JP2016045405A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent a situation where image formation cannot be performed due to a reduction in the intensity of light from a light source.SOLUTION: There is provided an image forming apparatus that controls lighting of a light source irradiating a recording material with light according to an image signal indicating the details of an image to form an image on the recording medium, the image forming apparatus determining the presence or absence of a deterioration tendency of the light source (S11 and S12), when determined that the deterioration tendency is present, reduces the intensity of light from the light source during image formation and the rate of the image formation (S15). Criteria of the deterioration tendency are considered to be a case where the total lighting time of the light source exceeds a value obtained by multiplying a target life prescribed in the specification of the light source by a predetermined coefficient smaller than 1, and a case where an applied current value necessary for obtaining a predetermined intensity of light has increased to a predetermined ratio or more compared with that at the start of use of the light source.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an image forming apparatus.

  In an image forming apparatus that forms an image on a recording medium by irradiating the recording medium with light from the light source, even if the light source deteriorates and the light quantity becomes insufficient, control is performed to compensate for the shortage of the light quantity, thereby forming an image. Techniques for performing are already known.

  For example, in Patent Document 1, in an image forming apparatus using a plurality of light sources, when a decrease in the light amount of any of the plurality of light sources is detected, the light amounts of all the light sources are added to the light amounts of the light sources with the reduced light amounts. In addition, a technique is disclosed in which a process for reducing the process speed, a process for changing an image formation setting value for the process process, and the like are performed, and control is performed so as to compensate for an insufficient amount of light from the light source.

However, when the light source begins to deteriorate, the amount of light suddenly decreases. Therefore, even if control is started after detection of a decrease in the amount of light as in the technique described in Patent Document 1, a light source that is insufficient in amount of light cannot be turned on immediately. There is a possibility of becoming. In this case, there is a problem that even if control for compensating for the shortage of light quantity is performed, the shortage of light quantity cannot be sufficiently compensated, and image formation cannot be performed.
An object of the present invention is to solve such a problem and to effectively prevent a situation in which image formation cannot be performed due to a decrease in the amount of light of a light source.

  In order to achieve the above object, the present invention forms an image on the recording medium by controlling the lighting of a light source that irradiates the recording medium with light according to an image signal indicating the content of the image. An image forming unit that performs determination, a determination unit that determines whether or not the light source has a deterioration tendency, and a notification unit that notifies a predetermined notification destination that the light source has a deterioration tendency when the determination unit determines that there is a deterioration tendency And a control means for reducing the light amount of the light source and the image forming speed in the image forming means when the determining means determines that the light source tends to deteriorate.

  According to the above configuration, it is possible to effectively prevent a situation in which image formation cannot be performed due to a decrease in the light amount of the light source.

1 is a diagram illustrating a hardware configuration of an image forming apparatus according to an embodiment of the present invention. It is a graph which shows the relationship between the cumulative lighting time of a laser diode, and an operating current. 2 is a flowchart of control processing executed by a CPU of the image forming apparatus shown in FIG. It is a graph which shows the relationship between the applied electric current applied to a laser diode, and optical output in the degree of degradation. 6 is a flowchart illustrating another example of control processing executed by the CPU of the image forming apparatus illustrated in FIG. 1.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
First, FIG. 1 shows a hardware configuration diagram of an image forming apparatus 10 according to an embodiment of the present invention.
As shown in FIG. 1, the image forming apparatus 10 includes a CPU 101, a RAM 102, a ROM 103, an HDD (hard disk drive) 104, an engine I / F (interface) 105, an engine unit 106, an operation unit I / F 111, and an operation unit 112. These are connected by a system bus 113.

Of the above configuration, the CPU 101 controls the entire image forming apparatus 10 by executing a program stored in the ROM 103 or the HDD 104 using the RAM 102 as a work area, and implements various functions to be described later.
The engine I / F 105 is an interface for connecting the engine unit 106 to the system bus 113 and enabling control from the CPU 101.

The engine unit 106 is an image forming unit that forms an image on a recording medium by controlling lighting of a light source that irradiates the recording medium such as paper according to an image signal indicating the content of the image. Here, an LD (laser diode) is used as a light source, and an electrophotographic image forming unit that develops an electrostatic latent image written on a photosensitive member by a beam output from the LD with toner.
The engine unit 106 includes an optical sensor 107, an LD 108, a timer 109, and a current sensor 110 as a configuration related to detection of presence or absence of a light source deterioration tendency, which is one of the features of this embodiment.

  In this specification, the deterioration of the light source refers to a state in which the amount of light is reduced to such an extent that a substantial defect occurs in image formation, such as unevenness in what is printed in image formation. In addition, the light source is in a tendency to deteriorate refers to a state in which a predetermined standard that can determine that a substantial defect will occur in the near future has not yet occurred in the image formation. A specific example of the reference will be described later.

  The optical sensor 107 has a function of measuring the light amount of the beam output from the LD 108. The LD 108 functions as the light source. The timer 109 has a function of measuring the cumulative lighting time of the LD 108. The current sensor 110 has a function of measuring a current for causing the LD 108 to emit light.

The operation unit I / F 111 is an interface for connecting the operation unit 112 to the system bus 113 and enabling control from the CPU 101.
The operation unit 112 is a user interface including an operation unit such as a key, a button, and a touch sensor for receiving an operation from the user, and a display unit such as a display for presenting information to the user.
The image forming apparatus 10 can be configured as an MFP (Multi Function Peripheral) having functions such as scanning, copying, facsimile transmission, and document storage in addition to the print function.

The image forming apparatus 10 described above can first determine the deterioration tendency of the LD 108 serving as a light source with reference to the cumulative lighting time of the light source. Therefore, the characteristics of the cumulative lighting time (t) and the operating current (Iop) of the LD as the light source will be described using the graph shown in FIG.
The graph shown in FIG. 2 shows the relationship between the cumulative lighting time (t) of the LD and the operating current (Iop). Also, FIG. 2 shows data for an LD having a target life of 500 hours, which is an average lighting time until deterioration.

As shown in FIG. 2, the value of the operating current of the LD is substantially the same until the cumulative lighting time (t) is around 400 hours. However, even before reaching the target life, the operating current (Iop) gradually increases from about 400 hours to about 450 hours, and the rate of increase suddenly increases after about 450 hours. To do.
As described above, the LD has a characteristic that the operating current (Iop) starts to gradually increase when the cumulative lighting time (t) approaches a certain ratio within the target life, and then the operating current (Iop) increases rapidly. There is.

Using this characteristic, a cumulative lighting time (t) at which the operating current (Iop) starts to increase gradually is used as a threshold value, and when the cumulative lighting time (t) exceeds this threshold value, it is determined that there is a tendency to deteriorate. It is possible.
For example, it is determined that the LD tends to deteriorate at 400 hours when the operating current starts to gradually increase, and “target life defined by the LD specification × 0.8” is used as the threshold for determining the deterioration tendency. It is possible to do.
Accordingly, it is possible to effectively prevent a situation in which image formation cannot be performed due to a decrease in the light amount of the light source before the LD used as the light source deteriorates.

Since this coefficient varies depending on the LD specification, data is previously taken for each LD specification to determine which coefficient of the LD 108 mounted in the image forming apparatus 10 is to be set.
In addition, if there is a possibility that the specifications of the LD 108 mounted on the image forming apparatus 10 may be different before and after the replacement, the settings may be changed as necessary after checking the specifications at the time of replacement. Alternatively, data for each LD specification may be stored in the ROM 103 or the HDD 104 in advance, and the CPU 101 may change the setting as necessary after confirming the LD specification when replacing the LD 108.

  Next, a description will be given of the control executed by the CPU 101 using the above-described characteristics to determine the presence or absence of a deterioration tendency based on the cumulative lighting time of the light source, and based on the result. FIG. 3 is a flowchart of processing related to the control.

  The CPU 101 starts the process shown in the flowchart of FIG. 3 when it is detected that the image forming apparatus 10 starts to form an image and periodically during image formation. First, processing for confirming the cumulative lighting time of the light source is performed (S11). The cumulative lighting time is separately calculated and stored when the LD 108 is turned on when an image is formed by the image forming apparatus 10.

Next, the CPU 101 determines whether or not the confirmed cumulative lighting time has exceeded a value obtained by multiplying the target life by a predetermined coefficient n (S12). The target life is defined by the specifications of the light source as described above. The predetermined coefficient n is for calculating a threshold value used for determination of the deterioration tendency, and is a value smaller than 1. In either case, the image forming apparatus 10 is set in advance.
If Yes in step S12, the CPU 101 determines that the LD 108 has a deterioration tendency, and if No, determines that there is no deterioration tendency.
As the predetermined coefficient, “0.8” described in FIG. 2 can be considered.
The processes in steps S11 and S12 are processes of determination procedures. In these processes, the CPU 101 functions as a determination unit.

In the case of No in step S <b> 12, it is not necessary to perform any special processing any more, so this processing ends.
In the case of Yes in step S12, the CPU 101 notifies the user that the LD 108 is in a deterioration tendency (S13), and inquires of the user whether or not the light amount of the LD 108 and the image forming speed are to be reduced (S14).
The process in step S14 is a notification procedure, and the CPU 101 functions as a notification unit in this process.

If the response from the user is “decrease” (Yes in S14), the CPU 101 decreases the light amount of the LD 108 and the image formation speed in the subsequent image formation (S15), and then ends this process. Note that when the reduction process is performed during image formation, the process waits for an appropriate timing such as after an appropriate number of images have been formed.
On the other hand, if the response from the user is “do not decrease” (No in S14), the CPU 101 does not do anything and ends this processing.
The process of step S15 is a process of a control procedure, and the CPU 101 functions as a control unit in this process.

The above is the processing performed by the CPU 101 when determining whether the LD 108 serving as the light source has a tendency to deteriorate based on the cumulative lighting time of the light source and controlling the light source.
By performing the above processing, the user can know that the light source of the image forming apparatus 10 that is trying to form an image or is in the process of forming an image tends to deteriorate. It is possible to make preparations for such as.

  In addition, the user can temporarily extend the life of the light by instructing the light source and the image forming speed to decrease. Also, if the user gives an instruction not to reduce the speed, the image can be formed as it is for the time being. In this case, it is expected that the light source will deteriorate soon and the image formation will be hindered. However, if the user arranges replacement of the light source promptly based on this, the problem can be avoided. . In any case, the user only has to select a desirable one for himself.

In addition to the above, the image forming apparatus 10 can also determine the presence or absence of a deterioration tendency of the LD, which is a light source, based on the applied current and the amount of light. Next, this determination will be described.
FIG. 4 shows the relationship between the applied current of the LD, which is a light source, and the light output for each degree of deterioration.
In FIG. 4, Pth is a threshold for laser oscillation.

  First, (a) shows the characteristics of the beam output by the LD when the LD is in the initial state (not deteriorated). In (a), the value of the forward current necessary for obtaining the prescribed optical output Po is Iop. On the other hand, (c) and (d) show the characteristics of the beam output by the LD when the LD is deteriorated. In (c) and (d), the slope in the region where the light output exceeds the threshold value Pth is not constant, and the amount of light obtained by applying the same current is significantly lower than in the case of (a). It can also be seen that even if the forward current value is increased, the prescribed light output Po cannot be obtained, and the amount of light necessary for desired image formation cannot be obtained.

  On the other hand, (b) shows the characteristics in the state between the state of (a) and the state of (c) and (d) where the output beam is lower than the initial state but has not yet deteriorated. ing. In this case, the slope of the graph is constant in the region where the light output exceeds the threshold value Pth, and the prescribed light output Po can be obtained. However, the inclination is smaller than in the case of (a), and the forward current Iop * necessary for obtaining the prescribed optical output Po is a value larger than Iop in the case of (a).

  Therefore, it can be considered that the LD tends to be deteriorated in the state (b) before reaching the state (c) or (d). This determination may be performed, for example, based on when the forward current Iop * necessary for obtaining the light output Po is equal to or greater than “Iop × 1.15”. By doing so, it is possible to effectively prevent a situation in which image formation cannot be performed due to a decrease in the light amount of the light source.

Since this coefficient “1.15” varies depending on the LD specification, data is previously taken for each LD specification to determine which coefficient of the LD 108 mounted in the image forming apparatus 10 is, and to set the coefficient. Keep it.
In addition, if there is a possibility that the specifications of the LD 108 mounted on the image forming apparatus 10 may be different before and after the replacement, the settings may be changed as necessary after checking the specifications at the time of replacement. Alternatively, data for each LD specification may be stored in the ROM 103 or the HDD 104 in advance, and the CPU 101 may change the setting as necessary after confirming the LD specification when replacing the LD 108.

  Next, a description will be given of the control that is performed based on the result of determining the presence or absence of a deterioration tendency using the above-described characteristics based on the current value applied to the light source by the CPU 101. FIG. 5 is a flowchart of processing related to the control.

  First, the CPU 101 starts the processing shown in the flowchart of FIG. 5 when it is detected that the image forming apparatus 10 starts to form an image and during image formation. First, an applied current to the LD 108 necessary for obtaining a predetermined light quantity is measured (S21). The predetermined light amount here is a light amount that can normally form an image, and corresponds to Po in FIG. If feedback control of the applied current is performed at any time, the applied current to the LD 108 during image formation may simply be measured.

Next, the CPU 101 determines whether or not the applied current value measured in step S21 has increased to a predetermined ratio or more compared to when the use of the light source is started (S22).
The processes in steps S21 and S22 are determination procedure processes, and the CPU 101 functions as a determination unit in these processes.

In the case of No in step S <b> 22, it is not necessary to perform any special processing any more, so this processing ends.
In the case of Yes in step S22, the CPU 101 notifies the user that the LD 108 is in a deterioration tendency (S23), and inquires of the user whether or not the light amount of the LD 108 and the image forming speed are to be reduced (S24). If the answer is “decrease”, the CPU 101 reduces the light amount of the light source and the image forming speed (S25). These processes are the same as those after step S13 in FIG.

The above is the processing performed by the CPU 101 when the deterioration tendency of the LD 108 serving as the light source is determined based on the applied current value and the light source is controlled.
By performing the above processing, the same effect as in the case of performing the processing of FIG. 3 can be obtained. The processing in FIG. 3 and the processing in FIG. 5 may be performed at the same time or only one of them.

Although the description of the embodiment has been completed above, in the present invention, the specific configuration of the apparatus including the light source, the specific processing procedure, the threshold value, and the like are not limited to those described in the embodiment.
For example, in the above-described embodiment, the processes in steps S13 and S14 in FIG. 3 can be omitted. That is, when it is determined that the light source tends to deteriorate, the light amount of the light source and the image forming speed may be immediately reduced.
Even if it does in this way, since the load to a light source can be reduced preventively before deterioration of a light source starts, the lifetime of a light source can be extended compared with the case where the light quantity and speed are not reduced. The same applies to the processing of FIG.

  In addition, although the destination notified by the CPU 101 in step S13 is the user, it is not limited to this and may be notified to a predetermined notification destination. For example, the deterioration tendency of the light source may be notified to a contractor or departmental device in charge of maintenance of the image forming apparatus 10 such as an external management device registered in advance. In this way, it is possible to arrange replacement of the light source promptly. In addition, the predetermined notification destination for notifying the occurrence of the deterioration tendency may be arbitrary including the device or the person.

In the above-described embodiment, an example in which the light source is the LD 108 has been described. However, the present invention can also be applied to an image forming apparatus that uses a light source using an LED (light emitting diode) for image formation.
In addition to the image forming apparatus, the present invention can also be applied to a light irradiation apparatus that controls lighting of a light source that irradiates light from a light source onto a recording medium. Further, the irradiation destination of light may not be a recording medium. It can also be considered that the image forming apparatus itself is a light irradiation device.

In the embodiment of the program of the present invention, the CPU 101 controls the necessary hardware in the computer to realize the function of the image forming apparatus 10 described above, particularly the function of performing the processing of FIG. 3 and / or FIG. It is a program.
Such a program may be stored in a ROM or other nonvolatile storage medium (flash memory, EEPROM, etc.) provided in the computer from the beginning. However, it can also be provided by being recorded on an arbitrary nonvolatile recording medium such as a memory card, CD, DVD, or Blu-ray disc. By installing the program recorded in those recording media in a computer and executing it, the above-described determination of the presence or absence of the deterioration tendency can be executed.

Furthermore, it is also possible to download from an external device that is connected to a network and includes a recording medium that records the program, or an external device that stores the program in a storage unit, and install and execute the program on a computer.
It goes without saying that the configurations of the embodiments, operation examples, and modification examples described above can be arbitrarily combined and implemented as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 10: Image forming apparatus, 101: CPU, 105: Engine I / F, 106: Engine part, 107: Optical sensor, 108: LD (laser diode), 109: Timer, 110: Current sensor

JP 2003-323010 A

Claims (4)

An image forming unit that forms an image on the recording medium by controlling lighting of a light source that irradiates the recording medium with light according to an image signal indicating the content of the image;
Determining means for determining the presence or absence of a deterioration tendency of the light source;
A notification means for notifying the predetermined notification destination that the light source is in a deterioration tendency, when the determination means determines that the deterioration tendency is present;
An image forming apparatus comprising: a control unit configured to reduce a light amount of the light source and an image forming speed in the image forming unit when the determining unit determines that the light source has a tendency to deteriorate. The image forming apparatus according to claim 1,
The determination means measures the cumulative lighting time of the light source, and there is a tendency to deteriorate when the cumulative lighting time exceeds a value obtained by multiplying a target life defined in the specification of the light source by a predetermined coefficient smaller than 1. And an image forming apparatus. The image forming apparatus according to claim 1, wherein
The determination means determines that there is a tendency to deteriorate when an applied current value necessary for obtaining a predetermined light amount by turning on the light source has increased to a predetermined ratio or more compared to when the light source is started to be used. An image forming apparatus. The image forming apparatus according to any one of claims 1 to 3,
The control unit receives an instruction from the user as to whether or not to reduce the light amount of the light source and the image forming speed in the image forming unit when the determining unit determines that there is a tendency to deteriorate. In this case, the light quantity of the light source and the image forming speed are not reduced.

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