JP3878805B2 - Image processing apparatus, image processing method, and storage medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, a color image to be transferred is formed by sequentially superimposing a plurality of color toner images sequentially formed on a photoreceptor on an intermediate transfer body, and the color image to be transferred is transferred onto a recording medium. The present invention relates to a color image forming apparatus such as a full-color digital copier of the type that obtains the above. The present invention also provides a color image forming method used in such a color image forming apparatus, a storage medium for storing a program installed in a computer provided in such a color image forming apparatus, and such a color image. The present invention relates to a color image forming system using a forming apparatus.
[0002]
[Prior art]
In this type of color image forming apparatus, since it is necessary to form a color image to be transferred by superimposing a plurality of color toner images on the intermediate transfer member, it is necessary to align the toner images of the respective colors. For example, when obtaining a full-color image, it is necessary to superimpose at least cyan, magenta and yellow, and if necessary, a black toner image on an intermediate transfer member. Don't be. Therefore, conventionally, a belt mark is provided on the intermediate transfer member, and the overlapping timing of the toner images of the respective colors is defined based on the detection of the belt mark.
[0003]
In order to achieve high image quality in such a color image forming apparatus, in Japanese Patent Laid-Open No. 10-42158, the reading operation of an original by an image reading apparatus such as a scanner is slowed down and performed in one reading operation (scanning). The image data is stored in the image memory, and the image data is read out from the image memory every time the toner image of each color is formed. There has been disclosed a technique that suppresses noise and vibration associated with a reading operation and realizes high-precision image reading.
[0004]
Further, in order to improve the image forming efficiency and increase the productivity, it is desirable to execute the image forming operation in the image processing unit in parallel with the document image reading operation in the image reading apparatus. Therefore, in the above-described color image forming apparatus, the original image reading operation and the first color image forming operation in the image reading apparatus may be performed in parallel.
[0005]
However, when such parallel processing is executed, if the image forming speed in the image processing unit is higher than the image reading speed in the image reading device, the number of lines for writing image data to the image memory There is a problem that the number of lines for reading image data from the image memory is overtaken and a normal image forming operation is not performed. In general, the image reading speed in the image reading unit and the read image quality are in a trade-off relationship. That is, as the image reading speed increases, the reading image quality decreases, and as the image reading speed decreases, the reading image quality improves. On the other hand, the image forming speed in the image processing section does not have such a problem, and the image forming speed has been dramatically increased in recent years. For this reason, in general, the image forming speed in the image processing unit is higher than the image reading speed in the image reading apparatus. Therefore, the number of lines for writing image data to the image memory is set to the image memory. There is a need for a solution to the problem of overtaking the number of lines for reading image data from.
[0006]
The technique disclosed in Japanese Patent Application Laid-Open No. 9-18618 provides a solution to such a problem. That is, in Japanese Patent Laid-Open No. 9-18618, the image reading operation speed in the image reading device and the image processing unit in the image processing unit are related to the output timing of the write start enable signal that triggers the image forming operation in the image processing unit. An invention is disclosed in which when the image speed is different and the image reading speed is slower, the number of image data write lines to the image memory is set so that the number of image data read lines from the image memory does not pass. ing. As a result, even if the image forming speed in the image processing unit is higher than the image reading speed in the image reading device, the number of lines of image data written to the image memory is reduced. The number of read lines is not overtaken, and the image forming operation is normally performed.
[0007]
However, the technique disclosed in Japanese Patent Laid-Open No. 9-18618 is not a technique relating to a color image forming apparatus but a monochrome image forming technique.
[0008]
[Problems to be solved by the invention]
Among color image forming apparatuses, in a color image forming apparatus using an intermediate transfer member, as described above, a belt mark is provided on the intermediate transfer member, and the toner image overlay timing of each color is determined based on the detection of the belt mark. It is trying to regulate. For this reason, the image forming operation cannot be started for any color unless the belt mark is detected.
[0009]
However, in the conventional color image forming apparatus, since the image data writing operation to the image memory and the start timing of the intermediate transfer member are not synchronized, the image data is written to the image memory and the image forming operation is performed. Even when it is possible to start, there is a problem that the image forming operation cannot be started until the belt mark of the intermediate transfer member is detected, and the image forming efficiency is lowered accordingly. That is, in order to improve the image forming efficiency, it is desirable that the belt mark of the intermediate transfer member is detected and the image forming operation is started simultaneously with the completion of the writing operation of the image data to the image memory. The time until the belt mark of the intermediate transfer member is detected after completion of the image data writing operation is not fixed, and in some cases, this time may be a very long time.
[0010]
In a color image forming apparatus, the writing operation of image data to the image memory and the start timing of the intermediate transfer member cannot be defined as a fixed relationship. This is because the exposure linear velocity in the image reading apparatus that outputs image data to the color image forming apparatus is different for each model, and the image reading conditions such as the document size and the presence / absence of scaling are indefinite. To do.
[0011]
An object of the present invention is to improve image forming efficiency and increase productivity.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided reading means for reading a document under predetermined reading conditions to generate image information, an image memory for storing the image information, and an intermediate transfer member based on the image information stored in the image memory. In an image processing apparatus having image forming means for forming an image on
After the write start ready signal is output, Each time a mark provided on the intermediate transfer member is detected, a control unit that executes an image forming operation on the intermediate transfer member based on image information stored in the image memory, and based on the reading condition, The image reading operation by the reading unit and the image forming operation of the first color by the image forming unit are executed in parallel under the condition that the reading line from the image memory does not pass the writing line to the image memory. In The output timing of the writable signal When the first timing control means to be controlled and the reading area of the original by the reading means are in the maximum range Also Said The mark of the intermediate transfer member can be detected immediately after the output of the writable signal when the writable signal is output and the writable signal is output when the read line from the image memory does not pass the write line to the image memory. The stop position of the intermediate transfer member And a second timing control means for controlling.
According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the second timing control unit is independent of a reading condition referred to by the reading unit.
According to a third aspect of the present invention, a document is read under predetermined reading conditions to generate image information, the image information is stored in an image memory, and an image is stored on an intermediate transfer member based on the image information stored in the image memory. In the image processing method for forming After the write start ready signal is output, Each time a mark provided on the intermediate transfer member is detected, an image forming operation is performed on the intermediate transfer member based on image information stored in the image memory, and the image memory is determined based on the reading condition. The image reading operation and the first color image forming operation are executed in parallel under the condition that the reading line from the image memory does not overtake the writing line to the image memory. The output timing of the writable signal When the reading area of the original by the reading means is within the maximum range Also Said The mark of the intermediate transfer member can be detected immediately after the output of the writable signal when the writable signal is output and the writable signal is output when the read line from the image memory does not pass the write line to the image memory. The stop position of the intermediate transfer member It is characterized by controlling.
According to a fourth aspect of the present invention, there is provided reading means for reading a document under predetermined reading conditions to generate image information, an image memory for storing the image information, and intermediate transfer based on the image information stored in the image memory. A storage medium storing a program for an image processing apparatus having image forming means for forming an image on a body, After the write start ready signal is output, Each time a mark provided on the intermediate transfer body is detected, control is performed to execute an image forming operation on the intermediate transfer body based on image information stored in the image memory, and based on the reading condition, The image reading operation by the reading unit and the image forming operation of the first color by the image forming unit are executed in parallel under the condition that the reading line from the image memory does not pass the writing line to the image memory. The output timing of the writable signal When controlled and the reading area of the original by the reading means is in the maximum range Also Said The mark of the intermediate transfer member can be detected immediately after the output of the writable signal when the writable signal is output and the writable signal is output when the read line from the image memory does not pass the write line to the image memory. The stop position of the intermediate transfer member A program to be controlled is stored.
[0063]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS.
[0064]
The color image forming apparatus according to the present embodiment is applied to a full-color digital copying machine 101 (see FIG. 2) as shown in FIG. The full-color digital copying machine 101 roughly includes a color scanner unit 1 as an image reading unit or an image reading device, a color printer unit 2 and an image processing unit 3 as main components. Among these, the color printer unit 2 and the image processing unit 3 constitute a color image forming apparatus.
[0065]
The color scanner unit 1 scans an original (not shown) placed on a contact glass 4 with an exposure scanning unit 5 using an exposure lamp, a mirror or the like, an imaging lens 6 and an exposure optical system 8 using an RGB-compatible CCD image sensor 7. Thus, the optical scanning is performed by exposure scanning. An electrical signal (analog signal) read by photoelectric conversion by the CCD image sensor 7 is converted into a digital signal and output to the image processing unit 3. The exposure scanning unit 5 is reciprocated in the sub-scanning direction by a scanner motor that is a stepping motor.
[0066]
The color printer unit 2 is configured as an image processing unit P that executes an electrophotographic process centered on a drum-shaped photoconductor 11. That is, a charging charger 12, an optical writing unit 13 using a semiconductor laser, a developing unit 14, a belt transfer charger 15 and the like are sequentially arranged around the photosensitive member 11 in accordance with an electrophotographic process. Here, the developing unit 14 has a revolver structure corresponding to each color toner of black BK, magenta M, cyan C, and yellow Y, and any one of the colors is selectively positioned at the developing position, so that the photoconductor. A toner image of each color is formed on 11. An intermediate transfer belt 16 as an intermediate transfer member is disposed at a transfer position by the belt transfer charger 15, and after the toner image on the photosensitive member 11 is once transferred onto the intermediate transfer belt 16, the intermediate transfer belt is then transferred. The toner image on 16 is finally transferred onto a transfer paper as a recording medium by a paper transfer charger 17. Therefore, a full color image can be obtained by sequentially forming toner images of the respective colors on the photoreceptor 11 and sequentially superimposing them on the intermediate transfer belt 16 and transferring the superimposed toner images onto the same transfer paper. Here, in the present embodiment, the intermediate transfer belt 16 has a toner image of a predetermined size, for example, a length of two letter horizontal sizes + an image forming margin. It is also possible to carry and transfer toner images of the same amount at the same time.
[0067]
Here, in the full-color digital copying machine 101 of the present embodiment, the color scanner unit 1, the color printer unit 2, and the image processing unit 3 are formed as separate bodies. Therefore, the color scanner unit 1 can be used as a scanner alone, and the color printer unit 2 can be used as a printer alone. Such a function is effectively utilized when the full-color digital copying machine of the present embodiment is used in a network environment.
[0068]
FIG. 2 is an example of system construction including the full-color digital copying machine 101 of the present embodiment. In this system, a full-color digital copying machine 101, a plurality of personal computers 102a to 102n, a printer 103, and a plurality of scanners 104a to 104n are connected via a network 105 such as a LAN. In such an environment, for example, image formation based on the image information of the original read by the scanners 104a to 104n can be executed by either the color printer unit 2 or the printer 103 of the full-color digital copying machine 101 of the present embodiment. So that the system is built.
[0069]
FIG. 3 is a functional block diagram of the control system. That is, the functional configuration for image forming sequence control including the hardware components as described above will be described with reference to the block diagram shown in FIG. First, there is provided an image reading means 21 for optically reading an original on the contact glass 4 by exposure scanning at a speed corresponding to the magnification and acquiring the image information as a digital signal. The image reading means 21 is mainly composed of the color scanner unit 1 in terms of hardware. The document image information read by the image reading unit 21 is written and stored in an image storage unit 22 as an image memory connected to the image reading unit 21 via a data bus (storage unit). An image processing means 23 is provided for converting and correcting a digital read image signal acquired by the image reading means 21 and stored in the image storage unit 22 into an image forming color image signal. The image processing means 23 is configured mainly by the image processing unit 3 in terms of hardware, and is connected to the image storage unit 22 via a data bus.
[0070]
Further, writing means 24 is provided for converting the image forming color image signal converted and corrected by the image processing means 23 into an optical signal and performing optical writing on the photosensitive member 11. This writing means 24 is constituted by an optical writing unit 13 connected to the image processing means 23 via a data bus in hardware. The photosensitive member 11, the charging charger 12, the optical writing unit 13 (writing means 24). ) And the developing unit 14 constitute an image forming means 25. That is, the image forming means 25 performs optical writing on the photoconductor 11 to form a latent image and visualize it as a toner image.
[0071]
The image reading unit 21, the image storage unit 22, the image processing unit 23, and the writing unit 24 described above are all bus-connected to the system control unit 26 stored in the image processing unit 3. Of these units, the writing means 24 is bus-connected to an I / O control unit 27 that is bus-connected to the system control unit 26.
[0072]
The I / O control unit 27 is also connected with an intermediate transfer body drive motor 28 that is a drive source of the intermediate transfer belt 16 and a mark sensor 29 that is provided on the intermediate transfer belt 16 and detects a belt mark (not shown). . These intermediate transfer body drive motor 28 and mark sensor 29 together with the belt transfer charger 15, the intermediate transfer belt 16, the paper transfer charger 17 and the like transfer a plurality of color toner images sequentially formed on the photoreceptor 11 onto the same transfer paper. It performs the function of superimposing and transferring. The I / O control unit 27 is also connected with a load 30 other than the intermediate transfer body drive motor 28 and a sensor 31 other than the mark sensor 29.
[0073]
Next, among the functions of the system control unit 26, functions of an image reading operation and an image forming operation will be described. The system control unit 26 is actually a microcomputer mainly composed of a CPU and a memory. The microcomputer executes various processes in accordance with programs stored in the memory, and this functions as an image reading operation and an image forming operation in the system control unit 26. Therefore, the memory of this microcomputer becomes a storage medium for storing the program. However, this storage medium may be configured as, for example, a portable floppy disk or an optical storage medium such as a CD-ROM, CD-R, DVD-ROM, DVD-RAM, or a hard disk, etc. It may be stored in a fixed storage medium. In other words, in this embodiment, the program to be installed in the memory (including the hard disk) of the microcomputer included in the full-color digital copying machine 101 of this embodiment is the program stored in the portable storage medium. It may be used, or may be downloaded from a server installed somewhere via a network.
[0074]
FIG. 4 is a timing chart regarding the image reading operation and the image forming operation. During the image reading operation, the system control unit 26 outputs an exposure lamp start pulse in the exposure scanning unit 5, and then waits for the exposure lamp rising stabilization time to output a scanner motor start pulse. At this time, a start pulse of the intermediate transfer member drive motor 28 is output, and the timing thereof will be described later. As a result, the color scanner unit 1 is activated in the image reading unit 21 and the reading operation of the document placed on the contact glass 4 is started. Then, the system control unit 26 negates the IPU-FGATE signal, and during that time, reading image information writing processing (Write) to the image storage unit 22 which is an image memory is executed. At this time, the writing of the read image information to the image storage unit 22 is executed for each line.
[0075]
Here, an example in which the image reading operation is executed using the color scanner unit 1 has been described. However, similar processing is performed using the scanners 104a to 104n shown in FIG.
[0076]
In the present embodiment, control is performed such that the image forming operation of the first color is executed in the image processing unit P while the writing processing of the read image information to the image storage unit 22 is performed. For this purpose, the system control unit 26 activates an activation pulse of the intermediate transfer member drive motor 28 at a predetermined timing to be described later, thereby starting the intermediate transfer member drive motor 28 to rotationally drive the intermediate transfer belt 16, and thereafter Is controlled to output a write start enable signal. This write start enable signal is a signal that allows the image processing section P to execute the image forming operation, and is output after the Tsa time has elapsed after the IPU-FGATE signal is negated. The Tsa time here is set to prevent the image forming line by the image processing unit P from overtaking the writing line of the read image information to the image storage unit 22. That is, in the present embodiment, the linear velocity in the exposure scanning unit 5 in the color scanner unit 1 is set slower than the image forming linear velocity in the image process unit P. This is for maintaining the reading quality. Therefore, if the writing process of the read image information to the image storage unit 22 and the image forming process by the image process unit P are started at the same time, the image forming process overtakes the reading process and the image forming operation is not performed correctly. Therefore, in the present embodiment, after the IPU-FGATE negation that allows the execution of the writing process (Write) of the read image information to the image storage unit 22 that is an image memory, the read image information write line to the image storage unit 22 is changed. The write start enable signal is output after being delayed by a time Tsa which is sufficient to prevent the image forming line from being overtaken by the image processing unit P (first timing control means, first timing). Control step, first timing control function).
[0077]
After outputting the write start enable signal, the system control unit 26 stands by until the mark sensor 29 receives the mark detection signal output by detecting the intermediate transfer belt 16. When the mark detection signal is received, the image storage unit 22 is received. An image read signal BFGATE for reading image information from the image signal and an image transfer signal WFGATE instructing to transfer the read image to the image processing means 23 are output. As a result, the output of the image read signal BFGATE is delayed by Twf, and the read image information (signal) by the color scanner unit 1 is read from the image storage unit 22 for each line (Read), and the read image information (signal). Are transferred to the image processing means 23 line by line. Then, the image processing means 23 first selects only the read image information (signal) of black, transfers it to the writing means 24, and causes the image processing section P to execute an image forming operation only for black. As a result, the black image forming operation in the image processing unit P and the document image reading operation in the color scanner unit 1 are performed in parallel.
[0078]
Thereafter, since the rotational speed of the intermediate transfer belt 16 is constant, the mark sensor 29 outputs a mark detection signal at a period of Tbelt. Therefore, every time this mark detection signal is output, an image forming operation by the image processing unit P is executed in the order of yellow, cyan, and magenta. As a result, a transferred full-color image by mixed colors of black, yellow, cyan, and magenta is formed on the intermediate transfer belt 16, so that the system control unit 26 drives and controls the image process unit P, and the transferred full-color image. Is transferred to transfer paper. In this way, a full color image is formed on the transfer paper (drive control means).
[0079]
Thereafter, the system control unit 26 outputs a Tstop signal to stop the intermediate transfer member drive motor 28. In response to the output of Tstop, the image processing unit P performs a stop process of the intermediate transfer member drive motor 28.
[0080]
Here, in the image forming process as outlined above, in order to improve the image forming efficiency and increase the productivity, the mark sensor 29 is attached to the intermediate transfer belt 16 immediately after outputting the writable signal. It is desirable to detect the belt mark. In the present embodiment, the system control unit 26 performs processing for that purpose (second timing control means, second timing control step, second timing control function). The first timing control means (first timing control step, first timing control function) and second timing control means (second timing control step, 2 timing control function) will be described.
[0081]
First, in the present embodiment, the second timing control means (second timing control step, second timing control function) is realized by setting the stop position of the intermediate transfer body drive motor 28. That is, the system control unit 26 defines the timing at which Tstop is output, thereby realizing the second timing control means (second timing control step, second timing control function). Specifically, the intermediate transfer body drive motor 28 is started at the same time as or immediately after the start of the scanner motor, and then the intermediate transfer body is set so that the first mark detection signal comes immediately after the output of the write start enable signal. The drive motor 28 is stopped. Thereby, at the time of the next image reading and image formation, the mark detection signal is output immediately after the output of the write start enable signal.
[0082]
Here, the Tsa time after the IPU-FGATE negation that triggers the output of the write start enable signal, that is, the time when the image information is read from the image storage unit 22 and the image forming operation is started is as follows: It differs depending on image reading conditions in the color scanner unit 1 such as size conditions, scaling conditions, trimming conditions, division conditions, scanner linear velocity and the like. In the present embodiment, the Tsa time after IPU-FGATE negation is changed in order to prevent the image forming line by the image processing unit P from overtaking the writing line of the read image information in the image storage unit 22 in this embodiment. Because. For this reason, the intermediate transfer body drive motor 28 is started at the same time as or immediately after the start of the scanner motor, and thereafter the intermediate transfer body drive motor is set so that the first mark detection signal comes immediately after the output of the write start enable signal. Strictly speaking, it is impossible to set the output of the first mark detection signal as the timing immediately after the output of the write start enable signal only by the process of stopping 28. Therefore, in the present embodiment, the motor stop time Tstop that is the timing for stopping the intermediate transfer belt 16 is set under the assumption that the document reading area is in the maximum range. That is, assuming the longest delay time Tsa when the document reading area is in the maximum range, the belt mark attached to the intermediate transfer belt 16 immediately after the delay time Tsa is detected by the mark sensor 29 and the mark detection signal. Therefore, the motor stop time Tstop is set so that is output.
[0083]
In such processing, the delay time Tsa is shortened due to the size of the original actually read by the color scanner unit 1 and various conditions, which may increase the time from the delay time Tsa to the output of the mark detection signal. In the present embodiment, such a time delay is interpreted as being included in the category that the mark detection signal is output immediately after the delay time Tsa. That is, in consideration of the conventional example in which the second timing control means (second timing control step, second timing control function) is not executed, a time close to the belt period Tbelt for one period after the output of the write start enable signal is performed. Although it is expected that the belt detection signal is not output, when compared with such a time delay, the similar time delay in the present embodiment is that the mark detection signal is output immediately after the delay time Tsa. Not enough to be interpreted as output.
[0084]
FIG. 5 is a flowchart showing the flow of the motor stop time calculation process. Here, the process for obtaining the motor stop time Tstop is executed under the assumption that the reading area of the document is in the maximum range. First, it waits for transmission of scanner linear velocity data from the color scanner unit 1 and the scanners 104a to 104n (step S101). In this processing, it is predicted that the scanner linear velocity will be known in advance when a scanner incorporated in the full-color digital copying machine 101 of the present embodiment such as the color scanner unit 1 is used. When the image forming operation based on the image information read by the other scanners 104a to 104n is executed, since the scanner linear velocity is not known, it is particularly important to obtain the scanner linear velocity data from the scanners 104a to 104n. It has been placed.
[0085]
When the scanner linear velocity data is transmitted (Y in step S101), a process for obtaining the motor stop time Tstop is executed (step S102). Here, the maximum motor stop signal Tstopmax is obtained because the document reading area is in the maximum range. That means
Tsamax: maximum delay time Tsa
ScanMax: Maximum reading range
Cwr: writing speed to the image storage unit 22
Crd: Reading speed from the image storage unit 22
Tbelt: Belt mark detection cycle
First of all,
Tsamax = (ScanMax / Cwr) − (ScanMax / Crd) is obtained. The scanner linear velocity data acquired in step S101 is referred to the writing speed Cwr to the image storage unit 22. Based on the Tsamax thus determined, the maximum motor stop signal Tstopmax is
Tstopmax = Tbelt−Tsamax
Asking.
[0086]
FIG. 6 is a flowchart showing the flow of the image reading process and the image forming process. First, the system control unit 26 refers to the image reading conditions in the color scanner unit 1 such as the document size condition, scaling condition, trimming condition, and division condition for the document to be copied, and obtains the delay time Tsa (step). S151). These reference values are transmitted from, for example, the color scanner unit 1 and the scanners 104a to 104n, or set by the image processing unit 3. The obtained delay time Tsa is set in the image storage unit 22 (step S152), and then the intermediate transfer member drive motor 28 is turned on (step S153). At this time, although not shown, as a parallel process, the scanner motor is also turned on at the same time as or before the intermediate transfer member drive motor 28 is turned on. As a result, the printing operation is executed (step S154), and if it is determined that the printing operation is completed (Y in step S155), it waits for detection of the belt mark (step S156). If a belt mark is detected (Y in step S156), the Tstopmax count process (decrement process) obtained by the process shown in the flowchart of FIG. 5 is started (step S157), and the count is continued until Tstopmax becomes zero. Decrement is executed (step S159). If the count is incremented (Y in step S158), the intermediate transfer member drive motor 28 is turned off (step S160). In this way, the intermediate transfer belt 16 is positioned at a position where the intermediate transfer belt 16 stops when the maximum stop time Tstopmax determined by the processing shown in the flowchart of FIG.
[0087]
In such an image reading process and image forming process, in the present embodiment, in the printing operation (step S154), the storage of the read image data in the image storage unit 22 is not performed for each color, but only once. In addition, the first color image forming operation is executed in parallel with the document image reading operation. In such parallel processing, the image storage unit 22 is used so that the image forming line by the image processing unit P does not pass the writing line to the image storage unit 22 by setting the delay time Tsa (first timing control). Step, first timing control function). Also, the belt mark attached to the intermediate transfer belt 16 immediately after the delay time Tsa is detected by the mark sensor 29 (second timing control means (second timing control step, second timing control function)). Thereby, the image forming efficiency is improved and the productivity is increased.
[0088]
A second embodiment of the present invention will be described with reference to FIGS. The same parts as those of the first embodiment are denoted by the same reference numerals, and description thereof is also omitted.
[0089]
In the present embodiment, the second timing control means (second timing control step, second timing control function) is different from that of the first embodiment. In other words, in the present embodiment, the start timing (Tstart in FIG. 3) of the intermediate transfer member drive motor 28 is controlled, so that the image forming operation can be performed immediately after the delay time Tsa, that is, in the image processing unit P. Immediately after that, control is performed such that the belt mark attached to the intermediate transfer belt 16 is detected by the mark sensor 29. Therefore, in the present embodiment, the motor stop time Tstop is set under the assumption that the document reading area is the minimum range. As a result, the start timing of the intermediate transfer body drive motor 28 is delayed in accordance with the size of the document to be actually read, so that the image processing section P is attached to the intermediate transfer belt 16 immediately after the image forming operation is enabled. The drive control of the intermediate transfer belt 16 is achieved so that the detected belt mark is detected by the mark sensor 29.
[0090]
The timing chart shown in FIG. 7 differs from the timing chart shown in FIG. 5 as the timing chart in the first embodiment only in that Tstart for determining the start timing of the intermediate transfer body drive motor 28 is indefinite.
[0091]
FIG. 8 is a flowchart showing the flow of the motor stop time calculation process. Here, the process for obtaining the motor stop time Tstop is executed under the assumption that the reading area of the document is in the minimum range. First, it waits for transmission of scanner linear velocity data from the color scanner unit 1 and the scanners 104a to 104n (step S201). In this processing, it is predicted that the scanner linear velocity will be known in advance when a scanner incorporated in the full-color digital copying machine 101 of the present embodiment such as the color scanner unit 1 is used. When the image forming operation based on the image information read by the other scanners 104a to 104n is executed, since the scanner linear velocity is not known, it is particularly important to obtain the scanner linear velocity data from the scanners 104a to 104n. It has been placed.
[0092]
When the scanner linear velocity data is transmitted (Y in step S201), a process for obtaining the motor stop time Tstop is executed (step S202). Here, since the document reading area is in the minimum range, the minimum motor stop signal Tstopmin is obtained. That means
Tsamin: minimum delay time Tsa
ScanMin: Minimum reading range
Cwr: writing speed to the image storage unit 22
Crd: Reading speed from the image storage unit 22
Tbelt: Belt mark detection cycle
First of all,
Tsamine = (ScanMax / Cwr) − (ScanMax / Crd) is obtained. The scanner linear velocity data acquired in step S101 is referred to the writing speed Cwr to the image storage unit 22. Based on the Tsamine thus obtained, the minimum motor stop signal Tstopmin is
Tstopmin = Tbelt-Tsamin
Asking.
[0093]
FIG. 9 is a flowchart showing the flow of the image reading process and the image forming process. First, the system control unit 26 refers to the image reading conditions in the color scanner unit 1 such as the document size condition, scaling condition, trimming condition, and division condition for the document to be copied, and obtains the delay time Tsa (step). S251). These reference values are transmitted from, for example, the color scanner unit 1 and the scanners 104a to 104n, or set by the image processing unit 3. The obtained delay time Tsa is set in the image storage unit 22 (step S252).
[0094]
Next, the system control unit 26 waits for reception of the image transfer start time Tle (step S253). The image transfer start time Tle is the time required for the exposure scanning unit 5 of the color scanner unit 1 and the exposure scanning unit (not shown) in the scanner 104a-n to move to the start position of the effective reading range after the scanner motor is driven. The information is transmitted and output from the color scanner unit 1 and the scanners 104a to 104n to the system control unit 26.
[0095]
When the system control unit 26 receives the image transfer start time Tle (Y in step S253), the system control unit 26 obtains a start time for determining the start timing of the intermediate transfer member drive motor 28 (step S254). This process
Tsa = (ScanMax / Cwr) − (ScanMax / Crd)
After obtaining the delay time Tsa, the start time Tstart for determining the start timing of the intermediate transfer body drive motor 28 is
Tstart = Tsa-Tsamin + Tle
Asking. As understood from this equation, the activation time Tstart becomes longer as the delay time Tsa becomes longer.
[0096]
After obtaining the activation time Tstart in this way, the system control unit 26 executes a process of activating the intermediate transfer body drive motor 28 after the elapse of the activation time Tstart (steps S255 to 257). That is, the system control unit 26 decrements the activation time Tstart until the activation time Tstart becomes 0 (step S255) (step S256), and if the activation time Tstart becomes 0 (Y in step S255), the intermediate transfer member is driven. The motor 28 is turned on (step S257). By such processing, a belt mark attached to the intermediate transfer belt 16 immediately after the delay time Tsa is detected by the mark sensor 29 (second timing control means (second timing control step, second timing control). function).
[0097]
Thereafter, a printing operation is executed (step S258), and if it is determined that the printing operation is finished (Y in step S259), the process waits for detection of a belt mark (step S260). If the belt mark is detected (Y in step S260), the Tstopmin counting process (decrement process) obtained by the process shown in the flowchart of FIG. 8 is started (step S261), and the count is continued until Tstopmin becomes zero. Decrement is executed (step S263). If the count is incremented (Y in step S262), the intermediate transfer body drive motor 28 is turned off (step S264). Thus, the intermediate transfer belt 16 is positioned at a position where the intermediate transfer belt 16 stops when the minimum stop time Tstopmin determined in the process shown in the flowchart of FIG.
[0098]
In such an image reading process and image forming process, in the present embodiment, in the printing operation (step S258), the storage of the read image data in the image storage unit 22 is not performed for each color, but only once. In addition, the first color image forming operation is executed in parallel with the document image reading operation. In such parallel processing, the image storage unit 22 is used so that the image forming line by the image processing unit P does not pass the writing line to the image storage unit 22 by setting the delay time Tsa (first timing control). Step, first timing control function). Further, the belt sensor attached to the intermediate transfer belt 16 immediately after the delay time Tsa is detected by the mark sensor 29 (second timing control means (second timing control step, second timing control function). As a result, the image forming efficiency is improved and the productivity is increased.
[0099]
A third embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment and the second embodiment are denoted by the same reference numerals, and description thereof is also omitted.
[0100]
In this embodiment, a color digital copying machine 201 in which a color scanner unit 1 as an image reading unit, a color printer unit 2 and an image processing unit 3 are integrally incorporated in the same housing and cannot be separated from each other. It is configured.
[0101]
【The invention's effect】
According to the first to fourth aspects of the present invention, the read image data is stored only once in the image memory, the first color image forming operation is executed in parallel with the original image reading operation, and the original is read by the reading unit. When the reading area is the maximum range Also Said The mark of the intermediate transfer member can be detected immediately after the output of the writable signal when the writable signal is output and the writable signal is output when the read line from the image memory does not pass the write line to the image memory. The stop position of the intermediate transfer member is Since it is controlled, the image forming efficiency can be improved and the productivity can be increased.
[Brief description of the drawings]
FIG. 1 is a longitudinal front view of a color image forming apparatus showing a first embodiment of the present invention.
FIG. 2 is a schematic diagram showing a system construction example including a color image forming apparatus of the present embodiment.
FIG. 3 is a functional block diagram of a control system.
FIG. 4 is a timing chart regarding an image reading operation and an image forming operation.
FIG. 5 is a flowchart showing a flow of a motor stop time calculation process.
FIG. 6 is a flowchart illustrating a flow of an image reading process and an image forming process.
FIG. 7 is a timing chart relating to an image reading operation and an image forming operation according to the second embodiment of the present invention.
FIG. 8 is a flowchart showing a flow of a motor stop time calculation process.
FIG. 9 is a flowchart illustrating a flow of an image reading process and an image forming process.
FIG. 10 is a longitudinal front view of a color image forming apparatus showing a third embodiment of the present invention.
[Explanation of symbols]
1 Image reading unit, image reading device (color scanner unit)
11 photoconductor
16 Intermediate transfer member (intermediate transfer belt)
22 Image memory (image storage unit)
P Image process part

Claims (4)

Reading means for reading a document under predetermined reading conditions to generate image information, an image memory for storing the image information, and an image forming means for forming an image on the intermediate transfer member based on the image information stored in the image memory In an image processing apparatus having
Control for executing an image forming operation on the intermediate transfer body based on the image information stored in the image memory every time a mark provided on the intermediate transfer body is detected after a write start enable signal is output Means,
Based on the reading condition, an image reading operation by the reading unit and an image forming operation of the first color by the image forming unit are performed under a condition in which a reading line from the image memory does not pass a writing line to the image memory. First timing control means for controlling the output timing of the writable signal to be executed in parallel;
Even if the reading area of the document by the reading means is the maximum range, the writing is possible when the writing line to the image memory satisfies the condition that the reading line from the image memory does not pass and the writable signal is output. An image processing apparatus comprising: a second timing control unit that controls a stop position of the intermediate transfer member so that the mark of the intermediate transfer member can be detected immediately after the signal is output .   The image processing apparatus according to claim 1, wherein the second timing control unit is independent of a reading condition referred to by the reading unit. In an image processing method of reading an original under predetermined reading conditions to generate image information, storing the image information in an image memory, and forming an image on an intermediate transfer member based on the image information stored in the image memory.
After the writing start enable signal is output , every time a mark provided on the intermediate transfer body is detected, an image forming operation is performed on the intermediate transfer body based on image information stored in the image memory,
Based on the reading condition, the image reading operation and the first color image forming operation are executed in parallel under the condition that the reading line from the image memory does not pass the writing line to the image memory. While controlling the output timing of the writable signal ,
Satisfies the read line is not overtaken condition of the reading region of the document is to write line to the image memory even when the maximum range by the reading means from the image memory, when outputting the write enable signal, the writable An image processing method , wherein the stop position of the intermediate transfer member is controlled so that the mark of the intermediate transfer member can be detected immediately after the signal is output . Reading means for reading a document under predetermined reading conditions to generate image information, an image memory for storing the image information, and an image forming means for forming an image on the intermediate transfer member based on the image information stored in the image memory A storage medium storing a program for an image processing apparatus having
Control for executing an image forming operation on the intermediate transfer body based on the image information stored in the image memory every time a mark provided on the intermediate transfer body is detected after a write start enable signal is output Let
Based on the reading condition, an image reading operation by the reading unit and an image forming operation of the first color by the image forming unit are performed under a condition in which a reading line from the image memory does not pass a writing line to the image memory. Controlling the output timing of the writable signal to be executed in parallel; and
When reading area of the document by the reading means in each case a maximum range satisfies the read line is not overtaken conditions the write line to the image memory from the image memory, and outputs the enable signal write the said write A storage medium storing a program for controlling a stop position of the intermediate transfer member so that the mark of the intermediate transfer member can be detected immediately after the enable signal is output .

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