing, and reference numeral 17 denotes a sheet discharge roller for discharging the sheet. When performing double-sided printing on a sheet, the printer 1 switches back the sheet with the sheet discharge roller 17. Reference numeral 18 denotes a sheet cassette.
[0031]
When performing double-sided printing on the sheet, the printer 1 performs single-sided printing on the sheet fed from the sheet cassette 18 by the photosensitive drum 11 a, passes through the fixing unit 14, and is then switched back and conveyed by the sheet discharge roller 17. . Then, the sheet is sent to the sheet refeed roller 20 via the conveyance path 16 for duplex printing by the conveyance rollers 19a and 19b for duplex printing, and is shifted to the duplex printing operation.
[0032]
The conveyance path 16 for duplex printing is located directly below the engine control unit 115 and above the sheet cassette 18.
[0033]
The double-sided printing operation in the printer 1 will be described based on the flowchart of FIG.
[0034]
In the printer 1 of the first embodiment, the number of sheets to be printed is experimentally determined in advance to determine the number of electrical components to be heated, and when the number is exceeded, the engine control unit 115 causes the double-sided printing. By reducing the printing speed of printing, the accumulation of heat is avoided and the temperature rise of the conveyance path is suppressed.
[0035]
When the printer 1 receives a double-sided printing operation command from a host computer (not shown), the time measuring unit 115a has completed the previous (N-1 times) double-sided printing (step (hereinafter simply referred to as “S”). (Abbreviated, abbreviated) 21), measuring the elapsed time (t0) until the start of the current (N times) double-sided printing, and comparing the engine control unit 115 with a predetermined time (T0). in the fixing means 14 to confirm the cold condition of the residual heat in the transport path 16 due to the previously used, the process proceeds to duplex printing operation (S22). This is to cope with the next double-sided printing instruction before the conveyance path 16 cools to a predetermined temperature.
[0036]
If it is determined that “t0> T0” as a result of the comparison, it is determined that the transport path 16 is sufficiently cooled. Then, the engine control unit 115 monitors and counts the number of continuous duplex printings performed by the sheet counting unit 115c (S23). If double-sided printing is continuously performed, the heat of the sheet that has passed through the fixing unit 14 and has been switched back accumulates in the conveyance path 16 for double-sided printing, which may result in a high temperature. When the temperature rises, the temperature of the electrical components in the engine control unit 115 is increased and the service life is affected. Therefore, experimentally, the number (A) of how many times the electrical components are continuously printed increases the number of sheets (A), and is stored in the sheet number storage means 115d. A) (S24), the engine control unit 115 controls the rotation speed of the sheet conveying rotation means 23 and the conveying rollers 19a and 19b to reduce the printing speed of double-sided printing (S25), thereby avoiding heat accumulation, The temperature rise of the conveyance path 16 is suppressed.
[0037]
If not exceeding (S24), the engine control unit 115 (a <A) maintains the current printing speed (S26). The printer 1 repeats the above operation until the double-sided printing operation is completed (S27).
[0038]
Further, when it is determined that the comparison result of the elapsed time is “t0 ≦ T0” (S21), the engine control unit 115 determines that the conveyance path 16 has not been cooled, and the number of double-sided prints that are continuously performed is determined. Is monitored and counted by the sheet counting means 115c (S29). Also in this case, experimentally, the number (B) of how many times the electrical components are continuously printed will be stored in the sheet number storage means 115d to obtain the number (B). b ≧ B) (S30), the engine control unit 115 reduces the printing speed of double-sided printing (S31), thereby avoiding the accumulation of heat and suppressing the temperature rise of the conveyance path 16. If not exceeding (b <B), the current printing speed is maintained (S32). The printer 1 repeats the above operation until the double-sided printing operation ends (S33).
[0039]
The relationship between the numbers A and B and the numbers a and b is “A> B” and “a> b”.
[0040]
Furthermore, in this embodiment, there are two cases for the elapsed time, two cases for the number of printed sheets and two printing speeds for one elapsed time. It may be divided.
[0041]
(First Reference Example )
The printer of the first reference example , in advance, experimentally obtains the number of sheets of electrical components that will increase in temperature when printing is performed in advance, and determines the number of sheets, and if that number is exceeded, increases the fan speed. Therefore, accumulation of heat is avoided and temperature rise in the conveyance path is suppressed.
[0042]
The engine control unit 215 of the printer of the first reference example shown in FIG. 3 includes a time measurement unit 215a, a sheet count unit (temperature information unit) 215c that counts sheets, and a sheet number storage unit (temperature information unit) 215d. Is provided.
[0043]
FIG. 4 is a flowchart showing the double-sided printing operation of the printer in the first reference example of the present invention.
[0044]
When the printer 1 receives a double-sided printing operation instruction from a host computer (not shown), the time measurement unit 215a performs the current (N times) double-sided printing after the previous (N-1 times) double-sided printing is completed. The elapsed time (t1) until the start is measured, and the engine control unit 215 compares it with a time (T1) arbitrarily determined in advance (S41). After confirming how much residual heat has cooled, shift to duplex printing. This is to cope with the next double-sided printing instruction before the conveyance path 16 cools to a predetermined temperature.
[0045]
If it is determined that “t1> T1” as a result of the comparison, it is determined that the transport path 16 is sufficiently cooled. Then, the engine control unit 215 monitors and counts the number of continuous duplex printings performed by the counting unit 215c (S42, S43). If double-sided printing is continuously performed, the heat of the sheet that has passed through the fixing unit 14 and has been switched back accumulates in the conveyance path 16 for double-sided printing, and there is a risk of high temperature. When the temperature becomes high, the temperature of the electrical components in the engine control unit 215 is increased and the life is affected. For this reason, experimentally, the number (D) of how many continuous printing is performed and the temperature of the electrical component rises is obtained and stored in the sheet number storage means 215d. If the number exceeds (d) ≧ D) (S44), the engine control unit 215 increases the rotation speed of the fan 13 (S45), thereby avoiding heat accumulation and suppressing an increase in the temperature of the conveyance path.
[0046]
If not exceeded (S44), the engine control unit 215 (d <D) maintains the rotational speed of the fan 13 (S46). The printer 1 repeats the above operation until the double-sided printing operation ends (S47).
[0047]
Further, when it is determined that the comparison result of the elapsed time is “tl ≦ Tl” (S41), the engine control unit 215 determines that the transport path 16 for double-sided printing has not been cooled, and continuously performs the process. The number of double-sided printed sheets is monitored and counted (S48, S49). In this case as well, the number (E) of the number of sheets of electrical components that will be heated up experimentally is obtained and stored in the sheet number storage means 215d. If this number is exceeded, (E ≧ E) (S50), the engine control unit 215 increases the rotation speed of the fan 13 (S51), thereby avoiding heat accumulation and suppressing an increase in the temperature of the conveyance path 16. If not exceeding (e <E), the current rotational speed of the fan 13 is maintained (S52). The printer 1 repeats the above operation until the double-sided printing operation ends (S53).
[0048]
The relationship between the numbers D and E and the numbers d and e is “D> E” and “d> e”.
[0049]
Furthermore, in this reference example , the case of elapsed time is divided into two ways, the number of printed sheets is divided into two ways with respect to one elapsed time, and the number of rotations of the fan 13 is two. You may divide into the above.
[0050]
(Second reference example )
In the printer of the second reference example , the temperature at which the electrical components of the engine control unit affect is experimentally determined in advance, and if the temperature is exceeded, the engine control unit reduces the printing speed of double-sided printing, This prevents the accumulation of heat and suppresses the temperature rise in the conveyance path for double-sided printing.
[0051]
The engine control unit 315 of the printer of the second reference example shown in FIG. 5 includes a temperature detection sensor (temperature information means) 315d for detecting the temperature in the printer body and the engine control unit, and an engine control unit experimentally in advance. Temperature storage means (temperature information means) 315e for obtaining the temperature affected by the electrical component and storing the temperature.
[0052]
FIG. 6 is a flowchart showing the double-sided printing operation of the printer in the second reference example of the present invention.
[0053]
Upon receiving a double-sided printing operation instruction from a host computer (not shown), the printer 1 starts a double-sided printing operation (S61). At this time, the temperature detection sensor 315d monitors the temperature in the printer body 10, particularly the temperature of the engine control unit 315 (S62, S63). If double-sided printing is continuously performed, the heat of the sheet that has passed through the fixing unit 14 and has been switched back accumulates in the conveyance path 16 for double-sided printing, and there is a risk of high temperature. When the temperature rises, the electrical components in the engine control unit 315 are heated to affect the life. For this reason, the temperature (β) at which the electrical component affects is experimentally obtained in advance and stored in the temperature storage means 315e. If the temperature is exceeded (α ≧ β) (S63), the engine control unit 315 reduces the printing speed of double-sided printing (S64), avoids heat accumulation, and suppresses the temperature rise of the conveyance path 16 for double-sided printing.
[0054]
If not exceeding (α <β), the engine control unit 315 maintains the current duplex printing speed (S65).
[0055]
The printer 1 repeats the above operation until the double-sided printing operation ends (S66).
[0056]
In the present embodiment, two cases of temperature in the printer main body 11 and engine controller 315 and two cases of printing speed are provided, but three or more cases may be provided.
[0057]
( Third reference example)
The printer of the third reference example experimentally obtains the temperature affected by the electrical parts beforehand, and if that temperature is exceeded, the fan speed is increased to avoid heat accumulation and the temperature of the conveyance path. It is designed to suppress the rise.
[0058]
The engine control unit 415 of the printer of the third reference example shown in FIG. 7 includes a temperature detection sensor (temperature information means) 415b that detects the temperature in the printer body and the engine control unit, and an engine control unit in advance experimentally. Temperature storage means (temperature information means) 415e for obtaining the temperature affected by the electrical component and storing the temperature.
[0059]
FIG. 8 is a flowchart showing the double-sided printing operation of the printer in the third reference example of the present invention.
[0060]
When the printer receives a duplex printing operation command from a host computer (not shown), the printer starts the duplex printing operation (S71). At this time, the temperature detection sensor 415b monitors the temperature of the printer body, in particular, the temperature of the engine control unit 451 (S72). If double-sided printing is continuously performed, the heat of the sheet that has passed through the fixing unit 14 and has been switched back accumulates in the conveyance path 16 for double-sided printing, and there is a risk of high temperature. When the temperature rises, the electrical components in the engine control unit 451 are heated to affect the life. For this reason, the temperature (γ) affected by the electrical component is experimentally obtained in advance and stored in the temperature storage means 415e. If the temperature is exceeded (δ ≧ γ) (S73), the engine control unit 451 increases the rotational speed of the fan 13 (S74), thereby avoiding heat accumulation and suppressing an increase in the temperature of the conveyance path.
[0061]
If not exceeding (δ <γ), the current rotational speed of the fan 13 is maintained (S75).
[0062]
The printer repeats the above operation until the double-sided printing operation ends (S76).
[0063]
In this reference example , there are two cases of temperature in the printer main body and in the engine control unit 451, and two cases of fan rotation speed. However, the present invention is not limited to this. .
[0064]
【The invention's effect】
In the image forming apparatus according to the present invention, when the number of conveyed sheets counted by the sheet counting unit exceeds a predetermined number, the control unit reduces the sheet conveying speed. By reducing the temperature, the temperature inside the apparatus main body can be lowered at a low cost, and the control means can be prevented from being adversely affected by heat.
[0065]
In the image forming apparatus of the reference example of the present invention, when the control unit obtains temperature information that the temperature in the image forming apparatus has risen above a predetermined temperature by the temperature information unit, the cooling unit is operated. Therefore, the temperature rise in the apparatus main body can be prevented and the control means can be prevented from being adversely affected by heat. Moreover, the temperature rise of the control means can be prevented with a small size and low cost.
[0067]
In the image forming apparatus according to the reference example of the present invention, the temperature information is obtained from the temperature detection sensor, and the control unit is configured to operate the cooling unit when the temperature exceeds a predetermined temperature. Thus, the control means can be prevented from being adversely affected by heat.
[Brief description of the drawings]
FIG. 1 is a schematic front sectional view of an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart of a double-sided printing operation of the image forming apparatus according to the embodiment of the present invention.
FIG. 3 is a diagram illustrating only an engine control unit in the image forming apparatus according to the first reference example of the present invention.
FIG. 4 is a flowchart of double-sided printing operation of the image forming apparatus according to the first reference example of the present invention.
FIG. 5 is a diagram illustrating only an engine control unit in an image forming apparatus according to a second reference example of the present invention.
6 is a flowchart of a double-sided printing operations of the put that image forming apparatus in a second exemplary embodiment of the present invention.
FIG. 7 is a diagram illustrating only an engine control unit in an image forming apparatus according to a third reference example of the present invention.
FIG. 8 is a flowchart of double-sided printing operation of the image forming apparatus according to the third reference example of the present invention.
[Explanation of symbols]
S sheet 1 Printer (image forming device)
10 Printer body (image forming device body)
11 Process cartridge 11a Photosensitive drum 12 Optical unit 13 Fan (cooling means)
Reference Signs List 14 Fixing means 15 Engine control unit 15a Time measuring means 15b Temperature detection sensor 16 Conveyance path (image forming sheet conveyance path)
DESCRIPTION OF SYMBOLS 17 Sheet discharge roller 18 Sheet cassette 19a, 19b Conveyance roller for double-sided printing 20 Sheet refeed roller 21 Transfer charger 22 Image forming means 23 Sheet conveyance rotating body pair 24 Sheet conveyance path 115,215,315,415 Engine control part (Control means)
115a, 215a Time measuring means 115c, 215c Count means (temperature information means)
115d, 215d Sheet number storage means (temperature information means)
315d, 415b degree detection sensor (temperature information means)
315e, 415e Temperature storage means (temperature information means)

Claims (2)

A sheet conveying path for guiding a sheet conveyed by the sheet conveying rotating body pair;
An image forming unit disposed in the sheet conveying path and forming an image on a sheet conveyed through the sheet conveying path;
A fixing unit disposed in the sheet conveyance path and configured to fix the image formed on the sheet by the image forming unit to the sheet;
An image forming sheet conveyance path for conveying and guiding the sheet on which an image is formed by the fixing unit;
A control unit that is disposed in the vicinity of the image forming sheet conveyance path and that controls operation of each unit in the apparatus main body such as the sheet conveyance rotating body pair;
A time measuring means for measuring an elapsed time from the end of the previous image formation to the start of the current image formation;
Sheet counting means for counting the number of conveyed sheets , and
The control means compares the elapsed time measured by the time measuring means with a predetermined time, and when the elapsed time exceeds the predetermined time, counts by the sheet counting means. The control means slows down the sheet conveying speed on the sheet conveying path when the number of continuously formed images exceeds the first number;
When the elapsed time is equal to or shorter than the predetermined time, the control unit causes the sheet conveyance when the number of continuously formed images counted by the sheet counting unit exceeds a second number. Decrease the sheet transport speed on the road,
The image forming apparatus, wherein the first number is set to be larger than the second number .   The image forming sheet conveyance path reversely conveys and guides the sheet on which an image is formed on one side by the image forming unit to the image forming unit so as to form an image on the other side. The image forming apparatus according to claim 1, wherein the image forming apparatus is a road.

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