JP4324357B2 - Image forming apparatus and image forming method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus and an image forming method, such as a digital copying machine, a facsimile, and a printer, which store an input image in a page memory and print out the stored image.
[0002]
[Prior art]
In an image forming apparatus that forms a multicolor image of a document read by a document reading device or image information sent from a host device, images of black Bk, cyan C, magenta M, and yellow Y are formed and superimposed one by one. Therefore, the image forming speed is reduced. Therefore, in the past, a color image for one screen was formed on the intermediate transfer member (single chamfering mode), but the length was more than twice the reference image size in order to increase the color image forming efficiency. A so-called two-chamfer mode is employed in which a two-screen color image having a reference image size is formed on an intermediate transfer body having a thickness. In a color image forming apparatus that performs two-chamfering control, control is performed by switching between one-chamfering and two-chamfering. However, as in the conventional example shown below, switching from the two-chamfering control to the one-chamfering control is mainly based on the engine-side conditions.
[0003]
For example, in the invention described in Japanese Patent Laid-Open No. 2000-039813, a high-quality image is stably formed even when a transfer roller that feeds transfer paper changes with time and a transfer paper transfer time is delayed. In the invention described in Japanese Patent Application Laid-Open No. 2000-137422, it is possible to reliably perform image formation over time even if the image interval between two screen images continuously formed on the intermediate transfer belt is reduced. ing. In the invention described in Japanese Patent Laid-Open No. 2000-255134, in an image forming system including a one-drum image forming apparatus, printing is started sequentially before all pages are developed regardless of the same or different printing conditions. Therefore, continuous and most efficient printing is performed without causing a cycle down as much as possible during printing.
[0004]
[Patent Document 1]
JP 2000-039813 A
[0005]
[Patent Document 2]
JP 2000-137422 A
[0006]
[Patent Document 3]
JP 2000-255134 A
[0007]
[Problems to be solved by the invention]
However, in an actual color machine, it is necessary to determine whether or not to perform two-sided chamfering from the viewpoint of whether or not an image can be prepared, as well as the two-sided chamfering condition for reasons of the engine. If this is not taken into consideration, the image preparation is delayed and in the worst case, an image shift occurs between the colors and miscopying occurs.
[0008]
Here, in the case where the two-sided image cannot be obtained because the preparation of the image formation image is not in time, it can be predicted from the mode factors to some extent in advance, but the resource state of the HDD for image formation changes every moment. It is difficult to accurately predict image preparation.
[0009]
The present invention has been made in view of such a background, and an object of the present invention is to output image misalignment and output a miscopy even when a situation occurs in which image preparation is not in time during two-sided scanning. It is to provide a recovery mode in which output is normally performed without any problems.
[0010]
Another object is to define basic configuration means for preventing miscopying of abnormal images and the like even when the two-chamfering sequence cannot be executed during execution of the two-chamfering sequence.
[0011]
Another object is to define a mode in which no miscopy occurs even when the two-chamfering sequence cannot be executed.
[0012]
Another object is to specify details when switching from two-sided chamfering to one-sided chamfering in a two-chamfering recovery in a situation where image preparation cannot be performed.
[0013]
Another object is to more efficiently realize a recovery process caused by the fact that the image is not in time when two images are taken.
[0014]
Yet another object is to prescribe a case where an image cannot be prepared even in the recovery mode.
[0015]
[Means for Solving the Problems]
  In order to achieve the above object, the first means includes a primary transfer means for transferring a color image sequentially formed on the photosensitive member so as to be superimposed on the intermediate transfer member;
  Secondary transfer means for transferring the superimposed images transferred onto the intermediate transfer body onto the transfer paper in a batch;
  A two-chamfering mode is provided in which the superimposed image is formed on the intermediate transfer member for two screens along the moving direction of the intermediate transfer member, and the superimposed images for the two screens are continuously transferred to transfer paper. In the image forming apparatus,
  Primary storage means in which writing and reading of image data is performed substantially in synchronization with a data transfer rate required at the time of input and output of image data;
  A large amount of image data can be stored, the compressed image data from the primary storage means is written, and the read image data is decompressed and output to the primary storage means side. Means,
  Primary compression / decompression means for compressing and decompressing image data at the time of data writing to the primary storage means and at the time of data reading from the primary storage means;
  SaidFrom primary storage meansSecondary compression / decompression means for compressing and decompressing image data at the time of writing data to the secondary storage means and at the time of reading data from the secondary storage means to the primary storage means;
  2 chamfer execution feasibility determination means for determining whether 2 chamfer execution is possible;
  2 chamfering sequence control means for performing a 2 chamfering sequence;
  1 chamfering sequence control means for performing 1 chamfering sequence;
  An imaging sequence switching means capable of switching between a two-chamfering sequence and a one-chamfering sequence control;
  An image forming image preparation state monitoring means for monitoring whether an image is prepared in time for the image forming sequence;
  If the two-chamfering sequence cannot be executed during execution of the two-chamfering sequence by the two-chamfering sequence control means, the image formation by the two-chamfering sequence is interrupted for the subsequent images of the corresponding image, and the images are formed in the order of image pages. 2 chamfer recovery means to continue
With
  When the image forming image preparation state monitoring unit determines that the image is not prepared in time for the image forming sequence in the compression / decompression process by the secondary compression / decompression unit, the two-sided chamfering recovery unit It is determined that the execution is impossible, and the two-capping recovery process is started.
[0016]
According to the first means, the basic configuration means for detecting a state in which the two-chamfering sequence cannot be executed during execution of the two-chamfering sequence and preventing a miscopy of an abnormal image or the like is defined. Even if a state in which the two-sided chamfering sequence cannot be executed during execution of the sequence occurs, good image formation without miscopying can be performed.
[0021]
  First2Means1In the above-mentioned means, the two-side chamfering recovery means switches the two-sided chamfering sequence to the one-sided chamfering sequence during the two-sided chamfering sequence by the image forming sequence switching unit, and causes the primary transfer unit and the secondary transfer unit to perform image formation It is characterized by that.
[0022]
  First2According to the above means, if a situation occurs in which image preparation cannot be performed during execution of the two-chamfering sequence, the image preparation time can be approximately doubled and the image preparation can be easily performed if the two-chamfering is switched to the single chamfering. The So, when this happens, take 2 chamfers and 1 chamfer.Cut intoIt is possible to prevent miscopying due to the failure to prepare an image by creating an image by switching.
[0023]
  First3Means1 or 2In the above-mentioned means, the two-chamfer recovery means executes the preceding image in the two-chamfered two images in the one-chamfering sequence, and subsequently forms the subsequent image in the two-chamfered two images in the one-chamfered sequence. It is characterized by.
[0024]
  First3According to the means, even when the image preparation can be performed, since the one-chamfering sequence is performed separately for the preceding screen and the succeeding screen, it is possible to prevent the occurrence of miscopying due to image shift. Output is also done in the correct page order.
[0025]
  First4Means2Or second3In the above-mentioned means, after the recovery process by the two-chamfer recovery means, the one-chamfering sequence is switched to the two-chamfering sequence to create an image.
[0026]
  First4According to the above means, after the recovery is completed, the image forming process is resumed by returning to the pre-recovery image forming sequence mode. Therefore, after the recovery process, the optimum two-sided sequence mode is not affected by the recovery mode. It can be executed continuously.
[0027]
  First5Means2In the above-mentioned means, the two-chamfer recovery means performs the image forming operation continuously when switching from the two-chamfer sequence to the one-chamfer sequence.
[0028]
  First5According to the means, the switching process from the two-chamfering sequence to the one-chamfering sequence is executed without stopping the machine, so that a decrease in productivity can be minimized.
[0029]
  If the second or third means determines that the image preparation is not in time by the image forming image preparation state monitoring means while executing the one chamfering sequence by the two chamfer recovery means in the second or third means, The image forming operation by the chamfer recovery means is interrupted, and the image forming apparatus is stopped.
[0030]
  First6According to this means, since the recovery is performed by switching from the two-chamfering sequence to the one-chamfering sequence, the image preparation time is increased approximately twice, and the possibility that an image preparation cannot be performed is reduced. However, even in this case, if the image is not complete and the image cannot be prepared even in the recovery mode, the recovery is interrupted and the machine is stopped. As a result, it is possible to prevent the occurrence of miscopying that causes color misregistration.
[0031]
  First7Means6The above-mentioned means is characterized by providing warning means for displaying that there is an image that cannot be prepared in time for the image formation sequence in time for image formation.
[0032]
  First7According to this means, since the recovery is performed by switching from the two-chamfering sequence to the one-chamfering sequence, the image preparation time has increased by a factor of about 2, but if this still fails, this image is already set. It is impossible to print in the selected mode. Therefore, a warning is displayed, and a warning instruction is issued to switch the print mode (color mode → monochrome mode, etc.) for printing. This allows the user to know why the machine stops.
[0033]
  The eighth means transfers the color image sequentially formed on the photosensitive member by the primary transfer so as to be superimposed on the intermediate transfer member, and the superimposed image transferred on the intermediate transfer member by the secondary transfer. The images are collectively transferred onto a transfer sheet, and the superimposed image is formed on the intermediate transfer member for two screens along the moving direction of the intermediate transfer member. In an image forming method having a two-chamfering mode for transferring to
  Primary storage means in which writing and reading of image data is performed substantially in synchronization with a data transfer rate required at the time of input and output of image data;
  A large amount of image data can be stored, and compressed image data from the primary storage means is written, and the read image data is decompressed and output to the primary storage means side. Secondary storage means;
  Primary compression / decompression means for compressing and decompressing image data at the time of data writing to the primary storage means and at the time of data reading from the primary storage means;
  SaidPrimary storage meansSecondary compression / expansion means for compressing and decompressing image data at the time of data writing from the secondary storage means to the secondary storage means and at the time of data reading from the secondary storage means to the primary storage means,
  During execution of the two-chamfering mode by the two-chamfering sequence, the image is not prepared in time for the image forming sequence by the compression / decompression processing by the secondary compression / decompression unit, and the two-chamfering sequence cannot be executed. In some cases, switching to the one-chamfering sequence is performed for a predetermined image, and when the two-chamfering sequence can be executed, the image is returned to the two-chamfering sequence for image formation.
[0034]
  First8According to this means, even when a situation occurs in which the image preparation is not in time during the two-sided image taking, normal output can be performed without outputting the image shift and outputting the miscopy.
[0035]
In a later-described embodiment, the two-chamfering execution determination unit for determining whether or not two-chamfering can be performed is performed in the operation mode changing unit 53, the two-chamfering sequence control unit, the single-chamfering sequence control unit is in the CPU 68, and the image forming sequence switching unit. The image forming image preparation state monitoring means corresponds to the transfer sheet interval detection section 52, and the two-sided recovery means corresponds to the operation mode change 53, respectively. 5 is executed.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0037]
1. overall structure
First, the structure of the image forming apparatus according to the embodiment of the present invention will be described with reference to FIGS. 1 is a configuration diagram of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram of an image forming unit, FIG. 3 is a block diagram illustrating a configuration of a control unit, and FIG. 4 is a diagram 2 formed on an intermediate transfer belt. FIG. 5 is a block diagram showing the internal configuration of the image processing unit, and FIG. 6 is a block diagram showing the internal configuration of the memory controller and the image memory.
[0038]
As shown in FIG. 1, the image forming apparatus includes a scanner unit 1, a printer unit 2, and a paper feed unit 3. The scanner unit 1 sends image information of a document placed on the contact glass 11 to a color CCD image sensor (hereinafter referred to as a color CCD) 13 by an optical scanning unit 12 having a light source, a plurality of mirrors, and a lens. The color CCD 13 separates the colors into red R, green G, and blue B, reads each color, and converts it into an electrical image signal. The image signal color-separated into red R, green G, and blue B is subjected to color conversion processing by the image processing unit, converted into color image data of black Bk, cyan C, magenta M, and yellow Y and sent to the printer unit 2. It is done.
[0039]
The printer unit 2 includes an image forming unit 21, a fixing unit 22, and a recording paper transport unit 23. As illustrated in the configuration diagram of FIG. 2, the image forming unit 21 includes a photoconductor 24, a revolver unit 25, a transfer unit 26, and a writing unit 27. On the outer periphery of the photoconductor 24, along the rotation direction of the photoconductor 24, a static elimination lamp 28, a charging charger 29, a revolver unit 25, a toner adhesion amount sensor 30, a pre-transfer static elimination lamp 31, a transfer unit 26 and a drum cleaning unit 32. Is provided.
[0040]
The revolver unit 25 includes developing devices 251, 252, 253, and 254 for black Bk, cyan C, magenta M, and yellow Y, and a revolver home position sensor 255. The transfer unit 26 includes an intermediate transfer belt 261, a belt transfer charger 263, a mark sensor 264, a paper transfer charger 265, and a belt cleaning unit 266. When the mark sensor 264 obtains the intermediate transfer portion, the mark sensor 264 reads the reference mark 262 provided on the 261. The intermediate transfer belt 261 is wound around a plurality of rollers, and includes a reference mark 262, for example, two sheets of A4 horizontal size, and a space between the transfer sheet and each transfer sheet (inter-sheet gap). The image has a length twice as long as the image, and two images of the same color can be formed on the intermediate transfer belt 261 by two rotations of the photosensitive member 24. The recording paper transport unit 23 provided on the upstream side of the paper transfer charger 265 is provided with a registration roller 231 for feeding the transfer paper and a front end detection sensor S1 for detecting the front end of the transfer paper, and the front end detection sensor S1. Is disposed upstream of the registration roller 231 by a certain distance Lr.
[0041]
The paper feed unit 3 has a plurality of paper feed trays 41, 42, and 43. A paper feed claw 44 and a paper feed roller 45 are disposed in each of the paper feed trays 41 to 43. On the side, transfer paper detection sensors S2, S3 and S4 for detecting the transfer paper are provided. The transfer paper fed from the paper feed unit 3 is sent to the recording paper transport unit 23 by a transport roller 46 provided at the exit of the paper feed unit 3.
[0042]
As shown in the block diagram of FIG. 3, the control unit 5 of the image forming apparatus includes a central control unit 51, a transfer paper interval detection unit 52, an operation mode change unit 53, and an image processing unit (hereinafter referred to as IPU) 100. Have. The central control unit 51 controls the operations of the scanner unit 1, the printer unit 2, and the paper feeding unit 3, and executes display control for displaying an operation state and the like on the display unit 4. The transfer sheet interval detection unit 52 inputs transfer sheet detection signals from the leading edge detection sensor S 1 provided in the printer unit 2 and the transfer sheet detection sensors S 2, S 3, S 4 provided in the sheet feeding unit 3, and is applied to the intermediate transfer belt 261. When performing two-sided chamfering to form an image for two sides, the interval between the trailing edge of the transfer sheet sent to the first sheet and the leading edge of the transfer sheet sent to the second sheet is detected. When the interval between the first transfer sheet and the second transfer sheet detected by the transfer sheet interval detection unit 52 is greater than a predetermined reference value (when the timing is delayed), the operation mode changing unit 53 Control is performed to disable the two-sided operation mode and change to an operation mode in which an image is formed on each surface of the intermediate transfer belt 261.
[0043]
When forming one full color image by the image forming apparatus configured as described above, the image forming unit 21 rotates the intermediate transfer belt 261 of the photosensitive member 24 and the transfer unit 26, and the mark sensor of the transfer unit 26. In 264, reading of the black Bk image data is started at a predetermined timing after the reference mark 262 of the intermediate transfer belt 261 is detected. Based on the black Bk image data, the optical writing unit 27 rotates the photosensitive member 29 of the charging charger 29. Optical writing is performed on the photoconductor 24 on the downstream side in the direction, and an electrostatic latent image is formed on the photoconductor 24. The electrostatic latent image formed on the photoreceptor 24 is visualized by the black Bk developing unit 251 of the revolver unit 25. The visualized black image Bk is primarily transferred to the intermediate transfer belt 261 by the belt transfer charger 263 at a timing based on the detection of the reference mark 262 of the intermediate transfer belt 261 by the mark sensor 264. When the primary transfer of the black image Bk of the first color is completed, the revolver unit 25 is rotated to bring the cyan C developing device 252 into contact with the photosensitive member 24. Thereafter, a cyan image C is formed on the photosensitive member 24 in the same manner as described above, and the formed cyan image C is primarily transferred to the intermediate transfer belt 261 at a timing based on the detection of the reference mark 262 by the mark sensor 264. The first color black image Bk and the second color cyan image C are superimposed. This image formation and primary transfer are repeated for each image of magenta M and yellow Y, and a full color toner image is formed on the intermediate transfer belt 261. The full color toner image formed on the intermediate transfer belt 261 is secondarily transferred to the transfer paper sent from the recording paper transport unit 23 by the paper transfer charger 265, and the transfer paper onto which the full color toner image is transferred is the recording paper transport belt. 33 is sent to the fixing unit 22 to be fixed and discharged. A belt cleaning unit 266 is brought into contact with the intermediate transfer belt 261 on which the toner image is secondarily transferred to the transfer paper, and the toner remaining on the surface of the intermediate transfer belt 261 is removed to prepare for the next image formation. .
[0044]
When forming an image of one color, it is not necessary to superimpose toner images of different colors on the intermediate transfer belt 261. Therefore, image formation is started without detecting the reference mark 262, and writing and development are performed at a predetermined timing. The primary transfer, the secondary transfer, and the cleaning of the intermediate transfer belt 261 are sequentially performed. Further, when a plurality of images are continuously formed, image formation is performed at a necessary image interval regardless of the rotation of the intermediate transfer belt 261.
[0045]
In the two-chamfering operation mode in which a full-color image is formed on the intermediate transfer belt 261 by two sides, when the intermediate transfer belt 261 rotates and the mark sensor 264 detects the reference mark 262, the first black image Bk1 is displayed. As shown in the development view of FIG. 4, the black image Bk1 formed on the photosensitive member 24 is transferred to the belt transfer charger at a timing based on the detection of the reference mark 262 of the intermediate transfer belt 261 by the mark sensor 264. By H.263, primary transfer is performed to the intermediate transfer belt 261. Subsequently, a second black image Bk2 is formed on the photosensitive member 24, and the formed black image Bk2 is primarily transferred to an area on the intermediate transfer belt 261 after the area where the black image Bk1 is transferred. When the secondary transfer of the black images Bk1 and Bk2 of the first color is completed, the revolver unit 25 is rotated so that the cyan C developing unit 252 is brought into contact with the photosensitive member 24, and the first cyan is applied to the photosensitive member 24 in the same manner as described above. An image C1 is formed, and the formed cyan image C1 is primarily transferred to the intermediate transfer belt 261 at a timing based on the detection of the reference mark 262 by the mark sensor 264, and the first color black image Bk1 and the second color cyan image. Overlay C1. Thereafter, a second cyan image C2 is formed on the photosensitive member 24, and the formed cyan image C2 is primarily transferred onto the intermediate transfer belt 261 and superimposed on the black image Bk2. This image formation and primary transfer are repeated for each of the magenta M and yellow Y images, and the first full color image FC1 and the second full color image FC2 are formed on the intermediate transfer belt 261. After starting the image formation of the yellow Y image, which is the final color of the first image FC1, the registration roller 231 is rotated at a constant secondary transfer timing, and the first full color image FC1 is transferred onto the transfer paper. The second full color image FC2 is secondarily transferred to the transfer paper and fixed on the transfer paper that is subsequently transferred and fixed.
[0046]
When the two images FC1 and FC2 are formed on the intermediate transfer belt 261 in this way, as shown in FIG. 4, if the circumference of the intermediate transfer belt 261 is L, the leading edge and the second face of the first image FC1 are displayed. When the distance La to the leading edge of the image FC2 is made constant regardless of the image length, that is, the length of the transfer paper for secondary transfer, various image forming control timings can be simplified regardless of the transfer paper size. The distance LD1 between the image FC1 on the first side and the image FC2 on the second side, that is, the interval between the two transfer papers sent in the case of two-sided chamfering is the maximum transfer paper length for performing two-sided chamfering, for example, the length of A4 size or LT Minimum when the size is short. The interval LD1 is determined to be an operable length according to the transfer paper feed interval, the return speed of the scanner unit 1, and the like. Further, the distance LD2 from the end of the image FC2 on the second surface to the start end having the reference mark 262 of the intermediate transfer belt 261 is a portion that does not affect the sheet interval of the transfer paper, and the color change speed of the revolver unit 25 and the scanner unit 1 The return speed is determined, and LD1 = LD2 is normally set.
[0047]
In the IPU 100, as shown in the block diagram of FIG. 5, the image information of the document from the optical scanning unit 12 is photoelectrically converted by the color CCD 13, and converted into a digital signal by the A / D converter 61. The image signal converted into the digital signal is subjected to shading correction by the shading correction unit 62 and then subjected to MTF correction, γ correction, and the like by the image processing unit 63. The image signal that has passed through the scaling processing unit 72 that performs the scaling processing is enlarged / reduced in accordance with the scaling ratio and input to the selector 64. The selector 64 switches the image signal destination to either the writing γ correction unit 71 or the memory controller 65. The image signal that has passed through the writing γ correction unit 71 is corrected for writing γ according to the image forming conditions, and is sent to the writing unit 57. The memory controller 65 and the selector 64 are configured to be able to input and output image signals in both directions.
[0048]
Although not clearly shown in FIG. 5, the IPU 100 also receives image data supplied from the outside (for example, data output from a data processing device such as a personal computer) in addition to the image data input from the scanner unit 1. It has a function of inputting and outputting a plurality of data so that it can be processed. Further, a CPU 68 for setting the memory controller 65 and the like and controlling the scanner unit 1 and the writing unit 57, and a ROM 69 and a RAM 70 for storing programs and data thereof are provided. Further, the CPU 68 writes and reads data in the image memory 66 via the memory controller 65. The memory controller 65 and CPU 68 and the display unit 4 are also configured so that image data 73 can be input and output bidirectionally via the I / O port 67. As a result, the CPU 68 executes various controls according to the program stored in the ROM 69 while using the RAM 70 as a work area.
[0049]
2. Image data storage means
FIG. 6 is a block diagram showing details of the memory controller 65 and the image memory 66 in FIG. FIG. 6 shows details of individual storage devices of the storage means in this embodiment, and the image memory 66 is also connected to the individual storage devices. The memory controller 65 serving as a data input / output control unit includes an input data selector 201, an image composition unit 202, a primary compression / decompression unit 203, an output data selector 204, and a secondary compression / decompression unit 205. Setting of control data in each block is performed by the CPU 68. Addresses and data in FIG. 5 are for image data, and data and addresses connected to the CPU 68 are not shown.
[0050]
On the other hand, the image memory 66 includes primary and secondary storage devices 206 and 207. The primary storage device 206 is substantially synchronized with the data transfer speed required for inputting / outputting image data when writing data to the specified area of the memory or reading data from the specified area of the memory at the time of image output. For example, a memory that can be accessed at high speed, such as DRAM, is used. The primary storage device 206 has a configuration (an interface unit with a memory controller) that can divide into a plurality of areas according to the size of image data to be processed and can simultaneously execute input / output of image data. The secondary storage device 207 is a large-capacity nonvolatile memory for synthesizing and sorting input images and for accumulating data. If the primary storage device 206 has a sufficient capacity for processing image data and is non-volatile, it is not necessary to input / output data to / from the secondary storage device 207. If the secondary storage device 207 can write / read data almost synchronously with the data transfer speed required at the time of image input / output, the data can be directly written / read to / from the secondary storage device 207. It becomes possible. In such a case, it is possible to process data without distinguishing between primary and secondary.
[0051]
When the secondary storage device 207 cannot write / read data in synchronization with the data transfer speed required at the time of image input / output, for example, a storage medium such as a hard disk or a magneto-optical disk is used for the secondary storage device 207 Even in this case, the input / output of data to the secondary storage device can be processed according to the data transfer capability of the secondary storage device 207 by interposing the primary storage device 206.
[0052]
Here, a specific usage example of the primary storage device 206 and the secondary storage device 207 in each application will be given, and an operation example of the memory controller 65 will be described.
[0053]
2.1 Examples of using the primary storage device 206 and the secondary storage device 207 in each application
(1) One copy in copy application
In the case of one copy, first, image data from the scanner unit 1 is input to the primary storage device 206. The data is output to the image forming unit 21 at almost the same timing, but at the same time, the data is stored in the secondary storage device 207. When the image formation is completed normally, the data stored in the secondary storage device 207 is erased without being used. However, when a jam occurs, the jam is obtained by reading the image data from the secondary storage device 207. There is no need to read the image from the scanner after the occurrence.
[0054]
(2) Sorting in copy application (multiple copies)
Even in the case of two or more copies, image data from the scanner unit 1 is first input to the primary storage device 206. The first copy is output from the primary storage device 206 to the image forming unit 21 and the data is also stored in the secondary storage device 207 at the same time as in the above (1). The image data for the second and subsequent copies is output from the secondary storage device 207 to the primary storage device 206 and the image forming unit 21, so that the scanner unit 1 does not need to read the second and subsequent copies. When the required number of copies is completed, the image data stored in the secondary storage device 207 is deleted.
[0055]
(3) Image storage from the scanner
In this case, the image data from the scanner unit 1 is stored in the secondary storage device 207 via the primary storage device 206. At this time, the image data remains stored unless intentional erasure is performed.
[0056]
(4) Printing from an external input device (for example, a personal computer)
This case is almost the same as the cases (1) and (2), and the input source of the image data is not the scanner unit 1 but the external input device.
[0057]
(5) Image storage from external input device
In this case, it is almost the same as (3) above, and the input source of the image data is not the scanner unit 1 but the external input device.
[0058]
(6) Print accumulated image
When printing the image accumulated in (3) and (5), the image is read from the secondary storage device 207 and buffered in the primary storage device 206, and is selected from the primary storage device via the memory controller 65. Image data is sent to 64, optical writing is performed to the writing unit 57, and printing is performed by the image forming unit 21.
[0059]
2.2 Operation example of memory controller 65
Here, an example in which the secondary storage device 207 cannot write / read data substantially in synchronization with the data transfer speed required at the time of image input / output is shown.
[0060]
(1) Image input (save to image memory 66)
The input data selector 201 selects image data to be written to the primary storage device 206 in the image memory 66 from a plurality of data. The image data selected by the input data selector 201 is supplied to the image composition unit 202 and synthesized as necessary. The image data processed by the image composition unit 202 is compressed by the primary compression / decompression unit 203, and the compressed data is written to the primary storage device 206. The data written in the primary storage device 206 is further compressed by the secondary compression / decompression unit 205 as necessary, and then stored in the secondary storage device 207.
[0061]
(2) Image output (reading from image memory 66)
At the time of image output, image data stored in the primary storage device 206 is read out. When the image to be output is stored in the primary storage device 206, the image data read from the primary storage device 206 is decompressed by the primary compression / decompression unit 203, and the decompressed data or The data after the image composition of the decompressed data and the input data is selected by the output data selector 204 and output. When the image to be output is stored in the secondary storage device 207, the output target image data stored in the secondary storage device 207 is decompressed by the secondary compression / decompression unit 205, and after decompression. Are written in the primary storage device 206, and then an image output operation is performed in accordance with the processing of the image data read from the primary storage device 206.
[0062]
3. Image input / output control using page memory
The page memory is configured in the primary storage device 206, and temporarily holds images in units of pages. Further, although the size of the normal page memory changes according to the resolution or the like, the memory capacity in units of A4 size is managed in units of one page. For example, when an A3 size input is made, image input is performed using two pages of page memory. Further, in the case of color input, image data of magenta M, cyan C, yellow Y, and black Bk, which are color components of the color, is input from the scanner unit 1 to the page memory for each color component.
[0063]
The same applies to output, and if there is a color component to be printed on the page memory, the image data developed on the page memory is output to the printer unit 2. When the color component of the designated image does not exist in the page memory but exists in the secondary storage device 207, first, the designated image is read from the secondary storage device 207 to the page memory, and then the image data of the image Is output to the printer unit 2. In the case of a color copying machine, there is a function called a so-called ACS (auto color select) mode that automatically determines the color of an image of an original image and performs copying in either monochrome or full color.
[0064]
4). Action
FIG. 7 is a diagram showing a one-chamfering sequence, and FIG. 8 is a diagram showing a two-chamfering sequence. As shown in FIG. 7, in the single chamfering sequence, one image is formed in the order of K, C, M, and Y. With this as one cycle, full-color printing is performed by repeating a single chamfering sequence. On the other hand, in the two-chamfering sequence, as shown in FIG. 8, two images are formed for each color component, and the images are formed in the order of M, K, C, M, and Y. In the case of two chamfering, the image forming interval is shorter by about half when the image forming size is the same as that of one chamfering, and therefore the time for preparing an image is short. Will occur. Whether or not the two-chamfering is in time is whether the paper size, the paper size direction, two image forming requests are aligned by the two-chamfering timing, are two or more images formed, or are the colors used in the two surfaces the same? The image preparation was realized by a hardware configuration and a productivity setting with sufficient time.
[0065]
However, in response to the increasing functionality of color copiers, in recent years, image finishing in complex modes has been demanded. Furthermore, multi-applications such as FAX, printer copy, and scanner are used, and there are problems such as resource contention. Further, high speed printing is also required, and there are various factors that tend to cause delay in image preparation. For this reason, it has become necessary to determine whether or not two-chamfering control is possible from the viewpoints of both image forming conditions and whether or not image preparation is possible.
[0066]
FIG. 10 to FIG. 12 are flowcharts showing the operation at this time. FIG. 10 and FIG. 11 show the control procedure of the recovery mode when two chamfering is impossible, and FIG. 9 shows an example of the recovery operation.
[0067]
First, the recovery mode will be described in detail with reference to FIGS. 9 and 10.
[0068]
In this mode, it is checked in S11 whether the two-chamfering sequence is being executed. If not, the one-chamfering sequence shown in FIG. 7 is executed (step S14). If the two-chamfering sequence is being executed in step S11, it is checked in step S12 whether image preparation has been completed at the image forming timing of the two-chamfering sequence. If ready, the two chamfering sequence shown in FIG. 8 is executed in step S13.
[0069]
If the image is not ready in step S12 (FIG. 9 PC-2), the canceling process of the two-chamfer sequence control is executed, that is, the two-chamfering is stopped and the recovering counter is initialized (step S16). Then, the image forming sequence is set to a single chamfering sequence (step S17), and further, a recovery parameter is set (step S18). Thereafter, recovery image forming processing is executed in a one-sided chamfering sequence (step S19), and recovery imaging of a two-sided image is performed (step S20). When all the recovery images have been created (steps S22, S18, S18, and S20), the image creation sequence is set to a two-chamfering sequence (step S21), and the process is completed.
[0070]
As a case where the image is not in time in S12,
-It takes time to call an image from the HDD.
[0071]
-Resources such as HDD and page memory are batting, and usage status is pending
・ It takes too much time to edit images
Such a case can be considered.
[0072]
As described above, in the process of FIG. 10, when executing the recovery mode, the image forming sequence mode is switched from the two-chamfer sequence mode to the single-chamfer sequence mode in S17). As a result, the time required for image preparation is approximately doubled, and an image that is not in time for the two-chamfering sequence can be prepared with a sufficient margin. In step S18, parameters for recovery operation are set. This is because parameter setting is performed depending on whether recovery is performed on the preceding image (FIG. 9A) and the succeeding image (FIG. 9B) of the two images in the two-chamfering sequence. The subroutine is shown in the flowchart of FIG.
[0073]
In the flowchart of FIG. 11, it is checked by evaluating the recovery counter whether or not the recovery is the recovery of the top image (FIG. 9A) (step S30). In this check, if the head image is recovered, the image to be started for recovery is set as the first color component in the order of image formation of the two-chamfered head image (step S31), and the subsequent image is recovered. If so, the image for which image formation is started for recovery is set as the first color component in the image formation order of the top image of the two chamfers (step S32). In this way, in the process of FIG. 11, the first image designation for recovery is performed.
[0074]
Next, in S19, an image forming process is performed in a single chamfering sequence from the image set in S18. If the designated image is “P1,” images are created in the order of “P1-K” → “P1-C” → “P1-M” → “P1-Y”.
[0075]
When the recovery process (FIG. 9A) for the preceding image out of the two chamfered images is completed, the process proceeds to the execution of the subsequent image in S20 and S22. In S18 and 19, the recovery process for the succeeding process (FIG. 9B is completed, and all the recovery processes are completed. When the recovery process is completed, the image forming sequence mode before the recovery is completed in S21 after the recovery is completed. The image forming sequence mode is switched to the two-sided sequence mode so that the image forming process can be continued and the image forming process can be continued.
[0076]
FIG. 9 is a diagram showing a specific operation of the control shown in FIGS. 10 and 11.
[0077]
In FIG. 9, after two chamfering is performed and image formation “P1-K”, “P2-K”, and “P1-C” are executed, a situation occurs in which image preparation cannot be performed with image formation “P2-C”. ing. Here, the two-chamfer recovery process starts. That is, the recovery mode is executed. Therefore, the image forming process by the two-chamfering sequence after “P2-C” is prohibited. In addition, the two-chamfering sequence is canceled halfway (step S15 described above).
[0078]
Then, in order to switch to the single chamfering sequence and recover the images in page order, “P1-K” → “P1-C” → “P1-M” → “P1” is the preceding image in the two-chamfering mode. The image is formed in the order of “P1-Y” (recovery image formation of the preceding image P1 with the chamfered area A-2). Further, the image is continuously created in the order of “P2-K” → “P2-C” → “P2-M” → “P2-Y” with respect to “P2” which is the succeeding image in the two-chamfer mode (region B− Recovery imaging of the succeeding image P2 with two chamfers—steps S19, 20). In this way, the recovery operation for the images P1 and P2 that have been impossible to execute the two-sided processing is completed.
[0079]
Since the recovery is performed by switching from the two-chamfering sequence to the one-chamfering sequence, the image preparation time is increased approximately twice, and the image can be prepared. Further, the recovery mode ends at the end of “P2-Y” image formation. Therefore, after completion of the recovery mode, the image forming sequence mode is returned to the two-chamfering sequence mode again and image forming is continued (area C). Note that these sequence mode switching operations are continuously performed without stopping the machine.
[0080]
In the recovery mode, since the two-chamfering sequence is switched to the one-chamfering sequence, the image preparation time is increased by a factor of about 2, and the possibility that an image preparation cannot be performed is reduced. However, even in this case, it is not complete, and there is a possibility that an image cannot be prepared even in the recovery mode.
[0081]
The flowchart of FIG. 12 shows the correspondence in that case. When an image cannot be prepared even in the recovery mode, the recovery is interrupted and the machine is stopped. That is, in the subroutine for checking the image preparation status in the recovery mode, if the recovery mode is in effect (step S41-yes), it is checked whether the image preparation is completed in time for the image forming sequence (step S42). If it is possible, the process returns as it is, and if it is not ready, the execution of the recovery means is interrupted and the image forming apparatus is stopped (step S43). Furthermore, it is impossible to print this image in the already set mode. Therefore, a warning is displayed so that a warning is displayed, and the print mode is switched (color mode → monochrome mode, etc.) (step S44). This allows the user to know why the machine stops.
[0082]
By executing the recovery mode as described above, even if a situation occurs in which image preparation is not in time during two-sided image capture, image misalignment is output and output is performed normally without outputting miscopy. It becomes possible.
[0083]
【The invention's effect】
  Since the state of resources such as HDDs for image formation changes every moment and it is difficult to accurately predict image preparation, it is recommended that recovery mode for reimaging is performed only when “image preparation cannot be performed”. By doing so, the implementation effect of the two-sided coverage mode can be maximized.
  As described above, according to the present invention, it is possible to obtain a normal output image without outputting a miscopy even when a situation occurs in which image preparation is not in time during two-sided printing.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.
2 is an enlarged configuration diagram illustrating an image forming unit of the image forming apparatus in FIG. 1;
3 is a block diagram illustrating a configuration of a control unit of the image forming apparatus in FIG. 1. FIG.
FIG. 4 is a development view showing images of two surfaces formed on an intermediate transfer belt.
5 is a block diagram showing an internal configuration of the image processing unit in FIG. 3. FIG.
6 is a block diagram showing an internal configuration of a memory controller and an image memory in FIG. 5. FIG.
FIG. 7 is a diagram showing a single chamfering sequence.
FIG. 8 is a diagram showing a two-chamfering sequence.
FIG. 9 is a diagram showing a recovery operation when two chamfering is impossible.
FIG. 10 is a flowchart showing a control procedure in a recovery mode when two-sided chamfering is impossible.
FIG. 11 is a flowchart showing the contents of a subroutine of step S18 of FIG.
FIG. 12 is a flowchart illustrating a response when an image cannot be prepared even in the recovery mode.
[Explanation of symbols]
1 Scanner section
2 Printer section
3 Paper feeder
4 display section
5 Control unit
12 Optical scanning means
13 color CCD
21 Imaging Department
22 Fixing part
24 photoconductor
25 Revolver unit
26 Transfer unit
51 Central control unit
68 CPU
65 Memory controller
66 Image memory
100 Image processing unit (IPU)
201 Input data selector
202 Image composition unit
203 Primary compression / decompression unit
204 Output data selector
205 Secondary compression / decompression unit
206 Primary storage device
207 Secondary storage device

Claims (8)

Primary transfer means for transferring a color image sequentially formed on the photosensitive member so as to be superimposed on the intermediate transfer member;
Secondary transfer means for transferring the superimposed images transferred onto the intermediate transfer body onto the transfer paper in a batch;
A two-chamfering mode is provided in which the superimposed image is formed on the intermediate transfer member for two screens along the moving direction of the intermediate transfer member, and the superimposed images for the two screens are continuously transferred to transfer paper. In the image forming apparatus,
Primary storage means in which writing and reading of image data is performed substantially in synchronization with a data transfer rate required at the time of input and output of image data;
A large amount of image data can be stored, the compressed image data from the primary storage means is written, and the read image data is decompressed and output to the primary storage means side. Means,
Primary compression / decompression means for compressing and decompressing image data when data is written to the primary storage means and when data is read from the primary storage means;
When writing data to the secondary storage unit from said primary storage means, and a secondary compression / decompression means for compressing and decompressing each image data during data read into the primary storage means from said secondary storage means ,
2 chamfer execution feasibility determination means for determining whether 2 chamfer execution is possible;
2 chamfering sequence control means for performing a 2 chamfering sequence;
1 chamfering sequence control means for performing 1 chamfering sequence;
An imaging sequence switching means capable of switching between a two-chamfer sequence and a one-chamfer sequence control;
An image forming image preparation state monitoring means for monitoring whether an image is prepared in time for the image forming sequence;
If the two-chamfering sequence cannot be executed during execution of the two-chamfering sequence by the two-chamfering sequence control means, the image formation by the two-chamfering sequence is interrupted for the subsequent images of the corresponding image, and the images are formed in the order of the image pages. 2 chamfer recovery means to continue
With
When the image forming image preparation state monitoring unit determines that the image is not prepared in time for the image forming sequence in the compression / decompression process by the secondary compression / decompression unit, the two-sided chamfering recovery unit Determining that execution has become impossible, and starting a two-sided recovery process,
An image forming apparatus.   The two-side chamfer recovery means is characterized in that the image forming sequence switching means switches the two-side chamfering sequence to the one-side chamfering sequence during the two-side chamfering sequence and executes image formation by the primary transfer means and the secondary transfer means. The image forming apparatus according to claim 1.   The two-chamfer recovery means executes a preceding image in a two-chamfered image in a one-chamfering sequence, and subsequently forms a subsequent image in a two-chamfered two image in a one-chamfered sequence. The image forming apparatus according to claim 1.   4. The image forming apparatus according to claim 2, wherein after the recovery process by the two-chamfer recovery means, the one-chamfering sequence is switched to a two-chamfering sequence to form an image.   3. The image forming apparatus according to claim 2, wherein the two-chamfer recovery unit continuously performs the image forming operation when switching from the two-chamfer sequence to the one-chamfer sequence.   During execution of the single chamfering sequence by the two-chamfer recovery means, if the image preparation state monitoring means determines that the image preparation is not in time, the image forming operation by the two-chamfer recovery means is interrupted, and the image forming apparatus is 4. The image forming apparatus according to claim 2, wherein the image forming apparatus is stopped.   7. The image forming apparatus according to claim 6, further comprising warning means for displaying that there is an image that cannot be prepared in time for the image formation sequence when the image is formed. The color images sequentially formed on the photosensitive member by the primary transfer are transferred so as to be superimposed on the intermediate transfer member, and the superimposed images transferred on the intermediate transfer member by the secondary transfer are collectively put on the transfer paper. A two-sided chamfering mode in which the superposed image is formed on the intermediate transfer member for two screens along the moving direction of the intermediate transfer member, and the superposed images for the two screens are continuously transferred to transfer paper. In an image forming method comprising:
Primary storage means in which writing and reading of image data is performed substantially in synchronization with a data transfer rate required at the time of input and output of image data;
A large amount of image data can be stored, and compressed image data from the primary storage means is written, and the read image data is decompressed and output to the primary storage means side. Secondary storage means;
Primary compression / decompression means for compressing and decompressing image data when data is written to the primary storage means and when data is read from the primary storage means;
When writing data to the secondary storage unit from said primary storage means, and a secondary compression / decompression means for compressing and decompressing each image data during data read into the primary storage means from said secondary storage means ,
During execution of the two-chamfering mode by the two-chamfering sequence, the image is not prepared in time for the image forming sequence by the compression / decompression processing by the secondary compression / decompression unit, and the two-chamfering sequence cannot be executed. Sometimes, the image forming method is characterized by switching to the one-chamfering sequence to form a predetermined image and returning to the two-chamfering sequence when the two-chamfering sequence can be executed.

Images