JP2007225818A - Image forming apparatus and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To adjust a timing of forming an image on a recording material when forming an image, and also, to dispense with a registration processing when the judgement is made that an image carrier and an intermediate transfer body are scratched or soiled, or that an exposure part is abnormally inclined. <P>SOLUTION: Regarding the image forming apparatus, prior to the image to be formed by an image forming operation, a patch is formed, and an image forming timing is adjusted based on the timing when the patch is detected by a patch detecting part and a timing when the recording material is detected by a recording material detecting part. By using a bar code image 505 as the patch, the occurrence of an abnormal state is judged based on the detected bar code image data. When the apparatus is in a normal state, the timing is adjusted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a control method for adjusting a conveyance timing of a recording material and a conveyance timing of an image to be formed.

  Image forming apparatuses such as electrophotographic printers require alignment (registration) between an image to be formed and a recording material such as a sheet. Patent Document 1 discloses a method of forming a patch prior to an image to be transferred to a sheet, and adjusting registration using this patch as a reference. This method improves the registration accuracy by feeding back the patch detection result to the sheet conveyance speed. However, this method has a problem that the feedback system breaks down when the patch is contaminated with scratches or dirt on the image carrier.

Patent Document 2 discloses a method for detecting a level of dirt (background level) by reading a portion without a patch with a sensor as a technique for detecting scratches or dirt. Patent Document 3 discloses a method of forming a cross-shaped patch on an image carrier and determining that the maximum value of the patch density histogram does not coincide with the center line of the patch as dirt or a flaw.
JP 2000-351472 A JP 05-061369 A Japanese Patent Laid-Open No. 06-051607

  However, in the method of Patent Document 2, stain is detected based on a relative density difference between the background level and the patch level, and improvement in registration accuracy between the image to be formed and the recording material cannot be expected.

  Further, the method of Patent Document 3 may detect a patch without being affected by the density difference between the background level and the patch level. However, this method is not suitable for registration control requiring real-time performance because the processing required for flaw detection is complicated.

  The present invention has been made in view of the above-described problems. By using a patch that represents data for determining an abnormality occurring in the image forming apparatus as an image, the conveyance timing of the recording material is preferably used. The purpose is to adjust.

  The present invention relates to an image forming apparatus. The image forming apparatus includes an image forming unit that forms a patch expressing data for determining whether or not an abnormality has occurred in the image forming apparatus as an image, and a patch detection unit that detects the patch. In addition, the image forming apparatus includes a determination unit that recognizes data from the detected patch and determines whether an abnormality has occurred in the image forming unit based on the recognized data. Furthermore, the image forming apparatus includes a timing adjustment unit that adjusts the conveyance timing of the recording material based on the patch detection timing when no abnormality has occurred.

  The present invention can suitably adjust the conveyance timing of a recording material by using a patch in which data for determining an abnormality occurring in an image forming apparatus is expressed as an image.

  Hereinafter, embodiments according to the present invention will be described with reference to the drawings. The following embodiments do not limit the present invention according to the claims, and all the combinations of features described in the present embodiments are not necessarily essential to the solution means of the present invention. Absent.

[Embodiment 1]
FIG. 1 is a diagram showing an outline of an image forming apparatus according to the present invention. In the present embodiment, a printer is taken as an example of the image forming apparatus, but the present invention is not limited thereto. For the sake of clear and concise description, FIG. 1 will be described with a focus on portions that are deeply related to the present invention.

  The printer 100 includes a photosensitive drum 101 (image carrier), a developing device 102, an exposure unit 103, and a hopper unit 104 as an image forming unit. The developing device 102 visualizes the toner by attaching toner to the latent image formed on the photosensitive drum 101. The exposure unit 103 exposes image information on the photosensitive drum 101 to form a latent image. The hopper unit 104 supplies toner to the developing device 102. The printer 100 includes a secondary transfer unit 105 that forms a toner image visualized on the photosensitive drum 101 on a recording material. Further, the printer 100 includes an intermediate transfer body 106 on which an image is primarily transferred from the photosensitive drum 101 and a conveyance path 107 for conveying a recording material.

  The photosensitive drum 101 functioning as an image carrier forms an image on the intermediate transfer member 106. The image formed on the intermediate transfer member 106 is secondarily transferred by the secondary transfer unit 105 to the recording material conveyed on the conveyance path 107. Further, according to the present embodiment, in the printer 100, a patch having data set in advance prior to an image formed by the photosensitive drum 101 is formed on the intermediate transfer body 106. The patch is formed in order to realize the alignment between the image and the recording material when the secondary transfer unit 105 forms the image on the recording material. Further, by using the patch, it is possible to determine abnormality such as scratches or dirt on the photosensitive drum 101 and the intermediate transfer member 106 or an abnormal inclination of the exposure unit 103 with respect to the photosensitive drum 101.

  FIG. 2 is a block diagram illustrating a configuration of each control unit provided in the image forming apparatus according to the present embodiment. Here, descriptions of main control units related to the present embodiment will be described.

  In the printer control unit 200, a CPU 201 that performs basic control of the printer 100, a ROM 203 in which a control program is written, a work RAM 202 for performing processing, and an input / output port 206 are connected by an address bus and a data bus. A partial area of the RAM 202 is a backup RAM in which data is not erased even when the power is turned off.

  The CPU 201 includes a patch detection unit that detects a patch generated by the patch processing unit 209 included in the printer control unit 200. The patch processing unit 209 generates a patch image from preset data. Further, the patch processing unit 209 detects a patch formed on the intermediate transfer body 106 by a patch sensor installed around the intermediate transfer body 106, and converts it into code data (numerical value or the like). Detailed processing of the patch processing unit 209 will be described later with reference to FIG.

  Further, the CPU 201 includes a determination unit that recognizes data from the detected patch and determines an abnormality occurring in each device based on the recognized data. Further, the CPU 201 includes a timing adjustment unit that adjusts the conveyance timing of the recording material based on the patch detection timing when no abnormality has occurred.

  The input / output port 206 includes various load devices such as a motor and a clutch controlled by the CPU 201. The input / output port 206 is connected to a registration sensor that is a recording material detection unit that detects that the recording material has been conveyed, a patch sensor that is a patch detection unit that detects a patch, and the like. The CPU 201 sequentially controls input / output via the input / output port 206 in accordance with the contents of the control program stored in the ROM 203, and executes image forming processing.

  The printer control unit 200 further includes an image processing unit 204, an image memory unit 205, an operation unit 207, and a communication I / F 208 that transmits / receives data to / from an external device. The image processing unit 204 processes an image to be formed. In the present embodiment, patch image control is also executed. The image memory unit 205 stores an image to be formed. Further, the image memory unit 205 may store information on patches to be formed.

  The CPU 201 controls the display unit and key input unit of the operation unit 207. The user instructs the CPU 201 to switch the image forming operation mode and display through the key input unit. In response to an instruction from the user, the CPU 201 controls the output of the operation unit 207 to display the operation state of the printer 100 and the operation mode set by key input. Details will be described later with reference to FIG.

  FIG. 3 is a schematic diagram illustrating an operation panel of the image forming apparatus according to the present embodiment. Here, only the main parts related to the present embodiment in the operation panel will be described.

  The operation panel 300 includes an output unit 301 that outputs various messages such as operation states of the apparatus and work instructions to the user, work procedures, and the like. According to the present embodiment, the output unit 301 detects scratches or dirt on the photosensitive drum 101 and the intermediate transfer member 106 or an abnormal inclination of the exposure unit 103 with respect to the photosensitive drum 101, and displays the occurrence of the abnormality. The surface of the output unit 301 is constituted by a touch panel, and functions as a selection key by touching the surface. The operation panel 300 includes a numeric keypad 302 for inputting numbers and a start key 303 for starting image formation.

  FIG. 4 is a block diagram relating to patch formation of the image forming apparatus according to the present embodiment. According to this embodiment, the position of the image to be formed and the recording material is aligned by forming the patch together with the image at the time of image formation. In this embodiment, a barcode image is used as a patch, but the present invention is not limited to this.

  First, the CPU 201 transmits preset data to the encoding unit 401. The encoding unit 401 converts the data into barcode image data and transmits the barcode image data to the CPU 201. The CPU 201 sets the transmitted barcode image data in the pattern generator (PG) unit 403.

  Thereafter, the CPU 201 controls the laser driver (LD) unit 404 based on the image data. The LD unit 404 forms a barcode-like registration patch on the photosensitive drum 101 based on the barcode image data set in the PG unit 403. Further, the registration patch transferred onto the intermediate transfer member 106 by the photosensitive drum 101 is read by a patch sensor 406 that is a patch detection unit. The electrical signal read by the patch sensor 406 is converted into digital data by the AD conversion unit 405 included in the input / output port 206 and is passed to the CPU 201.

  Finally, the CPU 201 converts the digital data received from the input / output port 206 into numerical data by the decoding unit 402. The converted numerical data is used to determine whether or not the detected barcode image data is normal. Note that the CPU 201 determines whether or not the image forming unit is normal by comparing the preset data used when forming the above-described barcode image with the converted numerical data.

  Note that the registration sensor 408 detects the recording material conveyed on the conveyance path 107. The CPU 201 adjusts the timing for forming an image on the recording material based on the timing at which the barcode image is detected by the patch sensor 406 and the timing at which the recording material is detected by the registration sensor 408.

  FIG. 5 is a diagram for explaining adjustment of the conveyance timing of the recording material according to the present embodiment. According to this embodiment, the patch processing unit 209 forms a patch prior to an image to be formed. Further, the CPU 201 adjusts the timing for forming an image based on the timing when the patch (tip) is detected by the patch sensor 406 and the timing when the recording material (tip) is detected by the registration sensor 408. Further, according to the present embodiment, the CPU 201 determines whether or not the patch is normally formed based on the information detected by the patch sensor 406.

  The photosensitive drum 101 of the image forming unit in this embodiment is provided for each of four color components. That is, the yellow photosensitive drum 101a, the cyan photosensitive drum 101b, the magenta photosensitive drum 101c, and the black photosensitive drum 101d are arranged around the intermediate transfer member 106. For example, the photosensitive drum 101 primarily transfers the barcode image 505 transmitted from the image processing unit 204 and the image 502 formed on the recording material 504 to the intermediate transfer member 106. Finally, the image 502 formed on the intermediate transfer member 106 is transferred to the recording material 504 at the position of the secondary transfer roller 501.

  Each image is formed on the photosensitive drum 101 with a predetermined length with respect to the distance between the barcode image 505 and the image 502. Further, the intermediate transfer member 107 is driven in a state where a constant speed is maintained. Therefore, the time until the barcode image 505 reaches the secondary transfer roller 501 at the timing when the barcode image 505 passes through the patch sensor 406 is estimated.

  The leading edge of the recording material 504 conveyed on the conveyance path is detected by a registration sensor 408 that is a recording material detection unit after passing through the registration roller 503. The CPU 201 adjusts the timing for forming the image 502 on the recording material 504 from the time from when the barcode image 505 is detected to the timing when the recording material 504 is detected. Note that the timing adjustment is performed by adjusting the conveyance speed of the recording material 504. In other words, this timing adjustment synchronizes the image 502 formed by adjusting the conveyance speed of the recording material 504 with respect to the image 502 that reaches the position of the secondary transfer roller 501 at a predetermined timing, and the recording material 504. Take. Further, the conveyance speed of the recording material 504 is adjusted by the registration roller 503.

  FIG. 6 is a diagram illustrating timing adjustment according to the present embodiment. In this embodiment, the image formation timing is calculated according to the procedure described below. However, a table for calculating the image formation timing may be stored in the ROM 203 in advance. In other words, the table may store the adjustment value of the conveyance speed for conveying the recording material corresponding to the time from when the patch is detected until the recording material is detected.

  In the graph shown in FIG. 6, the vertical axis represents the distance L, the horizontal axis represents the time t, and the slope of the line represents the recording material conveyance speed and the patch movement speed (movement speed of the surface of the intermediate transfer member). The timing chart shown in FIG. 6 represents the detection timing of the barcode image, which is a specific example of the patch, the detection timing of the recording material 504, and the deceleration timing of the recording material 504 after the registration sensor detection.

  The barcode image 505 and the image 502 are conveyed together with the intermediate transfer member 106 at a constant speed, for example, 300 mm / s, and detected by the patch sensor 406 at the position of ImageTop shown in the drawing. Thereafter, the barcode image 505 and the image 502 are conveyed while maintaining 300 mm / s, and reach the position of the secondary transfer roller 501 at the position of Tr2 shown in the drawing.

  The recording material 504 is conveyed by the registration roller 503 at a speed of 600 mm / s. After passing through the registration sensor 408, the recording material 504 is conveyed to a predetermined position at a process speed of 300 mm / s. This deceleration position is determined from the timing at which the barcode image 505 is detected by the patch sensor 406 and the timing at which the leading edge of the recording material 504 is detected by the registration sensor 408.

  For example, when the recording material 504 is detected by the registration sensor 408 at a timing such as SheetTop1 shown in the drawing, the conveyance speed of the recording material 504 is reduced at the position D1 shown in the drawing. Similarly, when the recording material 504 is detected by the registration sensor 408 at a timing such as SheetTop2 shown in the drawing, the recording material 504 is decelerated at the position D2 shown in the drawing.

The time Tpatch from when the barcode image 505 is detected by the patch sensor 406 to when the barcode image 505 reaches the secondary transfer roller 501 is obtained as follows.
Tpatch = 600x1000 / 300 = 2000ms
Here, the distance from the patch sensor 406 to the secondary transfer roller 501 is 600 mm, and the conveyance speed of the barcode image 505 and the image 502 is 300 mm / s.

The time Treg from when the registration sensor 408 detects the leading edge of the recording material 504 until the barcode image 505 reaches the secondary transfer roller 501 is expressed as follows.
Treg = Tpatch-T = 2000-T
Here, T is the time from when the bar code image 505 is detected by the patch sensor 406 until the registration sensor 408 detects the leading edge of the recording material 504.

The distance from the registration sensor 408 to the secondary transfer roller 501 is 300 mm. Therefore, if the shift time is ignored, the time Tdec from when the leading edge of the recording material 504 passes through the registration sensor 408 until it decelerates is expressed as follows.
300 mm = 600 × Tdec / 1000 + 300 × (Treg−Tdec) / 1000
Tdec = T-1000 (ms)
That is, the CPU 201 of the present embodiment can determine the timing for decelerating after the recording material 504 passes through the registration sensor 408 by measuring the time T. Strictly speaking, since the shift time of the registration roller 503 is also taken into consideration, the above parameters are slightly different. Further, since the distance between the leading edge of the barcode image 505 and the image 502 is defined by the number of main scanning lines, the secondary transfer timing is adjusted at a deceleration timing so that the leading edge of the image 502 and the leading edge of the recording material 504 are exactly aligned. Is done.

  FIG. 7 is a diagram for explaining the relationship between the barcode image and the image formed on the recording material according to the present embodiment.

  As shown in FIG. 7, the barcode image 505 and the image 502 are formed on the intermediate transfer member 106 while maintaining a distance d from the leading end of the barcode image 505 to the leading end of the image 502. The barcode image 505 is formed on the intermediate transfer member 106 so that the longitudinal direction of the barcode image 505 is parallel to a direction (width direction) orthogonal to the conveyance direction of the intermediate transfer member 106. The patch sensor 406 is a line sensor and is arranged so as to be parallel to the width direction of the intermediate transfer body 106, and scans the intermediate transfer body 106 to detect the edge of the barcode image 505 and read the barcode image. . The barcode data of the barcode image 505 is obtained by encoding preset data.

  Here, for example, it is assumed that there is a scratch 701 on the intermediate transfer member 106 and the barcode image 505 formed on the photosensitive drum 101 has been transferred onto the scratch 701 of the intermediate transfer member 106. In this case, decoding the barcode of the barcode image 608 does not return to the preset data. Thereby, in the present invention, it is possible to detect scratches and dirt on the photosensitive drum 101 and the intermediate transfer member 106 or an abnormal inclination of the exposure unit 103.

  Note that the CPU 201 according to the present embodiment may record the detected position of the scratch or dirt on the intermediate transfer member 106 in the ROM 203. As a result, it is desirable that the CPU 201 avoids the formation of an image at the position of the scratch or dirt during the next image formation.

  FIG. 8 is a diagram for explaining the relationship between the barcode image and the read value. In the present embodiment, it is assumed that 8-bit data (AAh) is converted into a barcode image and formed on the intermediate transfer member 106 and read by the patch sensor 406. The 8-bit data is an example and is not limited. 8 indicates the position read by the patch sensor 406 as the tip of the barcode image 505. The normally formed barcode image 505 passes through the reading position of the patch sensor 406. However, when an abnormality occurs in the image forming unit, the formed barcode image 505 is detected by shifting the reading position or by passing scratches or dirt on the reading position.

  As shown in FIG. 8a, if the photosensitive drum 101 and the intermediate transfer member 106 are in a good state, the read value (decode value) is AAh, which matches the preset data. Further, as shown in FIG. 8B, when the barcode image 505 is contaminated by scratches or dirt, the read value is a value such as 04h, for example. Therefore, the read value is different from the preset data.

  As the photosensitive drum 101 and the intermediate transfer member 106 are consumed, the difference in reading level between the barcode image 505 and the surface of the intermediate transfer member 106 becomes relatively small. In this case, as shown in FIG. 8c, the read value is a value such as 22h, for example. This is different from preset data. Further, as shown in FIG. 8D, when there is an inclination of the exposure unit 103, an inclination of the patch sensor 406, or the like, the read value becomes a value such as 02h, for example. Therefore, in this case as well, the read value is different from the preset data.

If the read value is different from the preset data, the patch processing unit 209 cannot accurately detect the leading edge of the barcode image 505. For this reason, when such an abnormal value is detected, registration failure occurs even if an attempt is made to align the position with the recording material 504 using the detected edge. That is, if the preset data (for example, AAh) and the data obtained by decoding the barcode image 505 do not match, it can be determined that the barcode image 505 could not be read normally for some reason.

FIG. 9 is a flowchart showing a registration process of a recording material and an image formed on the recording material according to the present embodiment. The patch processing unit 209 of the present embodiment forms a patch image (barcode image) prior to the formed image in order to align the positions of the recording material 504 and the image 502 formed on the recording material 608.

  In step S <b> 901, the CPU 201 generates a barcode image 505 from data set in advance using the image processing unit 204. Note that the CPU 201 may read the barcode image 505 stored in the image memory unit 205 in advance. In step S <b> 902, the CPU 201 transmits data of the barcode image 505 and the image 502 to be formed to the image forming apparatus including the photosensitive drum 101, the developing device 102, and the exposure unit 103, and the image is transmitted to the intermediate transfer member 106. Form.

  In step S903, the CPU 201 evaluates the barcode image 505 formed on the intermediate transfer body 106 based on the signal detected by the patch sensor 406. Specifically, the CPU 201 decodes the signal detected by the patch sensor 406 as described above and converts it into predetermined numerical data. In step S <b> 904, the CPU 201 compares the converted numerical data with preset data used when generating the barcode image 505. If the two data match, the CPU 201 determines that the barcode image 505 has been formed normally, and the process proceeds to step S905. On the other hand, if the two data described above are different, the CPU 201 determines that the barcode image 505 has not been formed normally, and the process proceeds to step S906.

  In step S905, when the barcode image 505 is normally formed, the CPU 201 obtains a timing to decelerate the recording material 504 after passing the registration sensor 408 in order to align the position of the image 502 and the recording material 504. On the other hand, in step S <b> 906, if the barcode image 505 is not normally formed, the CPU 201 interrupts the image forming process and outputs an error display or a jam display to the output unit 301.

  FIG. 10 is a flowchart showing a barcode image generation process according to this embodiment. FIG. 10 illustrates details of the processing in step S901 in FIG.

  In step S <b> 1001, the CPU 201 passes preset data (for example, AAh) to the encoding unit 401 and converts it into image data of a barcode image 505. Next, in step S1002, the CPU 201 sets the image data converted in step S1001 in the PG unit 403. In step S1003, the CPU 201 transmits a formation start signal to the LD unit 404 at the image formation start timing. As a result, the LD unit 404 generates a latent image on the photosensitive drum 101 based on the image data set in the PG unit 403. Thereafter, the image generated on the photosensitive drum 101 is primarily transferred onto the intermediate transfer member 106.

  FIG. 11 is a flowchart showing a barcode image determination process according to this embodiment. FIG. 11 illustrates details of the processing in steps S903 and S904 of FIG. Here, it is assumed that the preset data is AAh.

  In step S1101, the CPU 201 instructs the patch sensor 406 to start detecting the barcode image 505 formed on the intermediate transfer body 106, and determines whether the barcode image 505 has started to be detected. This determination is repeated until the barcode image 505 starts to be detected, and the repetition ends when the detection starts. Note that the detection start timing may be based on the image formation start timing given to the LD unit 404. In step S <b> 1102, when the barcode image 505 starts to be detected, the CPU 201 converts the electrical signal read by the patch sensor 406 into digital data by the AD conversion unit 405 and buffers it in the work RAM 202.

  In step S1103, the CPU 201 continues buffering until the timing when the barcode image 505 will pass through the patch sensor 406, and calculates the edge line of the barcode image 505 from the buffered data. Next, in step S1104, the CPU 201 passes the determined edge line to the decoding unit 212 and converts it into numerical data.

  The CPU 201 determines whether or not this numerical data matches the preset data (AAh) used in S1001. If they match, in step S1106, the CPU 201 sets TRUE (for example, 0 value) as the return value and ends the processing. On the other hand, if they do not match, in step S1107, the CPU 201 sets FALSE (for example, 1 value) as the return value and ends the processing.

  As described above, according to the image forming apparatus of the present embodiment, a patch is formed prior to an image formed on a recording material, and it is determined whether an abnormality has occurred from the detected patch data. . In addition, when the detected patch data is normal, the image forming apparatus adjusts the timing for forming an image on the recording material. Therefore, the present invention does not perform registration when an abnormality occurs in the image forming unit. Therefore, the registration accuracy can be improved without being affected by the abnormality of each apparatus.

  The present invention is not limited to the above embodiment, and various modifications are possible. For example, the image forming apparatus may further include an output unit that outputs the occurrence of the abnormality determined by the determination unit. Thus, according to the present invention, when an abnormality occurs, the user can be notified of the occurrence of the abnormality, and unnecessary printing processing can be avoided.

  The image forming apparatus according to the present invention may use a barcode image as a patch. Accordingly, the present invention can easily determine the occurrence of an abnormality based on the barcode image data detected by the patch detection unit. Therefore, the present invention can speed up the registration process.

  Further, the barcode image in the present invention may be formed such that the longitudinal direction of the barcode image is parallel to the direction orthogonal to the moving direction of the intermediate transfer member. As a result, the present invention can detect an abnormality in the tilt of the exposed portion. Therefore, useless processing can be avoided even in an error in which a barcode image tilted by the tilt of the exposure unit is formed.

  In the present invention, the determination unit may determine whether the detected value is a flaw or a stain on the image carrier and the intermediate transfer member or occurrence of abnormality in the exposure unit. Thereby, even if the above-mentioned abnormality has occurred, the present invention can determine the occurrence of the abnormality in real time and maintain the registration accuracy. The barcode image in the present invention may be a two-dimensional barcode.

  Furthermore, the determination unit according to the present invention may store a position where an abnormality has occurred. As a result, the present invention can form a patch while avoiding the position where the abnormality has occurred during the next image formation. Therefore, the occurrence of abnormality during image formation can be reduced.

[Embodiment 2]
In the present embodiment, a plurality of barcode images of the first embodiment are formed to reduce the influence of scratches and dirt and improve registration accuracy. Since the elements having the same numbers as those in the first embodiment are the same in this embodiment, detailed description thereof is omitted.

  FIG. 12 is a diagram for explaining the relationship between the barcode image according to the present embodiment and the image formed on the recording material. Here, the description will be made assuming that there are two barcode images in the present embodiment, but the present invention is not limited thereto.

  The barcode image 505 and the barcode image 1201 are formed prior to the image 502. Here, for example, it is assumed that there is a scratch 701 on the intermediate transfer body 106 and a barcode image 1201 is formed thereon. In this case, the value detected by the patch sensor 406 is a normal value in the barcode image 505 and an abnormal value in the barcode image 1201. Therefore, the CPU 201 in this embodiment determines the timing between the image 502 and the recording material 504 using the timing at which the barcode image 505 is detected.

  Note that the value detected from the barcode image 1201 may be determined that an abnormality has occurred and may be notified to the user via the output unit 301. Further, the CPU 201 according to the present embodiment may record the detected position of the scratch or dirt on the intermediate transfer body 106 in the ROM 203. Accordingly, it is desirable that the CPU 201 according to the present embodiment avoids forming a barcode image at the position of the scratch or dirt at the next image formation.

  According to the present embodiment, the patch processing unit 209 can reduce the influence of scratches or dirt on the photosensitive drum 101 and the intermediate transfer body 106 by forming a plurality of barcode images.

  FIG. 13 is a table showing a barcode image employed for registration when a plurality of barcode images are formed in the present embodiment. The table shown in FIG. 13 is preferably stored in advance in the ROM 203 as a table.

  If both the barcode image 505 (barcode image I) and the barcode image 1201 (barcode image II) are abnormal, the CPU 201 performs an error or jam display. When either one is normal, the CPU 201 aligns the position of the image 502 formed using the normal barcode image and the recording material 504. Note that the CPU 201 may notify the user of the occurrence of an abnormality. If both barcode images are normal, the CPU 201 aligns the positions of the image 502 and the recording material 504 formed using the predetermined barcode image.

  FIG. 14 is a flowchart showing a process for aligning the recording material and the formed image according to the present embodiment. In addition, what overlaps with description of FIG. 9 in Embodiment 1 is abbreviate | omitted.

  In steps S1401 and S1402, the CPU 201 generates data of the barcode image 505 and the barcode image 1201 from preset data in order to match the timing of forming the image 502 on the recording material 504. Note that the generated data may be generated based on the same data. Subsequently, in step S1403, the CPU 201 transmits the two generated barcode images and the image data of the formed image 502 to the patch processing unit. Finally, the transmitted image data is formed on the intermediate transfer member 106 by the photosensitive drum 101 which is an image forming unit.

  Next, in steps S1404 and S1405, the CPU 201 detects and evaluates the barcode image 505 and the barcode image 1201 by the patch sensor 406, respectively. In step S1406, the CPU 201 determines whether the data detected from the barcode image 505 matches the preset data. In steps S1407 and S1409, the CPU 201 determines whether or not the data detected from the barcode image 1201 matches the preset data.

  If both the data detected from the two barcode images are normal, the CPU 201 forms an image 502 on the recording material 504 using the detection data from the barcode image determined in advance in step S1408. Find the timing to do. If either one is normal, in step S1410, the CPU 201 obtains the timing for forming the image 502 on the recording material 504 using a barcode image whose detected data is normal. Note that the CPU 201 may display any one of the abnormality types on the output unit 301. If both are abnormal data, the CPU 201 displays an error or jam display on the output unit 301 in step S1411.

  In this embodiment, when there are three or more barcode images to be formed, if at least two of the barcode images are normal, the barcode image formed closest to the image 502 is used. It is preferable to do so. This is because the closer the barcode image and the image 502 are, the less affected by driving fluctuations.

  As described above, according to the image forming apparatus of the present embodiment, a plurality of barcode images are formed, and the barcode image determined to be normal among the detected barcode image data is used for timing adjustment. Use. Therefore, the present invention can realize the alignment of the image formed on the recording material even when the image carrier or the intermediate transfer member is scratched or stained. Therefore, the error termination due to the abnormality of each device can be reduced.

1 is a diagram showing an outline of an image forming apparatus according to the present invention. FIG. 3 is a block diagram illustrating a configuration of each control unit provided in the image forming apparatus according to the present embodiment. FIG. 2 is a schematic diagram illustrating an operation panel of the image forming apparatus according to the embodiment. 1 is a block diagram relating to patch formation of an image forming apparatus according to an embodiment. FIG. 5 is a diagram for explaining adjustment of a conveyance timing of a recording material according to the present embodiment. It is a figure explaining the timing adjustment which concerns on this embodiment. It is a figure explaining the relationship between the barcode image which concerns on this embodiment, and the image formed in a recording material. It is a figure explaining the relationship between the barcode image which concerns on this embodiment, and a read value. 6 is a flowchart illustrating a registration process of a recording material and an image formed on the recording material according to the present embodiment. It is a flowchart showing the barcode image generation process which concerns on this embodiment. It is a flowchart showing the process of the barcode image determination which concerns on this embodiment. It is a figure explaining the relationship between the barcode image which concerns on this embodiment, and the image formed in a recording material. It is a table | surface which shows the barcode image employ | adopted as a registration at the time of forming the several barcode image in this embodiment. 4 is a flowchart showing a process for aligning a recording material and a formed image according to the present embodiment.

Explanation of symbols

101 (a to d): photosensitive drum 106: intermediate transfer member 406: patch sensor 408: registration sensor 501: secondary transfer roller 502: image 503: registration roller 504: recording material 505: barcode image

Claims (8)

An image forming apparatus,
An image forming unit for forming a patch expressing data for determining whether or not an abnormality has occurred in the image forming apparatus as an image;
A patch detector for detecting the patch;
A determination unit that recognizes the data from the detected patch and determines whether an abnormality has occurred in the image forming unit based on the recognized data;
An image forming apparatus comprising: a timing adjustment unit configured to adjust a conveyance timing of the recording material based on a detection timing of the patch when the abnormality has not occurred.   The image forming apparatus according to claim 1, further comprising an output unit that outputs the occurrence of the abnormality determined by the determination unit. The patch is a barcode image representing the data with a barcode,
The image forming apparatus according to claim 1, wherein the determination unit determines the occurrence of the abnormality by comparing the data with data recognized from the detected barcode image.   The image forming unit forms the barcode image as the patch so that a longitudinal direction of the barcode image is parallel to a direction orthogonal to a moving direction of an intermediate transfer member included in the image forming apparatus. The image forming apparatus according to claim 3.   The determination unit determines, as the abnormality, a scratch or a stain on the image carrier or the intermediate transfer member included in the image forming apparatus or an inclination of an exposure unit according to the detected state of the barcode image. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. The image forming unit forms a plurality of the barcode images,
The timing adjustment unit adjusts the timing for forming the image based on the detection timing of the barcode image determined to be normal by the determination unit and the detection timing of the recording material detected by the recording material detection unit. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. A storage unit for storing an abnormality occurrence position in the image carrier or the intermediate transfer member included in the image forming apparatus;
The image forming apparatus according to claim 1, wherein the image forming unit forms the patch while avoiding the stored occurrence position of the abnormality. An image forming apparatus control method comprising:
Forming a patch expressing data for determining whether an abnormality has occurred in the image forming apparatus as an image;
Detecting the patch;
Recognizing the data from the detected patch and determining whether an abnormality has occurred in the image forming unit based on the recognized data;
Adjusting the conveyance timing of the recording material based on the detection timing of the patch when the abnormality does not occur.

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