JP5181820B2 - Image forming apparatus, image forming method, and image forming program - Google Patents

Description

The present invention relates to image formation, and more particularly to an image forming apparatus, an image forming method, and an image forming program that can efficiently cope with the size of an image that must be created.

In general, an image forming apparatus is desired to support not only regular-size image formation but also irregular-size image formation. The irregular size is fed from the manual feed tray instead of the paper feed stage unlike the normal paper feed conveyance. The upper limit of the size of the transfer paper from the manual feed tray is limited by the physical size of the manual feed tray in the main scanning direction, but the sub-scanning direction can be physically infinitely long. The upper limit of the length in the sub-scanning direction is determined from the specifications of the image forming apparatus.
For example, the maximum size for the A3 machine is 432 mm for the normal tray, but the maximum is 12 for the manual feed tray.
It is possible to print up to 60mm. In A0, the normal tray has a maximum of 1189 mm, but the manual feed tray can print up to a maximum of 15000 mm in consideration of roll paper feeding. Thus, the maximum print area in the sub-scanning direction corresponds to a long size including an irregular size.

  As a technique for forming an image on an image area using an image forming apparatus, for example, Patent Document 1 is known. Patent Document 1 discloses a video signal processing circuit for writing an image on an image carrier by main scanning / sub scanning based on image information. The disclosure is related to a method for generating a sub-scanning image effective area signal for controlling an image area in the sub-scanning direction by a video signal processing circuit. In generating a sub-scanning effective area signal, a state machine and a sub-scanning counter are provided. The sub-scanning effective area signal is generated based on the sub-scanning counter and the area threshold.

In Patent Document 1, a sub-scanning effective area signal is generated based on a sub-scanning counter and a threshold value of the area length by a video signal processing circuit which is the center of a writing control unit. Therefore, the sub-scanning counter needs a counter bit number that matches the maximum sub-scanning image length. When an image is formed with the above-described sub-scanning long size, it is necessary to correspond to the maximum size of the sub-scanning long size. Consider an image forming apparatus with a resolution of 1200 dpi in the sub-scanning direction as an example.
It is sufficient that 432 mm is a 20409 (0x4FB9) line and has a 15-bit width sub-scan counter. The maximum size of the sub-scanning length is 1260 mm, which is 59527 (0xE887) lines, and a 16-bit width sub-scanning counter is required. On the other hand, the normal size: 1189 mm is 56173 (0xDB6D) line and 16-bit width is sufficient for the A0 machine. is necessary. In addition, the value in parenthesis shows the value of hexadecimal notation.

As the transfer paper size becomes longer, the required bit width of the sub-scanning counter increases. When the bit width of the counter increases, it is also necessary to increase the bit width of the register that stores the threshold value of the area to be compared with the counter value. For example, the area registers necessary for controlling the sub-scanning image area include various registers such as the number of sub-scan writing lines, the number of sub-scanning image data transfer effective lines, the sub-scan trim front end position, and the sub-scan trim rear end position. Consists of including. Since these registers also support a long size like the sub-scanning counter, it is necessary to expand the bit width (
A3 machine: 15 bits → 16 bits, A0 machine: 16 bits → 20 bits).

In addition, only one sub-scan counter is not mounted on the image forming apparatus. For example, in the case of a tandem type color image forming apparatus having a plurality of photosensitive drums for outputting a plurality of colors, the image forming timing differs for each color, so it is necessary to adopt a circuit configuration that can be controlled exclusively. For this reason, it is necessary to mount the same number of sub-scan counters as the colors to be output.
In a full-color image forming apparatus using a laser diode as a light source, color image formation is performed using four colors of Bk (black), M (magenta), Y (yellow), and C (cyan). The circuit configuration has a total of four for each color.

In addition to the sub-scan counter, there may be a plurality of area registers. When using multiple types of transfer member sizes (A3, A4) and different resolutions and modes on the front and back of the transfer member using interleave processing, etc., a circuit that mounts multiple area registers and uses them appropriately for each mode In some cases, it may take a configuration.

JP 2005-138429 A

As described above, in the configuration in which the conventional image forming apparatus generates the sub-scanning effective area signal based on the sub-scanning counter and the threshold value of the area register, in order to correspond to the sub-scanning long size,
In accordance with the standard specifications of the image forming apparatus, the bit widths of the sub-scanning counter and the area register must be excessive, which causes a problem of enlarging the circuit configuration. For this reason, the circuit configuration and control software are complicated, and there is a problem in that a different memory configuration must be designed for each transfer member.

That is, according to the present invention, the standard size (A5, A4, A3, A0, B5, B4) can be obtained by changing only the software setting without greatly modifying the hardware configuration and the software configuration each time. , B3, etc.) to an indeterminate size (long size or long width size), and an object is to provide an image forming apparatus, an image forming method, and an image forming program.

In order to solve the above-described problems and achieve the object, an image forming apparatus according to the present invention corresponds to a forming unit that forms a latent image on input image data and the image data for one line. Counts the number of times the latent image is formed in the sub-scanning direction, and detects the sub-scan end position when the upper-limit value of the number of times is determined and the sub-scan size of the area where the image is formed is long. Control means for controlling the forming means using a flag that is set to be active until the control means is configured to control the forming means according to the upper limit value of the counter when the flag is inactive. When the latent image forming operation is executed and the flag is active, the latent image is formed in the sub-scanning direction by the forming unit exceeding the upper limit value of the counter. And wherein and Turkey to continue.

In the video signal processing circuit included in the write control unit, the present invention reduces the bit width of the sub-scanning counter and the area register used when generating the sub-scanning effective area signal, thereby preventing the circuit configuration from becoming enormous. In the present invention, the bit width of the sub-scanning counter or the area register is adjusted to the sub-scanning length of the standard size that is normally used, instead of generating the sub-scanning effective area signal having the bit width matching the maximum sub-scanning size. Give it.

The image forming apparatus switches the sub-scanning direction control using the value of the sub-scanning counter and the value of the area register and the sub-scanning direction control using the sub-scanning forced flag for continuing the scanning in the sub-scanning direction, Sub-scanning direction control is executed. In the case of the standard size, the image forming apparatus ends the control in the sub-scanning direction when the sub-scanning counter counts up to the value loaded in the area register. On the other hand, when a transfer member size that requires image formation exceeding the set sub-scan counter or area register value is set, the sub-scan forced flag is set to an appropriate timing during the count-up of the sub-scan counter. Set with.

When the sub-scan counter has expired, the image forming apparatus determines whether or not the sub-scan forced flag is set. When the sub-scan counter has expired and the sub-scan forced flag is not set, the sub-scan counter is set. End control. When the sub-scan counter expires and the sub-scan forced flag is asserted (activated), the sub-scan forced flag is negated (inactivated)
Until this is done, the sub-scanning direction control is continued. Note that the expiration of the sub-scanning counter means that the sub-scanning counter has reached the count value loaded in the area register and the sub-scanning counter has reached the full count.

In the present invention, by adopting the above-described processing, the bit width of the sub-scanning counter and the area register can be maximized while flexibly supporting not only a standard size but also an irregular size such as a sub-scan long size. Can be reduced. Furthermore, in order to be able to output an irregular size, it is not necessary to significantly change hardware settings and the like, and it is possible to easily cope with the irregular size.

In addition, in the internal circuit configuration of the write control unit, the function of controlling the sub-scanning effective area signal is used not only by the control system by the sub-scan counter but also by the control system by flag setting, so that the bit width of the sub-scan counter and the area register And the cost of the circuit can be reduced.

Furthermore, when the sub-scanning effective area signal is switched and controlled using two types of flag setting control method and sub-scanning counter control method, priority is assigned to both methods. That is, on the software, the image formation is started with the same control sequence as the normal standard size for the sub-scan long-size irregular-size image, and only the image formation end timing is switched to the control method dedicated to the sub-scan long size. It is possible to easily cope with the problem simply by correcting the processing.

(First embodiment)
Hereinafter, although this invention is demonstrated with embodiment, this invention is not limited to embodiment. FIG. 1 shows an embodiment of an image forming apparatus. The image forming apparatus 100 includes an optical device 102 including optical elements such as a semiconductor laser and a polygon mirror, an image forming unit 112 including a photosensitive drum, a charging device, and a developing device, and a transfer unit 122 including an intermediate transfer belt. Consists of including. The optical device 102 deflects a light beam emitted from a light source such as a semiconductor laser (not shown) by a polygon mirror 102c and makes it incident on an fθ lens 102b. In the illustrated embodiment, a number of light beams A corresponding to each color of cyan (C), magenta (M), yellow (Y), and black (K) are generated, and after passing through the fθ lens 102b, the reflection mirror 102a is reflected.

The WTL lens 102d, after shaping the light beam, deflects the light beam toward the reflection mirror 102e, and forms the photosensitive drums 104a, 106a, 106b as the light beam L used for exposure.
108a and 110a are irradiated with a light beam in an image form. Photoconductor drums 104a, 106a,
Since the irradiation of the light beam L to 108a and 110a is performed using a plurality of optical elements as described above, timing synchronization is performed in the main scanning direction and the sub-scanning direction.
Hereinafter, the main scanning direction is defined as the light beam scanning direction, and the sub-scanning direction is a direction orthogonal to the main scanning direction. In many image forming apparatuses 100, the photosensitive drums 104a and 10
It is defined as the direction of rotation of 6a, 108a, 110a.

  Each of the photosensitive drums 104a, 106a, 108a, and 110a includes a photoconductive layer including at least a charge generation layer and a charge transport layer on a conductive drum such as aluminum. The photoconductive layer is disposed corresponding to each of the photosensitive drums 104a, 106a, 108a, and 110a, and is charged with a surface charge by the chargers 104b, 106b, 108b, and 110b including a corotron, a scorotron, or a charging roller. Is granted.

Each of the chargers 104b, 106b, 108b, and 110b causes the photosensitive drums 104a and 10b.
The electrostatic charges applied on 6a, 108a, and 110a are imagewise exposed by the light beam L to form an electrostatic latent image. The electrostatic latent images formed on the photosensitive drums 104a, 106a, 108a, and 110a are developed by a developing device 10 including a developing sleeve, a developer supply roller, a regulating blade, and the like.
Development is performed by 4c, 106c, 108c, and 110c to form a developer image.

  The developer images carried on the photosensitive drums 104a, 106a, 108a, and 110a are transferred onto the intermediate transfer belt 114 that moves in the direction of arrow B by the conveyance rollers 114a, 114b, and 114c. The intermediate transfer belt 114 is conveyed to the secondary transfer unit while carrying C, M, Y, and K developers. The secondary transfer unit includes a secondary transfer belt 118 and conveying rollers 118a and 118b. The secondary transfer belt 118 is conveyed in the direction of arrow C by the conveyance rollers 118a and 118b. A transfer member 124 such as high-quality paper or a plastic sheet is supplied to the secondary transfer unit from an image receiving material storage unit 128 such as a paper feed cassette by a conveying roller 126.

The secondary transfer unit applies a secondary transfer bias to transfer the multicolor developer image carried on the intermediate transfer belt 114 to a transfer member 124 held by suction on the secondary transfer belt 118. The transfer member 124 is supplied to the fixing device 120 along with the conveyance of the secondary transfer belt 118. The fixing device 120 includes a fixing member 13 such as a fixing roller including silicone rubber or fluorine rubber.
0, the transfer member 124 and the multicolor developer image are pressurized and heated, and the printed material 13
2 is output to the outside of the image forming apparatus 100. The transfer belt 114 after transferring the multi-color developer image is supplied to the next image forming process after the transfer residual developer is removed by a cleaning unit 116 including a cleaning blade.

FIG. 2 is a control block 20 for explaining the data flow of image data of the image forming apparatus 100.
0 embodiment is shown. In the image forming apparatus 100, an engine control unit 210 including a central processing unit (CPU) sets control parameters of each control unit used by the image forming apparatus 100.
When the start switch of the image forming apparatus 100 is pressed or a print job start signal from the print host is validated, an image data signal is output from the scanner unit 202 or the printer driver 204 to the image processing unit 206. The image processing unit 206 performs various image processing such as image area separation, image rotation, and editing on the image data, and outputs the image data to the writing control unit 208.

The writing control unit 208 performs timing processing for developing the input image data into a two-dimensional image in order to form an image on the transfer member, and converts the image data developed into the two-dimensional image to L
The format is converted in accordance with the driver setting of the D drive unit 212 and output. The LD driving unit 212 includes a driver IC for driving a laser diode. The LD drive unit 212
Based on the input image data, the laser diode connected to the writing optical unit 214 is driven, and the photosensitive member is exposed to a laser beam to form an electrostatic latent image.

FIG. 3 shows a detailed configuration of peripheral blocks that control the writing control unit 208 of the image forming apparatus 100. The control of the image forming apparatus 100 is controlled by the engine control unit 210 so as to correspond to a predetermined operation. The engine control unit 210 notifies the image processing unit 206 and the writing control unit 208 of a command transmission / reception signal for performing image formation. Command communication is performed using serial transfer, and the control state is managed by confirming reception of the status of each control unit of the engine control unit 210. After the various control parameters are set, the writing control unit 208 outputs a lighting signal that causes the LD driving unit 212 to light the LD 214a at a predetermined timing and a rotation signal to the polygon motor 214b that is a deflector. The laser beam emitted from the LD 214a is deflected by the polygon motor 214b. At the start of scanning in the main scanning direction, the laser beam is incident on an optical sensor mounted on the synchronization detection plate 218. The synchronization detection plate 218 detects the laser beam and generates a synchronization detection signal. The synchronization detection signal generated by the synchronization detection plate 218 is output to the writing control unit 208 and used for control in the sub-scanning direction.

The writing control unit 208 performs timing control using the synchronization detection signal as a reference signal in the main scanning direction. In the image data transfer from the image processing unit 206 to the writing control unit 208, an image data signal is received from a scanner unit (not shown) or a printer driver (not shown).
6 is output. Therefore, it is necessary to transfer the data processed by the image processing unit 206 to the LD driving unit 212. Regarding the transfer timing, it is necessary to perform registration at the timing when the transfer member is finally output. A job start command is transmitted from the engine control unit 210 to the writing control unit 208 at a timing synchronized with the paper conveyance control.

Upon receiving the job start command, the writing control unit 208 outputs a sub-scanning image data transfer area signal for requesting the image processing unit 206 to transfer image data. The image processing unit 206 receives the transfer area signal and outputs an image data signal to the write control unit 208. At this time, it is necessary to synchronize the timings of the main and sub scanning in the writing control unit 208 and the image processing unit 206. In order to synchronize the timing in the main scanning direction, the main scanning synchronization timing signal and the main scanning image data transfer area signal are used. The main scanning synchronization timing signal is a signal generated using the synchronization detection signal from the synchronization detection plate 218 as a reference signal, and is transferred from the writing control unit 208 to the image processing unit 206.

The image processing unit 206 receives the main scanning synchronization timing signal, generates a main scanning image data transfer area signal indicating an effective area of the image data to be transferred, and outputs the main scanning image data transfer area signal to the writing control unit 208 together with the transfer image data. Timing synchronization between the writing control unit 208 and the image processing unit 206 transfers image data and control signals according to a rule for transferring image data to be written into the surface of the polygon motor 214b for one pulse of the main scanning synchronization timing signal. The engine control unit 210 needs to recognize when an image is formed after outputting a job start signal in order to determine when to set various control parameters for the next image formation. This recognition can be recognized by passing the sub-scan writing area signal from the writing control unit 208 to the engine control unit 210 at the timing when the laser diode is driven by the LD driving unit 212 which is the final control block. it can. Based on the sub-scanning writing area signal, the engine control unit 210 confirms the image formation timing in the writing control unit 208.

FIG. 4 shows a detailed internal configuration of the write control unit 208 shown in FIG. The write control unit 208 is configured as a microprocessor such as an ASIC (Application Specified Integrated Circuit). In the embodiment illustrated in FIG. 4, a detailed configuration for implementing a timing control function in the sub-scanning direction is illustrated. In the present embodiment, the timing in the sub-scanning direction is
Control is performed using a sub-scan counter, sub-scan area register, and sub-scan forced flag. The sub-scanning counter is a counter that manages the writing control timing in the sub-scanning direction. The sub-scanning counter starts counting up in synchronization with the assertion of the sub-scanning image data transfer area signal that requests image data transfer from the writing control unit 208 to the image processing unit 206 in response to a start signal in response to a job start command. Specifically, the sub-scanning counter loads an initial value from a ROM, EEPROM, or EPROM (not shown) used by the writing control unit 208, and counts up each time a synchronization detection signal is detected.

The writing control unit 208 compares the sub-scanning area register value 208b in which the sub-scanning image length, the sub-scanning trim leading edge, and the rear-end position for controlling the sub-scanning area are set with the sub-scanning counter value 208a. In response, sub-scan image data transfer area signal, sub-scan write area signal, and sub-scan trim area signal are generated. The sub-scan trim area signal is a signal used inside the writing control unit 208, and is used to validate the image data inside the trim area and mask the image data to the LD driving unit 212. The final writing area of the image data is set by the sub-scanning trim area signal.

Further, the sub-scan forced flag 208c is asserted / negated, and when asserted, image formation in the sub-scan direction is activated for each area signal in the sub-scan direction regardless of the sub-scan counter value and the register value. Let the state continue. On the other hand, the sub-scanning forced flag 208
If c is negated, the sub-scanning area register value 208b and the sub-scanning counter 208a are used to control each area signal in the sub-scanning direction.

In this embodiment, the sub-scanning forced flag 208c is mounted as a switching module of the engine control unit 210 when the following conditions are satisfied, and the mounted sub-scanning forced flag 208c is asserted, and the image in the sub-scanning direction is asserted. By forcibly continuing the formation, it is possible to execute image formation on the transfer member having an irregular size without a large setting change to the writing control unit 208. The switching module can switch counter control, counter / flag control, or flag control by executing the following determination processing, for example.
(A) A case where data that explicitly notifies the setting of the sub-scanning forced flag is included in a predetermined area of the data bits of the main-scanning image data transfer area signal sent by the image processing unit 206.
(B) When the writing control unit 208 determines that a value larger than the set value registered in the ROM or the like is designated corresponding to the effective area of the image designated by the main scanning image data transfer area signal.
(C) A register value that designates a sub-scanning forced flag setting registered in advance in a ROM or the like is designated.

When any one of the above conditions (a) to (c) is satisfied, the image forming apparatus 100 sets the sub-scanning forced flag 208c, executes image formation on the transfer member having an irregular size, and (a) When any one of the conditions (c) to (c) is not satisfied, the sub-scanning direction control using the sub-scan counter value and the register set value is executed.

  FIG. 5 is a timing chart of image area control executed by the writing control unit 208. The sub-scan forced flag is not set, and sub-scan direction control using the sub-scan counter value and the register set value is executed. As shown in FIG. 5, in the image forming apparatus 100, when a start signal according to a job start command is input to the writing control unit 208, the writing control unit 208 loads a delay counter initial load value: A to the sub-scanning delay counter. Then, -1 is decremented according to the synchronization detection signal. The sub-scanning delay counter is a counter that adjusts the registration amount in the sub-scanning direction, and changes the initial load value: A according to the sub-scanning registration adjustment value. When the sub-scanning delay counter becomes 0 by the decrement operation, the writing control unit 208 asserts the sub-scanning image data transfer area signal and loads the counter initial load value: D to the sub-scanning counter.

The sub-scanning counter is incremented by +1 in accordance with the synchronization detection signal. When the sub-scanning image length register value: E is reached, the count operation is stopped and the reset initial value: 0x
It is a counter that stops resetting at 7F00. The sub-scan writing area signal is asserted when the sub-scan counter reaches 0, and negated when the sub-scan image length register value: E is reached. The sub-scan trim area signal is asserted when the sub-scan counter reaches the sub-scan trim leading edge position register value (assumed to be set to 2 in FIG. 5), and the sub-scan trim trailing edge position register value ( In the figure, the signal is negated when E-3) is reached. The sub-scan writing area signal and the sub-scan trim area signal can be set for each sub-scanning line in accordance with the set value of the register. In the following description, as described above, the sub-scan writing area signal and the sub-scan trim area signal are described on the premise that they are set in units of sub-scanning lines according to the set value of the register. It is also possible to set in units of two lines or more.

  In FIG. 5, the sub-scan trim area signal is negated in synchronization with the timing when the sub-scan counter becomes the value (E-3), and the sub-scan write area signal is synchronized with the timing when the sub-scan counter becomes the value E. Is negated, the sub-scanning counter value is reset to the reset initial value 0x7F00, and the sub-scanning direction control ends. In the example shown in FIG. 5, since the above-described sub-scanning forced flag setting condition is not satisfied, control using the sub-scanning counter and the register value is executed, and image formation is performed on a standard size transfer member.

  FIG. 6 shows another example of a timing chart regarding image area control of the writing control unit 208. In the timing chart shown in FIG. 6, the sub-scanning image data transfer area signal is asserted in synchronization with the sub-scanning counter having loaded the initial value: D, and in synchronization with reaching the sub-scanning image length register value: E. Negated. Since the image data transferred from the image processing unit 206 has the same number of lines as the number of sub-scan writing lines, the image data needs to be negated in advance. However, as shown in FIG. 7 which will be described later, the processing for adding white line data to the rear end portion of the sub-scan in the image processing unit 206 and the output for the extra white area by the sub-scan rear end trim function in the writing control unit 208 In an example using mask processing, the negation timing of the sub-scanning image data transfer area signal and the sub-scanning writing area signal can be controlled to the same timing. Note that the assert timing may differ depending on the mode of the image processing unit 206.

  For example, the case where the assertion intervals of the sub-scanning image data transfer area signal and the sub-scanning writing area signal are different can be the case where the number of processing delay lines in the image processing unit 206 is different. In response to the assertion of the sub-scanning image data transfer area signal, the image processing unit 206 outputs the image data signal to the writing control unit 208. The number of processing delay lines Td until the start line data is output: Td is not determined in general because it varies depending on the image processing mode executed by the image processing unit 206. Therefore, the change in the number of processing delay lines: Td is associated with the processing mode by absorbing the change by changing the initial load value of the sub-scanning counter. Corresponding to this, in the timing chart of the example shown in FIG. 6 in the example shown in FIG. 5, Td = 2 line delay in the timing chart shown in FIG. 5 is shown in FIG. In the timing chart, Td = 3 line delay is set. In response to this, the writing control unit 208 sets a sub-scanning counter initial load value different from 0x7FFD in FIG. 5 and 0x7FFC in FIG. 6, and responds to the difference in the number of processing delay lines in the image processing unit 208. Yes.

FIG. 7 shows still another example of a timing chart of image area control of the writing control unit 208. In the example shown in FIG. 7, the above-described commands or conditions (a) to (c) are satisfied, and the sub-scan forced flag 208c is asserted (activated) at an appropriate timing before the sub-scan counter reaches the full count. ) Appropriate timing is clearly distinguished from other control timings such as sub-scan counter count-up, sub-scan write area signal assert / negate, or sub-scan trim area signal assert / negate. It means a timing that does not affect other control timing even if it is used. Specifically, the appropriate timing includes various sub-scan image data transfer area signal, image data signal transfer start, sub-scan counter count start, sub-scan write area signal assert, or sub-scan trim area signal assert. From this timing, it can be assumed that the set delay time has elapsed.

  In the example shown in FIG. 7, the sub-scanning delay counter is activated from the start signal, and the sub-scanning image data transfer area signal is asserted. Then, the writing control unit 208 activates the sub-scanning counter, receives an image data signal input from the image processing unit, asserts the sub-scanning writing area signal and the sub-scanning trim area signal, and starts an image forming operation. The timing chart shown in FIG. 7 is a timing chart when long-size image formation is performed, and controls image formation in the sub-scanning direction when the sub-scanning image length exceeds the full count value of the sub-scanning counter. It is.

In the conventional sub-scanning direction control, even when the sub-scanning image length register is set to 0x7F00 which is the same value as the full-counting value of the sub-scanning counter, if the sub-scanning counter reaches the full count during image formation, the counter is set to 0x7F00. It stops, and control in the sub-scanning direction over the full count becomes impossible. Therefore, the maximum value (0x7F00) is stored in the 15-bit width sub-scanning image length register.
Is set to the same value as the sub-scanning counter value, so the sub-scanning image data transfer area signal,
The sub-scan writing area signal and the trim area signal are negated and the image formation is terminated. This requires a bit size of the sub-scanning counter and register memory corresponding to the long size in order to correspond to the long size, and requires a design burden for both hardware design and software design, and the device cost. Will also increase.

  On the other hand, in the example shown in FIG. 7, it is determined whether or not the sub-scanning forced flag 208c is set by a program described in an assembler language or C language. This determination is made before the timing for comparing the count value of the sub-scanning counter with the initial load value D. The engine control unit 210 transmits a job start command to the write control unit 208, and after a predetermined time has elapsed, the engine control unit 210 monitors the sub-scanning image data transfer region signal from the write control unit 208. It is confirmed that the image forming operation is started by detecting the activation.

  FIG. 8 is a processing flow relating to the sub-scanning control of the timing chart of the image area control performed by the write control unit 208 shown in FIG. As shown in FIG. 8, when the engine control unit 210 issues a job start command to the write control unit 208 (step S801), the write control unit 208 performs the sub-scanning area control process (step S802) shown in FIG. Do.

  In the sub-scanning area control process shown in FIG. 9, first, the writing control unit 208 determines whether or not the sub-scanning writing area signal is asserted (step S901), and when it is not determined that it is asserted (step S901; No), Wait until asserted. On the other hand, when it is determined that the sub-scanning writing area signal is asserted (step S901; Yes), the writing control unit 208 further determines whether or not the sub-scanning size of the area where the image is formed is a long size (step S902). ).

  If it is determined that the sub-scan size of the area where the image is to be formed is not a long size (step S902; No), it is further determined whether or not the sub-scan write signal has been negated (step S906). Is determined not to be negated (step S906; No), it waits until the sub-scan writing signal is negated. On the other hand, if it is determined that the sub-scan writing signal is negated (step S906; Yes), the sub-scanning area control process shown in FIG. 9 is terminated.

  On the other hand, when it is determined that the sub-scanning size of the area where the image is to be formed is a long size (step S902; Yes), the writing control unit 208 sets the sub-scanning forced flag 208c to active (step S903), and further It is determined whether or not the sub-scan end position is detected with the sub-scan forced flag active (step S904). If it is determined that the sub-scan end position is not detected (step S904; No), the sub-scan end is completed. When the sub-scanning end position is detected (step S904; Yes), the sub-scanning forced flag 208c activated in step S903 is made inactive (step S905), and the sub-scanning area control process is performed. finish.

  Returning to FIG. 8, when the sub-scanning control process ends in step S802, the writing control unit 208 determines whether there is a print request for the next page, that is, an image data transfer request (step S803). If it is determined that there is any (step S803; Yes), the process returns to step S801, and the processes after step S802 are repeated. On the other hand, if it is determined that there is no print request (step S803; No), the process related to the sub-scanning control is terminated.

  In the example shown in FIG. 7, the setting of the sub-scanning forced flag 208c is based on the delay time until the sub-scanning trim area becomes active after the sub-scanning image data transfer area signal is asserted. Asserted later. When the sub-scanning region forced flag 208c is asserted, processing steps for determining the magnitude relationship between the sub-scanning counter value 208a and the sub-scanning region register value 208, and processing for negating the sub-scanning writing region signal and the sub-scanning trim region signal The step is skipped and the sub-scan writing area signal and sub-scan trim area signal negation are controlled in synchronization with the negation (inactivation) of the sub-scanning forced flag 208c. By executing this processing, the sub-scanning image data transfer area signal is controlled in response to assertion / negation of the sub-scanning forced flag 208c, so that image formation is performed even after the sub-scanning counter value 208a reaches the full count. Can continue.

The image formation end timing is designated by the negation of the sub-scanning forced flag 208c. Various modifications can be used for negating the sub-scanning forced flag 208c. For example, in the example shown in FIG. 5, the end position of the long size can be detected by means that can be detected by the engine control unit 210. After a sufficient time for image formation has elapsed up to the end of the transfer paper at the detected timing, the sub-scanning region forced flag is set to invalid in the writing control unit 208. Thereafter, the area signal is negated at the timing of the next synchronization detection signal cycle after the sub-scanning area forced flag 208c is negated, and the sub-scanning image formation is completed.

An abnormality caused by switching the sub-scanning direction control during scanning in the main scanning direction by negating each region signal at the next synchronization detection signal cycle without negating each region signal simultaneously with the timing when the sub-scanning region forcing flag 208c is negated. Generation of an image can be prevented. Note that when the sub-scanning end position of the long size in the engine control unit 210 can be detected with line-by-line resolution, detection in line units is used to control the sub-scan forced flag 208c. Can be reflected. If it is difficult to detect line by line, when the image data is viewed on the image after the effective image data in the sub-scanning direction of the image data transferred from the image processing unit 206 to the writing control unit 208, a white line is displayed. For example, a process of transferring dummy data that does not appear on the image can be added. The dummy data may be data that gives a white image, or a character that gives a white image may be given as a delimiter, and the character may be created by the image processing unit 206 and sent as image data.

The image forming apparatus 100 negates the sub-scanning forced flag 208c at an appropriate timing while the image of the added dummy data is being formed or during the period when the delimiter is detected, so that the sub-scanning end of the output image The image formation of the long size is finished without outputting the abnormal image to the part. By using the above-described processing, it is possible to form a sub-scan long size image without changing the hardware resources so as to secure the bit width of the sub-scan counter and area register corresponding to the sub-scan long size. Can be realized. Further, the sub-scanning region forced flag 208c
By subtracting the timing of sub-scanning image data transfer area signal assertion / negation by the minimum synchronization detection signal cycle by asserting / negating, an abnormal image from the head position in the main scanning direction can be prevented with a minimum delay time. Is possible.

  Furthermore, as shown in the examples of FIGS. 5 to 7, in this embodiment, in the image formation of a standard size, the sub-scan counter is 0 or more and the sub-scan is based on the magnitude relationship between the sub-scan counter and the sub-scan area register value. A range equal to or less than the image length setting register value is treated as the sub-scanning image effective area, and the counter value: 0 is controlled as the sub-scanning leading edge, and the counter value: sub-scanning image length setting register value is controlled as the sub-scanning trailing edge. On the other hand, in long-size image formation, the sub-scanning counter value: 0 is detected as the sub-scanning front end position based on the magnitude relationship between the sub-scanning counter and the sub-scanning area register value, as in the standard size. Further, by setting the sub-scanning forced flag 208c from the negated state to the asserted state after detecting the sub-scanning front end position, the sub-scanning area signal is held in the active state even after the sub-scanning counter value has stopped full counting. Note that the count process of the sub-scanning counter may be stopped simultaneously with the assertion of the sub-scanning forced flag 208c.

During the assertion period of the sub-scanning forced flag 208c, the active / inactive control of the sub-scanning area signal is executed without using the sub-scanning counter and the sub-scanning area register value,
During the period when the sub-scanning forced flag 208c is set, the active state is continued to enable image formation. The rear end of the sub-scan shifts the sub-scan forced flag 208c from the asserted state to the negated state, and shifts the sub-scanned image data area signal to the inactive state. Note that until the sub-scanning forced flag 208c is asserted, the writing control unit 208 controls the sub-scanning area signal according to the magnitude relationship between the sub-scanning counter and the sub-scanning area register value.

For this reason, when a fixed-size image is formed, the sub-scan forced flag is always used with the invalid setting, so that writing with the same control block configuration can be performed by using the conventional image forming method and correcting the minimum software configuration. The control unit 208 can realize standard-size and long-size image formation, and can expand the correspondence of the image forming apparatus 100 to the image formation size.

(Second Embodiment)
FIG. 10 shows a control block 800 corresponding to the data flow of image data when the image forming method of this embodiment is applied to a color image forming apparatus. Compared with the first embodiment shown in FIG. 2, the control block 800 of the color image forming apparatus receives RGB image data from the scanner unit 802 and the printer driver 804 in order to support color images. The image processing unit 806 executes RGB-KMYC color gamut conversion, color conversion, and the like. The color-converted image data is sent to the writing control unit 808 and output as four color data of KMYC corresponding to the toner color. The four-color data is sent to an LD driving unit 812 corresponding to each image forming color, and a laser diode responsible for the image forming color is driven to form an electrostatic latent image on the photosensitive drum.

(Third embodiment)
FIG. 11 shows a more detailed control block 900 of the control block 800 of the color image forming apparatus shown in FIG. FIG. 11 shows in detail the configuration with peripheral blocks that control the writing control unit 908 of the color image forming apparatus. The basic functional configuration includes functional blocks similar to those described in detail with reference to FIG. However, in order to function as a color image forming apparatus, data for four colors of KMYC is transferred as control signals for the engine control unit 910, the write control unit 908, the image processing unit 906, and the write control unit 908. In the writing control unit 908, sub-writing control units 908a to 908d corresponding to the respective colors of KMYC are mounted, and the image data of each color is developed independently to execute main / sub scanning timing control.

  In FIG. 11, the writing optical units 914a to 914e are described as having a layout that scans in both directions around a single polygon motor 914e. The present embodiment is not limited to the embodiment shown in FIG. 11, and may be configured to include an optical unit in which a polygon motor is arranged for each color. Since the synchronization detection plates 918a and 918b in FIG. 11 are described as a layout in which the polygon motor 914e is arranged at the center, the common detection plates 918a and 918b are used for two colors on one side of the scanning position, and the opposite sides are used. Therefore, another common synchronization detection plate 916c, 916d is used. That is, in the embodiment shown in FIG. 11, K and M colors and Y and C colors are subjected to synchronization control using the same synchronization detection board. Note that writing control for each color is performed in the same manner as described with reference to FIGS.

  FIG. 12 shows an internal data configuration of the writing control unit 1008 and timing control processing in the sub-scanning direction, which is executed by the control block 1000 of the color image forming apparatus shown in FIG. The image forming timing in a color tandem machine including a plurality of photosensitive drums needs to be formed at a timing corresponding to the position of the photosensitive drum for each color. That is, even in the image forming operation of the same page, the image forming timing in the sub-scanning direction differs for each image forming color. For this reason, the writing control unit 1008 responsible for writing control of a plurality of colors executes timing control in the sub-scanning direction for each color. For this reason, for each KMYC color, an independent sub-scanning counter and a sub-scanning area register for setting an area are associated with each other.

Even when the long size is supported, since the image forming timing is independent for each color in the sub-scanning direction, the sub-scanning forced flag independent for each color can be set for each of the sub-write control units 1008a to 1008d. In the embodiment shown in FIG. 12, the sub-scanning timing control using the sub-scanning forced flag is executed independently for each color, so that it is possible to easily realize the long size correspondence with the color tandem machine. The correspondence to the size can be performed with a minimum software correction while using the write control unit 1008 including the same hardware configuration.

(Fourth embodiment)
FIG. 13 shows a control block 1100 in yet another embodiment of the write control unit.
Indicates. Compared with the first embodiment shown in FIG. 4, the functional configuration for sub-scanning direction timing control in the writing control unit 1108 is different. That is, in the embodiment shown in FIG. 13, the writing control unit 1108 has one sub-scanning counter, and sets the sub-scanning image length and the sub-scanning trim leading and trailing end positions, and the sub-scanning forced register. The flag is controlled by being classified into A group 1108a and B group 1108b.

As shown in FIG. 13, the reason why the A group and the B group are configured is preferably applied to an image forming apparatus that forms an image when different sizes are mixed due to an interleave operation or the like in the embodiment of FIG. Can do. For example, when forming an image of a document in which A3 and A4 size transfer members are mixed, it is necessary to switch the image area instantaneously. At this time, when the image area register is shared by each size, the image area register value must be changed by serial command communication from the engine control unit 1110 when the size is changed. When the performance of the engine control unit 1110 is high, it is not necessary to delay the image formation timing at the time of the size change. However, in an image forming apparatus with insufficient performance, the image formation register between the pages is delayed at the time of the size change. After changing the setting, it is necessary to start image formation after the size change. As a result, the image forming performance such as PPM value (Print Per Minute) of the entire image forming apparatus is lowered.

In the embodiment shown in FIG. 13, two types of sub-scanning area registers, A group 1108a and B group 1108b, are mounted, and the A group register and the B group register are selected and selected in accordance with the size change of the transfer member. A pseudo thread process is executed in which the set value of the register group that has not been changed is changed when the other is selected. In the pseudo thread processing, for example, the A4 size setting is set in the A group,
At the time of A4 size image forming operation, the A group register is selected to form an image. On the other hand, if size change information for A3 is detected while the A4 size is being imaged, the microprocessor is caused to acquire a register value corresponding to the A3 size in the B group register, and the image formation target is A4. To A3
At the timing of changing to the size, the address setting of the data reading register is changed from group A to B.
Change to a group.

Therefore, it is possible to provide an image forming apparatus capable of forming an image without deteriorating the image forming performance depending on the performance of the engine control unit 1110 in particular. The same applies to the processing of a transfer member having an irregular size such as a long size. By configuring the sub-scanning forced flag for each of the A group and the B group, the image forming performance is also reduced in correspondence with the long size. First, by being able to execute image formation, the user can be notified of the situation via the client.

  FIG. 14 is a processing flow related to sub-scanning control in the timing chart of image area control performed by the writing control unit 1108 shown in FIG. The processing flow shown in FIG. 14 shows a case where an image is formed by setting a plurality of sheets of different sizes in the image forming apparatus. In the following description, the same processing as the processing shown in FIG. 8 may be performed. Omitted and only different processing is described.

  First, the writing control unit 1108 detects the size of the set paper or the like, and selects an area control register (group A) (step S1401). Thereafter, each process of steps S1402 to 1404 is performed, and it is determined whether or not the area in which the sub-scanning write signal is written is different from the area of the previous page (step S1405). If it is determined that the area in which the sub-scanning write signal is written is not different from the area of the previous page (step S1405; No), the process returns to step S1402, and the subsequent processes are performed.

  On the other hand, if it is determined that the area in which the sub-scan write signal is written is different from the area of the previous page (step S1405; Yes), the area control register (group A) selected in step S1401 is changed to the area control register (group B). (Step S1406). Thereafter, each process of steps S1407 to 1409 is performed, and similarly to step S1405, it is determined whether or not the area in which the sub-scan writing signal is written is different from the area of the previous page (step S1410). If it is determined that the area in which the sub-scanning write signal is written is not different from the area of the previous page (step S1410; No), the process returns to step S1407, and the subsequent processes are performed. On the other hand, if it is determined that the area in which the sub-scan write signal is written is different from the area of the previous page (step S1410; Yes), the area control register (group B) selected in step S1406 is changed to the area control register (group A). (Step S1411), the process returns to Step S1401 and the subsequent processes are repeated.

The above functions of the present invention can be realized by a program converted into a machine language by assembling programming written in an assembler language or C language executed by a microprocessor into a machine language, and devices such as ROM, EEPROM, EPROM, etc. It can be stored in a readable recording medium and distributed.

Although the present invention has been described above with embodiments, the present invention is not limited to the embodiments, and other embodiments, additions, changes, deletions, and the like are within the scope that can be conceived by those skilled in the art. It can be changed, and any aspect is within the scope of the present invention as long as the effects and effects of the present invention are exhibited.

1 is a schematic diagram of an image forming apparatus according to an exemplary embodiment. FIG. 3 is a diagram illustrating an embodiment of a control block for explaining a data flow of image data of the image forming apparatus. FIG. 3 is a diagram illustrating an embodiment of a detailed configuration of peripheral blocks that control a writing control unit of the image forming apparatus. It is the figure which showed the detailed internal structure of embodiment of the write-control part shown in FIG. It is the figure which showed 1st Embodiment of the timing chart of the image area control of a writing control part. It is the figure which showed 2nd Embodiment of the timing chart about the image area control of a writing control part. It is the figure which showed 3rd Embodiment of the timing chart of image area control of a writing control part. It is a process flowchart regarding the subscanning control of a writing control part. 10 is a process flowchart relating to the sub-scanning area control process shown in FIG. 9 shown in FIG. 8. FIG. 5 is a diagram illustrating a control block corresponding to a data flow of image data when the present embodiment is applied to a color image forming apparatus. It is the figure which showed the further detailed control block of the control block of the color image forming apparatus shown in FIG. FIG. 12 is a diagram illustrating an internal data configuration of a writing control unit and sub-scanning direction timing control processing executed by a control block of the color image forming apparatus illustrated in FIG. 11. It is the figure which showed the control block in another embodiment about a write control part. 14 is a process flowchart relating to sub-scanning control of the writing control unit illustrated in FIG. 13.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Image forming apparatus, 102 ... Optical apparatus, 102a, 102e ... Reflecting mirror, 102b
... fθ lens, 102c ... polygon mirror, 104a, 106a, 108a, 110a ...
Photoreceptor drum, 104b, 106b, 108b, 110b ... Charger, 104c, 106c
108c, 110c ... developer, 112 ... image forming unit, 114 ... intermediate transfer belt, 114a
, 114b, 114c... Transport roller, 118... Secondary transfer belt, 120.
DESCRIPTION OF SYMBOLS 2 ... Transfer part, 124 ... Transfer member, 130 ... Fixing member, 132 ... Printed matter, 200 ... Control block, 202 ... Scanner part, 204 ... Printer driver, 206 ... Image processing part, 208 ...
Write control unit 210 ... Engine control unit 212 ... LD drive unit 214 ... Write optical unit 216 ... Photosensitive drum 218 ... Synchronization detection plate 500, 600, 700 ... Timing chart

Claims (15)

Forming means for forming a latent image on the input image data;
A counter that counts the number of times the latent image corresponding to the image data for one line is formed in the sub-scanning direction, and that defines an upper limit value of the number of times;
Control means for controlling the forming means using a flag that is set to active until the sub-scanning end position is detected when the sub-scanning size of the image forming region is a long size,
Wherein if the flag is inactive, the counter to execute the forming operations of the latent image by the forming means in accordance with the upper limit value of, when the flag is active, exceeds the upper limit value of said counter an image forming apparatus comprising a Turkey to continue the formation of the latent image in the sub scanning direction by said forming means. The control means has a register in which a sub-scanning image length and a sub-scanning trim area are set, and when the flag is inactive, the sub-scan is based on the value of the counter and the set value of the register An image data transfer area, a sub-scan writing area, and a sub-scan trim area are controlled. When the flag is active, the sub-scan image data transfer area is independent of the counter value and the register setting value. The image forming apparatus according to claim 1 , wherein the sub-scan writing area and the sub-scan trim area are controlled . Before SL control means, if the size of a plurality of transfer members forming an image mixedly, the to independently control each flag corresponding to the size of the transfer member, assigned to each size of the different transfer members and a control unit write attempts multiple of book,
The image forming apparatus according to claim 1. The counter is a counter that counts a synchronization detection signal for detecting a writing start position in the main scanning direction.
The image forming apparatus according to claim 2 . The sub-scan image data transfer Okuryo area, the sub-scanning write Write-area, and the sub run 査To rim region, in the next cycle of the synchronization detection signal before SL flag is set from active to inactive Negated,
The image forming apparatus according to claim 4 . An image processing unit for transferring the image data to the control unit ;
The counter loads an initial value into a register in synchronization with issuance of a transfer request for the image data from the control unit to the image processing unit, and starts a count operation.
The image forming apparatus according to claim 1 . The counter can change the initial value;
The image forming apparatus according to claim 6 . Value before Symbol counter comprises a stop means for stopping said counter counting operation when a match with the sub-scanning image length set in the register,
The image forming apparatus according to claim 2 . Comprising stop means for stopping the count operation when the value of the counter reaches the upper limit value,
The image forming apparatus according to claim 1. Wherein said control means includes a control unit write attempts plurality of write for imaging color images, the flag is set independently in accordance with the number corresponding to the image forming color,
The image forming apparatus according to claim 1 . Forming means for forming a latent image on the input image data;
A counter that counts the number of times the latent image corresponding to the image data for one line is formed in the sub-scanning direction, and that defines an upper limit value of the number of times;
An image forming apparatus comprising: a control unit that controls the forming unit using a flag that is set to active until a sub-scanning end position is detected when the sub-scanning size of an image forming region is a long size ; An image forming method executed in
Wherein forming the control means, when the flag is inactive, the counter to execute the forming operations of the latent image by the forming means in accordance with the upper limit value of, when the flag is active, beyond the upper limit the sub-scanning the latent image sustained allowed Ru control steps in the formation of the direction by means,
An image forming method comprising: The control means has a register in which a sub-scanning image length and a sub-scanning trim area are set, and when the flag is inactive, the sub-scan is based on the value of the counter and the set value of the register An image data transfer area, a sub-scan writing area, and a sub-scan trim area are controlled. When the flag is active, the sub-scan image data transfer area is independent of the counter value and the register setting value. 12. The image forming method according to claim 11 , wherein the sub-scan writing area and the sub-scan trim area are controlled . The counter, it counts the synchronization detection signal for detecting the writing start position in the main scanning direction,
The image forming method according to claim 11 . The image forming apparatus further includes an image processing unit that transfers the image data to the control unit ,
The counter you start the image data transfer request issued in synchronization with the initial value loaded count operation register to the image processing unit from said control means,
The image forming method according to claim 11 . The image forming program characterized by executing the image forming method according to claim 11 to 14 in a computer.

Images