JP2004363852A - Image printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize density correction when a plurality of image processes are available. <P>SOLUTION: An image printer equipped with an image read means and a density detecting means of detecting the density of a formed image has a 1st image correcting means using the image read means and a 2nd image correcting means using the density detecting means, and has a plurality of kinds of image processing means of performing image formation; and a 1st correcting means among the plurality of kinds of image processing means carrys out all image processes and a 2nd correcting means performs representative processes. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printing device having an image reading device, and more particularly to a color printing device having a color image reading device.
[0002]
[Prior art]
Conventionally, in a copying machine, a specific pattern is printed by a printer unit as an image density correction, read using a reading unit, and an actual read value is compared with a known predetermined density read value to perform a density correction. Has been performed (for example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-60-054567
[0004]
[Problems to be solved by the invention]
When a plurality of image processing units are provided, it takes a lot of time to perform density correction on all the image processing units.
[0005]
[Means for Solving the Problems]
Therefore, in an image printing apparatus having an image reading unit and a density detecting unit for detecting an image density to be formed, a first image correcting unit using the image reading unit and a second image using the density detecting unit A plurality of types of image processing means for performing image formation, wherein the first correction means performs all of the image processing, thereby increasing the time. The density correction can be performed without inviting.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
[Overall configuration]
FIG. 1 is a schematic view of a printing apparatus embodying the present invention, and is a drawing that best illustrates the features of the present invention.
[0007]
In FIG. 1, reference numeral 101 denotes a reader frame, 102 denotes a document table, 103 denotes a light source, 104 denotes a photoelectric conversion unit, and 105 denotes an analog / digital conversion unit. 106 is a reader controller. Reference numeral 2001 denotes a printer main body; 2002, a DC controller that controls paper conveyance and image formation of the printer; and 2003, an image forming unit. A printer controller 2103 in FIG. 16 is built in the printer main body 2001 as shown in FIG. Reference numeral 2104 denotes the host computer of FIG. 16 connected to the printer controller 2103 one-to-one or via the network 2105. Reference numeral 2004 denotes a paper cassette deck that can be added as an option, 2005 denotes a sorter that can be added as an option, and 2006 denotes an option controller that controls the optional cassette deck and the optional sorter.
[0008]
The reader controller 106 controls digital image processing means output from the analog-to-digital conversion means, a motor control means (not shown) for reading a document, and communication control with the DC controller 2002 and the printer controller 2103. Has functions. In the present invention, the reader controller is arranged in the printer main body 2001 and does not have an external cable for controlling communication with the DC controller 2002 and the printer controller 2103.
[0009]
[Configuration of Printer Controller and Printer]
In this patent, a reader controller is connected between a printer controller and a printer, and processing is performed between the printer controller and the printer. Here, the configuration of the printer controller and the printer as the premise will be described first.
[0010]
First, an overall outline will be described with reference to FIG. Reference numeral 2101 denotes a video I / F which performs communication between a printer 2102 and a printer controller 2103, which will be described later. Details of each I / F signal will be described later. Reference numeral 2102 denotes a printer, which forms an electric image signal received via the I / F 2101 in a visible form, transfers it to recording paper, fixes it, and outputs it. In order to realize these image forming sequences, various loads are controlled. In addition, the function of detecting the status of the printer and notifying the printer controller is also performed. Reference numeral 2103 denotes a printer controller which receives data transmitted via a host computer indicated by 2104 or a network indicated by 2105. This is sent in various formats such as bitmap data and data described in PDL (Page Description Language). The data is developed in a memory and transferred to a printer 2102 as raster data. In this way, the data created by the host computer can be output to a printer.
[0011]
Next, the video I / F 2101 connecting the printer controller and the printer will be described in detail. Reference numeral 2103 in FIG. 2 denotes a printer controller. Reference numeral 2002 denotes an engine control unit (DC controller) that controls the engine inside the printer shown by reference numeral 2102 in FIG. Signals as shown in the figure are exchanged between the printer controller and the engine control unit.
[0012]
FIG. 3 shows a list of video I / F signals. Here, only the representative signals shown in FIG. 2 will be described.
[0013]
First, / PPRDY in 203 is a signal indicating that communication with the printer controller is enabled after processing such as initial setting is completed after power is supplied to the printer.
[0014]
A / CPRDY signal 204 indicates that power has been supplied to the printer controller and communication with the engine control unit has been enabled after processing such as initialization has been completed.
[0015]
The / RDY signal 205 is a signal indicating that the engine control unit has been enabled to perform a print operation in response to a print start instruction (/ PRNT signal described later) from the printer controller. The conditions under which this signal becomes true include various conditions of the printer, such as whether the temperature in the fixing unit has reached a predetermined temperature, whether recording paper remains in the printer, and whether the polygon mirror is rotating at a predetermined speed. Only if the part is working properly.
[0016]
The / PRNT signal 206 is a signal that the printer controller instructs the engine control unit to start or continue the printing operation.
[0017]
The / TOP signal 207 is a synchronization signal which is passed from the engine control unit to the printer controller and serves as a reference for vertical scanning of an image. This signal is output a predetermined time after the signal 206 is output from the printer controller.
[0018]
The / LSYNC signal 208 is a synchronization signal that is used as a reference for horizontal scanning by the printer controller. Like the / TOP signal, the / LSYNC signal is output to the printer controller a fixed time after the signal 206 is output from the printer controller. .
[0019]
The / VCLK signal 209 is a synchronous clock for the / VDOEN and / VDO signals, which will be described later, and generates a clock having a frequency corresponding to the image signal from the printer controller.
[0020]
The / VDOEN signal 210 is a signal for controlling the capture of the image signal output by the printer controller into the engine control unit. The engine control unit detects whether this signal is TRUE / FALSE in synchronization with the / VCLK signal, captures an image signal in the case of TRUE, and does not capture in the case of FALSE.
[0021]
The / VDO signal 211 is image data. The printer controller outputs the signal in synchronization with the / VCLK signal based on the / TOP signal in the vertical direction and the / LSYNC signal in the horizontal direction.
[0022]
The / CCLK signal 212 is a synchronous clock when the printer controller transmits a serial command to the engine controller and when the engine controller returns a serial status to the printer controller, and is output from the printer controller.
[0023]
A / CBSY signal 213 is a signal indicating to the engine control unit that the printer controller is transmitting a serial command using a / CMD signal described later.
[0024]
The / CMD signal 214 is a signal used when the printer controller transmits serial information to the engine control unit, and the serial information is referred to as a command.
[0025]
The / SBSY signal 215 is a signal indicating to the printer controller that the engine control unit is returning a serial status using the / STS signal.
[0026]
The / STS signal 216 is a signal used when the engine control unit returns serial information to the printer controller, and the serial information is called a status.
[0027]
The / CCRT signal 217 is a signal for reporting to the printer controller when the status inside the printer changes. When the printer controller receives this report signal, it issues a command inquiring about what has changed in the state of the engine using the / CMD signal, and the engine control unit notifies the state with the / STS signal.
[0028]
Next, a printer controlled by the engine control unit will be described with reference to FIG. FIG. 4 is a front view of the printer.
[0029]
Reference numeral 401 denotes a scanner which receives an image signal / VDO sent from a printer controller, converts it into a laser beam, and irradiates the photoconductor with a laser beam 402 to form an image on the photoconductor. The photoreceptor reaches the color developing device 403 and the black developing device 404 while rotating counterclockwise. The developing devices 403 and 404 function to apply (develop) the toner on the photoconductor in accordance with the charge charged on the photoconductor. When the image is black and white, only the developer unit 404 operates, and when the image is color, both the developer units 403 and 404 are used. Next, the image generated on the photoconductor is transferred to an intermediate transfer body 405 that rotates clockwise. This intermediate transfer member completes image formation on the intermediate transfer member by making one rotation for black and white and four rotations for color.
[0030]
On the other hand, the recording paper fed from the upper cassette 408 or the lower cassette 409 by the pickup roller 411 or 412 is conveyed by the feed roller 413 or 414, and further conveyed by the conveyance roller 415 to the position before the registration. Will be done.
[0031]
The timing is controlled so as to be between the intermediate transfer member 405 and the transfer belt 406 at the timing when the image formation is completed on the intermediate transfer member. When the recording paper arrives here, the transfer belt contacts the intermediate transfer member, and the toner is transferred to the recording paper. The image transferred to the recording paper is fixed on the recording paper by heat and pressure by a fixing roller 407.
[0032]
The recording paper on which the image has been fixed is conveyed to one of a face-up discharge port 417 or a face-down discharge port 418 designated in advance by the printer controller and discharged. As described above, the image information sent from the printer controller can be output.
[0033]
Next, the timing of signals exchanged between the video I / Fs is shown in FIG. This shows the signal description of the video I / F described above as time elapses.
First, when the preparation of the image information of the printer controller is completed, the / PRNT signal is set to Low (true) and transmitted to the engine control unit. At the same time, an image synchronizing signal / VCLK signal used for transferring the image signal is also generated.
[0034]
In response to this, the engine control unit performs various settings inside the printer and outputs an / TOP signal and a / LSYNC signal to the printer controller when an image can be received. The printer controller transfers the image signal / VDO and the image valid signal / VDOEN to the engine control unit in accordance with the vertical synchronization signal / TOP and the horizontal synchronization signal / LSYNC.
[0035]
Next, what commands and status are exchanged by serial communication during these printing operations will be described. FIG. 6 shows the timing of communication between the printer controller and the engine control unit.
[0036]
First, the case where the lowermost / CCRT signal is not used will be described. When the printer controller wants to issue a command to the engine control unit, it sets the / CBSY signal to Low (true) and sends command data to the / CMD signal in synchronization with the clock signal / CCLK. After confirming that the / CBSY signal is High (false), the engine control unit that has received it sets / SBSY to Low (true) and generates engine-side status data corresponding to the command from the printer controller. Sent to / STS in synchronization with the / CCLK signal. The printer controller receives the status data, and continues or interrupts the print control depending on the status.
[0037]
Next, the / CCRT signal will be described. This signal is a signal that becomes Low (true) when there is a change in the state of the engine specified in advance by the printer controller. For example, it is assumed that the printer controller has set / CMD in advance so that the / CCRT signal is made effective when the paper runs out. Therefore, it is assumed that there is only one remaining recording sheet, and the printer controller issues a printout request for two sheets. For the first sheet, the print sequence operation is normally processed without any problem. However, since the second recording sheet does not exist, the printer engine detects the change in the state at the stage when the second image formation is started, and changes the / CCRT signal from High to Low. This signal is transmitted to the printer controller. As soon as the printer controller detects this, the printer controller issues a command to the engine control unit requesting the paper feed unit paper presence status in order to know which paper feed cassette is out of paper. Accordingly, the engine control unit returns the status of the paperless cassette to the controller. The / CCRT signal is cleared to High at the timing when the status is returned and the / SBSY signal becomes Low.
[0038]
Next, the exchange of commands / status between the printer controller and the engine control unit will be described more specifically with reference to FIG. This assumes color output.
[0039]
When a print start request is generated, the printer controller checks the ready state of the printer with respect to the engine control unit while performing conversion processing of image data and the like. Next, a command for designating the paper feed stage of the recording paper is issued. Further, a command for requesting the recording paper size in the designated cassette is issued. In response to these series of commands, the engine control unit returns a corresponding status.
[0040]
Next, the discharge port is determined by a command for specifying the discharge port, and a page mode designation command for designating how many page images are formed is issued. Finally, by issuing a command for specifying monochrome / color, all settings on the printer side are completed.
[0041]
Thereafter, the printer controller generates a print request / PRNT signal to the engine control unit. In response to this, a / TOP signal is returned from the engine control unit for a predetermined time. The image is transferred to the engine control unit in synchronization with the / TOP signal in the vertical scanning direction, and further in synchronization with the / LSYNC signal in the horizontal direction, so that the / VDO signal is synchronized with / VCLK. In this case, since the color mode is set, the / TOP signal is generated four times, and an image for four colors of CMYK is formed.
[0042]
After the last / TOP signal is generated, the / PRNT signal is returned to High (false). As a result, the engine control unit detects that the print request has been completed, and shifts to post-processing such as an intermediate transfer body cleaning operation. Further, the transferred recording paper is discharged to a designated paper discharge port after passing through the fixing roller. Finally, the printer controller confirms to the engine control unit that the recording sheet is not in the transporting state (end of paper discharge), and then ends the printing, and waits in a ready state until the next print request is issued.
[0043]
If an illegal state occurs during the above operation, such as a jam of the recording paper, the absence of the recording paper, or the opening of the door by the user, the engine control unit immediately uses the above-described / CCRT signal to detect a printer abnormality. Notify the printer controller. The printer controller performs a corresponding process accordingly.
[0044]
The above is the processing performed between the printer controller and the printer (engine control unit).
[0045]
FIG. 15 is a schematic view of a printing apparatus having the electrical configuration described above. In FIG. 1, reference numeral 2001 denotes a printer main body; 2002, a DC controller for controlling paper transport and image formation of the printer; and 2003, an image forming unit. A printer controller 2103 in FIG. 16 is built in the printer main body 2001 as shown in FIG. Reference numeral 2104 denotes the host computer of FIG. 16 connected to the printer controller 2103 one-to-one or via the network 2105. Reference numeral 2004 denotes a paper cassette deck that can be added as an option, 2005 denotes a sorter that can be added as an option, and 2006 denotes an option controller that controls the optional cassette deck and the optional sorter.
[0046]
[Configuration with reader controller attached]
FIG. 8 shows the printing apparatus described above that optically reads not only image data output from a printer controller based on data transferred from a computer but also an original image on paper and converts it into a digital signal. FIG. 2 is an external view of a case where a reader controller that outputs data is attached.
[0047]
Reference numeral 801 denotes a document feeder for conveying a document to a portion where the document is optically read, and reference numeral 802 denotes an optical reader. Reference numeral 805 denotes a platen glass. The document feeding device is driven in synchronization with the optical reading device, and when a document image is transferred onto the document glass by the feeding device 801, the optical reading device moves in the left and right direction in the drawing. The image is scanned, and reflected light subjected to appropriate optical processing is sent to the photoelectric conversion unit 804. Reference numeral 803 denotes a printer main body.
[0048]
FIG. 9 is a block diagram showing the electrical connection when a reader controller for reading a document image is attached to the configuration diagram showing the connection between the printer controller and the engine control unit shown in FIG. FIG. That is, reference numeral 901 denotes a reader controller, which is disposed at an electrical intermediate point between the printer controller 2103 and the engine controller 2002 in FIG. The types of signal lines between the printer controller 2103 and the reader controller 901 and between the engine control unit 2002 and the reader controller 901 have the same functions as the types of signal lines shown in FIG. However, since signals between the printer controller 2103 and the signal between the engine control units 2002 are physically different, C is prefixed as a signal name and P is assigned to the latter to distinguish them. Reference numeral 902 denotes an image signal processing unit. Reference numeral 903 denotes a document scanning optical system control unit that controls the optical reading device 802, and reference numeral 904 denotes a document feeding control unit that controls the document feeding device 801. Reference numeral 905 denotes an operation unit. Reference numeral 906 denotes an image input unit. The image signal converted by the photoelectric conversion unit 804 is input from the image input unit and transferred to an image signal processing unit 902 inside the reader controller 901.
[0049]
Next, FIG. 17 shows a block diagram of the reader controller.
[0050]
9, reference numeral 901 denotes the reader controller shown in FIG. 9, 902 denotes the image processing unit shown in FIG. 9, and 906 denotes the image input unit shown in FIG. A selector 2201 selects either the output of the image processing unit or the signal sent from the printer controller and outputs the selected signal to the engine control unit. There are three signal systems switched by the selector: image clock / VCLK, image enable / VDOEN, and image data / VDO. Reference numeral 2202 denotes a serial communication controller that performs communication with the engine control unit. Reference numeral 2203 denotes an input / output port for exchanging signals for supplementing communication in the communication controller. Reference numeral 2204 denotes an interrupt controller. An image leading end request signal / PTOP and a printer state change signal / PCCRT are input to the interrupt controller. Reference numeral 2205 denotes a serial communication controller that communicates with the printer controller. Reference numeral 2206 denotes an input / output port for exchanging signals for supplementing communication in the communication controller. A gate 2207 controls whether a signal sent from the printer is sent to the printer controller. The gate control is performed on the image leading end request signal / TOP and the line synchronization signal / LSYNC. A control circuit 2208 having a gate function and a flag setting function controls the printer status change signal / CCRT. When the gate is opened or closed, it controls whether or not the printer status change signal / PCCRT issued by the engine control unit is transmitted to the printer controller. By setting a flag, the printer status change signal / CCRT is transmitted from the reader controller to the printer controller. Can be issued for Reference numeral 2209 denotes a CPU which controls the whole.
[0051]
[Operation when copying]
A method for reading a full-color original image using these and outputting the image from the image forming apparatus will be described. When a copy start key (not shown) on the operation unit 905 is input, the reader controller closes the gate unit 2207 and the signal control 2208 for the copy mode, and switches the selector 2201 to the image processing unit 902. Set so that the output of is selected. Then, the ready state signal / PRDY of the printer is checked with the engine control unit using the input / output port 2203. Next, various settings are performed using the serial communication controller 2202. First, a command for designating a paper feed stage for recording paper is issued. Further, a command for requesting the recording paper size in the designated cassette is issued. In response to these commands, the engine control unit returns a corresponding status.
[0052]
Next, the discharge port is determined by a command for specifying the discharge port, and a page mode designation command for designating how many page images are formed is issued. Finally, by issuing a command for specifying monochrome / color, all settings on the printer side are completed.
[0053]
After the document is fed onto the document table by the document feeder 801, the reader controller generates a print request / PPRNT signal to the engine control unit. In response to this, a / PTOP signal is returned from the engine control unit after a predetermined time. This is processed by the interrupt controller 2204, and the optical reading device 802 is operated so as to be synchronized with the / PTOP signal. The vertical scanning direction is synchronized with the / PTOP signal, the horizontal direction is further synchronized with the / PLSYNC signal, the / PVDO signal is synchronized with / PVCLK, and the signal input from the photoelectric conversion device 804 to the image processing unit 902 is synchronized. Transfer to engine control unit. Here, since the color mode is set, the optical reading device 2002 is operated four times, and an image for four colors of CMYK is formed in response to the / PTOP signal generated four times.
[0054]
Then, after the last / PTOP signal is generated, the / PPRNT signal is returned to High (false). As a result, the engine control unit detects that the print request has been completed, and shifts to post-processing such as an intermediate transfer body cleaning operation. Further, the transferred recording paper is discharged to a designated paper discharge port after passing through the fixing roller. Finally, the reader controller confirms to the engine control unit that the recording paper is not being conveyed (paper ejection is completed), and then the printing is completed, and waits in a ready state until the next print request is issued.
[0055]
[Operation during printing]
A method for outputting an image from the printer controller from the image forming apparatus will be described with reference to FIGS. At the stage where the copy operation has been completed, the reader controller becomes ready. At this time, the reader controller opens the gate unit 2207 and the signal control 2208 for the operation at the time of printing. The reader controller checks the printer ready status signal / PRDY with respect to the engine control unit using the input / output port 2203, and if OK, uses the input / output port 2206 to check the printer ready status with the printer controller. Set the signal / CRDY.
[0056]
Next, the printer controller performs communication for performing various settings, and the reader controller receives the data using the serial communication controller 2205, and the CPU 2209 interprets the data. According to the contents, the reader controller makes various settings using the serial communication controller 2202. In response to the series of commands, the engine control unit returns a corresponding status to the reader controller, and the reader controller receives the status using the serial communication controller 2202. The received content is interpreted by the CPU 2209, and this time, the serial communication controller 2205 is used to communicate with the printer controller.
[0057]
Next, the printer controller generates a print request / CPRNT signal to the reader controller, and the reader controller receives the signal to generate a print request / PPRNT signal to the engine controller. In response to this, a / PTOP signal is returned from the engine control unit after a predetermined time. This is passed through the gate control unit 2208 and returned to the reader controller as a / CTOP signal. The reader controller synchronizes the vertical scanning direction with the / CTOP signal, further synchronizes the / PLSYNC signal in the horizontal direction with the / CLSYNC signal that has passed through the gate control unit 2207, and synchronizes the / CVDO signal with / CVCLK. , Transfer to reader controller. In the reader controller, the selector 2201 is set to select a signal sent from the controller, and the signal sent from the controller is sent to the engine control unit as / PVCLK, / PVDOEN, / PVDO. Sent out.
[0058]
[Differences between print and copy operations]
Here, the difference between the operation at the time of printing and the operation at the time of copying will be described with respect to image transmission timing.
[0059]
Although a detailed description of the configuration of the printer controller 2103 is omitted, an image memory is provided therein, and image data for printing is prepared in advance there. Therefore, the time required for outputting the print data / VDO with respect to the image leading end request signal / TOP signal sent from the engine control unit is only the electrical delay time.
[0060]
On the other hand, in the copy mode, a document is read while the optical reading device 802 is moved, and image data is output. As shown in FIG. 19, from the state where the reading device is stopped to the state where the reading device is moving at a high speed for reading a document, it takes time to accelerate, for example, about several hundred mS. It takes time. Therefore, if the engine control unit sends the image leading end request signal / TOP signal in the copy mode at the same timing as the signal in the print mode, the print image data / VDO reaches the engine only in the copy mode. Will be delayed by several hundred milliseconds. There are the following two plans to address this.
[0061]
1. / TOP is transmitted earlier during copying than during printing.
[0062]
2. Another signal (RSTART) is provided for the copy mode.
[0063]
In order to perform the above-mentioned one plan, the configuration in the reader controller may be the same as that shown in FIG. 17, and in the copy mode, the reader controller starts the movement of the document reading device by the / TOP signal. In order to perform the above two alternatives, the configuration shown in FIG. That is, the image leading end request signal / PTOP sent from the engine control unit is a signal required only when the printer controller performs printing, and need not be input to the interrupt controller of the reader controller. The reading device movement start request signal / RSTART sent from the engine control unit is a signal required only in the copy mode, and need not be sent to the printer controller.
[0064]
[Control for setting commands]
Next, the characteristic control of the present invention will be described.
Since the reader controller is connected between the printer controller and the engine control unit, communication between the printer controller and the engine control unit is as follows.
[0065]
A description will be given of the case where the reader controller reads and outputs a document image using the engine control unit (copier mode), and the printer controller issues a setting command, for example, a paper cassette change command, to the printer. .
[0066]
On the other hand, FIG. 10 shows a control flow in the reader controller when the reader controller enters in between.
[0067]
In FIG. 10, the right diagram shows a flow of control for receiving a command from the printer controller and returning status to the printer controller. The reader controller receives a command at the serial communication controller 2205 from the printer controller via the / CCMD signal line shown in FIG. 9, and determines whether or not the command can be immediately issued to the engine control unit as it is. . For example, if there is no command currently being executed for the engine control unit in order for the reader controller to perform the copy mode operation, the command sent from the printer controller earlier to the engine control unit The same command is issued to the engine control unit through the signal line / PCMD using the serial communication controller 2202. On the other hand, if the paper feed cassette change command sent from the printer controller is issued to the engine control unit as it is, for example, when the reader controller specifies the paper feed cassette and performs a copy operation, the copy is performed. If the operation cannot be executed normally, the command is issued to the engine control unit from the printer controller without issuing the command to the engine control unit. Since a response to the command must be returned to the printer controller, the serial communication controller 2205 uses the serial communication controller 2205 to return a response to the printer controller via the / CSTS signal line, assuming that the command has been successfully executed from the reader controller.
[0068]
Next, a case will be described with reference to the left diagram of FIG. 10 in which the reader controller is ready to issue a command received from the printer controller to the engine control unit without affecting its own state. When such a state occurs, the reader controller issues a command stored in the engine command queue to the engine control unit using the serial communication controller 2202 through the signal line / PCMD and waits for a response. The command issued by the reader controller itself is also transmitted to the engine control unit through the / PCMD signal line. When the command execution is completed from the engine control unit, a response is returned to the reader controller via the / PSTS signal line. If the command execution is successful, delete this command from the engine command queue.
[0069]
If it is found at this point that the engine has failed in executing the command, it is processed as an error occurrence state.
[0070]
As described above, even in the configuration in which the reader controller is inserted between the printer controller and the printer controller, when issuing a normal command from the printer controller to the engine control unit, the command processing sequence can be operated without causing inconsistency in the operation.
[0071]
[Control for state change signal]
Next, in a configuration in which the reader controller is interposed, a process in the case where a state change on the engine side, for example, an error occurrence state is transmitted from the engine control unit side to the reader controller using the PCCRT using the PCCRT explain.
[0072]
In the case of a configuration in which the reader is interposed, there is a possibility that a change in the state that the reader controller and the printer controller want to know is different. For example, this is the case where a state change occurs such that the paper being transported jams.
[0073]
If a jam occurs while the engine is performing a copying operation under the control of the reader controller, this state is a state that only the reader controller wants to know. Since the printer controller is not in the process of outputting a jam while itself, the printer controller cannot perform appropriate post-processing even if notified of this state.
[0074]
In addition, if a control system equivalent to the leader controller is to be mounted, both controllers will also have software for jam processing control that the other should have, so they will be redundantly mounted, resulting in design man-hours, quality evaluation, software A lot of waste will occur on the capacity of the device.
[0075]
Therefore, basically, it is sufficient to notify the printer controller in the print mode and notify the reader controller in the copy mode. However, even in the copy mode, the printer controller sometimes wants an engine state change signal. For example, it is necessary to notify the printer controller of information such as a change in cassette size and the absence of paper. These do not strictly question the time from when the state change signal is issued by the engine control unit to when the processing is performed by each controller.
[0076]
Therefore, processing as described below is performed. That is, in the copy mode in which the reader controller controls the engine control unit, the state change signal / PCCRT notified from the engine control unit using the gate function of the control circuit 2208 is masked to the printer controller. However, only the leader controller receives through the interrupt controller 2204. The reader controller performs processing according to the control flow of FIG. That is, when the / PCCRT signal becomes true, the reader controller issues a command for acquiring a state change to the engine control unit. Then, look at the status returned and understand the details of the engine status change. Then, it is determined whether or not the content is a content to be notified also to the printer controller. For example, a state change such as a change in the size of the sheet cassette is notified. If it is determined that the notification is to be made, a flag is set using the control circuit 2208, a state change signal / CCCRT is generated, and this is notified to the printer controller.
[0077]
In a print mode in which the printer controller controls the engine control unit, the gate function of the control circuit 2208 is opened, and the state change signal / PCCRT notified from the engine control unit is set as the state change signal / CCCRT. Notify to
[0078]
[Control for execution command]
Next, control of an execution command will be described. For example, how the reader controller controls when the printer controller and the reader controller simultaneously issue a use request to the engine control unit will be described.
[0079]
FIG. 12 is a diagram showing the location of data and the exchange of data when a print request is issued during a copy operation. At this time, the engine control unit receives the image signal / PVDO sent from the reader controller and forms an image. In the operation, as described with reference to FIG. 7, the settings such as the specification of the paper feed cassette, the specification of the paper discharge port, and the image forming mode have already been set by serial communication between the reader controller and the engine control unit. Reference numeral 1301 denotes a buffer for various setting values, in which values set by the reader controller in the engine control unit and values set by the printer controller in the engine control unit are stored. Among the various setting values shown in the buffer 1301, the above-mentioned designated value is stored in the setting value for the reader. Here, when a print request is issued from the printer controller during the copy operation, it is difficult to think from the viewpoint of usability that the printout is performed by interrupting the copy operation. Therefore, the print request in this situation is postponed until the copying operation is completed. However, / CSTS must be returned for / CCMD from the printer controller. Therefore, of the setting values of 1301, only the setting value for the PDL from the printer is set in accordance with the request. When the set value for the reader is different from the set value for the PDL, the setting may be performed from the reader controller to the engine control unit before the copy operation is completed and the printer operation is started. The following is a description of a specific example.
[0080]
At present, copying is in progress, paper is fed from the upper cassette, and it is set to discharge to the face-up discharge port, and the image forming mode is also set to the color mode based on the judgment that the original is color. I do. Here, when a print request is issued from the printer controller, the print execution itself is postponed, but various settings can be made. Here, it is assumed that the print request is a request for feeding paper from the upper cassette, discharging the paper to the face-down discharge port, and further outputting a monochrome image. Regarding the sheet cassette designation, both the reader controller and the printer controller designate the upper cassette. Therefore, even when the copy operation is completed and the operation is switched to the print operation, there is no need to issue a paper feed cassette designation command to the engine control unit. Regarding the output port and the image forming mode, the copy operation and the print operation are specified differently. Therefore, when the copy operation is completed, a command for specifying the paper output port and specifying the image forming mode is sent from the reader controller to the engine controller again. Need to be issued.
[0081]
As described above, the reader controller does not judge the command from the printer controller only to postpone the execution of the command to the engine control unit, but the reader controller has already set the command to the engine control unit. For those already completed, a determination is made so that duplicate settings are not made.
[0082]
Next, a case where a copy request occurs during a printing operation will be described with reference to FIG. In this case, contrary to the case of FIG. 12, from the viewpoint of usability, it is better to be able to execute the copy operation in an interrupted manner than to be able to copy during the print operation even if the user presses the copy button in front of the copy machine. .
[0083]
In this case, / CVDO sent from the printer controller is selected by the selector 2201 and sent to the engine control unit as / PVDO. It is assumed that the settings are exactly the same as those described with reference to FIG. 12, and the settings from the printer controller are an upper cassette, a face-down discharge port, and a monochrome image mode. Since the engine control unit can detect the end only when the / PPRNT signal from the printer controller becomes High (false), it does not know how many sheets are printed out. Here, it is assumed that the printer is going to print out four images. If the reader does not issue a copy operation request by interruption, four / PTOP signals are generated from the engine control unit as shown in the image timing as shown in FIG. 5, and the image is accordingly transmitted from the printer controller via the reader controller. And sent to the engine control unit.
[0084]
Therefore, it is assumed that an interrupt copy request for copying one color document is issued to the reader controller during the second printout. This will be described with reference to FIG. In response to a / CPRNT request from the printer controller, the reader controller issues a / PPRNT request to the engine control unit, and the engine control unit supplies a / PTOP signal to the printer controller as a / CTOP signal via the reader controller. In this manner, the printing operation of the first image 1501 and the second image 1502 is executed.
[0085]
Here, a case where the reader controller issues an interrupt copy request during the printout operation of the second sheet will be described. The reader controller generates a / CCCRT signal to the printer controller. This does not mean that the state of the engine has actually changed, but that the reader requests the printer controller to open the engine in order to acquire the printer engine. The generation method uses the control unit 2208 as described above. In response to the / CCCRT signal, the printer controller issues a command for checking the status status of the engine, and the reader controller returns a status of "copying" to the printer controller. Then, the printer controller detects that the engine is performing a copy operation while keeping the / CPRNT signal Low (true), and continues waiting for the / CTOP signal to come. If it is not in the copy state, if / CPRNT remains Low (true) and / CTOP does not come, a timeout error will occur after a certain period of time. In the copy state, the timeout will be canceled by the printer controller and permanently Set to wait for the / CTOP signal. The / PTOP signal sent from the engine control unit this time is for performing a copy operation, and the reader controller uses the / PTOP signal. Also, as shown by 1505, the / PTOP signal sent from the engine side is masked to the printer controller. The image signal actually generated by the reader controller is only the image signal 1506. Then, after one interrupt copy is completed, the mask of the / PTOP signal is removed again and sent to the printer controller as / CTOP, thereby printing out the images 1503 and 1504 from the printer controller to the engine control unit. Can be. According to the above description, the interruption copy operation during the print operation can be realized.
[0086]
As described above, according to the state of the printer controller or the reader controller, the reader controller determines and controls who acquires the printer engine and at what timing the command is issued. The requests from the two controllers can be realized for the engine.
[0087]
[Control for setting confirmation command]
Next, control when the printer controller issues a setting content confirmation command will be described.
[0088]
When the printer controller wants to confirm the state set in the engine control unit, the printer controller issues a setting content confirmation command through / CCMD. The reader controller that has received it checks the setting value storage buffer in FIG. 12, and if the content that the printer controller wants to check is in the buffer, reads the content and notifies the printer controller via / CSTS. If the content does not exist in the buffer, the reader controller issues a setting content confirmation command through / PCMD. The engine control unit reads the contents, and notifies the reader controller of the setting contents via / PSTS, and the reader controller notifies the printer controller of the contents via / CSTS.
[0089]
[Density correction method]
Next, a description will be given of a density correction method for reducing variations in print density and outputting a desired print density.
[0090]
[Copy density correction method]
First, a density correction method when used as a copy will be described.
[0091]
FIG. 22 illustrates an image processing block in the reader.
[0092]
In the figure, 3001 is a CCD sensor, 3002 is a shading correction unit, 3003 is an input masking unit, 3004 is a background removal unit, 3005 direct mapping unit, 3006 is a data sampling unit, 3007 is an output γ unit, and 3008 output A processing unit 3009 is a PG (pattern generator) unit.
[0093]
The algorithm of the density correction method will be described.
[0094]
The PG unit 3009 generates a pattern including a plurality of predetermined density patches, and outputs the pattern from the printing unit.
[0095]
FIG. 25 shows an example. The output is placed on a document table of the reader unit and read. The read data passes through the image processing block shown in FIG. 22 and is sampled by the data sampling unit. The sampling result is processed by the CPU 2209 shown in FIG.
[0096]
FIG. 24 shows the processing contents. That is, correction is performed on the input digital data depending on the output density. For example, it is assumed that the pattern is printed and the output is sampled as described above, so that the input / output characteristics before correction are plotted as shown in FIG. In such a case, since the actual output density is lower than the ideal output density for the input digital data, the digital data is increased so as to obtain the ideal density. In this way, a correction table is created and reflected in the output γ unit 3007. Thereby, an ideal output density is obtained.
[0097]
[PDL density correction method]
FIG. 23 is an image processing block diagram inside the PDL.
[0098]
In the figure, 3101 is an input I / F from an external device such as a personal computer, 3102 is a reception buffer, 3103 is an object generation unit, 3104 is an object buffer, 3105 is a rendering unit, 3106 is a band buffer, and 3107 is an output to an engine unit. An I / F 3108 is a data correction unit, 3109 is a dither processing unit, 3110 is a CPU, 3111 is a communication controller, and 3112 is a PG unit.
[0099]
The algorithm will be described.
[0100]
Until the correction table is created, it is roughly the same as in the case of copying.
[0101]
First, the PG section 3112 in the PDL generates a pattern composed of a plurality of predetermined density patches, and outputs the pattern from the printing section.
[0102]
FIG. 25 shows an example. The output is placed on a document table of the reader unit and read. The read data passes through the image processing block shown in FIG. 22 and is sampled by the data sampling unit. The sampling result is processed by the CPU 2209 shown in FIG.
[0103]
FIG. 24 shows the processing contents. That is, correction is performed on the input digital data depending on the output density. For example, it is assumed that the pattern is printed and the output is sampled as described above, so that the input / output characteristics before correction are plotted as shown in FIG. In such a case, since the actual output density is lower than the ideal output density for the input digital data, the digital data is increased so as to obtain the ideal density. Thus, a correction table is created.
[0104]
Next, the created correction table is transmitted from the reader unit to the PDL unit using the communication unit.
[0105]
That is, the communication controller 2205 inside the reader and the communication controller inside the PDL are connected, and the contents of the correction table are transmitted to the inside of the PDL by using both communication controllers. The PDL CPU 3110 sets the data correction unit 3108 based on the correction table transmitted. As a result, the density correction is performed on the image data from the PDL in the same manner as the copy.
[0106]
Specifically, the communication content transmitted from the reader to the PDL may be the table content itself of the correction table in the PDL. Specifically, data of 256 gradations for each of three or four colors is communicated. The correction table may be created in the PDL. In that case, the read data is transmitted as it is. The data for the number of patches becomes the data amount for three or four color components. Alternatively, the difference between the read data and the ideal may be communicated.
[0107]
[Density correction during printing]
What has been described in the above paragraph 2 is the density correction in the initial state performed before the start of printing (copying).
[0108]
On the other hand, density correction during printing is also necessary to suppress fluctuations in density during continuous printing (copying).
[0109]
There are several examples of the density correction method during printing, but none of these methods can be performed manually, so that the method is performed in a closed system in the printer engine unit. For example, in the case of the printer engine having the configuration shown in FIG. 4 as described in the present embodiment, there is a portion called an intermediate transfer member 405 for forming a visible image. A patch pattern for density correction as described above is formed on the intermediate transfer member, and the patch pattern is read by the sensor 420, and density correction can be performed from the difference between the desired density and the actual density. The sensor 420 is of an optical type.
[0110]
The location where the density correction is performed does not need to be on the intermediate transfer member, and may be on a transfer material (paper). However, considering the mechanical configuration, the rotating intermediate transfer member is more preferable than the transferred transfer material. In the case of a configuration having no intermediate transfer member, there is a method of determining the density of a latent image by a potential sensor.
[0111]
By the way, when performing correction in a closed system in the printer engine, it is necessary to newly add a sensor as described above. In the case of performing the print correction in the initial state described above, data sampling can be performed using the read sensor that is already installed in the image reading unit. In the case of the correction, the reading sensor is not required for other uses, so that it is necessary to separately provide the reading sensor only for this correction. For this reason, increasing the number, accuracy, and the like of the sensors requires many costs.
[0112]
Therefore, in the present embodiment, the present invention is implemented by providing one optical sensor using a general-purpose phototransistor instead of an expensive image reading sensor. By rotating the rotating body on the rotating surface of the intermediate transfer body, patches are printed in a line at a position where the patch is read by the sensor. From the reading range of the reading sensor and the like, the patch size is 10 mm square and the number of patches is 32.
[0113]
FIG. 26 shows a state where the intermediate transfer member on which the patch is printed is spread on a plane. 401 is a patch, and 402 is an intermediate transfer member.
[0114]
[Multiple image processing]
The image processing when the tone is emphasized is different from the image processing when the resolution is emphasized.Therefore, since there are multiple image processings and the characteristics of the intermediate density area are different in each case, It is necessary to perform correction before starting and correction during printing for each of a plurality of image processes.
[0115]
[Correction before printing and during printing]
However, since it takes time to perform density correction, if correction is performed for every image processing before printing and during printing in all cases, a great deal of time will be consumed. Therefore, it is important to maintain the density in a short time (correction) by utilizing the characteristics of the respective density corrections.
[0116]
The correction before printing is performed by the user's voluntary action to make the correction, so that a certain amount of time can be consumed, while the correction during printing is for a user who does not intend to make correction Will also be affected. Therefore, the correction before printing is performed for all image processing, but the correction during printing is kept to the minimum necessary. As a result, density correction that can maintain an appropriate density without imposing too much load on the user can be realized.
[0117]
【The invention's effect】
Therefore, according to the present invention, in an image printing apparatus including an image reading unit and a density detection unit for detecting an image density to be formed, a first image correction unit using the image reading unit, the density detection unit And a plurality of types of image processing means for performing image formation, wherein the first correction means performs all image processing among the plurality of types of image processing means. Accordingly, the density correction can be performed without increasing the time.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a controller and a printer.
FIG. 2 Connection diagram
FIG. 3 List of video I / F signals
FIG. 4 is a mechanical paper transport diagram.
FIG. 5 is an image signal timing chart.
FIG. 6 is a serial communication timing chart.
FIG. 7 shows communication during a printing operation.
FIG. 8 is an external view when a reader unit is attached.
FIG. 9 is a connection diagram in a configuration in which a reader controller is interposed.
FIG. 10 is a communication sequence when a reader is attached.
FIG. 11 shows a state change process in / CCRT when a reader is attached.
FIG. 12 shows processing of a print request during a copy operation.
FIG. 13 illustrates processing of a copy request during a printing operation.
FIG. 14 is a timing chart at the time of interrupt copying.
FIG. 15 is a schematic view of a printer.
FIG. 16 is a system connection diagram of the printer.
FIG. 17 is a detailed block diagram in the reader controller.
FIG. 18 is a detailed block diagram in the reader controller.
FIG. 19 is a timing difference between copying and printing.
FIG. 20 shows how to mount a conventional reader.
FIG. 21 shows a conventional reader mounting method.
FIG. 22 is an image processing block in the reader
FIG. 23 is a block diagram of image processing inside the PDL.
FIG. 24: Correction processing method
FIG. 25 shows an example of a predetermined density patch.
FIG. 26 is a diagram illustrating a patch on an intermediate transfer member.
[Explanation of symbols]
101 Leader frame
106 Reader Controller
2001 Printer body
2103 Printer controller
2002 Engine control unit
2104 Host computer
2201 selector
2207 gate
2208 control circuit
1301 Set value buffer
2205 and 3111 communication controllers
3108 Data correction unit
3112 PG section

Claims (7)

In an image printing apparatus including an image reading unit and a density detection unit that detects an image density to be formed, a first image correction unit using the image reading unit;
A second image correcting unit using the density detecting unit; a plurality of image processing units for forming an image; a first correcting unit performing all image processing among the plurality of types of image processing units; An image printing apparatus characterized in that: 2. The image printing apparatus according to claim 1, wherein, among the plurality of types of image processing, the second correction unit performs a typical image processing. The first image correction unit has a pattern forming unit in the printing device, prints a pattern formed on the paper based on data formed by the pattern forming unit on paper, and uses the image reading device to print the pattern. 3. The image printing apparatus according to claim 2, wherein by reading the data, data sampling and density detection are performed. The second image correcting means has a pattern forming unit in the printing apparatus, and performs data sampling of a pattern formed on the basis of data formed by the pattern forming unit in a state of a latent image by a potential sensor, and performs density sampling. 3. The image printing apparatus according to claim 2, wherein detection is performed. The second image correction unit has a pattern forming unit in the printing device, and performs data sampling by an optical sensor in a visualized state on a pattern formed based on data formed by the pattern forming unit, 3. The image printing apparatus according to claim 2, wherein density detection is performed. The plurality of types of image processing means are processing suitable for gradation images and processing suitable for character images. Representative image processing targeted by the first correction means is processing suitable for gradation images. 3. The image printing apparatus according to claim 2, wherein 3. The image printing apparatus according to claim 2, wherein the second correction unit automatically performs a correction process according to the number of prints.

Images