JPH04270336A - Method for controlling halogen lamp for light source for image forming device - Google Patents

Abstract

PURPOSE:To keep a calorific value from a halogen lamp for light source to necessary minimum. CONSTITUTION:In an image forming device where soft start control is performed at the time of starting the lighting of the halogen lamp, the temperature of the tube wall of the halogen lamp 2 or a filament part is predicted by using data on the number of copied sheets and/or the size of a copying paper in a 1JOB or by using data on the accumulated on-time of the halogen lamp in the 1JOB as a predicting means, and a soft start control time is shortened by changing the number of phase angle steps and/or the interval of phase angle step switching time in the soft start control of the halogen lamp based on the predicted value, the lamp lighting time is kept to the necessary minimum and the calorific value form the halogen lamp is kept the necessary minimum.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a halogen lamp for a light source of an image forming apparatus.

0002

2. Description of the Related Art Conventionally, image forming apparatuses have been well known that use a halogen lamp as an image reading light source to read an original image, and form a copy image on a transfer material such as copy paper through an electrophotographic image forming means. ing. FIG. 4 is a schematic diagram showing a configuration example of an image forming apparatus used in a copying machine, etc. In the figure, reference numeral 1 is a contact glass on which a document is placed, and 2 is an exposure light source for image reading. Lamp, 3 is the first
4 is a second mirror, 5 is a third mirror, 6 is an original density sensor, 7 is an imaging lens, 8 is an AC drive plate for driving an exposure lamp, 9 is a microcomputer (CPU) and various control circuits. etc., the main control board, 10 is the 4th
mirror, 11 is a fifth mirror, 12 is a sixth mirror, 13 is a belt-shaped photoreceptor, 14 is a developing device, 15 is a charging device,
Reference numeral 16 indicates a cleaning device. Note that illustration of a transfer material conveyance means, a transfer device, a fixing device, etc. is omitted.

In FIG. 4, a document is placed on a contact glass 1.
When the copying operation is started, first, the exposure lamp 2 is turned on.
is lit and illuminates the document surface. The light reflected from the original is
The photoreceptor 13 is exposed to light through the first mirror 3 , the second mirror 4 , the third mirror 5 , the imaging lens 7 , the fourth mirror 10 , the fifth mirror 11 , and the sixth mirror 12 . At this time, the photoreceptor 13 is uniformly charged by the charging device 15, and an electrostatic latent image is formed on the photoreceptor 13 by exposure to the light image from the document. The electrostatic latent image on the photoreceptor 13 is developed by a developer in a developing device 14, and the developed image is transferred to a transfer material such as copy paper, thereby forming a copy image on the transfer material. Further, after the photoreceptor 13 is transferred, it is cleaned by a cleaning device 16, and the charge is removed by a charge removal lamp or the like.

Next, FIG. 5 is an explanatory diagram showing an example of a control circuit when a halogen lamp is used as the exposure lamp 2. Voltage control of the lamp is performed by zero-cross control using an alternating current (AC) power source. The effective value of the lamp voltage is fed back to the main control board (CPU etc.) 9 as dimming detection to keep the lamp voltage constant. by the way,
In the conventional technology, soft start control as shown in the control waveform of FIG. 6 (A) is performed when lighting the lamp, but in this soft start control when lighting the lamp, the temperature rise of the lamp tube wall and filament part is Regardless of the phase angle step number and the phase angle step switching time interval were always constant. In addition, in order to lower the temperature of the lamp and the surrounding area of the lamp, forced cooling was performed using a fan (FANM), etc.

[0005]

[Problems to be Solved by the Invention] By the way, a halogen lamp as a light source is an easy-to-use light source because it can obtain a larger amount of light than fluorescent tubes and can always provide a constant amount of light without being affected by room temperature, etc. However, on the other hand,
It has the disadvantage that it generates heat at the same time as it emits light. Also,
When the lamp is cold or cold, a considerable amount of inrush current flows, so conventionally, the inrush current countermeasure has been taken by gradually increasing the temperature of the filament of the halogen lamp using soft start control as shown in Figure 6 (A). It was. However, in conventional control methods, the number of phase angle steps and the phase angle step switching time interval are always constant regardless of the temperature rise of the lamp tube wall or filament as described above. There is a problem in that the halogen lamp generates a large amount of heat when the lamp is turned on when the temperature of the lamp tube wall or filament is high, such as during copying.

The present invention has been made in view of the above circumstances, and focuses on the fact that the inrush current value during lighting varies depending on the filament temperature of a halogen lamp. Instead of keeping it constant regardless of the temperature, as shown in Figure 6 (B) and (C), the soft start control time can be shortened to the minimum necessary each time according to the filament temperature, and the ON timing of the halogen lamp can be delayed. The purpose is to suppress the amount of heat generated from halogen lamps to the necessary minimum.

[0007]

[Means for Solving the Problem] In order to achieve the above object, the invention as claimed in claim 1 of the present application reads an original image using a halogen lamp as a light source for image reading, and passes it through an electrophotographic image forming means to a copy paper or the like. In a method for controlling a halogen lamp for a light source of an image forming apparatus that forms a copy image on a transfer material, the halogen lamp performs soft start control at the time of starting lighting of the halogen lamp. predict the part temperature,
The present invention is characterized in that the number of phase angle steps and/or the phase angle step switching time interval in the soft start control of the halogen lamp is changed based on the predicted value.

[0008] The invention as set forth in claim 2 of the present application provides a method for controlling a halogen lamp for a light source of an image forming apparatus as set forth in claim 1, as means for predicting the tube wall or filament temperature during one job (one copying process). It is characterized by using the number of copies and/or copy paper size data.

[0009] The invention as set forth in claim 3 of the present application is a method for controlling a halogen lamp for a light source of an image forming apparatus as set forth in claim 1, in which cumulative halogen lamp ON during one job is used as means for predicting the tube wall or filament temperature. It is characterized by using time data.

0010

[Operation] According to the method for controlling a halogen lamp for a light source of an image forming apparatus according to the present invention, the temperature of the tube wall or filament portion of the halogen lamp can be controlled by using the number of copies per job and/or copy paper size data, or The soft start is performed by predicting by using the accumulated halogen lamp ON time data during one job and changing the number of phase angle steps and/or the phase angle step switching time interval in the soft start control of the halogen lamp based on the predicted value. The control time can be shortened, and the lamp lighting time can be kept to the minimum necessary.

[0011]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. Incidentally, as an example of the configuration of the image forming apparatus, FIG.
, and is similar to that shown in FIG. 5, and a description thereof will be omitted. 1 and 2 are flowcharts showing an embodiment of the method for controlling a halogen lamp for a light source according to the present invention, in which the temperature of the tube wall or filament of the halogen lamp, the number of copies per job, and/or copy paper size data are determined. Based on the predicted value, the number of phase angle steps and/or
Alternatively, the phase angle step switching time interval is changed. Note that this control program is stored in advance in the memory in the main control board 9 of the image forming apparatus shown in FIGS. 4 and 5, and the CPU in the main control board 9
executed by

First, FIG. 1 shows how the temperature of the tube wall or filament of a halogen lamp is predicted by using the number of copies per job and copy paper size data, and the advantages and disadvantages of soft start control are selected for each copy paper size. It is a flow chart showing control operation. When the control is started, first, the transfer paper size is detected in steps S1 to S2 of The number of copies (the number of copies determined from the data of the graph in Figure 7 (A)) at which the temperature at which the light intensity rise time is saturated is determined by the data of A.
(accumulator). Next, in the determination section (2), a copy counter (a counter that counts how many copies are being executed) is compared with the contents of A above. Next, in the process of ■, S
In step 7 or S8, if the copy counter is equal to or greater than the contents of A, set the soft start shortening flag (set the flag to 1), and if it is less than the contents of A, reset the soft start shortened flag (set the flag to 0). Do) Do.

Next, FIG. 2 is a flowchart for executing shortened or normal soft start control. In Figure 2, in the part marked ■, it is determined whether or not to start and execute the soft start. Exit from the flow shown in FIG. 2 and return to main control. Note that the soft start flag is set after a certain period of time has elapsed since reference signal detection (scanner HOME POSITION, registration ON, etc.). If it is the soft start start execution timing, the soft start shortening flag is set and reset as described above in the flow of FIG. 2, and the flow returns to step U2 of FIG.
It is determined whether the soft start shortening flag is set or reset, and if the flag is set, the shortening soft start control in step U3 ((B) in FIG. 6; shortening the phase angle switching step time and/or (C ); decrease the number of phase angle steps), and if the flag is reset, the normal soft start control in step U4 (Fig. 6 (A)
). Note that the soft start flag is reset when each soft start control ends.

Next, FIG. 3 shows a case where cumulative halogen lamp ON time data during one job is used as a means of predicting the tube wall or filament temperature, and the merits and demerits of soft start control are selected based on the halogen lamp cumulative ON time data. FIG. In FIG. 3, in the part (■), first, the ON state of the lamp is determined in step T1, and if the lamp is ON, the lamp OFF timer is reset in step T2, and if the lamp is in the OFF state, the process goes to step T5 (■). . In the part (2), if the lamp OFF timer is 30 seconds or more, it is determined that the lamp tube wall and filament temperature has fallen sufficiently, and the lamp ON cumulative timer is reset, and if it is less than 30 seconds,
Judging that the temperature of the lamp tube wall and filament is rising,
The process returns to the control shown in FIG. 2 without doing anything. In addition, in the part (■), the lamp cumulative timer is 30 in the determination at step T3.
If the time is longer than 30 seconds, a soft start shortening flag is set in step T4, and if it is less than 30 seconds, the soft start shortening flag is reset in step T7, and the process returns to the control shown in FIG.

As described above, according to the method for controlling a halogen lamp for a light source of an image forming apparatus according to the present invention, the temperature of the tube wall or filament portion of the halogen lamp is determined using the number of copies in one job and/or copy paper size data. or by using the accumulated halogen lamp ON time data during one job, set and reset the soft start shortening flag according to the flowchart of FIG. 1 or 3, and set and reset the soft start shortening flag as shown in the flowchart of FIG. Based on the setting and resetting of the soft start shortening flag, the number of phase angle steps and/or phase angle step switching time interval in the soft start control of the halogen lamp is set as shown in FIGS. 6(B) and (C). By changing the soft start control time, it is possible to shorten the soft start control time according to the temperature of the tube wall or filament part of the lamp, and it is possible to make the lamp lighting time the minimum necessary.

【Effect of the invention】

As explained above, according to the method of controlling a halogen lamp for a light source of an image forming apparatus according to the present invention, the temperature of the tube wall or filament portion of the halogen lamp can be controlled by 1 J.
The phase angle in soft start control of the halogen lamp is predicted by using the number of copies and/or copy paper size data in the OB or by using the cumulative halogen lamp ON time data in one job, and based on the predicted value, the phase angle in the soft start control of the halogen lamp is predicted. By changing the number of steps and/or the phase angle step switching time interval, the soft start control time can be shortened depending on the lamp wall or filament temperature, and the lamp lighting time can be kept to the minimum necessary. can. Therefore, according to the present invention, it is possible to minimize the amount of heat generated by the halogen lamp, and for this reason, for example, instead of two cooling fans, which were conventionally required due to the large amount of heat generated by the halogen lamp, only one cooling fan can be used. This makes it possible to replace a large-capacity cooling fan with a small-capacity fan, which reduces the manufacturing cost of image forming devices, and also provides advantages in terms of device layout. Miniaturization can also be achieved. Further, it is also possible to reduce noise caused by the cooling fan.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an embodiment of a halogen lamp control method for a light source according to the present invention, and is a flowchart for selecting the merits and demerits of soft start control according to copy paper size.

FIG. 2 is a flowchart showing an embodiment of the method for controlling a halogen lamp for a light source according to the present invention, and is a flowchart for selecting whether or not to execute a soft start.

FIG. 3 is a flowchart showing an embodiment of the method for controlling a halogen lamp for a light source according to the present invention, and is a flowchart for selecting the merits and demerits of soft start control based on cumulative lamp ON time.

FIG. 4 is a schematic main part configuration diagram showing an example of the configuration of an image forming apparatus.

FIG. 5 is an explanatory diagram showing an example of a control circuit when a halogen lamp is used as an exposure lamp of the image forming apparatus shown in FIG. 4;

FIG. 6 is a diagram showing the phase control state of the voltage applied to the halogen lamp during soft start control, where (A) shows the normal soft start control state, and (B) shows the soft start control shortening time set. A diagram showing a control state when the phase angle switching time is shortened, and (C) a diagram showing a control state when the soft start control shortening time is set and the number of phase angle steps is reduced.

[Fig. 7] (A) is a graph showing the relationship between the number of continuous copies for each paper size and lamp tube wall temperature, and (B) is a graph showing the relationship between lamp tube wall temperature and the time required for lamp startup to reach the required lamp light amount. This is a graph showing.

[Explanation of symbols]

2 Exposure lamp (halogen lamp) 8
AC drive board 9 for driving the exposure lamp Main control board

Claims (3)

[Claims] 1. An image forming apparatus that reads an original image using a halogen lamp as a light source for image reading, and forms a copy image on a transfer material such as copy paper through an electrophotographic image forming means, the apparatus comprising: a halogen lamp; In a method for controlling a halogen lamp for a light source of an image forming apparatus that performs soft start control at the start of lighting, the tube wall or filament temperature of the halogen lamp is predicted, and the phase in the soft start control of the halogen lamp is determined based on the predicted value. A method for controlling a halogen lamp for a light source of an image forming apparatus, the method comprising changing the number of angular steps and/or the time interval for switching phase angle steps. 2. A method for controlling a halogen lamp for a light source of an image forming apparatus according to claim 1, wherein the number of copies in one job and/or copy paper size data is used as means for predicting the tube wall or filament temperature. A method for controlling a halogen lamp for a light source of an image forming apparatus. 3. A method for controlling a halogen lamp for a light source of an image forming apparatus according to claim 1, wherein cumulative halogen lamp ON time data during one job is used as means for predicting tube wall or filament temperature. A method for controlling a halogen lamp for a light source in a forming device.