JP2011112816A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image forming apparatus which can reduce downtime. <P>SOLUTION: A print engine 11 inhibits execution of the registration correction when restoring from the sleep mode, when an instruction to implement printing is issued to restore from a sleep mode, if predicted time required for temperature rise from current temperature detected by a temperature sensor 12 to temperature shown by detected temperature data 32 in the previous registration correction, which is stored in a storage device 13, is shorter than necessary time for the registration correction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus.

  In a tandem color image forming apparatus, a plurality of color photoreceptors such as cyan, magenta, yellow, and black and a developing device are arranged, and the toner images of the respective colors are intermediated by the photoreceptor and the developing device. The image is transferred to a transfer belt, and toner images of a plurality of colors are transferred from the intermediate transfer belt to a sheet (see, for example, Patent Document 1).

  Since a toner image is transferred from a plurality of independent photoconductors to the intermediate transfer belt, color misregistration occurs if the toner images are not transferred from the photoconductors of the respective colors to the intermediate transfer belt at an appropriate timing. Registration processing is performed in order to prevent this color shift.

  Since such a color misregistration amount changes due to mechanical minute deformation of the exposure apparatus due to temperature fluctuations, registration correction is performed (see, for example, Patent Document 1). Usually, the registration correction is executed every predetermined time or every predetermined number of printed sheets. However, a certain image forming apparatus determines whether or not to perform registration correction according to the temperature difference between the exposure apparatus having the highest temperature and the exposure apparatus having the lowest temperature among the plurality of exposure apparatuses (for example, Patent Document 2).

  In addition, a certain image forming apparatus changes a transfer current or a transfer voltage according to temperature (for example, Patent Document 3).

JP 2006-198896 A Japanese Patent Laid-Open No. 2000-263843 JP 2005-010450 A

  Since it takes about 1 to 2 minutes to perform the above-described registration correction, a downtime occurs in the apparatus, and printing cannot be performed during that time. Such downtime is not preferable because it gives stress to the user.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can reduce downtime.

  In order to solve the above problems, the present invention is configured as follows.

  An image forming apparatus according to the present invention includes a temperature sensor for detecting a temperature of an exposure apparatus, a storage device for storing detected temperature data indicating a temperature detected by the temperature sensor at the time of registration correction, and a sleep return by a print execution command In the case where the estimated time required for the temperature rise from the current temperature by the temperature sensor to the temperature indicated by the detected temperature data at the previous registration correction stored in the storage device is shorter than the time required for the registration correction. Includes a registration execution unit that prohibits execution of registration correction when returning from sleep.

  Thereby, when the temperature of the exposure apparatus rises in a short time to the temperature at the previous registration correction, the registration correction is not executed. For this reason, downtime can be reduced.

  In addition to the image forming apparatus described above, the image forming apparatus according to the present invention may be configured as follows. In this case, if the print execution command is for a text document and the predicted time is shorter than the time required for registration correction, the registration execution unit prohibits execution of registration correction when returning from sleep and performs printing. When the command is for an image original, registration correction at the return from sleep is executed regardless of the estimated time.

  Thereby, in the case of an image original, the influence of color misregistration on the image quality is large, so that the image quality of the image original can be maintained by executing registration correction regardless of the prediction time.

  The image forming apparatus according to the present invention may be configured as follows in addition to any of the image forming apparatuses described above. In this case, when the print execution command is for monochrome printing, the registration execution unit prohibits execution of registration correction when returning from sleep regardless of the estimated time.

  Thereby, in the case of monochrome, no color misregistration occurs, so that registration correction at the time of return from sleep is not performed. For this reason, downtime can be reduced.

  The image forming apparatus according to the present invention may be configured as follows in addition to any of the image forming apparatuses described above. In this case, the storage device has temperature rise curve data actually measured from the startup to the steady state in the image forming apparatus. And a registration execution part calculates | requires prediction time from the temperature at the present time by a temperature sensor, detected temperature data, and temperature rise curve data.

  The image forming apparatus according to the present invention may be configured as follows in addition to any of the image forming apparatuses described above. In this case, the image forming apparatus further includes a display device and a controller that causes the display device to display at least one of a print end time, a registration correction start time, and a registration correction end time.

  According to the present invention, the downtime of the image forming apparatus can be reduced.

FIG. 1 is a side view showing a mechanical internal configuration of the image forming apparatus according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus according to Embodiment 1 of the present invention. FIG. 3 is a flowchart illustrating an operation related to registration correction of the image forming apparatus shown in FIGS. 1 and 2. FIG. 4 is a view showing an example of temperature variation of the exposure apparatus in FIG. FIG. 5 is a diagram showing an example of a temperature rise curve based on the temperature rise curve data in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.

  FIG. 1 is a side view showing a mechanical internal configuration of the image forming apparatus according to Embodiment 1 of the present invention. The image forming apparatus is an apparatus having a printing function, such as a printer, a facsimile machine, a copier, and a multifunction machine.

  The image forming apparatus according to the first embodiment includes a tandem color developing device. The color developing device includes photosensitive drums 1a to 1d, an exposure device 2, and developing devices 3a to 3d. The photoconductor drums 1a to 1d are four-color photoconductors of cyan, magenta, yellow, and black.

  The exposure device 2 is a device that forms an electrostatic latent image by irradiating the photosensitive drums 1a to 1d with laser beams. Each exposure apparatus 2 is a laser scanner unit. As this laser scanner unit, for example, the one described in Japanese Patent Application Laid-Open No. 2008-51841 is used. The exposure apparatus 2 includes a laser diode that is a light source of laser light and optical elements (lens, mirror, polygon mirror, etc.) that guide the laser light to the photosensitive drums 1a to 1d. There is one exposure apparatus 2 for each color, and the exposure apparatus 2 is attached to a structure such as a housing inside the apparatus. For this reason, the optical element in the exposure apparatus 2 is mechanically displaced due to the temperature fluctuation, thereby causing a shift in the optical system, and a color shift occurs even if the registration process is performed at a certain temperature. For this reason, registration correction is required.

  Further, the developing devices 3a to 3d form toner images by attaching the toner in the toner cartridges to the electrostatic latent images on the photosensitive drums 1a to 1d.

  The photosensitive drum 1d and the developing device 3d develop magenta, the photosensitive drum 1c and the developing device 3c develop cyan, and the photosensitive drum 1b and the developing device 3b develop yellow. Then, black development is performed by the photosensitive drum 1a and the developing device 3a.

  During the registration process (including registration correction), each of the developing devices 3a to 3d develops a color resist pattern.

  The intermediate transfer belt 4 is an annular image carrier that contacts the photosensitive drums 1a to 1d and transfers the toner images on the photosensitive drums 1a to 1d. The intermediate transfer belt 4 is stretched around the driving roller 5 and circulates in the direction from the contact position with the photosensitive drum 1d to the contact position with the photosensitive drum 1a by the driving force from the driving roller 5. The intermediate transfer belt 4 carries a color resist pattern during the registration process.

  The transfer roller 6 brings the conveyed paper into contact with the transfer belt 4 and transfers the toner image on the transfer belt 4 to the paper. The sheet on which the toner image has been transferred is conveyed to the fixing device 9 and the toner image is fixed on the sheet.

  The roller 7 is in contact with the intermediate transfer belt 4 and removes the toner remaining on the intermediate transfer belt 4 after the transfer of the toner image onto the paper.

  The sensor 8 irradiates the intermediate transfer belt 4 with a light beam and detects the reflected light. During the registration process, the sensor 8 irradiates the color resist pattern on the intermediate transfer belt 4 with a light beam and detects the reflected light of the light beam.

  FIG. 2 is a block diagram showing an electrical configuration of the image forming apparatus according to Embodiment 1 of the present invention. In FIG. 2, a print engine 11 is a processing circuit that controls a driving source (not shown) that drives the above-described rollers and the exposure apparatus 2 to perform paper feeding, printing, and paper ejection.

  The temperature sensor 12 is an element that is installed in the exposure apparatus 2 and detects the temperature of the exposure apparatus 2. For example, a thermistor or the like is used for the temperature sensor 12. When the exposure apparatuses 2 for a plurality of colors are installed separately, the temperature sensor 12 is installed in any one of the exposure apparatuses 2.

  The storage device 13 has a nonvolatile storage medium (flash memory, hard disk drive, etc.) for storing various data. Here, the storage device 13 stores temperature rise curve data 31 and detected temperature data 32. The temperature rise curve data 31 is data including temperatures actually measured at predetermined times from the startup to the steady state in the image forming apparatus. For example, the temperature rise curve data 31 is generated by periodically sampling the output value of the temperature sensor 12 at a predetermined timing from the start of the apparatus. The detected temperature data 32 is data indicating the temperature detected by the temperature sensor at the previous (that is, the latest) registration correction.

  The display device 14 is a liquid crystal display in an operation panel or the like. The controller 15 is a circuit that receives user operations and jobs and controls internal devices such as the print engine 11 and the display device 14.

  Here, the print engine 11 will be described in detail.

  In the registration process, the print engine 11 samples and monitors the output signal of the sensor 8 every predetermined sampling period, and the time when the resist pattern of each color is detected by the sensor 8 (from the predetermined reference time to the detection time). The correction amount for eliminating the current color misregistration is calculated based on the time until the image misalignment is performed, and each unit is controlled so as not to cause the color misregistration according to the correction amount, and the image is printed on the paper.

  The print engine 11 sets the operation mode to either the normal mode or the sleep mode. The print engine 11 changes the operation mode to the sleep mode when no user operation or job occurs for a predetermined time, and changes the operation mode to the normal mode when a user operation or job occurs in the sleep mode. . In the normal mode, power supply to the exposure apparatus 2 and a drive source (not shown) is maintained. In the sleep mode, power is supplied only to the minimum necessary circuits such as the controller and the print engine 11 for user operation and job reception. Supply is maintained, and power supply to the other exposure apparatus 2, a drive source (not shown), etc. is stopped. Note that the operation mode may be switched by the controller 15 and notified to the print engine 11.

  Then, the print engine 11 samples the temperature value detected by the temperature sensor 12 and obtains it as data, and the detected temperature data 32 in the storage device 13 is obtained from the current temperature by the temperature sensor when returning from sleep by the print execution command. When the estimated time required for the temperature rise to the temperature indicated by is shorter than the time required for the registration correction, the execution of the registration correction at the return from sleep is prohibited.

  Next, the operation of the above apparatus relating to registration correction will be described. FIG. 3 is a flowchart illustrating an operation related to registration correction of the image forming apparatus shown in FIGS. 1 and 2.

  First, an outline of temperature variation of the exposure apparatus 2 will be described. FIG. 4 is a view showing an example of temperature variation of the exposure apparatus 2 in FIG. As shown in FIG. 4, in the normal mode, since each unit is in an energized state, the temperature of the exposure apparatus 2 is relatively high even during standby and rises further when printing is executed. When the mode is shifted to the sleep mode, the amount of heat generated in the apparatus decreases, so the temperature of the exposure apparatus 2 decreases. When a long time elapses in the sleep mode, the temperature of the exposure apparatus 2 becomes the outside temperature of the apparatus. It is almost the same as (environment temperature). Thereafter, when the mode is shifted from the sleep mode to the normal mode at time T1, the amount of heat generated in the apparatus increases, so that the temperature of the exposure apparatus 2 rises. Similarly, when the mode is shifted from the sleep mode to the normal mode at time T2 during the temperature decrease, the temperature of the exposure apparatus 2 increases from the temperature at that time.

  When the controller 15 accepts a user operation or a print execution command from the host device in the sleep state (step S1), the print engine 11 shifts the operation mode to the normal mode and executes the following processing.

  First, the print engine 11 determines whether or not the print execution instruction is for monochrome printing (step S2). If the print execution command is for monochrome printing, the print engine 11 does not execute registration correction.

  On the other hand, if the print execution command is not for monochrome printing, the print engine 11 reads the detected temperature data 32 from the storage device 13 (step S3) and acquires the current temperature by the temperature sensor 12 (step S4). . Then, the print engine 11 refers to the temperature rise curve data 31 and specifies the estimated time required from the present time until the temperature of the exposure apparatus 2 rises to the temperature indicated by the detected temperature data 32 (step S5).

  FIG. 5 is a diagram showing an example of a temperature rise curve based on the temperature rise curve data 31 in FIG. As shown in FIG. 5, by referring to the temperature rise curve data 31, a predicted time is obtained as a difference between two times corresponding to the previous detected temperature (data 32) and the current detected temperature. The temperature rise curve data 31 is a set of data at a plurality of discrete points made up of pairs of time and temperature. For this reason, the time corresponding to the detected temperature can be obtained from one of the plurality of points closest to the detected temperature or by interpolation from a plurality of points around the detected temperature.

  Then, the print engine 11 determines whether or not the specified predicted time is longer than the time required for registration correction (for example, 2 minutes) (step S6). If the identified predicted time is longer than the time required for registration correction, the print engine 11 executes registration correction (that is, registration processing again) (step S7), and the detected temperature at the current detected temperature. The value of the data 32 is updated (step S8). On the other hand, when the specified predicted time is equal to or shorter than the time required for registration correction, the print engine 11 does not perform registration correction (that is, prohibits execution of registration correction) until the predicted time elapses. Waiting (in the meantime, other executable processing (data processing, etc.) may be executed) (step S9).

  Note that the controller 15 calculates at least one of a print end time, a registration correction start time, and a registration correction end time when returning from sleep, and causes the display device 14 to display the calculated time.

  As described above, according to the first embodiment, when the print engine 11 returns from sleep according to the print execution command, the previous registration stored in the storage device 13 is determined from the current temperature by the temperature sensor 12. When the estimated time required for the temperature rise to the temperature indicated by the detected temperature data 32 at the time of correction is shorter than the time required for registration correction, execution of registration correction at the time of return from sleep is prohibited.

  Thus, when the temperature of the exposure apparatus 2 rises in a short time to the temperature at the previous registration correction, the registration correction is not executed. For this reason, downtime in the image forming apparatus can be reduced. Further, since unnecessary registration correction is not executed, toner consumption is reduced.

Embodiment 2. FIG.

  In the second embodiment, the print engine 11 prohibits execution of registration correction when returning from sleep if the predicted execution time is shorter than the time required for registration correction when the print execution command is for a text document. When the print execution instruction is for an image original, registration correction at the return from sleep is executed regardless of the estimated time.

  Since the other configuration and operation of the apparatus in the second embodiment are the same as those in the first embodiment, description thereof is omitted.

  As described above, according to the second embodiment, in the case of an image original, the effect of color misregistration on the image quality is large. Therefore, the image quality of the image original is maintained by executing registration correction regardless of the prediction time. it can.

  Each embodiment described above is a preferred example of the present invention, but the present invention is not limited to these, and various modifications and changes can be made without departing from the scope of the present invention. It is.

  For example, in each of the above embodiments, a temperature sensor that measures the outside air temperature of the device is provided, a plurality of temperature rise curve data corresponding to a plurality of different outside air temperatures are held in the storage device 13, and the outside air temperature when returning from sleep Depending on the above, temperature rise curve data may be selected.

  In each of the above embodiments, a temperature sensor is provided for each of the plurality of exposure apparatuses 2, and representative values such as an average value, a maximum value, and a minimum value of the plurality of temperature sensors are detected by the above-described temperature sensor. It may be used as a temperature.

  In each of the above-described embodiments, the print engine 11 executes registration correction when the previous detected temperature is higher than the maximum temperature in the temperature rise curve data 32 because the predicted time cannot be specified.

  Further, in each of the above embodiments, from the detected temperature at the time of starting the apparatus, the detected temperature at the time of printing (print execution command) and the elapsed time from the time of starting the apparatus to the current time (as a predetermined function using these as parameters) A temperature rise curve may be obtained. The temperature rise curve may be a straight line.

  In the above description, the case where the prediction is performed based on the temperature rise from the temperature at the start-up using the temperature rise curve data has been described. However, the temperature rise from the temperature at the start-up is not limited, and from the temperature immediately before the start of printing. By making a prediction based on the temperature rise, more accurate processing becomes possible.

  The present invention is applicable to, for example, a printer, a multifunction machine, and the like.

2 Exposure device 11 Print engine (an example of a registration execution unit)
12 Temperature sensor 13 Storage device 14 Display device 15 Controller 31 Temperature rise curve data 32 Detected temperature data

Claims (5)

In an image forming apparatus that forms an image by an electrophotographic process using an exposure apparatus,
A temperature sensor for detecting the temperature of the exposure apparatus;
A storage device for storing detected temperature data indicating the temperature detected by the temperature sensor at the time of registration correction;
At the time of return from sleep by a print execution command, the estimated time required for the temperature rise from the current temperature by the temperature sensor to the temperature indicated by the detected temperature data at the previous registration correction stored in the storage device is registered. A registration execution unit that prohibits execution of registration correction when returning from sleep,
An image forming apparatus comprising:   The registration execution unit prohibits execution of registration correction when returning from sleep if the predicted execution time is shorter than the time required for registration correction when the print execution command is for a text document. 2. The image forming apparatus according to claim 1, wherein when the execution instruction is for an image original, registration correction at the time of return from sleep is executed regardless of the estimated time.   2. The image according to claim 1, wherein when the print execution instruction is for monochrome printing, the registration execution unit prohibits execution of registration correction when returning from sleep regardless of the estimated time. Forming equipment. The storage device has temperature rise curve data measured from the start-up to the steady state in the image forming apparatus,
The registration execution unit obtains the predicted time from the current temperature by the temperature sensor, the detected temperature data, and the temperature rise curve data;
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. A display device;
A controller that causes the display device to display at least one of a print end time, a registration correction start time, and a registration correction end time;
The image forming apparatus according to claim 1, further comprising:

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