JP2006116800A - Printing system and printing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the result of printing from largely changing by the apparatus of printing. <P>SOLUTION: A printing system has a density correcting means for correcting the density in accordance with the result of measurement on density characteristics, a judging means for automatically judging a case when the density correction is necessary, a first printing apparatus with an informing means for informing that the density correction has been performed, and a second printing apparatus for performing the density correction using the information from the first printing apparatus as a trigger. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printing apparatus having a density correction function for correcting density characteristics, and a printing system having a plurality of the printing apparatuses.

  With the improvement of printing technology, color printing has become widespread and it has become possible to print more easily viewable documents. Among them, changes in output images due to changes in temperature, humidity, etc., or changes in image due to deterioration of consumable parts such as toner on the photosensitive drum and toner cartridge when the printing apparatus is an electrophotographic system. There are printing apparatuses that perform density control in order to correct the above and supply a stable image.

Further, in a system having a plurality of printing apparatuses, there is a printing system that performs distributed printing that improves printing performance by printing one document divided into a plurality of printing apparatuses.
JP-A-1-41375

  Conventionally, in one type of printing system, the timing of density correction varies depending on the printing apparatus, so that the color tone differs depending on the printing apparatus that performed printing when performing distributed printing. Further, even in the case of non-distributed printing, there is a problem that the hue varies depending on the printing apparatus.

  In addition, in one type of printing apparatus, there is a printing apparatus that can input density correction information from a host apparatus. In a printing system having a plurality of printing apparatuses, only one density correction information is input. In this case, when distributed printing is performed, the hue varies depending on the printing apparatus. Even in the case of distributed printing, the hue varies depending on the printing apparatus.

  In order to solve the above problems, the present invention comprises the following arrangement.

  The printing system according to claim 1 has density correction means for measuring density characteristics and correcting density according to the measurement result, and has judgment means for automatically judging when correction is necessary, and density correction is performed. A first printing apparatus having means for notifying other printers connected to the network via communication means that the density correction has been performed, and measuring the density characteristics; And a second printing apparatus that does not actively perform density correction and performs density correction using a notification from the first printing apparatus as a trigger. To do.

  According to a second aspect of the present invention, the printing apparatus includes density correction means for inputting density correction information from a host apparatus and correcting the density according to the density correction information. Information indicating that the density correction has been performed to another connected printer, and means for transmitting the density correction information, and the density correction information is input from another printing apparatus, and the density is corrected according to the density correction information. And a density correction means for correcting the above.

  According to the present invention, it is possible to avoid the problem that the printing result (color) differs greatly depending on the printing apparatus.

Example 1
Before describing the configuration of this embodiment, the configuration of a laser beam printer and an ink jet printer suitable for applying this embodiment will be described with reference to FIG. Needless to say, the printer to which the present embodiment is applied is not limited to the laser beam printer and the ink jet printer, and may be a printer of another printing method.

  FIG. 1 is a cross-sectional view showing a configuration of a first output device to which the present invention can be applied. For example, a laser beam printer (LBP) is shown.

  In the figure, a laser beam emitted from a laser output unit (213) that converts an image signal into an optical signal is reflected by one side of a polygon mirror 214, and rotates in the direction indicated by an arrow through an f / θ lens 215 and a mirror 216. The surface of the photosensitive drum 217 is scanned linearly (raster scan). As a result, an electrostatic latent image corresponding to the document image is formed on the surface of the photosensitive drum 217.

  Reference numeral 218 denotes a developing unit that develops an electrostatic latent image formed on the surface of the photosensitive drum 217 by laser exposure, and has the following configuration. Reference numerals 218Y, 218M, 218C, and 218BK denote developing sleeves that are directly in contact with the photosensitive drum 217 for development. Note that the symbols Y, M, C, and BK of the components described above indicate colors. That is, “Y” is yellow, “M” is magenta, “C” is cyan, and “BK” is black. When a magenta toner image is formed, magenta toner development processing is performed at the position shown in FIG. When a black toner image is formed, the developing unit 218 is rotated about the axis in the drawing so that the black developing sleeve 218BK contacts the photosensitive drum 217. Yellow and cyan development works similarly.

  Reference numeral 223 denotes a transfer drum that transfers a toner image formed on the photosensitive drum 217 to a sheet.

  On the other hand, reference numerals 224 and 225 denote sheet feeding cassettes for storing sheets. In the embodiment, for example, the sheet feeding cassette 224 stores A4 size sheets, and the sheet feeding cassette 225 stores A3 size sheets. The paper supplied from the cassette is conveyed via a roller, wound around a transfer drum 223, and proceeds to an image forming process. Whether to select one of the paper feed cassettes 224 and 225 is determined by an instruction of the main control unit 201 that controls the entire printer, and only the selected paper is supplied.

  In this manner, each color of YMCK is developed, transferred, heat-fixed, and then discharged to the discharge tray 227. In the case of monochrome, image formation, development, transfer, and fixing may be performed for BK1 color.

  FIG. 2 shows a printing system to which the present invention is applied, and shows a system configuration including a host computer 1000 and a printer 1030. A host computer control unit 1001 in the host computer 1000 that uses the printer controls the operation of the host computer. The control unit 1001 includes a CPU 1002 that controls the operation of the entire computer, a program ROM 1003 that contains a program that describes the operation of the CPU, a communication code 1 that transmits and receives control codes and data between the host computer and external devices (1007). ), Communication means 2 (1008), communication means 3 (1009), input / output buffers 1004, 1005, 1006 to the respective communication means, the control code, calculation necessary for data interpretation and printing, processing of print data RAM 1010 used as a work memory for an application, an application program (AP program) 1011 which is a program describing the operation of application software or a driver operating on a computer, and data for printing when printing is performed in each communication Assigned to the means Communication means scheduling unit 1012 for performing juling, a display 1013 for displaying a computer-processed image to a user, a display controller 1014 for controlling the image, a keyboard 1015 for receiving a command from the user, and controlling it A keyboard controller 1016, an external memory 1017 used for storing print data and various host computer information, a memory controller 1018 for controlling the external memory 1017, and a system bus 1019 for connecting the units.

  A printer control unit 1031 in the printer 1030 controls the operation of the printer. The control unit 1031 includes the communication unit 1 (1007), the communication unit 2 (1008), the communication unit 3 (1009), and the input / output buffers for the respective communication units, which exchange control codes and data with the host computer 1000. 1032, 1033, 1034, a CPU 1035 for controlling the operation of the entire printer, a program ROM 1036 containing a program describing the operation of the CPU, the control code, calculation necessary for data interpretation and printing, and print data processing A RAM 1037 used as a work memory, an image information generation unit 1038 that generates various image objects from data received from a host computer, a bitmap image transfer unit 1040 that transfers an expanded bitmap image to a printer engine, and actually Print on paper A memory controller 1044 that controls the printer engine unit 1041, a panel 1042 that operates the printer, and an external memory 1043 that is used to store print data and information on various printing apparatuses, and a system bus 1045 that connects the units. The system is composed of

  FIG. 3 is a block diagram showing a logical structure of a printing system to which the present invention is applied.

  Data input from the host computer 1000 is stored in the input / output buffer via the input unit 3000 which is a module that controls the input interface. In the printer of this embodiment, there are a plurality of input / output buffers. Here, the input / output buffer 1 is used as an example. When the input of print data is started, the input unit notifies the print control unit 3007 that the input has started. The print control unit 3007 is a module that controls the overall operation related to printing, and has a role of instructing each module. When the print control unit 3007 receives a notification of input start from the input unit 3000, the print control unit 3007 instructs the analysis unit 3002 to start data analysis. Upon receiving an instruction to start data analysis, the analysis unit 3001 reads the print data from the input / output buffer, analyzes the data, and gives an instruction to the image information generation unit 3002 according to the analysis result to generate a drawing image 3009 (drawing object). At this time, the analysis unit acquires density correction data from the density control unit 3006, performs density correction, and generates a drawing image (drawing object) as a result of the density correction. Further, the density correction data used at this time is stored in the storage area 3004. When the analysis unit 3001 finishes generating the drawing image for one page, it notifies the print control unit 3007 that the drawing image for one page has been generated.

  Upon receiving the notification, the print control unit 3007 instructs the bitmap image transmission unit 1040 to output video. Alternatively, when reprinting is instructed by a command in a state where a drawing image has already been generated and saved, the bitmap image transmission unit 1040 is instructed to output video. Note that the reprint instruction by the command is performed via the input unit 3000 in the figure.

  Upon receiving the instruction, the video transfer unit 3005 reads the drawing image 3009 from the area 3003, converts it into a video signal and transfers it to the engine 1041, and the engine 1041 receives the video signal, prints the image, and discharges the paper.

  FIG. 4 is a diagram schematically illustrating patches used during density control. In the figure, reference numeral 4001 denotes a drawing area of an intermediate transfer member that can make toner conspicuous. 4002X (where X is Y (yellow), M (magenta), C (cyan), and K (black) are input densities (density set to the object by the user) 0.5, 0.75, 1.. This indicates a patch generated at 0. The direction indicated by the arrow in the figure coincides with the rotation direction of the intermediate transfer member shown in Fig. 1. These patches are read by the density sensor 2044C. If the result is output density (density actually printed by the printer), for example, in the case of yellow, the relationship is obtained as a curve like 5001 shown in Fig. 5. The horizontal axis represents the input density, and the vertical axis represents the input density. The above-described measurement for each color is four points, but this curve 5001 is expressed as a function based on data collected from prior tests such as printer toner and intermediate transfer material, temperature, and humidity. Buru are of, indexed from those values. And 5002 is ideal density to be output to the actually input density.

  From the density measurement curve 5001, the output density is 0.5, 0.75, 0.93, and 1.0 when the input density of Y is 0.25, 0.5, 0.75, and 1.0, respectively. On the other hand, when the input density is 0.5, 0.75, 0.96, 1.0, the correction is performed to make 0.25, 0.5, 0.75, 0.93, 1 0.0 is obtained as the output density.

  In this way, the input density shown in FIG. 5 is converted so as to obtain an ideal output density. FIG. 6 is a diagram showing the relationship between the input density and the corrected input density in this case for creating the density correction table, and 6001 is a curve showing the relationship between the input density and the corrected input density. By performing density control in this way and using a density correction table created using the actually measured output density, image density control is performed, and printing is performed at an ideal density.

  FIG. 7 is a diagram for explaining the configuration of the printing system shown in this embodiment. A plurality of host computers and a plurality of printing apparatuses are connected via a network. The host computer 7001 has an application for performing distributed printing and a printer driver. Distributed printing is a mechanism that prints a document divided into a plurality of printing devices. For example, when printing 10 copies of a certain printed matter, 5 copies are printed on the printing device A (7002) and 5 copies are printed on the printing device B (7003). Print 5 copies at a time. This can improve the printing performance.

  At this time, in order to make the colors of the printing apparatus A and the printing apparatus B the same, when the printing apparatus A performs density correction processing, the printing apparatus B is notified, and the printing apparatus B also performs density correction processing. Do. The density differs in color before and after the correction process, so if the timing is different for each printing apparatus, the color will be different for each printing apparatus when distributed printing is performed.

  Next, the flow of processing of the printing apparatus shown in this embodiment will be described.

  FIG. 8 is a flowchart showing the main processing of the first printing apparatus (the one issuing the notification) shown in the present embodiment. Step 801 is an input data wait loop. When input from the host is started, the process proceeds to step 802 to perform data input processing. In the data input process, data is stored in the print data storage area 1032 (input / output buffer).

  In step 803, the input data is analyzed. In step 804, it is determined whether the analysis result is a paper discharge command or a job end command. If the result of the determination is a paper discharge command or a job end command, printing processing is performed in step 807. The printing process is performed by the bitmap image sending unit 1040 shown in FIG. 4 reading the drawing image 3009 from the drawing image storage area 3003, converting the image into a video signal, and transferring it to the engine 1041.

  If it is determined in step 804 that the data is not a paper discharge command or a job end command, drawing processing is performed in step 805. The drawing process is a process for generating drawing image data 3009 according to each drawing command.

  In step 806, it is determined whether or not there is data in the input buffer. As a result of the determination, if there is still data in the input buffer, the process returns to step 803 to repeat the data analysis process. If there is no data in the input buffer as a result of determination, the process returns to step 801 to wait for data input.

  FIG. 9 is a flowchart showing a flow of status monitoring processing of the printing apparatus shown in the present embodiment. The state monitoring process is a timer process and is executed periodically. When the state monitoring process is started, first, in step 901, the current density characteristic of the engine is examined. Next, in step 902, the previously checked density characteristic stored in the memory is read out. Next, in step 903, the density characteristic obtained in step 901 is compared with the density characteristic obtained in step 902. As a result, if there is a difference, the process proceeds to step 904, and if there is no difference, the process ends. In step 904, density correction processing is performed. (Specifically, the processing described with reference to FIGS. 4 to 6) In step 905, the other printers in the network are notified that the density control has been performed. In this embodiment, SNMP / TRAP is used as a specific method of notification, but the same method is used when other protocols are used. In step 906, the current density characteristic is stored (updated) in the memory.

FIG. 10 is a flowchart showing the processing of the second printing apparatus (the side receiving the notification) shown in this embodiment. (Basically the same as FIG. 8, but a process for receiving notification is added)
Step 1001 is an input data wait loop. When input from the host is started, the process proceeds to step 1002 to perform data input processing. In the data input process, data is stored in the print data storage area 1032 (input / output buffer).

  In step 1003, the input data is analyzed.

  Here, it is assumed that the determination includes whether the data is print data or SNMP data. If the data input as a result of the analysis is a density correction notification by SNMP / TRAP, determination is made at step 1004 and density correction processing is performed at step 1005. If it is not a density correction notification, the process proceeds to step 1006.

  In step 1006, it is determined whether the analysis result is a paper discharge command or a job end command. If the result of the determination is a paper discharge command or a job end command, printing processing is performed in step 1007. The printing process is performed by the bitmap image sending unit 1040 shown in FIG. 4 reading the drawing image 3009 from the drawing image storage area 3003, converting the image into a video signal, and transferring it to the engine 1041.

  If it is determined in step 1006 that the data is not a paper discharge command or a job end command, a drawing process is performed in step 1007. The drawing process is a process for generating drawing image data 3009 according to each drawing command.

  In step 1008, it is determined whether or not there is data in the input buffer. As a result of the determination, if there is still data in the input buffer, the process returns to step 1003 to repeat the data analysis process. If there is no data in the input buffer as a result of determination, the process returns to step 1001 to wait for data input.

(Modification 1)
The same applies to the case where the measurement by the scanner (within the printer) is added as a means for measuring the density. FIG. 11 shows a configuration diagram when a scanner is used. In FIG. 11, a scanner 11001, a density control unit 2 (11002), a density correction data storage area (3004), and density correction data (3010) are added to the configuration diagram of FIG. The scanner 11001 reads an image output from the engine at the time of output, and transfers data to the density control unit 2. The density control unit 2 creates correction data for correction based on the scanned data and stores it in the density correction data storage area (3004). The bitmap image sending unit (1040) reads out the correction data (3010), performs correction, and transfers the corrected image to the engine (1041).

(Modification 2)
In this embodiment, a description will be given of a type in which an output image is read from a scanner connected to a host computer, correction data is generated by the host, and the correction data is downloaded to a printing apparatus. The configuration is shown in FIG. FIG. 12 is substantially the same as FIG. 8 except that a density correction area 3004, density correction data 3010, a sheet 12002, and a scanner 12001 are added.

  The paper 12002 output from the engine 1041 is read from the scanner 12001 (manual). The image read by the scanner is transferred to the host computer, and the host computer generates correction data for correcting the color shift. Download the created correction data to the printing device. The analysis unit 3001 (which uses a download command or the like) analyzes the download command and stores the downloaded data (density correction data) in the density correction area 3004. The bitmap image sending unit (1040) reads out the correction data (3010), performs correction, and transfers the corrected image to the engine (1041).

  FIG. 13 is a configuration diagram of a printing system using the printing apparatus shown in this embodiment. Assume that printer A and printer B exist, and printer A is set as a reference printing apparatus. The paper output from the printer A is read from the scanner 13004 and the data is transferred to the host computer 1000. The host computer 1000 corrects the color, generates correction data, and downloads the correction data to the printer A. Printer A performs density correction, notifies printer B that the density correction has been performed, and transfers correction data to printer B. Printer B receives the density correction data and performs density correction.

  When distributed printing is performed from the host computer to the printer A and the printer B, printing is performed from both printers in a state of being corrected with the printer A as a reference.

(Modification 3)
The first printing apparatus and the second printing apparatus shown in the above-described embodiment are the same printing apparatus, and are switched to the first printing apparatus and the second printing apparatus by setting (mode setting). It doesn't matter.

1 is a cross-sectional view illustrating a configuration of a printer according to an embodiment of the present invention. 1 is a block diagram illustrating a configuration of a printer system according to an embodiment of the present invention. 1 is a block diagram illustrating a logical structure of a printer according to an embodiment of the present invention. It is a figure which shows typically the patch utilized at the time of density control. It is a figure explaining the relationship between input density and output density. It is a figure explaining density correction data. System Configuration. 3 is a flowchart of main processing of the first printing apparatus. It is a flowchart of a state monitoring process. 10 is a flowchart of main processing of the second printing apparatus. It is a block diagram of the other Example 1. It is a block diagram of the other Example 2. It is a system configuration diagram.

Claims (2)

A density correction unit that measures density characteristics and corrects the density according to the measurement result; a determination unit that automatically determines when density correction is necessary; and a communication unit that performs density correction. A first printing device having means for notifying other printers or higher-level devices that density correction has been performed on another printer connected to the network via
A density correction unit that measures density characteristics and corrects the density according to the measurement result has a density correction unit that does not actively perform density correction and performs density correction using a notification from the first printing apparatus as a trigger. A printing system comprising: a printing apparatus. It has density correction means for inputting density correction information from the host device and corrects the density according to the density correction information. When density correction is performed, another printer connected to the network via the communication means is used. , Information that density correction has been performed, and means for transmitting density correction information;
A printing apparatus comprising density correction means for inputting the density correction information from another printing apparatus and correcting the density according to the density correction information.

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