JP5358904B2 - Image forming apparatus, control method, and control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of automatically resetting generation of a synchronizing signal by controlling image formation and transfer operation of a transfer object when detecting abnormal occurrence of the synchronizing signal. <P>SOLUTION: When detecting the abnormal generation of the synchronizing signal, an image forming state to an image carrier by an optical scanning means, and the transfer operation state of the transfer object for transferring an image formed on the image carrier, are specified. Image formation to the image carrier and the transfer operation of the transfer object are controlled according to the specified image forming state and the transfer operation state to reset timing of emitting light from light sources 8, 9 to thereby reset the generation of the synchronizing signal. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser printer, a digital copying machine, a facsimile machine, and a digital multifunction machine, and more particularly to an image forming apparatus capable of performing an image writing process using a light beam and the image forming apparatus. The present invention relates to a control method and a control program.

  In an image forming apparatus in which light emitted from a light source such as an LD (laser diode) is deflected and scanned by a polygon mirror and an image is formed on the photoreceptor with the deflected and scanned light, the writing position in the main scanning direction Therefore, it is essential to synchronize every line scan.

  In addition, as a method of synchronizing every line scanning, for example, the following method can be cited.

  First, a synchronization signal generator is installed so as to receive light in the non-image area. The synchronization signal generator generates a synchronization signal when light is received.

  Next, based on the frequency used to drive the light source such as the LD, the laser light is emitted from the light source when the synchronization signal generator is ready to receive the light. The synchronization signal generator generates a synchronization signal when receiving the laser beam emitted from the light source, and develops an image in the main scanning direction based on the synchronization signal.

  When the image forming apparatus performs a normal operation, a synchronization signal is generated for each line scan, and an intended writing process is performed.

  However, if a synchronization signal abnormality (synchronization error) occurs, the intended writing process is not performed in the next scan, and an abnormal image is formed.

  For this reason, when an abnormality of the synchronization signal occurs, it is determined that the image forming apparatus is abnormal, and the operation of the image forming apparatus is stopped.

  Examples of the cause of the abnormality of the synchronization signal include the following. In addition, the following causes are examples and are not limited to the following causes.

First cause: An object that obstructs light reception is attached to the synchronization sensor mounted on the synchronization signal generator.
Second cause: An object that prevents reflection of light adheres to the reflection surface of the polygon mirror.
Third cause: When the synchronous sensor cannot recognize light due to insufficient output due to deterioration of the light source.
Fourth cause: When light cannot be output to the synchronous sensor due to abnormal rotation of the polygon mirror or changes in lens characteristics due to temperature changes.

  In general, it is possible to detect the occurrence of an abnormality in the synchronization signal. However, the present situation is that the generation of the synchronization signal cannot be automatically restored after the occurrence of the abnormality is detected.

  For this reason, when the occurrence of the synchronization signal abnormality is detected, the user temporarily stops the image forming apparatus, performs a recovery operation for restoring the generation of the synchronization signal, and resumes printing. For this reason, the current situation is that the efficiency until the printing is restarted after detecting the occurrence of the synchronization signal abnormality is poor.

  For this reason, it is necessary to develop a control method that automatically recovers the generation of the synchronization signal when the occurrence of the synchronization signal abnormality is detected.

  Further, when the generation of the synchronization signal described above is automatically restored, it is necessary to determine how to control the image output by exposure and the transfer operation of the transfer target.

  The image output by exposure means that light irradiated from a light source such as an LD (laser diode) is deflected and scanned by a polygon mirror, and an image is formed on the photosensitive member by the deflected and scanned light. That is, image formation.

  The transfer operation of the transfer object is a control operation for conveying the transfer object for transferring an image formed on the photoconductor.

  The reason for determining how to control the image output by exposure and the transfer operation of the transfer object is, for example, when the generation of the synchronization signal is automatically restored (automatically When the transfer operation of the transfer object is not performed even though the image output by exposure is performed when the return operation is started), the image output by exposure is transferred. As a result, the image output is wasted.

  In addition, when the transfer operation of the transfer object is performed when the automatic return operation is started, the abnormal image that is output in the state in which the occurrence of the synchronization signal abnormality (synchronization error) is detected is displayed. There is a risk of transfer to the transfer body.

  In addition, since the transfer operation of the transfer object may not be able to be stopped when the transfer operation has started, if the automatic return operation is started during the transfer operation, Since the output is interrupted, it is possible to prevent the abnormal image from being transferred unnecessarily to the transfer target, but the normal image cannot be transferred to the transfer target. As a result, a transferred object on which no image is formed is output.

  For this reason, when the occurrence of an abnormality in the synchronization signal is detected, the output of the image (image formation) by exposure and the transfer operation of the transfer target can be controlled to automatically return the generation of the synchronization signal. Development of a control method to make it will be necessary.

  As a technical document filed prior to the present invention, there is a document that discloses a digital image forming apparatus that can reliably detect an abnormality in horizontal synchronization (see, for example, Patent Document 1).

  Further, there is a document that discloses a digital image forming apparatus that can quickly detect a synchronization signal abnormality in the digital image forming apparatus (see, for example, Patent Document 2).

Further, there is a document that discloses an image forming apparatus that prevents an inappropriate warning from being issued when a synchronization detection abnormality signal is generated due to a trouble of the generating apparatus (see, for example, Patent Document 3).
Japanese Patent No. 3508364 JP 2003-326759 A JP 2003-57580 A

  As disclosed in Patent Documents 1 to 3, it is possible to detect the occurrence of a synchronization signal abnormality. However, Patent Documents 1 to 3 disclose that when the occurrence of a synchronization signal abnormality is detected, the image formation and the transfer operation of the transfer target are controlled, and the generation of the synchronization signal is automatically restored. There is no mention or suggestion of its necessity.

  The present invention has been made in view of the above circumstances, and controls the image formation and the transfer operation of the transfer object when the occurrence of the synchronization signal abnormality, which is the problem described above, is detected. An object of the present invention is to provide an image forming apparatus, a control method, and a control program capable of automatically restoring the occurrence of the above.

  In order to achieve this object, the present invention has the following features.

An image forming apparatus according to the present invention includes:
A light source;
Light source control means for controlling the light source and emitting light from the light source at a predetermined timing;
Optical scanning means for deflecting and scanning light emitted from the light source, writing light on the image carrier, and forming an image on the image carrier;
Synchronization signal generating means for generating a synchronization signal when the light is detected;
Error detection means for detecting occurrence of abnormality of the synchronization signal;
When the occurrence of the abnormality is detected, an image forming state on the image carrier by the optical scanning unit and a transfer operation state of a transfer body that transfers an image formed on the image carrier are specified. Specific means,
Automatic reset means for resetting the timing for emitting light from the light source and returning the generation of the synchronization signal when the occurrence of the abnormality is detected,
The automatic return means is
The image forming state specified by the specifying unit is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is before the start of the transfer to be started, the optical scanning unit stops the image formation in which light is written on the image carrier, and waits for the transfer operation to transfer the image formed on the image carrier. , Return the generation of the synchronization signal,
The image forming state specified by the specifying unit is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is after the start of the transfer that has been started, the image formation in which light is written on the image carrier by the optical scanning unit and the transfer operation to transfer the image formed on the image carrier are stopped, Resuming generation of the synchronization signal;
Wherein said image forming condition which is specified by the specifying means, when a state after the image forming you write light to said image bearing member by said optical scanning means, said transfer operation state, the to the transfer receiving material even transcription start before starting the image transfer, even the transcription start later started, returning the generation of the synchronization signal while performing the transfer operation for transferring the image formed on the image bearing member as is It is characterized by making it.

Further, the control method according to the present invention includes:
A light source;
Light source control means for controlling the light source and emitting light from the light source at a predetermined timing;
Optical scanning means for deflecting and scanning light emitted from the light source, writing light on the image carrier, and forming an image on the image carrier;
A synchronization signal generating means for generating a synchronization signal when the light is detected, and a control method performed by an image forming apparatus comprising:
An error detection step of detecting occurrence of an abnormality in the synchronization signal;
When the occurrence of the abnormality is detected, an image forming state on the image carrier by the optical scanning unit and a transfer operation state of a transfer body that transfers an image formed on the image carrier are specified. Specific process,
When the occurrence of the abnormality is detected, the image forming apparatus performs an automatic return step of resetting the timing for emitting light from the light source and returning the generation of the synchronization signal,
The automatic return process includes
The image forming state specified by the specifying step is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is before the start of the transfer to be started, the optical scanning unit stops the image formation in which light is written on the image carrier, and waits for the transfer operation to transfer the image formed on the image carrier. , Return the generation of the synchronization signal,
The image forming state specified by the specifying step is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is after the start of the transfer that has been started, the image formation in which light is written on the image carrier by the optical scanning unit and the transfer operation to transfer the image formed on the image carrier are stopped, Resuming generation of the synchronization signal;
Wherein said image forming condition which is specified by the specifying step, if a state after the image forming you write light to said image bearing member by said optical scanning means, said transfer operation state, the to the transfer receiving material even transcription start before starting the image transfer, even the transcription start later started, returning the generation of the synchronization signal while performing the transfer operation for transferring the image formed on the image bearing member as is It is characterized by making it.

Further, the control program according to the present invention is:
A light source;
Light source control means for controlling the light source and emitting light from the light source at a predetermined timing;
Optical scanning means for deflecting and scanning light emitted from the light source, writing light on the image carrier, and forming an image on the image carrier;
A control program to be executed in an image forming apparatus having synchronization signal generating means for generating a synchronization signal when detecting the light,
An error detection process for detecting occurrence of an abnormality in the synchronization signal;
When the occurrence of the abnormality is detected, an image forming state on the image carrier by the optical scanning unit and a transfer operation state of a transfer body that transfers an image formed on the image carrier are specified. Specific processing,
When the occurrence of the abnormality is detected, the image forming apparatus is caused to execute an automatic return process for resetting the timing for emitting light from the light source and returning the generation of the synchronization signal,
The automatic return process is
The image forming state specified by the specifying process is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is before the start of the transfer to be started, the optical scanning unit stops the image formation in which light is written on the image carrier, and waits for the transfer operation to transfer the image formed on the image carrier. , Return the generation of the synchronization signal,
The image forming state specified by the specifying step is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is after the start of the transfer that has been started, the image formation in which light is written on the image carrier by the optical scanning unit and the transfer operation to transfer the image formed on the image carrier are stopped, Resuming generation of the synchronization signal;
Wherein said image forming condition identified by a specific process, if a state after the image forming you write light to said image bearing member by said optical scanning means, said transfer operation state, the to the transfer receiving material even transcription start before starting the image transfer, even the transcription start later started, returning the generation of the synchronization signal while performing the transfer operation for transferring the image formed on the image bearing member as is It is characterized by making it.

  According to the present invention, when the occurrence of a synchronization signal abnormality is detected, it is possible to control the image formation and the transfer operation of the transfer target to automatically return the generation of the synchronization signal.

  First, the outline of the image forming apparatus of this embodiment will be described with reference to FIG.

  The image forming apparatus of the present embodiment controls a light source (equivalent to a preceding light source: 8, a trailing light source: 9) and a light source (8, 9), and emits light from the light source (8, 9) at a predetermined timing. Light source control means for emitting light (corresponding to the LD control unit 206) and light emitted from the light sources (8, 9) are deflected and scanned, and light is written on an image carrier (not shown), and an image is formed on the image carrier. Optical scanning means (corresponding to polygon mirror: 1, first lens: 2, second lens: 3, first mirror: 4, second mirror: 5) and a sync signal when light is detected Synchronization signal generating means (equivalent to a synchronization signal generator: 7) to be generated.

  The image forming apparatus according to the present exemplary embodiment transfers the image formed on the image carrier by the optical scanning unit and the image formed on the image carrier when the occurrence of the synchronization signal abnormality is detected. The transfer operation state of the body (not shown) is specified. Then, according to the specified image forming state and the transfer operation state, the image formation on the image carrier and the transfer operation of the transfer target are controlled, and light is emitted from the light sources (8, 9). To reset the generation timing of the synchronization signal.

  As a result, the image forming apparatus according to the present embodiment controls the image formation and the transfer operation of the transfer target and automatically returns the generation of the synchronization signal when the occurrence of the synchronization signal abnormality is detected. Is possible. The technical idea of the present embodiment described above is not particularly limited in the number of light sources, and can be applied to an image forming apparatus having one light source. Hereinafter, the image forming apparatus of this embodiment will be described in detail with reference to the accompanying drawings.

(First embodiment)
<Configuration of image forming apparatus>
First, the configuration of the image forming apparatus of this embodiment will be described with reference to FIG.

  The image forming apparatus of this embodiment includes an optical writing device (100) and a control unit (200).

  The optical writing device (100) is synchronized with the polygon mirror (1), the first lens (2), the second lens (3), and the first to third mirrors (4, 5, 6). A signal generator (7), a leading light source (8), and a trailing light source (9) are included.

  The first and second mirrors (4, 5) are for guiding light to a photoreceptor (not shown). The third mirror (6) is for guiding light to the synchronization signal generator (7).

  The synchronization signal generator (7) generates a synchronization signal. The leading light source (8) and the trailing light source (9) irradiate light to the polygon mirror (1).

  The control unit (200) includes a general abnormality detection unit (201), an automatic return control unit (202), a main scanning counter (203), a synchronization detection unit (204), and a polygon control unit (205). And an LD control unit (206).

  The comprehensive abnormality detection unit (201) confirms whether or not there is an abnormality in the preceding light source (8), the trailing light source (9), the polygon mirror (1), and the like.

  The automatic return control unit (202) performs automatic return control of the synchronization signal when the cause of abnormality of the synchronization signal is detected.

  The main scanning counter (203) counts the main scanning count value of one line scanning.

  The synchronization detection unit (204) detects the synchronization signal generated by the synchronization signal generator (7).

  The polygon control unit (205) controls the rotational drive of the polygon mirror (1).

  The LD control unit (206) controls the leading light source (8) and the trailing light source (9).

  The image forming apparatus according to the present exemplary embodiment irradiates light to the polygon mirror (1) from two light sources (leading light source: 8, trailing light source: 9) at a predetermined timing. The light irradiated to the polygon mirror (1) is guided to the first and second mirrors (4, 5), and the light reflected by the first and second mirrors (4, 5) is a photosensitive member (not shown). To reach. Thereby, an image is formed on the photoreceptor.

  The light irradiated on the polygon mirror (1) is guided to the synchronization signal generator (7) through the third mirror (6).

  As a result, the light deflected and scanned by the polygon mirror (1) is applied to the synchronization signal generator (7) in the course of scanning. The synchronization signal generator (7) in the present embodiment is equipped with a synchronization sensor, and generates a synchronization signal when light is detected by the synchronization sensor.

  FIG. 2 is a diagram showing a state where the optical writing device (100) shown in FIG. 1 is viewed from the side. As shown in FIG. 2, the optical writing device (100) differs in the height of the optical path irradiated from the two light sources (8, 9) to the polygon mirror (1). For this reason, the optical writing device (100) of the present embodiment can simultaneously perform optical scanning from the two light sources (8, 9).

  In the optical writing device (100) in this embodiment, the light irradiated from the preceding light source (8) hits the polygon mirror (1), and the light deflected and scanned by the polygon mirror (1) is the third mirror. This is input to the synchronization signal generator (7) via (6).

  The synchronization signal generator (7) generates a synchronization signal when light is detected by the synchronization sensor mounted on the synchronization signal generator (7), and the generated synchronization signal is used as the synchronization detection unit (204). Output to.

  The synchronization detection unit (204) determines whether the synchronization signal is the synchronization signal of the preceding light source (8) or the synchronization signal of the following light source (9) based on the synchronization signal output from the synchronization signal generator (7). .

  As a determination method for determining whether the synchronization signal of the preceding light source (8) or the following light source (9) is used, for example, the synchronization signal output from the synchronization signal generator (7) is detected by synchronization. The method of judging in the order which the part (204) received is mentioned.

  For example, as shown in FIG. 3, the synchronization detection unit (204) first determines the synchronization signal received from the synchronization signal generator (7) as the synchronization signal of the preceding light source (8), and then the synchronization signal generator. The synchronization signal received from (7) is determined as the synchronization signal of the succeeding light source (9), and then the synchronization signal received from the synchronization signal generator (7) is determined as the synchronization signal of the preceding light source (8). To do.

  Thereby, as shown in FIG. 3, the synchronization detection unit (204) determines the odd number of synchronization signals as the synchronization signal of the preceding light source (8), and the even number of synchronization signals are synchronized with the subsequent light source (9). It can be determined as a signal.

  When the synchronization detection unit (204) determines that the signal is the synchronization signal of the preceding light source (8), the LD control unit (206) emits light from the subsequent light source (9) at a predetermined interval. Control to do. The predetermined interval may be, for example, a method of counting the clocks of the light sources (8, 9).

  The light emitted from the trailing light source (9) hits the polygon mirror (1), and the light deflected and scanned by the polygon mirror (1) passes through the third mirror (6) to generate a synchronization signal generator ( 7).

  When the synchronization signal is detected by the synchronization sensor, the synchronization signal generator (7) generates a synchronization signal and outputs the generated synchronization signal to the synchronization detection unit (204).

  Based on the synchronization signal output from the synchronization signal generator (7), the synchronization detection unit (204) determines whether the synchronization signal from the preceding light source (8) or the following light source (9) is synchronized. Judgment will be made.

  When the synchronization detection unit (204) cannot determine whether the synchronization signal is the synchronization signal of the preceding light source (8) or the subsequent light source (9), the synchronization detection unit (204) With the occurrence of an abnormality cause (synchronization error) of the preceding light source (8), it becomes impossible to start the light irradiation of the succeeding light source (9). As a result, an abnormal cause (synchronization error) of the trailing light source (9) also occurs.

<Automatic return operation>
Next, an automatic return operation in the image forming apparatus of this embodiment will be described with reference to FIGS. FIG. 4 is a flowchart of the automatic return operation.

  First, the synchronization detection unit (204) detects the synchronization signal output from the synchronization signal generator (7) (step S1), and determines whether the synchronization signal is output from the synchronization signal generator (7). (Step S2).

  When the synchronization detection unit (204) determines that the synchronization signal is not output from the synchronization signal generator (7) (step S2 / No), the synchronization detection unit (204) indicates that the synchronization signal is abnormal (synchronization error). ) Has occurred.

  Next, the synchronization detection unit (204) determines whether or not the light source in which the synchronization signal abnormality (synchronization error) has occurred is the preceding light source (8) (step S3).

  For example, as shown in FIG. 3, it is assumed that the odd number of synchronization signals are the synchronization signals of the preceding light source (8) and the even number of synchronization signals are the synchronization signals of the following light source (9).

  In this case, the synchronization detection unit (204) determines that the preceding light source (8) is a light source in which an abnormality (synchronization error) of the synchronization signal has occurred when an odd number of synchronization signals cannot be detected (step S102). S3 / Yes), the synchronization detection unit (204) notifies the general abnormality detection unit (201) to that effect, and sets the preceding light source (8) as the light source for the automatic return operation (step S4).

  In addition, when the synchronization detection unit (204) can detect an odd number of synchronization signals, the subsequent light source (9) determines that the synchronization signal abnormality (synchronization error) has occurred (step S3 / No), the synchronization detection unit (204) notifies the general abnormality detection unit (201) to that effect, and sets the subsequent light source (9) as the light source for the automatic return operation (step S5).

  Next, the comprehensive abnormality detection unit (201) first checks whether there is any abnormality in the light sources (8, 9) and the polygon mirror (1) (steps S6, S7).

  When the general abnormality detection unit (201) determines that there is no abnormality in the light source (8, 9) and the polygon mirror (1) (step S6 / Yes and step S7 / Yes), the general abnormality detection The unit (201) requests the automatic return control unit (202) to execute an automatic return operation.

  The automatic return control unit (202) controls the LD control unit (206), and forcibly continuously emits the light sources (8, 9) that are the targets of the automatic return operation by the processes in steps S4 and S5.

  At this time, as shown in FIG. 5, the automatic return control unit (202) operates the shutter (10) to control light so as not to irradiate the photoconductor.

  When light is continuously emitted from the light sources (8, 9) for the automatic return operation, one line scanning is performed (step S8).

  Note that the synchronization sensor of the synchronization signal generator (7) detects light emitted from the light source (8, 9) subject to automatic return operation somewhere during the one-line scanning, and the synchronization signal generator (7) outputs a synchronization signal when light is detected by the synchronization sensor. As a result, the main scanning count value of the synchronization signal generation interval is stored in the main scanning counter (203).

  The automatic return control unit (202) acquires the main scan count value stored in the main scan counter (203) when the process of step S8 is performed (step S9).

  The automatic return control unit (202) acquires the main scan count value during one line scan, and estimates the detection position of the sync sensor of the sync signal generator (7) based on the acquired main scan count value. It becomes possible to do.

  In FIG. 6, before the automatic return operation, the main scan count value during one line scan is “10000”, and when a synchronization signal abnormality (synchronization error) occurs (step S 2 / No), the synchronization detection unit (204) becomes unable to detect the synchronization signal, and then performs the one-line scanning by the above-described automatic return operation (step S8), and acquires the main scanning count value during the one-line scanning (step S10 / Yes). An example in which the acquired main scanning count value is “8000” is shown.

  FIG. 6 shows the light detection position of the synchronization sensor of the synchronization signal generator (7) when the light source (8, 9) is controlled to be lit at the position of the count value “10000”. However, the main scan count value per line scan changes due to, for example, abnormal rotation of the polygon mirror (1) or lens characteristic change, and the light source (8, 9) at the position of the count value “8000”. If the control is not performed so that the light is turned on, the synchronization sensor of the synchronization signal generator (7) cannot detect light.

  For example, even if the light source (8, 9) is controlled to light at the position of the count value “10000” in the state of FIG. 6, the light from the light source (8, 9) is emitted from the synchronization signal generator (7 ) And the synchronization sensor cannot detect light. As a result, the synchronization signal generator (7) cannot output a synchronization signal.

  For this reason, the image forming apparatus according to the present exemplary embodiment acquires the main scan count value “8000” stored in the main scan counter (203) during the automatic return operation, and sets the position of the acquired count value “8000”. Therefore, it is estimated that it is the light detection position of the synchronization sensor of the synchronization signal generator (7).

  Then, after the automatic return operation, the image forming apparatus of the present embodiment controls the count value for turning on the light sources (8, 9) as “8000”, so that the light of the synchronization sensor of the synchronization signal generator (7). The light sources (8, 9) can be turned on at the detection position.

  Therefore, when the automatic return control unit (202) acquires the main scan count value for one line scan (step S10 / Yes), it detects the synchronization signal based on the acquired main scan count value for one line scan. Therefore, the lighting position of the light source (8, 9) is reset (step S11). Then, the automatic return control unit (202) ends the automatic return control.

  Thereafter, the operation returns to normal operation, and the synchronization detection unit (204) determines again whether or not the synchronization signal is output from the synchronization signal generator (7), and the synchronization after the automatic return is performed as in step S2. It is determined whether or not the signal is normal (step S12).

  When the synchronization detection unit (204) determines that the synchronization signal after the automatic return is normal (step S12 / Yes), the synchronization detection unit (204) proceeds to step S1, and the synchronization detection unit (204) The synchronization signal output from (7) is detected (step S1).

  In addition, when the synchronization detection unit (204) determines that the synchronization signal after the automatic return is not normal (step S12 / No), the synchronization detection unit (204) notifies the total abnormality detection unit (201) to that effect, and the total abnormality detection unit (201) stops the polygon control unit (205) and the LD control unit (206) (step S13).

  When the general abnormality detection unit (201) determines that there is an abnormality in at least one of the light source (8, 9) and the polygon motor (step S6 / No, step S7 / No), the general abnormality is detected. The detection unit (201) stops the polygon control unit (205) and the LD control unit (206) (step S13).

  Further, if the main scan count value for one line scan cannot be acquired, the automatic return control unit (202) continues to acquire the main scan count value until a predetermined number of retries is exceeded. If the main scan count value can be acquired before the predetermined number of retries is exceeded, the automatic return control unit (202) detects the synchronization signal based on the acquired main scan count value for one line scan. Therefore, the lighting position of the light source (8, 9) is reset (step S11).

  In addition, if the main scan count value cannot be acquired even after a certain number of retries has been exceeded, the automatic return control unit (202) notifies the general abnormality detection unit (201) to that effect, and the general abnormality detection unit (201) stops the polygon control unit (205) and the LD control unit (206) (step S13).

  As described above, in the image forming apparatus according to the present exemplary embodiment, when the synchronization detection unit (204) detects the occurrence of the synchronization signal abnormality, the automatic return control unit (202) emits light from the light sources (8, 9). Reset the timing to emit light and restore the generation of the synchronization signal.

  As a result, the image forming apparatus according to the present exemplary embodiment can automatically return the generation of the synchronization signal when the occurrence of the synchronization signal abnormality is detected.

  Further, in the image forming apparatus according to the present exemplary embodiment, when the synchronization detection unit (204) detects the occurrence of the synchronization signal abnormality, the light source (8 or 9) from which the abnormality occurs is specified. . Then, the automatic return unit (202) resets the timing of the identified light source (8 or 9) and returns the generation of the synchronization signal of the light source.

  As a result, the image forming apparatus according to the present exemplary embodiment identifies whether the light source in which the synchronization signal abnormality (synchronization error) has occurred is the preceding light source (8) or the trailing light source (9), and the synchronization signal It is possible to identify the light source (8 or 9) that caused the abnormality occurrence and automatically return the generation of the synchronization signal of the light source (8 or 9) that caused the abnormality occurrence It becomes. As a result, the image forming apparatus according to the present embodiment does not perform an automatic light source return operation that does not cause an abnormality, so that it is possible to improve the performance of the entire image forming apparatus.

  In the image forming apparatus according to the present embodiment, the synchronization signal generator (7) receives light from a plurality of light sources (leading light source: 8, trailing light source: 9), generates a synchronization signal, and generates the generated signal. The synchronization signal is output to the synchronization detector (204). Then, the synchronization detection unit (204) determines which light source (8, 9) is the synchronization signal based on the synchronization signal output from the synchronization signal generator (7).

  As a result, the image forming apparatus of the present embodiment can reduce the number of synchronization signal generators (7) and reduce the cost.

  Further, the image forming apparatus according to the present embodiment specifies that the abnormality has occurred from the trailing light source (9) when the synchronization signal of the preceding light source (8) can be detected, and the preceding light source (8). If the synchronization signal cannot be detected, it is determined that an abnormality has occurred from the preceding light source (8). As a result, the image forming apparatus according to the present exemplary embodiment can identify the true problem of occurrence of abnormality (synchronization error) of the preceding light source (8).

  Further, in the image forming apparatus according to the present embodiment, when the occurrence of abnormality (synchronization error) occurs from the preceding light source (8), the light source to be restored to return the generation of the synchronization signal is set as the preceding light source (8). Control. In addition, when an abnormality (synchronization error) occurs from the trailing light source (9), control is performed so that the returning light source for returning the generation of the synchronizing signal is the trailing light source (9).

  As a result, the image forming apparatus according to the present embodiment automatically detects the succeeding light source (9) that may be operating normally when an abnormality (synchronization error) of the preceding light source (8) is detected. It is possible not to use the light source. As a result, the image forming apparatus according to the present exemplary embodiment does not perform a useless automatic return operation, so that the performance of the entire image forming apparatus can be improved.

  Further, the image forming apparatus according to the present embodiment cannot use the preceding light source (8) and the following light source (9) when the recovery of the generation of the synchronization signal of the preceding light source (8) fails. And Further, when the recovery of the generation of the synchronization signal of the trailing light source (9) fails, the control is performed so that the trailing light source (9) cannot be used and the leading light source (8) can be used. .

  As a result, the image forming apparatus according to the present embodiment disables the light source that has caused the occurrence of an abnormality (synchronization error), thereby preventing the occurrence of an abnormal image.

  Further, the image forming apparatus according to the present exemplary embodiment stops the control of the image forming apparatus when an abnormality occurrence (synchronization error) is detected, and when there is a light source that can be used after the automatic return operation ends, The usable light source is controlled so as to resume the control of the image forming apparatus.

  As a result, the image forming apparatus according to the present exemplary embodiment is limited in control performed by the image forming apparatus, but controls the image forming apparatus using a light source that has not caused an abnormality (synchronization error). This can be done continuously.

  In addition, the image forming apparatus according to the present embodiment stops the control of the image forming apparatus when an abnormality (synchronization error) is detected, and there is an unusable light source after the automatic return operation is completed. Then, control is performed to stop the operation of the image forming apparatus. In this case, the image forming apparatus according to the present exemplary embodiment is preferably controlled to perform error notification.

  As a result, the image forming apparatus according to the present embodiment can disable the entire image forming apparatus and prompt the user to repair the image forming apparatus.

(Second embodiment)
Next, a second embodiment will be described.

  In the image forming apparatus according to the second embodiment, when the occurrence of a synchronization signal abnormality is detected, the image forming state on the photoconductor and the transfer operation state of the transfer target that transfers the image formed on the photoconductor , Specify. Then, according to the specified image forming state and transfer operation state, the image formation on the photosensitive member and the transfer operation of the transfer target are controlled, and the timing for emitting light from the light source is reset. The generation of the synchronization signal is restored.

  As a result, the image forming apparatus according to the present embodiment controls the image formation and the transfer operation of the transfer target and automatically returns the generation of the synchronization signal when the occurrence of the synchronization signal abnormality is detected. Is possible. The technical idea of the present embodiment described above is not particularly limited in the number of light sources, and can be applied to an image forming apparatus having one light source. Hereinafter, the image forming apparatus of this embodiment will be described in detail with reference to FIGS.

<Configuration of image forming apparatus>
First, the configuration of the image forming apparatus in this embodiment will be described with reference to FIG. FIG. 7 is a diagram illustrating a configuration example of the image forming apparatus according to the present exemplary embodiment.

  The image forming apparatus according to the present exemplary embodiment includes an optical writing device (100), a control unit (200), a photoreceptor (300), a transfer roller (400), a conveyance roller (500), and a detection sensor (600). ).

  The optical writing device (100) writes light on the photoconductor (300) to form an image on the photoconductor (300). Any configuration can be applied to the optical writing device (100) as long as an image can be formed on the photoreceptor (300). For example, the optical writing device (100) of the first embodiment is applicable. ) Can be applied.

  The control unit (200) controls the image forming apparatus, and includes an automatic return control unit (202), a general abnormality detection unit (201), an image output control unit (207), and a transfer operation control unit (208). ).

  The image output control unit (207) controls the optical writing device (100) and performs image output control. The image output control unit (207) includes the main scanning counter (203), the synchronization detection unit (204), the polygon control unit (205), the LD control unit (206), and the like described in the first embodiment. Have and configure.

  The transfer operation control unit (208) performs control when transferring the image formed on the photoconductor (300) to the transfer target (700).

  The automatic return control unit (202) performs automatic return control of the synchronization signal when the cause of abnormality of the synchronization signal is detected.

  The general abnormality detection unit (201) checks whether or not there is an abnormality in the image output control unit (207), the transfer operation control unit (208), and the like.

  The general abnormality detection unit (201) inquires of the transfer operation control unit (208) about the transfer operation state, and acquires the transfer operation state from the transfer operation control unit (208). Further, the general abnormality detection unit (201) inquires of the image output control unit (207) about the image formation state, and acquires the image formation state from the image output control unit (207).

<Judgment method of transfer operation state>
Next, a method for determining the transfer operation state of this embodiment will be described with reference to FIG.

  When a general image forming apparatus transfers an image formed on a photoconductor (300) to a transfer object (700) such as paper, the transfer object (700) is just before the transfer portion near the transfer roller (400). ) And the transfer of the transfer target (700) is started in accordance with the feed timing of the image formed on the photosensitive member (300).

  In order to determine whether or not the transfer target (700) has been transported to just before the transfer portion, a detection sensor (600) for detecting the transfer target (700) is mounted, and the transfer target (700) is transported. In this case, there is a method of changing the signal of the detection sensor (600). Note that a photo sensor or the like is applicable as the detection sensor (600).

  In the above-described image forming apparatus, the transfer operation control unit (208) conveys the transfer target (700) just before the transfer unit, and determines whether the transfer of the transfer target (700) is started for transfer. By memorizing, it is determined whether or not the transfer operation is started.

  In the image forming apparatus described above, the image formed on the photoconductor (300) is transferred to the transfer target (700), but the image is formed on a transfer belt used as an alternative to the photoconductor (300). It is also possible to construct such that the image is transferred to the transfer target (700).

  As described above, any method can be applied to the method for determining the transfer operation state according to the present embodiment as long as the transfer operation state of the transfer target (700) can be grasped.

<Method for Judging Image Forming State>
Next, a method for determining the image forming state of this embodiment will be described with reference to FIG.

  As a method for determining the image formation state, for example, the image output control unit (207) shown in FIG. 8 controls the LD control unit (212) configured by the ASIC, and turns on an image output start trigger.

  As a result, the LD control unit (212) counts synchronization for a preset count value, and inputs an image data transfer start signal to the image transfer unit (211) configured by the ASIC.

  When an image data transfer start signal is input, the image transfer unit (211) acquires image data necessary for image formation from the image storage unit (210), and acquires the acquired image data as an LD control unit ( 212).

  Note that when transfer of image data to the LD controller (212) starts, the transfer signal changes from OFF to ON.

  When receiving the image data, the LD control unit (212) converts the received image data into the amount of light of the LD (light source: 213), emits light from the LD (213), and the photoreceptor (300). To form a latent image.

  When the transfer of image data to the LD control unit (212) is completed, the transfer signal is turned from ON to OFF.

  Note that the image output control unit (207) of this embodiment stores whether or not the image output start trigger is turned on, and determines whether or not image output has started.

  In addition, the image output control unit (207) of the present embodiment turns on the trigger for starting image output, and confirms that all the transfer signals used for image output have been turned from ON to OFF, thereby completing the image output. It will be judged whether or not.

  As described above, any method can be applied to the image forming state determination method of this embodiment as long as the image output control unit (207) can grasp the image forming state.

  It should be noted that the general abnormality detection unit (201) of the present embodiment is connected to the image output control unit (207) so as to perform the operation of the list shown in FIG. 9 according to the image forming state and the transfer operation state. The transfer operation control unit (208) is controlled, and the automatic return control unit (202) performs automatic return control of the synchronization signal. FIG. 9 is a diagram showing a list showing the behavior of image formation and transfer operation when the automatic return operation execution conditions are met.

In FIG. 9, when the image formation state is “before” image formation and the transfer operation state is “before” the transfer operation starts, the comprehensive abnormality detection unit (201) The automatic return control unit (202) performs the automatic return control of the synchronization signal.

  When the image formation state is “before” image formation and the transfer operation state is “after” the transfer operation start, the comprehensive abnormality detection unit (201) waits for image formation and performs the transfer operation. The automatic return control unit (202) performs the automatic return control of the synchronization signal.

  When the image formation state is “medium” image formation and the transfer operation state is “before” the transfer operation start, the comprehensive abnormality detection unit (201) stops the image formation and performs the transfer operation. The automatic return control unit (202) performs the automatic return control of the synchronization signal.

  When the image formation state is “medium” image formation and the transfer operation state is “after” the transfer operation starts, the comprehensive abnormality detection unit (201) recognizes the occurrence of the abnormal image and forms the image. Then, the transfer operation is stopped, and the automatic return control unit (202) performs automatic return control of the synchronization signal.

  Further, when the image forming state is “after” image formation, the general abnormality detection unit (whether the transfer operation state is “before” or “after” the transfer operation is started) 201) execute the transfer operation as it is, and the automatic return control unit (202) performs automatic return control of the synchronization signal.

<Automatic return operation>
Next, an automatic return operation in the image forming apparatus according to the present embodiment will be described with reference to FIGS. FIG. 10 is a flowchart of the automatic return operation.

  First, the synchronization detector (204) detects the synchronization signal output from the synchronization signal generator (7) (step A1), and determines whether the synchronization signal is output from the synchronization signal generator (7). (Step A2).

  When the synchronization detection unit (204) determines that the synchronization signal is not output from the synchronization signal generator (7) (step A2 / No), the synchronization detection unit (204) indicates that the synchronization signal is abnormal (synchronization error). ) Has occurred.

  Next, the comprehensive abnormality detection unit (201) checks whether or not there is an abnormality in the light sources (8, 9) and the polygon mirror (1) (steps A3, 4).

  When the general abnormality detection unit (201) determines that there is no abnormality in the light source (8, 9) and the polygon mirror (1) (step A3 / Yes and step A4 / Yes), the general abnormality detection The unit (201) inquires of the image output control unit (207) about the image formation state, and acquires the image formation state from the image output control unit (207) (step A5).

  The general abnormality detection unit (201) inquires of the transfer operation control unit (208) about the transfer operation state, and acquires the transfer operation state from the transfer operation control unit (208) (step A6).

  Next, the general abnormality detection unit (201) performs image output so as to perform the operation of the list shown in FIG. 9 according to the image forming state and the transfer operation state acquired in steps A5 and A6. The control unit (207) and the transfer operation control unit (208) are controlled (step A7), and the general abnormality detection unit (201) requests the automatic return control unit (202) to execute the automatic return operation. . Then, the automatic return control unit (202) performs automatic return control of the synchronization signal.

  First, the automatic return control unit (202) controls the LD control unit (206) to forcibly and continuously emit the light source that is the target of the automatic return operation.

  At this time, as shown in FIG. 5, the automatic return control unit (202) operates the shutter (10) to control light so as not to irradiate the photoconductor.

  When light is continuously emitted from the light source for the automatic return operation, one line scanning is performed (step A8).

  Note that the synchronization sensor of the synchronization signal generator (7) detects light emitted from the light source subject to automatic return operation somewhere during the one-line scanning, and the synchronization signal generator (7) When light is detected by the synchronization sensor, a synchronization signal is output. As a result, the main scanning count value of the synchronization signal generation interval is stored in the main scanning counter (203).

  The automatic return control unit (202) acquires the main scanning count value stored in the main scanning counter (203) when the process of step A8 is performed (step A9).

  When the automatic return control unit (202) acquires the main scan count value of one line scan (step A10 / Yes), the automatic return control unit (202) detects synchronization signals based on the acquired main scan count value of one line scan. The lighting position of the light source is reset (step A11). Then, the automatic return control unit (202) ends the automatic return control.

  Thereafter, the operation returns to the normal operation, and the synchronization detection unit (204) determines again whether or not the synchronization signal is output from the synchronization signal generator (7), and the synchronization after the automatic return is performed as in step A2. It is determined whether the signal is normal (step A12).

  If the synchronization detection unit (204) determines that the synchronization signal after the automatic return is normal (step A12 / Yes), the synchronization detection unit (204) proceeds to step A1, and the synchronization detection unit (204) The synchronization signal output from (7) is detected (step A1).

  Further, when the synchronization detection unit (204) determines that the synchronization signal after the automatic return is not normal (step A12 / No), the synchronization detection unit (204) notifies the general abnormality detection unit (201) to that effect, and the general abnormality detection unit (201) stops the polygon control unit (205), the LD control unit (206), and the transfer operation control unit (208) (step A13).

  When the general abnormality detection unit (201) determines that at least one of the light source and the polygon motor is abnormal (step A3 / No, step A4 / No), the general abnormality detection unit (201) Stops the polygon control unit (205), the LD control unit (206), and the transfer operation control unit (208) (step A13).

  Further, if the main scan count value for one line scan cannot be acquired, the automatic return control unit (202) continues to acquire the main scan count value until a predetermined number of retries is exceeded. If the main scan count value can be acquired before the predetermined number of retries is exceeded, the automatic return control unit (202) detects the synchronization signal based on the acquired main scan count value for one line scan. The lighting position of the light source for is reset (step A11).

  In addition, if the main scan count value cannot be acquired even after a certain number of retries has been exceeded, the automatic return control unit (202) notifies the general abnormality detection unit (201) to that effect, and the general abnormality detection unit (201) stops the polygon control unit (205), the LD control unit (206), and the transfer operation control unit (208) (step A13).

  As described above, the image forming apparatus according to the present exemplary embodiment detects light scanning means (polygon mirror: 1, first lens: 2, second lens: 3, The image forming state on the photosensitive member by 1 mirror: 4 and the second mirror: 5) and the transfer operation state of the transfer target to which the image formed on the photosensitive member is transferred are specified.

  The image forming apparatus according to the present embodiment controls the image formation on the photosensitive member and the transfer operation of the transfer target according to the specified image forming state and the transfer operation state. The timing for emitting light is reset, and control is performed to restore the generation of the synchronization signal.

  As a result, the image forming apparatus according to the present embodiment controls the image formation on the photosensitive member and the transfer operation of the transfer target according to the image forming state and the transfer operation state, and emits light from the light source. The timing for emitting light is reset and the generation of the synchronization signal is restored.

  For this reason, the image forming apparatus according to the present exemplary embodiment performs control so that abnormal images are not output unnecessarily, control is performed so that abnormal images are not formed on the transfer target as much as possible, and transfer operation is not stopped uselessly. It becomes possible to control. As a result, the performance of the entire image forming apparatus can be improved.

  In the image forming apparatus according to the present exemplary embodiment, the image forming state is before the start of image formation on the photosensitive member, and the transfer operation state is before the image transfer to the transfer target is started. In this case, control is performed such that the image formation and the transfer operation are waited and the generation of the synchronization signal is restored.

  As a result, the image forming apparatus according to the present exemplary embodiment can resume image formation immediately after returning the generation of the synchronization signal without wasting the transfer target.

  In the image forming apparatus of this embodiment, the image forming state is before the start of image formation on the photoconductor, and the transfer operation state is after the start of image transfer to the transfer target. Then, control is performed so that image formation is waited, the transfer operation is stopped, and the generation of the synchronization signal is restored.

  As a result, the image forming apparatus of the present embodiment can prevent the formation of abnormal images.

  In the image forming apparatus according to the present exemplary embodiment, when the image forming state is in the process of forming an image on the photoconductor and the transfer operation state is before the image transfer to the transfer target is started, the image is formed. Is controlled, and the transfer operation is waited for and the generation of the synchronization signal is restored.

  As a result, the image forming apparatus according to the present embodiment avoids useless image formation in a state where the synchronization signal is out, while waiting for the transfer operation. Immediately after the occurrence is restored, the image formation can be resumed.

  The image forming apparatus according to the present exemplary embodiment is configured to perform image formation when the image forming state is during image formation on the photoconductor and the transfer operation state is after image transfer to the photoconductor is started. The transfer operation is stopped and the generation of the synchronization signal is controlled to be restored.

  As a result, the image forming apparatus according to the present embodiment recognizes the occurrence of an abnormality and stops image formation, thereby avoiding useless image formation in a state where the synchronization signal is off.

In the image forming apparatus of the present embodiment, when the image forming state is after the image formation on the photoconductor, even if the transfer operation state is before the image transfer to the transfer target is started, Even after the start, the transfer operation is executed as it is, and control is performed so as to restore the generation of the synchronization signal.

  As a result, the image forming apparatus according to the present exemplary embodiment can perform the transfer operation as it is and perform image formation when the synchronization signal deviation does not affect image formation.

  The above-described embodiments are preferred embodiments of the present invention, and are not intended to limit the scope of the present invention only to the above-described embodiments. It is possible to construct a form with various changes by making corrections and substitutions.

  For example, the technical ideas of the above-described embodiments can be appropriately combined.

  In addition, the control operation in each unit constituting the image forming apparatus in the above-described embodiment can be executed by hardware, software, or a combined configuration of both.

  In addition, when executing processing by software, a program in which a processing sequence is recorded is installed in a memory in a computer incorporated in dedicated hardware and executed, or a general-purpose capable of executing various processing It is possible to install and execute a program on a computer.

  For example, the program can be recorded in advance on a hard disk or a ROM (Read Only Memory) as a recording medium. Alternatively, the program is temporarily stored on a removable recording medium such as a floppy (registered trademark) disk, a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto optical) disk, a DVD (Digital Versatile Disc), a magnetic disk, or a semiconductor memory. Or can be stored (recorded) permanently. Such a removable recording medium can be provided as so-called package software.

  The program is installed on the computer from the removable recording medium as described above, or is wirelessly transferred from the download site to the computer, or is wired to the computer via a network such as a LAN (Local Area Network) or the Internet. On the other hand, the computer can receive the transferred program and install it on a recording medium such as a built-in hard disk.

  In addition to being executed in time series in accordance with the processing operations described in the above embodiments, the processing capability of the apparatus that executes the processing, or to be executed in parallel or individually as required Is also possible. In addition, the image forming apparatus described in the above-described embodiments can be configured to have a logical set configuration of a plurality of devices, or to have a configuration in which devices of each configuration exist in the same casing.

  The image forming apparatus, the control method, and the control program according to the present invention can be applied to a device that performs an image writing process using a light beam.

1 is a diagram illustrating a configuration example of an image forming apparatus according to a first embodiment. It is a figure which shows the structural example of the optical writing apparatus of a present Example. It is a figure for demonstrating the judgment method which judges whether it is a synchronizing signal of a preceding light source (8), or a synchronizing signal of a succeeding light source (9). FIG. 5 is a diagram illustrating a flowchart of an automatic return operation in the image forming apparatus according to the first embodiment. It is a figure for demonstrating the case where it controls so that a shutter (10) is operated, light is shielded, and a photoconductor is not irradiated with light. It is a figure which shows the example of the count value at the time of normal operation | movement, and the count value acquired by automatic return operation | movement. It is a figure which shows the structural example of the image forming apparatus of a 2nd Example. It is a figure for demonstrating the judgment method of an image formation state. It is a figure which shows the list | wrist which shows the behavior of image formation and transfer operation | movement when automatic return operation | movement execution conditions are met. FIG. 9 is a flowchart illustrating an automatic return operation in the image forming apparatus according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polygon mirror 2 1st lens 3 2nd lens 4 1st mirror 5 2nd mirror 6 3rd mirror 7 Sync signal generator 8 Leading light source 9 Subsequent light source 10 Shutter 100 Optical writing device 200 Control unit 201 Comprehensive abnormality detection part 202 Automatic Return Control Unit 203 Main Scan Counter 204 Synchronization Detection Unit 205 Polygon Control Unit 206 LD Control Unit 207 Image Output Control Unit 208 Transfer Operation Control Unit 300 Photoconductor 400 Transfer Roller 500 Conveyance Roller 600 Detection Sensor 700 Transferred Object

Claims (3)

A light source;
Light source control means for controlling the light source and emitting light from the light source at a predetermined timing;
Optical scanning means for deflecting and scanning light emitted from the light source, writing light on the image carrier, and forming an image on the image carrier;
Synchronization signal generating means for generating a synchronization signal when the light is detected;
Error detection means for detecting occurrence of abnormality of the synchronization signal;
When the occurrence of the abnormality is detected, an image forming state on the image carrier by the optical scanning unit and a transfer operation state of a transfer body that transfers an image formed on the image carrier are specified. Specific means,
Automatic reset means for resetting the timing for emitting light from the light source and returning the generation of the synchronization signal when the occurrence of the abnormality is detected,
The automatic return means is
The image forming state specified by the specifying unit is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is before the start of the transfer to be started, the optical scanning unit stops the image formation in which light is written on the image carrier, and waits for the transfer operation to transfer the image formed on the image carrier. , Return the generation of the synchronization signal,
The image forming state specified by the specifying unit is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is after the start of the transfer that has been started, the image formation in which light is written on the image carrier by the optical scanning unit and the transfer operation to transfer the image formed on the image carrier are stopped, Resuming generation of the synchronization signal;
Wherein said image forming condition which is specified by the specifying means, when a state after the image forming you write light to said image bearing member by said optical scanning means, said transfer operation state, the to the transfer receiving material even transcription start before starting the image transfer, even the transcription start later started, returning the generation of the synchronization signal while performing the transfer operation for transferring the image formed on the image bearing member as is An image forming apparatus. A light source;
Light source control means for controlling the light source and emitting light from the light source at a predetermined timing;
Optical scanning means for deflecting and scanning light emitted from the light source, writing light on the image carrier, and forming an image on the image carrier;
A synchronization signal generating means for generating a synchronization signal when the light is detected, and a control method performed by an image forming apparatus comprising:
An error detection step of detecting occurrence of an abnormality in the synchronization signal;
When the occurrence of the abnormality is detected, an image forming state on the image carrier by the optical scanning unit and a transfer operation state of a transfer body that transfers an image formed on the image carrier are specified. Specific process,
When the occurrence of the abnormality is detected, the image forming apparatus performs an automatic return step of resetting the timing for emitting light from the light source and returning the generation of the synchronization signal,
The automatic return process includes
The image forming state specified by the specifying step is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is before the start of the transfer to be started, the optical scanning unit stops the image formation in which light is written on the image carrier, and waits for the transfer operation to transfer the image formed on the image carrier. , Return the generation of the synchronization signal,
The image forming state specified by the specifying step is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is after the start of the transfer that has been started, the image formation in which light is written on the image carrier by the optical scanning unit and the transfer operation to transfer the image formed on the image carrier are stopped, Resuming generation of the synchronization signal;
Wherein said image forming condition which is specified by the specifying step, if a state after the image forming you write light to said image bearing member by said optical scanning means, said transfer operation state, the to the transfer receiving material even transcription start before starting the image transfer, even the transcription start later started, returning the generation of the synchronization signal while performing the transfer operation for transferring the image formed on the image bearing member as is The control method characterized by making it do. A light source;
Light source control means for controlling the light source and emitting light from the light source at a predetermined timing;
Optical scanning means for deflecting and scanning light emitted from the light source, writing light on the image carrier, and forming an image on the image carrier;
A control program to be executed in an image forming apparatus having synchronization signal generating means for generating a synchronization signal when detecting the light,
An error detection process for detecting occurrence of an abnormality in the synchronization signal;
When the occurrence of the abnormality is detected, an image forming state on the image carrier by the optical scanning unit and a transfer operation state of a transfer body that transfers an image formed on the image carrier are specified. Specific processing,
When the occurrence of the abnormality is detected, the image forming apparatus is caused to execute an automatic return process for resetting the timing for emitting light from the light source and returning the generation of the synchronization signal,
The automatic return process is
The image forming state specified by the specifying process is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is before the start of the transfer to be started, the optical scanning unit stops the image formation in which light is written on the image carrier, and waits for the transfer operation to transfer the image formed on the image carrier. , Return the generation of the synchronization signal,
The image forming state specified by the specifying step is a state during image formation in which light is written on the image carrier by the optical scanning unit, and the transfer operation state is image transfer to the transfer target. If it is after the start of the transfer that has been started, the image formation in which light is written on the image carrier by the optical scanning unit and the transfer operation to transfer the image formed on the image carrier are stopped, Resuming generation of the synchronization signal;
Wherein said image forming condition identified by a specific process, if a state after the image forming you write light to said image bearing member by said optical scanning means, said transfer operation state, the to the transfer receiving material even transcription start before starting the image transfer, even the transcription start later started, returning the generation of the synchronization signal while performing the transfer operation for transferring the image formed on the image bearing member as is A control program characterized by causing

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