JP2008257057A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stop electrification quickly and to prevent developer from blowing out, when an image forming apparatus becomes abnormal. <P>SOLUTION: A copying machine stops charging bias (charging of a photoreceptor 1) by a charging device 2 and developing bias (charging of developer) by a developing device 4 stepwise, according to a present bias state (electrification state), respectively when abnormality occurs in the copying machine itself. Here, the occurring abnormality is detected, a stopping method is selected according to the result, and the copying machine is stopped based on the selected stopping method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an electrophotographic multifunction peripheral, a copying machine, a facsimile machine, and a printer, and more particularly to an image forming apparatus having a device protection function when an abnormality occurs.

  In the image forming apparatus as described above, an electrostatic latent image is formed by exposing the photosensitive member rotating in the sub-scanning direction according to the original image or image data (which is uniformly charged in advance by the charging device) by the exposure device. A developer (toner) is attached to the electrostatic latent image by a developing device to form a toner image, and the toner image is transferred onto a transfer paper (paper) by a transfer device. A series of image forming processes are performed in which the toner image is fixed by heating and pressing with a fixing unit such as a fixing roller with a built-in fixing heater.

As such an image forming apparatus, for example, as can be seen in Japanese Patent Application Laid-Open No. H10-228707, a photosensitive member (an apparatus for performing image forming processing such as a charging device or an exposure device) before image formation is started up. There has been proposed a technique in which the charging voltage of the image bearing member) and the charging timing of the developer are matched to balance the charging voltage of the surface of the photosensitive member and the toner and prevent the excess developer from blowing out.
JP-A-9-329946

However, in the above method, charging is performed up to the target voltage all at once, and therefore, when a higher voltage is applied, more voltage transition time is required, and the charging voltages of the photosensitive member and the developer are not balanced.
Therefore, a method of performing charging in multiple stages is conceivable. However, when an abnormality occurs in the apparatus, if charging is stopped through multiple stages using the same technique, processing takes time and the abnormal state is prolonged. . Further, when charging is stopped at once from a high voltage, as described above, excess developer is blown out.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to quickly stop charging and prevent a developer from blowing out when an image forming apparatus is abnormal.

  In order to achieve the above object, the present invention provides an image carrier charging means for charging an image carrier, a developer charging means for charging a developer, and an image carrier and a developer, respectively. , Charging control means for stepwise charging by the developer charging means, timing control means for making the start timing and change timing of charging of the image carrier and the developer constant, the image carrier and the above A charging state acquisition unit that acquires a current charging state of the developer; and a charge stop control unit that stops charging of the image carrier and the developer, and performs image forming processing using these units. An image forming apparatus is characterized by the following.

In the image forming apparatus according to the first aspect, the charging stop control means stops the charging of the image carrier and the developer stepwise according to the current charging state when the image forming apparatus is abnormal. Is.
An image forming apparatus according to a second aspect of the present invention is the image forming apparatus according to the first aspect, wherein the charging stop control means stops charging the image carrier and the developer when the image forming apparatus is abnormal. In such a case, the charging is not stopped.

According to a third aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the charging stop control means is configured to cause the image carrier to be charged at a voltage equal to or lower than a predetermined threshold value when the image forming apparatus is abnormal. In the case where charging of the developer is stopped, both the charging are stopped stepwise after the developer is charged.
According to a fourth aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the charging stop control means is configured to cause the charge of the image carrier to be equal to or lower than a predetermined threshold value when the image forming apparatus is abnormal. In the case where the charging of the developer is also a voltage equal to or lower than a predetermined threshold, both chargings are stopped in a stepwise manner.

According to a fifth aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the charging stop control means is configured to charge the image carrier with a voltage equal to or higher than a predetermined threshold when the image forming apparatus is abnormal. And when the charge of the developer is a voltage below a predetermined threshold, after charging the developer above the threshold, both charges are stepped below the threshold, and then Is to stop automatically.
According to a sixth aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the charging stop control means is configured to charge the image carrier at a voltage equal to or higher than a predetermined threshold when the image forming apparatus is abnormal. In the case where the charging of the developer is also a voltage equal to or higher than a predetermined threshold, both charges are set to a voltage lower than the threshold in a stepwise manner and then stopped in a stepwise manner.

According to a seventh aspect of the present invention, there is provided the image forming apparatus according to the first aspect, wherein the charging stop control means has a voltage equal to or lower than a predetermined threshold value when the image carrier is charged when the image forming apparatus is abnormal. In the case where the charge of the developer is a voltage equal to or higher than a predetermined threshold, the charge of the developer is set to a voltage equal to or lower than the threshold, and then both charges are stopped stepwise.
An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to the first aspect, wherein the charging stop control means stops the charging of the image carrier when the image forming apparatus is abnormal, and the developer The charging of the developer is stopped when the charging of the developer is a voltage equal to or lower than a predetermined threshold.

According to a ninth aspect of the present invention, in the image forming apparatus of the first aspect, when the image forming apparatus is abnormal, the abnormality detecting means for detecting the abnormality of the apparatus, and the abnormality detected by the abnormality detecting means. A stop method selection unit that selects a stop method according to the stop method and a device control unit that stops the image forming apparatus based on the stop method selected by the stop method selection unit are provided.
An image forming apparatus according to a tenth aspect of the present invention is the image forming apparatus according to the ninth aspect, wherein the device control means includes the charge stop control means, and the charge stop control means is detected by the abnormality detection means. When the abnormality is an abnormality that requires the image forming apparatus to be stopped immediately, charging of the image carrier and charging of the developer are stopped simultaneously.

  An image forming apparatus according to an eleventh aspect of the present invention is the image forming apparatus according to the ninth aspect, further comprising a cleaning means for cleaning the image carrier, wherein the apparatus control means includes the charging stop control means, and the abnormality After the abnormality detected by the detecting means is an abnormality that requires the image forming apparatus to be stopped immediately, the image forming process is stopped by simultaneously stopping the charging of the image carrier and the charging of the developer. The image bearing member is cleaned by the cleaning unit before the next image forming process is performed.

  An image forming apparatus according to a twelfth aspect of the present invention is the image forming apparatus according to the ninth aspect, wherein the apparatus control means includes the charge stop control means, and an abnormality detected by the abnormality detection means is detected in the image forming apparatus. In the case of an abnormality that does not need to be stopped immediately, the currently executed image forming process is continued, and thereafter the charging of the image carrier and the charging of the developer are sequentially stopped step by step by the charging stop control means. It is.

  An image forming apparatus according to a thirteenth aspect of the present invention is the image forming apparatus according to the ninth aspect, further comprising cleaning means for cleaning the image carrier, wherein the apparatus control means includes the charge stop control means, and the abnormality If the abnormality detected by the detecting means is an abnormality that does not require the image forming apparatus to be stopped immediately, the image forming process that is currently being executed is continued, and then the charging of the image carrier and the developer are charged. After the image forming process is stopped in order by the charging stop control unit to stop the image forming process, the cleaning unit is not allowed to clean the image carrier before performing the next image forming process.

  An image forming apparatus according to a fourteenth aspect of the present invention is the image forming apparatus according to the ninth aspect, wherein the device control means includes the charge stop control means, and the charge stop control means detects an abnormality detected by the abnormality detection means. In the case of an abnormality in which it is necessary to stop the image forming apparatus as soon as possible, the stopping method is determined from the current charging state of the image carrier and the developer, and both charging is performed step by step according to the result. Is to stop.

  An image forming apparatus according to a fifteenth aspect of the present invention is the image forming apparatus according to the ninth aspect, further comprising cleaning means for cleaning the image carrier, wherein the apparatus control means includes the charge stop control means, and the abnormality When the abnormality detected by the detecting means is an abnormality that requires the image forming apparatus to be stopped as soon as possible, the stopping method is determined from the current charging state of the image carrier and the developer, and the result is Accordingly, after both charging is stopped stepwise and the image forming process is stopped, the cleaning unit is made to clean the image carrier before performing the next image forming process.

  According to the image forming apparatus of the present invention, when the image forming apparatus is abnormal, the charging of the image carrier and the developer is stopped stepwise according to the current charging state, so that the charging is quickly stopped and the development is performed. The agent can be prevented from blowing out.

Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings. In this embodiment, an example using a copying machine with a built-in electrophotographic image forming apparatus will be described.
[Configuration example of image forming device of copying machine]
First, an image forming apparatus for a copying machine according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a diagram showing a configuration example of an image forming apparatus of the copying machine.
This image forming apparatus includes a photosensitive member 1, a charging device 2, an exposure device 3, a developing device 4, a transfer device 5, a cleaning device 6, a neutralizing device 7, and the like.
The photoreceptor 1 is a drum-shaped image carrier that forms an image (image) for printing on paper. A belt-like photoreceptor can also be used.
The charging device 2 is a charging unit that charges the surface of the photoreceptor 1. The charging device 2 corresponds to an image carrier charging means.

The exposure device 3 is an exposure unit that exposes the surface (charged surface) of the photoreceptor 1 charged by the charging device 2 in accordance with an image of a document and forms an electrostatic latent image on the surface.
The developing device 4 is a developing unit that forms a toner image by attaching charged toner (developer) to the electrostatic latent image formed on the surface of the photoreceptor 1 by the exposure device 3. The developing device 4 also has a function as a developer charging unit.
The transfer device 5 is a transfer unit that transfers the toner image formed on the surface of the photoreceptor 1 by the developing device 4 to paper.

The cleaning device 6 is a cleaning unit that removes toner remaining on the surface of the photoreceptor 1 after the transfer by the transfer device 5 (cleans the surface of the photoreceptor 1).
The static eliminator 7 is a static eliminator that removes charges remaining on the surface of the photoreceptor 1 after cleaning by the cleaning device 6.
Reference numeral 8 denotes a paper conveying device including a pair of rollers. The paper S is transported between the photoreceptor 1 and the transfer device 5 by the paper transport device 8.

[Operation example of copier]
Next, the operation (including image forming processing) of the copying machine including the image forming apparatus configured as described above will be described with reference to FIG.
FIG. 2 is a timing chart showing an operation example of a copying machine including the image forming apparatus shown in FIG.

In response to a print start request, this copier starts operation as shown in FIG. 2 in order to place the image forming apparatus in a printable state. The operation is roughly classified into startup of the image forming apparatus, printing (image forming processing), and shutdown.
The operation of starting up the image forming apparatus is as shown in the following (A1) to (A8).
(A1) First, the photosensitive member 1 is driven and stably rotated.
(A2) The static eliminator 7 is driven.

(A3) A bias necessary for paper transfer is applied from the transfer device 5.
(A4) A primary bias (charging primary bias) is applied from the charging device 2 to the photosensitive member 1 to charge the surface of the photosensitive member 1.
(A5) When the surface of the photoreceptor 1 on which this charging has started reaches the developing device 4, a primary bias (developing primary bias) is applied from the developing device 4 to charge the toner.

(A6) After the elapse of a predetermined time (100 ms in this example) after applying the primary charging bias, the voltage value is stabilized, so the secondary bias (charging secondary bias) is applied from the charging device 2 to the photosensitive member 1.
(A7) Similarly, after a predetermined time (in this example, 100 ms) when the development primary bias is applied, the voltage value is stabilized, so a secondary bias (development secondary bias) is applied from the developing device 4.
(A8) After that, when the entire surface of the photosensitive member 1 is charged by the secondary bias applied from the charging device 2 (when charging starts and the photosensitive member 1 makes one turn), the printer is ready for printing.

  At the time of printing, the exposure device 3 removes the charge to form an image that forms a charged surface on the photoreceptor 1, and the toner from the developing device 4 adheres to the removed portion to form a toner image. The toner image is transferred onto the conveyed paper by the transfer device 5. At this time, the remaining toner that could not be transferred is scraped off from the surface of the photoreceptor 1 by the cleaning device 6. Thereafter, the charge remaining on the photoreceptor 1 is neutralized by the neutralization device 7. Here, the surface of the photoconductor 1 is zero in potential, and can be charged for the next image formation. This series of operations (image formation processing) is performed for the size of the paper. If there is a request, repeat for the number of requested sheets.

When printing is completed, the imaging device is lowered (stopped).
The operation of starting up the image forming apparatus is as shown in the following (B1) to (B7).
(B1) First, the bias application from the transfer device 5 is stopped.
(B2) The output (charging bias) of the charging device 2 is set to the primary bias.
(B3) When the surface of the photosensitive member 1 to which the charging primary bias is applied reaches the developing device 4, the output (developing bias) of the developing device 4 is set to the primary bias.

(B4) After a predetermined time (in this example, 100 ms) when the output of the charging device 2 is changed to the primary bias has elapsed, the voltage value has stabilized, so the charging device 2 is stopped.
(B5) Similarly, after a predetermined time (100 ms in this example) when the output of the developing device 4 is changed to the primary bias has passed, the developing device 4 is stopped because the voltage value has stabilized.
As a result, the surface of the photoreceptor 1 is not charged and the toner is not charged.
(B6) When the surface of the photosensitive member 1 whose charging has been stopped reaches the static eliminator 7, the static eliminator 7 is stopped.
(B7) The photosensitive member 1 is stopped.

In the above-described startup and shutdown operations of the image forming apparatus, the bias output from the charging device 2 and the developing device 4 is performed in two stages, and a time of 100 ms is left at the stage drive timing. This is because the rising characteristics of both biases are different.
If both are set to the target voltage in one stage, there will be a shift in the time to reach the target voltage. As a result, the balance between the charging bias and the developing bias is lost, and the developer containing toner adheres to the surface of the photoreceptor 1. By dividing the target bias and targeting a lower voltage, the time lag between the two decreases.
The copying machine repeats the above operation.

[Copier control software configuration example]
Next, control software for the copying machine will be described with reference to FIG.
FIG. 3 is a block diagram showing an example of the configuration of control software for a copier equipped with the image forming apparatus shown in FIG.

  As described above, the control software (program) is configured as shown in FIG. 3 in order to control the operation of the copying machine. This control software is stored in a storage device such as a ROM or a hard disk device (not shown), and a CPU (Central Processing Unit) (not shown) executes an operation according to the control software, and is a function related to the present invention. Various functions including functions as a control means, a timing control means, a charge state acquisition means, a charge stop control means, an abnormality detection means, a stop method selection means, and a device control means can be realized. For convenience of explanation, it is assumed that the control software executes the operation.

  In this copying machine, as shown in FIG. 3, a control unit (photosensitive member control unit 11, exposure device control unit 12, transfer device control unit 13, There are a neutralization device control unit 14, a charging device control unit 15, a developing device control unit 16, and an image forming device cleaning processing unit 17), and a sequence control unit (image forming device start-up unit 18, The image forming device printing unit 19, the image forming device falling unit 20, and the image forming device emergency stop unit 21) are located at the upper level. Further, these sequence control units are sequentially activated by the image forming device control unit 22. The paper conveyance control unit 23 and the fixing control unit 24 are at the same level as the image forming device control unit 22, and an operation instruction is performed by the highest-level print control unit 25.

Here, consider a case where an abnormality occurs when the copying machine is performing a printing operation. An abnormality is an abnormality of a device inside the copying machine or a paper jam. When these occur, it is necessary to stop the operation of the copying machine promptly. However, depending on the apparatus, if it is stopped immediately, damage to the apparatus or subsequent printing operation may be affected.
For this reason, when an abnormality occurs, the degree of abnormality is divided into “(a) Immediate device stop”, “(b) Stop while avoiding minimum device damage”, “(c) Complete the printing operation as usual, One of the three types of abnormal levels “report to user” is determined as an abnormal level when an abnormality occurs. This determination is performed by the abnormal level determination unit 26 in FIG. 3 and is transmitted to the image forming device control unit 22 via the print control unit 25.

The abnormal level (a) corresponds to an abnormality that requires the image forming apparatus (copier) to be stopped immediately, such as a temperature abnormality of the toner fixing heating device or an abnormality of the charging voltage control device. Abnormality is detected and all the image forming devices are stopped simultaneously. For this reason, the influence on the apparatus is the largest.
The abnormal level in (c) corresponds to an abnormality that does not require immediate stop of the image forming device, such as toner density abnormality or out of paper, and when the abnormality occurs, the abnormality is detected and printing is started now. The printing operation is continued for the paper, and when this is completed, all the remaining printing operations are canceled and the image forming apparatus is stopped as usual. For this reason, there is no influence on the apparatus.

The abnormal level (b) corresponds to an abnormality that requires the imaging device to be stopped as soon as possible, such as a paper jam or an exposure apparatus 3, and when the abnormality occurs, the abnormality is detected and the error is detected. Only the charging device 2 and the developing device 4 that are seriously damaged are specially stopped. Other devices will stop immediately due to minor damage.
The charging device 2 and the developing device 4 are stopped in the states shown in (1) to (7) of FIG. 2, which are the current output states of the charging device 2 and the developing device 4, respectively. The image forming device stop method determination unit 27 obtains from the unit 15 and the developing device control unit 16 and determines as follows.

(1) When neither the charging bias (charging of the image carrier) nor the developing bias (charging of the developer) is applied (stopped) The charging device 2 and the developing device 4 are left as they are, and the other devices are stopped. .
(2) When a primary bias (a voltage equal to or lower than a predetermined threshold) is applied as a charging bias and no developing bias is applied, the charging bias is stopped. The development bias is stopped after the primary bias is applied. That is, after applying the primary bias as the developing bias, the charging bias and the developing bias are stopped stepwise. Thereafter, the other devices are stopped.

(3) When the primary bias is applied as both the charging bias and the developing bias When the charging bias is stopped and the position where the charging on the surface of the photoreceptor 1 is stopped reaches the roller (developing roller) of the developing device 4, Stop developing bias. That is, the charging bias and the developing bias are stopped in stages. Thereafter, the other devices are stopped.

(4) When the secondary bias (voltage exceeding a predetermined threshold) is applied as the charging bias and the primary bias is applied as the developing bias, the charging bias is changed in the order of primary bias → stop. The development bias is a secondary bias. Thereafter, when the position where the charge on the surface of the photoreceptor 1 is changed reaches the developing roller, the developing bias is also changed in the order of primary bias → stop. That is, after the secondary bias is applied as the developing bias, the charging bias and the developing bias are gradually changed to the primary bias, and then the charging bias and the developing bias are stopped stepwise. Thereafter, the other devices are stopped.

(5) When the secondary bias is applied as the charging bias and the developing bias The bias is stopped in the same manner as in normal printing. That is, the charging bias and the developing bias are set to the primary bias stepwise, and then stopped stepwise. Thereafter, the other devices are stopped.

(6) When the primary bias is applied as the charging bias and the secondary bias is applied as the developing bias. The charging bias is changed in the order of primary bias → stop. The developing bias is changed to the primary bias when the position where the charging on the surface of the photosensitive member 1 is the primary bias reaches the developing roller. Thereafter, when the position where charging is stopped reaches the developing roller, the developing bias is stopped. That is, the developing bias is set to the primary bias, and then the charging bias and the developing bias are stopped stepwise.

(7) When the charging bias is not applied and the primary bias is applied as the developing bias, the charging bias is stopped. The developing bias stops when the position where charging on the surface of the photoreceptor 1 is stopped reaches the developing roller.

In this way, by changing the method of stopping the apparatus according to the current output state (bias state) of the charging device 2 and the developing device 4, the bias stop can be stopped as compared with the case where the charging bias and the developing bias are immediately stopped. Misalignment is reduced. As a result, the developer is not ejected onto the photosensitive member 1 to fix the toner, and the paper does not adhere to the paper during subsequent printing.
Also, when a recovery operation such as cleaning is performed after an abnormality, the time required for recovery can be reduced because the surface of the photoconductor 1 is not dirty or is less contaminated.

In this embodiment, the image forming device cleaning processing unit 17 shown in FIG. 3 applies to the cleaning device 6 when the abnormal level determining unit 26 determines that the abnormal level is (a) or (b) when the image forming device is started up. The photosensitive member 1 is cleaned. That is, in the case of the abnormal level of (a), the outputs of the charging device 2 and the developing device 4 are stopped simultaneously to stop printing (imaging device), and then to the cleaning device 6 before performing the next printing. The photosensitive member 1 is cleaned. In the case of the abnormal level (b), the stopping method is determined from the current output states of the charging device 2 and the developing device 4, and the output is stopped stepwise according to the result, and the printing is stopped. After that, the photosensitive member 1 is cleaned by the cleaning device 6 before the next printing is performed.
Furthermore, compared with the case of always stopping in two steps, the stop time is also shortened because it stops in one step when it is not necessary.

According to the copying machine of this embodiment, the following effects (D1) to (D15) can be obtained.
(D1) When the copying machine is abnormal, charging of the photosensitive member and developer (charging bias, developing bias) is stopped stepwise according to the current charging state (bias state), thereby quickly stopping charging. In addition, it is possible to prevent the developer from blowing out. As a result, the adhesion of the developer to the photoconductor (image carrier) is reduced, and the photoconductor can be prevented from deteriorating accordingly, so that the life of the photoconductor can be extended. In addition, the time for returning from an abnormality can be shortened. Further, it is possible to reduce the stain on the image formed after the recovery from the abnormality.

(D2) If the charging of the photosensitive member and the developer is stopped when the copying machine is abnormal, the time required for stopping the charging is reduced by not stopping the charging. Overall stop time can be reduced.
(D3) If the photoconductor is charged at a voltage equal to or lower than a predetermined threshold when the copying machine is abnormal, and the developer has stopped being charged, the developer is charged and the image carrier is charged. By aligning the charging and the charging of the developer and then stopping both charging step by step, the adhesion of the developer to the photoreceptor can be reliably reduced.

(D4) When the photocopier is abnormal, the charging of the photoconductor is a voltage below a predetermined threshold, and the charging of the developer is also a voltage below a predetermined threshold. By stopping (both charging is stopped through the same stage), the adhesion of the developer to the photoreceptor can be surely reduced.
(D5) When the copying machine is abnormal, if the charge of the photosensitive member is a voltage equal to or higher than a predetermined threshold and the charge of the developer is equal to or lower than a predetermined threshold, the developer is set to the threshold After aligning the charge of the image carrier and the charge of the developer as described above, both charges are stepped below the threshold voltage, and then stopped stepwise so that the developer adheres to the photoreceptor. Can be reliably reduced.

(D6) When the photocopier is abnormal, the charging of the photoconductor is a voltage that is equal to or higher than a predetermined threshold value, and the charging of the developer is also a voltage that is equal to or higher than a predetermined threshold value, both charging steps By setting the voltage to a value equal to or lower than the threshold value and then stopping in stages (both charging is stopped through the same stage), adhesion of the developer to the photoreceptor can be reliably reduced.
(D7) When the copying machine is abnormal, if the charge of the photosensitive member is a voltage not more than a predetermined threshold and the charge of the developer is not less than a predetermined threshold, the developer is charged. By aligning the charging of the image bearing member and the developer with a voltage equal to or lower than the threshold, and then stopping both charging stepwise, adhesion of the developer to the photoreceptor can be reliably reduced.

(D8) When charging of the photoconductor is stopped when the copying machine is abnormal and the charging of the developer is a voltage equal to or lower than a predetermined threshold, only charging of the developer is stopped, Since the time required to stop charging is reduced, the stop time of the entire copying machine can be reduced accordingly.
(D9) Possible by detecting (detecting) the abnormality when the copying machine is abnormal, selecting a stopping method according to the detection result, and stopping the copying machine based on the selected stopping method. Since the copying machine can be stopped as close to normal as possible, damage to the apparatus can be reduced and the life of the apparatus can be extended.

(D10) If the detected abnormality is an abnormality that requires the copier to be stopped immediately, it is possible to prevent a larger apparatus failure by simultaneously stopping the charging of the photosensitive member and the developer. An increase in device failures can be prevented and the device can be recovered quickly. Also, the safety of the device user can be ensured.
(D11) When the detected abnormality is an abnormality that requires the copier to be stopped immediately, the charging of the photosensitive member and the developer are stopped simultaneously to stop the image forming process, and then the next image forming By causing the cleaning device to clean the photoconductor before performing the processing, it is possible to remove the dirt adhering to the failure, thereby preventing the image from being damaged in the image forming process after the failure is restored. Can do.

(D12) If the detected abnormality is an abnormality that does not require the copier to be stopped immediately, the current image forming process is continued, and then the charging of the photoconductor and the charging of the developer are sequentially stopped step by step. By doing so, the copying machine can be surely stopped in a state as close to normal as possible, so that damage to the apparatus can be reliably reduced and the life of the apparatus can be extended.
(D13) If the detected abnormality is an abnormality that does not require the copier to be stopped immediately, the image forming process currently being executed is continued, and then the charging of the photosensitive member and the charging of the developer are sequentially stopped step by step. After the image forming process is stopped, the cleaning device is not cleaned before the next image forming process, so that the life of the apparatus can be extended by the amount of unnecessary cleaning. . In addition, the time for returning from an abnormality can be further shortened.

(D14) When the detected abnormality is an abnormality that requires the copying machine to be stopped as soon as possible, the stopping method is determined from the current charged state of the photosensitive member and the developer, and stepwise according to the result. By stopping both charging, the copying machine can be surely stopped in a state as close to normal as possible, so that damage to the apparatus can be reliably reduced and the life of the apparatus can be extended.
(D15) When the detected abnormality is an abnormality that requires the copying machine to be stopped as soon as possible, the stopping method is determined from the current charged state of the photosensitive member and the developer, and stepwise according to the result. After stopping the charging and stopping the image forming process, the photosensitive member is cleaned before the next image forming process, so that the dirt attached due to the failure can be removed. It is possible to prevent the image from being damaged by the image forming process.

  The embodiment in which the present invention is applied to a copying machine using an electrophotographic system has been described above. However, the present invention is not limited to this, and other image forming apparatuses such as a multifunction machine, a facsimile machine, and a printer using an electrophotographic system are described. It is also applicable to the device.

[Program for this invention]
This program allows a CPU (computer) that controls an image forming apparatus such as a copying machine to be charged with charge control means, timing control means, charge state acquisition means, charge stop control means, abnormality detection means, and stop, which are functions related to the present invention. This is a program for realizing functions as method selection means and apparatus control means. By causing the CPU to execute such a program, the above-described effects can be obtained.

Such a program may be stored in a storage means such as a ROM or an HDD from the beginning, but a CD-ROM or flexible disk as a recording medium, MO, CD-R, CD-RW, DVD + R, DVD + RW, It can also be provided by being recorded on a non-volatile recording medium (memory) such as a DVD-R, DVD-RW, or DVD-RAM, EEPROM, or memory card. The program recorded in the non-volatile recording medium is installed in the image forming apparatus and executed by the CPU, or the CPU reads out the program from the non-volatile recording medium and executes the program, thereby executing the above-described procedures. Can do.
Furthermore, it is also possible to download and execute 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 the storage unit.

  As is apparent from the above description, according to the present invention, when the image forming apparatus is abnormal, charging can be quickly stopped and the developer can be prevented from blowing out. Therefore, it is possible to provide an image forming apparatus capable of achieving a longer life of a device such as a photosensitive member, a reduction in time for a recovery operation from an abnormality, and a reduction in stains of an image formed after the recovery from the abnormality.

1 is a diagram illustrating a configuration example of an image forming apparatus of a copying machine according to an embodiment of the present invention. 3 is a timing chart illustrating an operation example of a copying machine including the image forming apparatus illustrated in FIG. 1. FIG. 2 is a block diagram illustrating a configuration example of control software of a copying machine including the image forming apparatus illustrated in FIG. 1.

Explanation of symbols

1: Photoconductor 2: Charging device 3: Exposure device 4: Development device 5: Transfer device 6: Cleaning device 7: Static elimination device 8: Paper transport device 11: Photoconductor control unit 12: Exposure device control unit 13: Transfer device control Unit 14: Static elimination device control unit 15: Charging device control unit 16: Developing device control unit 17: Image forming device cleaning processing unit 18: Image forming device start-up unit 19: Image forming device printing unit 20: Image forming device lowering unit 21: Image forming device emergency stop unit 22: Image forming device control unit 23: Paper transport control unit 24: Fixing control unit 25: Print control unit 26: Abnormal level determination unit 27: Image forming device stop method determination unit

Claims (15)

An image carrier charging means for charging the image carrier, a developer charging means for charging the developer, and the image carrier and developer are charged stepwise by the image carrier charging means and the developer charging means, respectively. A charge control means, a timing control means for making the start and change timings of the charge of the image carrier and the developer constant, and a charge for acquiring current charge states of the image carrier and the developer, respectively. An image forming apparatus having state acquisition means and charge stop control means for stopping charging of the image carrier and the developer, and performing image forming processing using these means;
The charging stop control unit stops charging of the image carrier and the developer stepwise according to a current charging state when the image forming apparatus is abnormal. The image forming apparatus according to claim 1.
The charging stop control unit does not stop charging when charging of the image carrier and the developer is stopped when the image forming apparatus is abnormal. The image forming apparatus according to claim 1.
The charging stop control means is configured such that when the image forming apparatus is abnormal, the charging of the image carrier is a voltage equal to or lower than a predetermined threshold, and when the charging of the developer is stopped, the developer An image forming apparatus characterized in that after both are charged, both charges are stopped stepwise. The image forming apparatus according to claim 1.
The charging stop control unit is configured such that, when the image forming apparatus is abnormal, the charging of the image carrier is a voltage that is equal to or lower than a predetermined threshold, and the charging of the developer is also equal to or lower than a predetermined threshold. In addition, the image forming apparatus is characterized in that both chargings are stopped in stages. The image forming apparatus according to claim 1.
The charging stop control unit is configured such that when the image forming apparatus is abnormal, the charging of the image carrier is a voltage that is equal to or higher than a predetermined threshold, and the charging of the developer is a voltage that is equal to or lower than a predetermined threshold. In addition, after the developer is charged to be equal to or higher than the threshold value, both charges are set to a voltage lower than the threshold value in a stepwise manner and then stopped in a stepwise manner. The image forming apparatus according to claim 1.
The charging stop control unit is configured such that, when the image forming apparatus is abnormal, the charging of the image carrier is a voltage that is equal to or higher than a predetermined threshold, and the charging of the developer is also a voltage that is higher than a predetermined threshold. In addition, the image forming apparatus is characterized in that both charges are set to a voltage lower than a threshold value in a stepwise manner and then stopped in a stepwise manner. The image forming apparatus according to claim 1.
The charging stop control unit is configured such that, when the image forming apparatus is abnormal, the charging of the image carrier is a voltage equal to or lower than a predetermined threshold, and the charging of the developer is equal to or higher than a predetermined threshold. In addition, the charge of the developer is set to a voltage equal to or lower than the threshold value, and then both the charge are stopped stepwise. The image forming apparatus according to claim 1.
The charging stop control means stops the charging of the developer when the charging of the image carrier is stopped when the image forming apparatus is abnormal and the charging of the developer is a voltage equal to or lower than a predetermined threshold. An image forming apparatus, wherein charging is stopped. The image forming apparatus according to claim 1.
When the image forming apparatus is abnormal, an abnormality detection unit that detects the abnormality of the apparatus, a stop method selection unit that selects a stop method according to the abnormality detected by the abnormality detection unit, and a selection by the stop method selection unit And an apparatus control unit for stopping the image forming apparatus based on the stopped method. The image forming apparatus according to claim 9.
The apparatus control means has the charging stop control means,
The charging stop control unit simultaneously stops the charging of the image carrier and the charging of the developer when the abnormality detected by the abnormality detecting unit is an abnormality that must immediately stop the image forming apparatus. An image forming apparatus. The image forming apparatus according to claim 9.
A cleaning means for cleaning the image carrier,
The apparatus control means includes the charging stop control means, and when the abnormality detected by the abnormality detection means is an abnormality that must immediately stop the image forming apparatus, the charging of the image carrier and the charging An image forming apparatus, wherein after the charging of the developer is stopped simultaneously and the image forming process is stopped, the image bearing member is cleaned by the cleaning unit before performing the next image forming process. The image forming apparatus according to claim 9.
The apparatus control means includes the charging stop control means, and performs an image forming process that is currently being executed when the abnormality detected by the abnormality detection means is an abnormality that does not require the image forming apparatus to be immediately stopped. The image forming apparatus is characterized in that the charging of the image carrier and the charging of the developer are stopped successively in a stepwise manner by the charging stop control unit. The image forming apparatus according to claim 9.
A cleaning means for cleaning the image carrier,
The apparatus control means includes the charging stop control means, and performs an image forming process that is currently being executed when the abnormality detected by the abnormality detection means is an abnormality that does not require the image forming apparatus to be immediately stopped. After that, the charging of the image carrier and the charging of the developer are sequentially stopped by the charging stop control unit in a stepwise manner to stop the image forming process, and then before the next image forming process is performed. An image forming apparatus characterized in that the image carrier is not cleaned by the means. The image forming apparatus according to claim 9.
The apparatus control means has the charging stop control means,
When the abnormality detected by the abnormality detection unit is an abnormality that requires the image forming apparatus to be stopped as soon as possible, the charging stop control unit determines whether the image carrier and the developer are currently charged. An image forming apparatus characterized by determining a stopping method and stopping both charging step by step according to the result. The image forming apparatus according to claim 9.
A cleaning means for cleaning the image carrier,
The apparatus control means includes the charging stop control means, and the abnormality detected by the abnormality detection means is an abnormality that requires the image forming apparatus to be stopped as soon as possible. After determining the stopping method from the current charged state of the developer, and stopping the image forming process by stopping both charging stepwise according to the result, the cleaning unit is informed before performing the next image forming process. An image forming apparatus, wherein the image carrier is cleaned.

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