JP4402083B2 - Image forming apparatus - Google Patents

Description

  The present invention is useful when applied to an image forming apparatus such as an electrophotographic type or electrostatic storage type copying machine or printer.

  With reference to FIG. 1, an outline of the overall configuration of a laser printer as an image forming apparatus will be described.

  As shown in FIG. 1, the laser printer forms an electrostatic latent image with image light formed based on an image signal transmitted from a controller (not shown) in an image forming unit, and develops the electrostatic latent image. The visible image is superimposed and transferred to form a color visible image, the color visible image is transferred to the transfer material 2, and the color visible image on the transfer material 2 is fixed. Photoconductor (5Y, 5M, 5C, 5K) for each station, injection charging means (7Y, 7M, 7C, 7K) as primary charging means, developing means (8Y, 8M, 8C, 8K), toner cartridge (11Y) 11M, 11C, 11K), an intermediate transfer member 12, a paper feeding unit, a transfer unit, and a fixing unit 11.

  The photoreceptor (5Y, 5M, 5C, 5K), the injection charging means (7Y, 7M, 7C, 7K) as the primary charging means, and the developing means (8Y, 8M, 8C, 8K) can be attached to and detached from the main body of the image forming apparatus. Are mounted on various process cartridges (22Y, 22M, 22C, 22K).

  The photosensitive drums (photoconductors) 5Y, 5M, 5C, and 5K are configured by applying an organic optical transmission layer on the outer periphery of an aluminum cylinder, and are rotated by the driving force of a driving motor (not shown) being transmitted. The photosensitive drums 5Y, 5M, 5C, and 5K are rotated counterclockwise according to the image forming operation. Exposure light to the photosensitive drums 5Y, 5M, 5C, and 5K is sent from the scanner units 10Y, 10M, 10C, and 10K, and is selectively exposed on the surfaces of the photosensitive drums 5Y, 5M, 5C, and 5K, so An image is formed.

  As primary charging means, four injection chargers 7Y, 7M, 7C, and 7K for charging yellow (Y), magenta (M), cyan (C), and black (K) photoconductors are provided for each station. Each injection charger is provided with sleeves 7YS, 7MS, 7CS, and 7KS.

  As developing means, in order to visualize the electrostatic latent image, four developing devices 8Y, 8M for developing yellow (Y), magenta (M), cyan (C), and black (K) at each station. , 8C, 8K, and each developing device is provided with sleeves 8YS, 8MS, 8CS, 8CK. Each developing device is detachably attached.

  The intermediate transfer body 12 is in contact with the photosensitive drums 5Y, 5M, 5C, and 5K, rotates clockwise when forming a color image, rotates with the rotation of the photosensitive drums 5Y, 5M, 5C, and 5K, and is visible. Receive image transfer. Further, the intermediate transfer body 12 simultaneously transfers a color visible image onto the intermediate transfer body 12 by transferring the transfer material 2 by nipping and conveying the transfer material 2 after contact with a transfer roller 9a, which will be described later.

  The transfer roller 9a is brought into contact with the intermediate transfer member while the color visible image is superimposed and transferred onto the intermediate transfer member 12, but is separated to a position 9b at the end of the printing process.

  The fixing unit 13 fixes the transferred color visible image while conveying the transfer material 2. The fixing unit 14 heats the transfer material 2 and pressurization for pressing the transfer material 2 against the fixing roller 14. And a roller 15. The fixing roller 14 and the pressure roller 15 are formed in a hollow shape, and heaters 16 and 17 are incorporated therein. That is, the transfer material 2 holding the color visible image is conveyed by the fixing roller 14 and the pressure roller 15, and the toner is fixed on the surface by applying heat and pressure.

  After the visible image is fixed, the transfer material 2 is discharged to the paper discharge unit and the image forming operation is completed.

  The paper discharge option device 30 sorts and stacks transfer materials by a first paper discharge bin 35, a second paper discharge bin 36, and a third paper discharge bin 37. The bin lifting motor 38 moves the discharge bins 35 to 37 up and down to sort the transfer material into the bins. The flapper 39 switches the conveyance of the transfer material sent to the paper discharge option device 30 so as to switch the front and back of the transfer material based on an instruction from the controller. When face-up is designated from the controller, the transfer material is guided to the roller 31 and sent to the paper discharge port as it is. Further, when face down is designated by the controller, the flapper 39 guides the roller 32 and the roller 33 and once the rear end of the transfer material exceeds the roller 32, the roller 33 is reversed. Then, it is fed to the roller 34 from the rear end of the transfer material and sent to the paper discharge port.

  The printer uses the lower conveyance sensor A23, the upper conveyance sensor A24, the lower conveyance sensor B25, the upper conveyance sensor B26, the registration sensor 19, the pre-fixing sensor 27, the fixed ejection sensor 20, and the ejection sensor 28 on the transfer material conveyance path. Manage the situation.

  The cleaning unit 21 cleans the toner remaining on the photosensitive drums 5Y, 5M, 5C, and 5K and the intermediate transfer body 12, and displays a visible image by the toner formed on the photosensitive drums 5Y, 5M, 5C, and 5K. Waste toner after being transferred to the intermediate transfer member 12 or waste toner after transferring the four color visible images formed on the intermediate transfer member 9 to the transfer material 2 is stored in a cleaner container.

  FIG. 2 is a block diagram for explaining the system configuration of the image forming apparatus. The controller 201 can communicate with the host computer 200, the paper discharge option control unit 202, and the engine control unit 203. The controller 201 receives image information and a print command from the host computer 200, analyzes the received image information and converts it into bit data, and prints a print reservation command, a print start command for each transfer material via the video interface unit 210, The video signal is sent to the engine control unit 203. At this time, the controller 201 also sends an instruction regarding the use of the paper discharge control option to the paper discharge option control unit 202 based on an instruction from the host computer 200.

  The controller 201 transmits a print reservation command to the engine control unit 203 in accordance with a print command from the host computer 200, and transmits a print start command to the engine control unit 203 at a timing when printing is possible.

  The engine control unit 203 prepares for execution of printing in the order of print reservation commands from the controller 201 and waits for a print start command from the controller. When the engine control unit receives the print instruction, the engine control unit outputs a / TOP signal, which is a reference timing for outputting the video signal, to the controller 201, and starts a print operation in accordance with a print reservation command. The controller 201 can be configured by an interface to the option control unit 202, the host computer 201, and the engine control unit 203, a processor, a memory, and the like.

  FIG. 5 is a flowchart of the printing operation of the engine control unit 203. Prior to printing, the controller 201 first transmits a reservation command (such as a print reservation command or a discharge bin reservation command) for reserving necessary resources in advance to the engine control unit 203 and the discharge option control unit 202. . In the reservation command, resources to be used corresponding to the order of print instructions to be issued are specified. For example, the reservation command reserves the use of the discharge bin 1 for the first print instruction, reserves the use of the discharge bin 2 for the next print instruction, or reserves the paper cassette to be used. I do. Thereafter, a print start signal is issued to the engine control unit in order to print the reserved contents.

  Upon receiving the print reservation command, the engine control unit 203 waits for the reception of the print start command (501), and executes preprocessing (hereinafter referred to as “pre-rotation sequence”) for performing the print operation (502). After completion of the pre-rotation sequence, the / TOP signal is output and the printing operation is started in accordance with the print reservation command for the first sheet (503). The / TOP signal corresponds to a vertical synchronization signal between the controller 201 and the engine control unit, and serves as a trigger for image data transmission for each page from the controller 201 to the engine control unit 203.

  If the next print reservation command has not been received by the next print operation start timing (hereinafter referred to as “normal print start timing”) for maintaining the throughput, the engine control unit 203 performs post-processing of the print operation ( Hereinafter, the “post-rotation sequence” is executed, and the printing operation is terminated (509). Note that the normal printing start timing is normally selected and given an optimum value due to restrictions such as a medium transport mechanism and an image forming mechanism. This value can also be obtained experimentally.

  If the print reservation command is received by the next normal print start timing and if the print start command for the print reservation command is received, the second print will be printed following the first print. The operation is started (502, 506).

  If the print reservation command has been received before the next normal print start timing and if the print start command has not been received, the post-rotation sequence is executed and the print start command is waited (508). Then, after receiving the print start command, the pre-rotation sequence is started (502).

  FIG. 3 is a communication sequence when two sheets are continuously printed on the same paper discharge bin.

  The controller 201 issues a print reservation command 1 (301) and a print reservation command 2 (302) to the engine control unit 203, and a discharge bin 1 discharge reservation command 1 (303) to the discharge option control unit 202. And a paper discharge bin 1 paper discharge reservation command 2 (304), and then a print start command 1 (304) is transmitted to the engine control unit 203.

  Upon receiving the print start command 1 (304), the engine control unit 203 executes a pre-rotation sequence, and then outputs a / TOP signal 1 (305) to the controller unit 201 to start an image forming operation. .

  The controller control unit 201 outputs a video signal in synchronization with the / TOP signal 1 (305), and outputs a print start command 2 (305) for the next print reservation command 2 (302).

  When the engine control unit 203 receives the print start command 2 (306), the engine control unit 203 transmits the / TOP signal 2 (308) to the controller 201 at the normal print start timing of the second sheet, and continues with the print reservation command. 2 (302) is continued.

  FIG. 4 is a timing chart of the engine control unit when two sheets are continuously printed on the same paper discharge bin. FIG. 4 is based on the assumption that print reservation commands for two sheets have already been transmitted from the controller unit 201.

  When the engine control unit 201 receives a print start command 1 (303) for the print reservation command for the first sheet, the engine control unit 201 starts a pre-rotation sequence. During the pre-rotation sequence, the engine control unit 203 applies the charging AC high voltage so as to rise at the end of the pre-rotation sequence 410, and after the pre-rotation sequence ends (simultaneously with the rising of the charging AC high voltage), the / TOP signal 1 (305 ) Is output to start the printing operation for the first sheet.

  When the engine control unit 203 receives the print start command 2 (306) by the normal print start timing (411) of the second sheet after transmitting the first / TOP signal 1 (305), the second sheet At the normal printing start timing (411), the / TOP signal 2 (307) is output, and the printing operation for the second sheet is started following the first sheet. Thereafter, when the print reservation command for the third sheet and the print start command are not received by the next normal print start timing, the post-rotation sequence is started and the print operation is ended. The engine control unit 203 stops the application of the charging AC high voltage simultaneously with the start of the post-rotation sequence (412).

  Next, a printing operation on different paper discharge bins will be described.

  FIG. 6 is a communication sequence when two sheets are continuously printed on different paper discharge bins.

  The controller 201 issues a print reservation command 1 (601) and a print reservation command 2 (602) for two sheets to the engine control unit 203, and a discharge bin 1 discharge reservation 1 (to the discharge option control unit 202). 603), a paper discharge bin 2 paper discharge reservation 2 (604) is transmitted. After transmitting the paper discharge bin 2 paper discharge reservation 2 (604), the controller 201 obtains the time required to move from the paper discharge bin 1 to the paper discharge bin 2 from the paper discharge option control unit 202 (605). .

  Thereafter, the controller 201 transmits a print start command 1 (606) to the engine control unit 203, whereby the engine control unit outputs the first / TOP signal 1 (607) and starts the printing operation. To do.

  When transmitting the print start command for the second sheet, the controller 201 needs to increase the interval between the first sheet and the second sheet as compared with a normal case by the time required for the sheet discharge option control unit 202 to switch the sheet discharge bin. is there.

  At this time, if the controller 201 transmits a print start command before the normal print start timing, the engine control unit 203 maintains the optimum throughput and continues the continuous printing (continues the continuous printing without expanding the paper interval). For this reason, the controller 201 needs to transmit the print start command 2 (609) at a timing at which a sheet space enough to discharge the transfer material to different paper discharge bins can be secured.

  FIG. 7 is a timing chart of the engine control unit when the transfer material is discharged to different discharge bins. FIG. 7 is based on the premise that print reservation commands for two sheets have already been transmitted from the controller unit 201.

  When engine control unit 201 receives print start command 1 (704), it starts the pre-rotation sequence. At the end of the pre-rotation sequence (705), the engine control unit 203 applies the charging AC high voltage so as to rise, and after the pre-rotation sequence ends, outputs the / TOP signal 1 (714) to perform the first printing operation. Start.

  In the case of successively discharging paper to different paper discharge bins, the controller 201 removes the paper discharge bin from the timing at which a sheet space sufficient to discharge the transfer material to different paper discharge bins can be secured, that is, from the normal print start timing (706). Only after the switching time C, the print start command 2 (708) is transmitted.

  Since the engine control unit 203 does not receive the print start command until the normal print start timing (706) (the paper discharge bin is not switched), the post-rotation sequence is once executed, and then the print start command 2 (708) is received. Wait and start the pre-rotation sequence.

  However, in the above-described sequence, the post-rotation sequence is executed after the first printing operation, and as a result, one printing operation is repeated twice. Therefore, originally, it is only necessary to widen the sheet interval by the time C required for switching the paper discharge bin, but the sheet interval is increased by the additional time D corresponding to the time of the previous rotation sequence. Extra downtime occurs only in front of the eye rotation sequence.

  In order to eliminate this down time, even if it is the normal print start timing (706), it waits for the print start command to be transmitted without executing the post-rotation sequence, and at the same time the print start command is received. The printing operation may be started.

  In FIG. 8, even if the print start command has not been received before the normal print start timing, if an unexecuted print reservation command is received, printing is started without executing the post-rotation sequence. The timing chart of the engine control part 203 in the case of waiting for a command is shown. FIG. 8 is based on the assumption that the print reservation command for two sheets has already been transmitted from the controller unit 201.

  When engine control unit 201 receives print start command 1 (806), it starts the pre-rotation sequence. The engine control unit 203 applies the charging AC high voltage so as to rise at the end of the pre-rotation sequence (807). Thereafter, simultaneously with the end of the pre-rotation sequence, the / TOP signal (815) is output to start the first printing operation.

  The controller 201 sends a print start command after a time C for switching the paper discharge bin after the next normal print start timing (816) (809).

  The engine control unit 203 does not send a print start command until the next normal print start timing (807), but has already received the print reservation command for the second sheet, so it does not start the post-rotation sequence and starts printing. Waiting for command. Thereafter, when a print start command (809) is received, a / TOP signal (817) is output, and the printing operation for two sheets is started.

  With the above sequence, even when the paper interval is widened, it is possible to prevent the occurrence of downtime as shown in FIG. 7 by the amount that the pre-rotation sequence is unnecessary before printing the second sheet.

  However, in this case, as compared with normal continuous printing, an extra charging AC bias is applied only during time C for switching the paper discharge bin.

  In general, the lifetime of the photosensitive drum mainly depends on the rotation time of the photosensitive drum and the application time of the charging AC high voltage applied to the photosensitive drum. Therefore, the life of the photosensitive drum is often set in consideration of these.

  For example, with regard to the charging AC high voltage, the charging AC high voltage is calculated based on the charging AC high voltage applied when printing one sheet (hereinafter referred to as “intermittent printing”).

  FIG. 10 shows a charging AC bias application state for intermittent printing. The charging AC high voltage is applied so as to rise immediately before the image formation start timing, and falls simultaneously with the start of the post-rotation sequence (1004). The life of the photosensitive drum is set with the rising period A, the falling period B, and the period (between 1003 and 1004) applied during the printing operation as the charging AC high voltage applied during intermittent printing.

  Therefore, in the sequence of FIG. 8, the charging AC high voltage application time is longer than the assumed charging AC high voltage application time by the period E (= C− (A + B)) compared to the set charging AC application time. This means that the photosensitive drum deterioration rate is faster than expected.

  The present invention has been made in view of the above prior art. For example, processing of an option control unit such as switching of paper discharge bins, or image development processing of a controller unit, etc., can not be continuously printed, and the paper interval is increased more than usual. Even in such a case, the purpose is to prevent useless downtime and delay the drum deterioration speed.

  In order to solve this problem, the invention according to the present application has the following configuration.

An image bearing member on which an image is formed, a charging unit for AC voltage Ru is applied to charge the image bearing member,
When the image formation of the first page and the image formation of the second page subsequent to the first page are executed at predetermined intervals, the charging unit is applied with an AC voltage applied to the charging unit. Control means for controlling the application operation of the AC voltage;
If image formation of the second page is not started at the preset interval after image formation of the first page is finished, the image of the second page based on the preset interval Transmission means for transmitting a delay time from the start of formation to the control means ,
When the control unit receives the delay time from the transmission unit and determines that the delay time is longer than a predetermined time , the control unit finishes image formation of the first page and then forms image of the second page. Application of the AC voltage to the charging unit is temporarily stopped before starting the charging, and when it is determined that the delay time is shorter than the predetermined time, the application of the AC voltage to the charging unit is continued. And

  According to the present invention, for example, processing of an optional control unit such as paper discharge bin switching, or image development processing of a controller unit, it is possible to reduce wasteful reduction even when continuous printing is not performed and the paper interval is increased more than usual. It has become possible to both prevent time and delay the deterioration rate of parts such as drum deterioration.

[Embodiment 1]
In this embodiment, the controller sends a print start command to the engine control unit when the paper interval is increased more than usual by processing of the option control unit such as paper discharge bin switching or image development processing of the controller unit. A method for postponing the post-rotation sequence (hereinafter referred to as “image formation timing postponement command”) before sending the image to prevent unnecessary downtime and delaying the deterioration rate of the photoconductor. Is.

  In the present embodiment, a case will be described in which the paper interval is increased more than usual by processing of an optional control unit such as paper discharge bin switching. The image forming apparatus (laser beam printer) itself is the same as that described with reference to FIGS.

<Communication sequence during printing>
FIG. 9 is a communication sequence (control of the controller 201) among the controller 201, the paper discharge option control unit 202, and the engine control unit 203 of the present embodiment.

  The controller 201 issues a print reservation command 1 (901) and a print reservation command 2 (902) for two sheets to the engine control unit 203, and a discharge bin 1 discharge reservation 1 (to the discharge option control unit 202). 903), the paper discharge bin 2 paper discharge reservation 2 (904) is transmitted. After transmitting the paper discharge bin 2 paper discharge reservation 2 (904), the controller 201 acquires the time Tt required to move from the paper discharge bin 1 to the paper discharge bin 2 from the paper discharge option control unit 202 (905). ).

  Thereafter, the controller 201 transmits a print start command 1 (906) to the engine control unit 203, so that the engine control unit starts the first print operation (outputs the / TOP signal 1 (907)). To do.

  Since the printing operation for the second sheet takes time to switch the paper discharge bin, the controller 201 adds the time required to widen the paper interval (hereinafter referred to as “postponement time”) until the normal printing start timing. An image formation timing postponement command is sent (909). The postponement time added to the image formation timing postponement command by the controller 201 is calculated based on the paper discharge bin switching time acquired from the paper discharge option control unit.

  When the cause of the delay is not the discharge bin switching, the delay time can be determined by a prediction process by the controller itself. As described in the section of the prior art, the controller 201 itself is configured with a processor as a core, and it is easy to perform such a prediction process by executing a program of a certain procedure. For example, when printing with banding processing, if there are a lot of objects included in the image to be printed and it takes a very long time for rendering processing, rendering may be performed in units of pages to prevent data underrun. is there. In such a case, since a print instruction is issued only after image data for one page is generated, there is a possibility that the space between pages may become clear. Therefore, the controller 201 estimates the time required for one page rendering based on the type and amount of the object, and the expected end time of rasterization of the page of interest after printing of the page immediately before the page of interest to be rasterized in units of pages is completed. The time until is determined as the delay time. Then, the delay time is added to the image formation timing postponement command and sent to the engine control unit 203.

  Thus, since the delay time can be predicted based on the cause of the delay, the delay time is determined by a method corresponding to the cause of the delay.

  Thereafter, the controller 201 sends a print start command for the second sheet by the postponed image formation timing (909), whereby the engine control unit is notified of the postponed image formation notified by the image formation timing postponement command. At the timing, the / TOP signal is output (911), and the image forming operation is started.

<Control procedure in engine control unit>
FIG. 13 is a flowchart of the engine control unit 203 of the present embodiment.

  Upon receiving the print reservation command, the engine control unit 203 waits for reception of a print start command (step 1301), and executes a pre-rotation sequence (step 1302). After completion of the pre-rotation sequence, the / TOP signal is output and the printing operation is started in accordance with the printing operation condition designated by the print reservation command for the first sheet (step 1303).

  If the next print reservation command has not been received by the normal print start timing, the engine control unit 203 executes post-processing of the print operation and ends the print operation (step 1315).

  If the next print reservation has been received before the normal print start timing for the second sheet, and if the image formation timing postponement command has not been received, the print start command for the second sheet print reservation is received. If it has been received, the second / TOP signal is output and image formation is started (steps 1306, 1312, and 1303). The rotation sequence is executed, and the reception of the print start command for the second sheet is awaited (steps 1313 and 1314).

  If the next print reservation command and the image formation timing postponement command are received before the normal printing start timing of the second sheet, the engine control unit 203 performs two processes in step 1307 depending on the designated postponement time. Branch to

(First process)
The first process is the case of FIG. When the designated postponement time C is longer than the time obtained by adding the time B (1107) for lowering the charging AC high voltage and the time A (1108) for raising the charging AC high voltage, the engine control unit 203 sets the second sheet At the normal printing start timing (1105), the charging AC high voltage is reduced (step 1308). Thereafter, the charging AC high voltage is applied so that the charging AC high voltage rises at the printing start timing (1105) of the second sheet after the delay time specified by the image formation timing delay command (timing 1109 in FIG. 11 and FIG. 13). Steps 1309 and 1310).

  After that, if the print start command has been received by the print start timing of the second sheet delayed by the delay time specified by the image formation timing postponement command, the / TOP signal is output and the second image formation is started. (Steps 1312, 1312, and 1303 in FIG. 13). If the print start command is not received by the print start timing of the second sheet that has been postponed for the time specified by the image formation timing postponement command, the post-rotation sequence is executed and the second print start command is sent. Wait (steps 1313 and 1314).

(Second process)
The second process is the case of FIG. If the designated postponement time C is shorter than the time obtained by adding the time B (1209) for lowering the charging AC high voltage and the time A (1210) for raising the charging AC high voltage, the engine control unit 203 If the print start command is received by the print start timing (1207) of the second sheet that is continuously applied and postponed for the time specified by the image formation timing postponement command, the / TOP signal is output and two sheets are output Is started (steps 1311 and 1312 in FIG. 13).

  On the other hand, if the print start command has not been received by the print start timing (1207) of the second sheet delayed by the time specified by the image formation timing postponement command, the post-rotation sequence is executed and the print start command is transmitted. (1313, 1314).

  With the control described above, even when the paper interval between the first page and the second page is increased more than usual by the processing of the option control unit such as paper discharge bin switching, the printing of the second page is started. Since the developing drum, which is a pretreatment, is charged in accordance with the time, useless downtime can be prevented. In addition, if the gap between the paper is longer than the time from when charging to the drum is temporarily stopped and then charging again and reaching the printable state, the drum deterioration speed is stopped by temporarily stopping the drum charging. Can be delayed.

  The above-described embodiment can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the invention. For example, the cause of the delay time is not necessarily caused by the processing of the option control unit, but may be caused by a delay in rendering. In addition, it is not limited to drum charging that should be stopped due to the extension between the sheets, but if the component is worn out in a standby state where printing can be performed immediately, the present invention can be applied to extend the service life. Can do.

  As described above, according to this embodiment, an instruction is given from the controller to the engine control unit so that printing can be started immediately without delay in accordance with the most critical processing in the image forming apparatus. In response to the instruction, it is further determined whether the operation of the consumable part, for example, charging of the drum should be stopped once.

[Embodiment 2]
The second embodiment is an embodiment in which image formation timing information is set for each sheet by adding delay time information of the image formation timing for each transfer material to the print reservation command. In this case, the engine control unit changes the control of the charging AC high voltage applied to the photoconductor according to the delay time information designated for each transfer material.

  In the present embodiment, a case will be described where delay information on image formation timing for each transfer material is added to the print reservation command in addition to the printing conditions for each transfer material. The image forming apparatus (laser beam printer) itself is the same as that described with reference to FIGS.

  FIG. 14 is a flowchart of the engine control unit 203 of the present embodiment. When the engine control unit 203 receives the print reservation command, it waits for the reception of the print start command (step 1401), and executes the pre-rotation sequence (step 1402). After completion of the pre-rotation sequence, the / TOP signal is output and the printing operation is started in accordance with the printing operation condition designated by the print reservation command for the first sheet (step 1403).

  If the next print reservation command has not been received by the normal print start timing, the engine control unit 203 executes post-processing of the print operation and ends the print operation (steps 1405 and 1415).

  If the next print reservation has been received before the normal print start timing for the second sheet, and the postponement time for the image formation timing is not specified in the print reservation, the print reservation for the second sheet It is determined whether or not a print start command has been received. If it has been received, the second / TOP signal is output to start image formation (steps 1406, 1412, and 1403). If not, the post-rotation sequence is executed and the reception of the print start command for the second sheet is awaited (steps 1413 and 1414).

  If the next print reservation command has been received before the normal print start timing for the second page, and if the print reservation command specifies a postponement time for image formation timing, the Depending on the postponement time, one of the following two processes is performed.

(First process)
If the designated postponement time C is longer than the time obtained by adding the time B (time 1107 in FIG. 11) for lowering the charging AC high voltage and the time A (time 1108 in FIG. 11) for raising the charging AC high voltage, engine control is performed. The unit 203 reduces the charging AC high voltage at the printing operation timing of the second sheet when the postponement time is not specified (timing 1105 in FIG. 11) (step 1408). Thereafter, at the printing start timing of the second sheet after the postponement time specified by the print reservation command (timing 1105 in FIG. 11), application of the charging AC high voltage is started so that the charging AC high voltage rises (timing in FIG. 11). 1109, steps 1409 and 1410 in FIG. 14, and if the print start command has been received by the end of the postponement time, the / TOP signal is output and the second image formation is started (steps 1412 and 1403). If the print start command is not received by the end of the postponement time, the post-rotation sequence is executed and the transmission of the print start command for the second sheet is waited (steps 1413 and 1414).

(Second process)
On the other hand, when the designated postponement time C is shorter than the time obtained by adding the time B (time 1209 in FIG. 12) for lowering the charging AC high voltage and the time A (time 1210 in FIG. 12) for raising the charging AC high voltage, The engine control unit 203 continues to apply the charging AC high voltage. If the print start command has been received before the print start timing for the second sheet after the postponement time (timing 1207 in FIG. 12), the / TOP signal is output to start the print operation for two sheets (step 1411, 1412) If the print start command is not received by the end of the postponement time, the post-rotation sequence is executed and the transmission of the print start command for the second sheet is waited (steps 1413 and 1414).

  As described above, the postponement time is included in the print reservation command, and the same effect as in the first embodiment can be achieved. That is, it is possible to prevent wasteful downtime and delay the drum deterioration speed even when the paper interval is increased more than usual by processing of the option control unit such as paper discharge bin switching.

  In the present embodiment, in the procedure of FIG. 6, the delay time due to the change of the discharge bin cannot be notified to the engine control unit at the time of print reservation. For this reason, in the present embodiment, it is desirable to perform processing in advance for matters that may cause a gap between sheets before print reservation. Referring to FIG. 6, the print reservation commands 601 and 602 are issued after receiving the paper discharge bin change time notification 605.

  Alternatively, in combination with the first embodiment, if there is a cause of the gap between the papers known at the time of printing reservation issuance, the postponement time resulting therefrom is transmitted to the engine control unit by a printing reservation command, and the paper that has been found after the printing reservation command is issued If there is a cause for the extension, the engine control unit is notified of this by an image formation timing postponement command.

  In this case, the engine control unit performs the process of step 1306 of FIG. 13 immediately before step 1406 of FIG. 14, branches to step 1406 if the determination result is “No”, and if “Yes”. Processing branches to step 1407. That is, if the delay time information is given by any command, the specified postponed time is tested in step 1407, and if it is not given by any command, it is treated as having no delay. To advance.

  The above-described embodiment can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the invention.

[Embodiment 3]
In the third embodiment, a case where delay time information of image formation timing for each transfer material is added to a print start command transmitted from the controller to the engine control unit will be described. The image forming apparatus (laser beam printer) itself is the same as described with reference to FIGS.

  In this case, the engine control unit changes the control of the charging AC high voltage applied to the photoconductor according to the delay time information of the image formation timing designated by the print start command.

  FIG. 15 is a flowchart of the engine control unit 203 of the present embodiment. When the engine control unit 203 receives the print reservation command, it waits for the reception of the print start command (step 1501) and executes the pre-rotation sequence (step 1502). After completion of the pre-rotation sequence, a / TOP signal is output and a printing operation is started in accordance with the printing reservation command for the first sheet (step 1503).

  If the next print reservation command has not been received by the normal print start timing of the second sheet, the engine control unit 203 executes post-processing of the print operation and ends the print operation (steps 1505 and 1515). .

  When the next print reservation is received by the normal print start timing of the second sheet, and the engine start unit 203 has not received a print start command for the print reservation, the engine control unit 203 performs the post-rotation sequence. To wait for transmission of the print start command for the second sheet (steps 1513 and 1514).

  The engine control unit 203 receives the next print reservation by the normal print start timing of the second sheet, and the image formation timing postponement time is specified by the print start command for the print reservation. In this case, one of the following two processes is performed depending on the designated postponement time.

  If the designated postponement time C is longer than the time obtained by adding the time B (time 1107 in FIG. 11) for lowering the charging AC high voltage and the time A (time 1108 in FIG. 11) for raising the charging AC high voltage, engine control is performed. The unit 203 reduces the charging AC high voltage at the normal printing start timing of the sheet (timing 1105 in FIG. 11) (step 1508).

  Thereafter, after the postponement time specified by the print start command has elapsed (timing 1105 in FIG. 11), application of the charging AC high voltage is started so that the charging AC high voltage rises (timing 1109 in FIG. 11, step 1510 in FIG. 1511) After the charging AC high voltage rises, the / TOP signal is output to start image formation for the second sheet (steps 1512 and 1503).

  When the designated postponement time C is shorter than the time obtained by adding the time B (time 1209 in FIG. 12) for lowering the charging AC high voltage and the time A (time 1210 in FIG. 12) for raising the charging AC high voltage, engine control is performed. The unit 203 continues to apply the charging AC high voltage, and after the postponement time, outputs the / TOP signal and starts the printing operation for two sheets (steps 1512 and 1503).

  As described above, it is possible to prevent wasteful downtime and delay the drum deterioration speed even when the paper interval is increased more than usual by the processing of the option control unit such as paper discharge bin switching. Become.

  Furthermore, in this embodiment, except that the print start command may include a postponement time, the same command as in the past may be issued at exactly the same timing, so there are few changes to the controller configuration and development. Etc. can be reduced.

  In this embodiment, since the printing sequence starts when the delay time notified by the print start command has elapsed, a problem may arise when the delay time predicted by the controller does not match the actual delay time. . Therefore, in order to solve this, when the predicted delay is shorter than the actual delay, the delay is extended by the image formation delay timing command, and in the opposite case, the currently proceeding delay is canceled. A method of providing a command for starting printing immediately can be considered.

  The above-described embodiment can be variously modified based on the gist of the present invention, and it is the same as that of the first embodiment that these are not excluded from the scope of the invention.

[Embodiment 4]
In the fourth embodiment, image formation timing information is set for each sheet by sending an image formation timing postponement command before sending a print reservation command for each sheet. In this case, the engine control unit changes the control of the charging AC high voltage applied to the photoconductor according to the delay time information designated for each transfer material.

  The image forming apparatus (laser beam printer) itself is the same as that described with reference to FIGS.

  FIG. 16 is a flowchart of the engine control unit 203 of the present embodiment. When receiving the print reservation command, the engine control unit 203 waits for the reception of the print start command (step 1601) and executes the pre-rotation sequence (step 1602). After completion of the pre-rotation sequence, the / TOP signal is output and the printing operation is started in accordance with the printing operation condition designated by the print reservation command for the first sheet (step 1603).

  If the next print reservation command is not received by the normal print start timing, the engine control unit 203 executes post-processing of the print operation and ends the print operation (steps 1605 and 1615).

  If the next print reservation has been received before the normal print start timing for the second sheet, and if the image formation timing postponement command has not been received before receiving the print reservation, the second sheet print reservation Whether or not a print start command is received is determined, and if received, the second / TOP signal is output to start image formation (steps 1606, 1612, and 1603) and received. If not, the post-rotation sequence is executed and the reception of the print start command for the second sheet is awaited (steps 1613 and 1614).

  If the next print reservation command has been received before the normal print start timing for the second sheet, and if the image formation timing postponement command has been received before the print reservation is received, the image formation timing postponement command Depending on the postponement time specified in, one of the following two processes is performed.

(First process)
If the designated postponement time C is longer than the time obtained by adding the time B (time 1107 in FIG. 11) for lowering the charging AC high voltage and the time A (time 1108 in FIG. 11) for raising the charging AC high voltage, engine control is performed. The unit 203 reduces the charging AC high voltage at the printing operation timing of the second sheet when the postponement time is not designated (timing 1105 in FIG. 11) (step 1608). Thereafter, application of the charging AC high voltage is started so that the charging AC high voltage rises at the printing start timing of the second sheet after the postponement time specified by the image formation timing postponement command has elapsed (timing 1105 in FIG. 11) (FIG. 11). When the print start command is received by the end of the postponement time, the / TOP signal is output and the second sheet image formation is started (steps 1612 and 1603). . If the print start command is not received by the end of the postponement time, the post-rotation sequence is executed and the transmission of the print start command for the second sheet is waited (steps 1613 and 1614).

(Second process)
On the other hand, when the designated postponement time C is shorter than the time obtained by adding the time B (time 1209 in FIG. 12) for lowering the charging AC high voltage and the time A (time 1210 in FIG. 12) for raising the charging AC high voltage, The engine control unit 203 continues to apply the charging AC high voltage. If the print start command is received before the print start timing for the second sheet after the postponement time (timing 1207 in FIG. 12), the / TOP signal is output to start the print operation for two sheets (step 1611, 1612) When the print start command is not received by the end of the postponement time, the post-rotation sequence is executed and the transmission of the print start command for the second sheet is waited (steps 1613 and 1614).

  As described above, the image formation timing postponement command is transmitted before the print reservation command, and the same effect as in the first embodiment can be achieved. That is, it is possible to prevent wasteful downtime and delay the drum deterioration speed even when the paper interval is increased more than usual by processing of the option control unit such as paper discharge bin switching.

  In the present embodiment, in the procedure of FIG. 6, the delay time due to the change of the discharge bin cannot be notified to the engine control unit at the time of print reservation. For this reason, in the present embodiment, it is desirable to perform processing in advance for matters that may cause a gap between sheets before print reservation. Referring to FIG. 6, the print reservation commands 601 and 602 are issued after receiving the paper discharge bin change time notification 605.

  The above-described embodiment can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the invention.

  In addition, the present invention can be applied to a system composed of a plurality of devices (for example, a host computer, interface device, reader, printer, etc.), or a device (for example, a copier, a facsimile device, etc.) composed of a single device. You may apply to.

  Another object of the present invention is to supply a storage medium (or recording medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded to a system or apparatus, and the computer (or CPU or (MPU) can also be achieved by reading and executing the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an operating system (OS) running on the computer based on the instruction of the program code. A case where part or all of the actual processing is performed and the functions of the above-described embodiments are realized by the processing is also included.

  Furthermore, after the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the function is based on the instruction of the program code. This includes a case where the CPU of the expansion card or the function expansion unit performs part or all of the actual processing and the functions of the above-described embodiments are realized by the processing.

1 is an overall configuration diagram of a laser printer as an image forming apparatus. 1 is a schematic system diagram of a laser printer as an image forming apparatus. It is a figure of the communication sequence 1 as a prior art example. It is the figure of the sequence chart 1 of the engine control part as a prior art example. It is a flowchart of the engine control part as a prior art example. It is a figure of the communication sequence 2 as a prior art example. It is the sequence chart 2 of the engine control part as a prior art example. It is the sequence chart 3 of the engine control part as a prior art example. FIG. 4 is a communication sequence according to the first embodiment. It is explanatory drawing of the charging AC high voltage | pressure application time as a prior art example. FIG. 3 is an explanatory diagram 1 of a printing time of charging AC high voltage according to the first embodiment, the second embodiment, and the third embodiment. FIG. 6 is an explanatory diagram 2 of a charging AC high voltage printing time according to the first embodiment, the second embodiment, and the third embodiment. 3 is a flowchart of an engine control unit according to the first embodiment. 6 is a flowchart of an engine control unit according to the second embodiment. 10 is a flowchart of an engine control unit according to the third embodiment. 6 is a flowchart of an engine control unit according to a fourth embodiment.

Explanation of symbols

2 Density sensor 6 Color misregistration measurement sensor 18 Drive roller 19 Pre-registration sensor 20 Fixing discharge sensor 23 Lower conveyance sensor A
24 Upper transport sensor A
25 Lower transport sensor B
26 Upper transport sensor B
27 Pre-fixing sensor 28 Paper discharge sensor

Claims (9)

An image bearing member on which an image is formed, a charging unit for AC voltage Ru is applied to charge the image bearing member,
When the image formation of the first page and the image formation of the second page subsequent to the first page are executed at predetermined intervals, the charging unit is applied with an AC voltage applied to the charging unit. Control means for controlling the application operation of the AC voltage;
If image formation of the second page is not started at the preset interval after image formation of the first page is finished, the image of the second page based on the preset interval Transmission means for transmitting a delay time from the start of formation to the control means ,
When the control unit receives the delay time from the transmission unit and determines that the delay time is longer than a predetermined time , the control unit finishes image formation of the first page and then forms image of the second page. Application of the AC voltage to the charging unit is temporarily stopped before starting the charging, and when it is determined that the delay time is shorter than the predetermined time, the application of the AC voltage to the charging unit is continued. An image forming apparatus. And the predetermined time after completion of image formation of the first page, until the charging unit is shifted to the stopped state through the completion operations including falling operation necessary to stop the operation of applying the AC voltage time and, in order to start image formation of the second page, the time until the charging section resumes the application operation through a preparatory operation including the start-up operation required to apply the AC voltage the image forming apparatus according to claim 1, wherein the time der Rukoto obtained by adding. A stacking device having a plurality of stacking units for stacking recording media discharged from the image forming apparatus is detachable;
The recording medium of the first page is imaged into a first stacking section, when the stacked recording medium in which the second page is the image formed to the second stacking section, the delay time, the second the image forming apparatus according to claim 1 or claim 2, characterized in that the first stacking portion including the time required to switch the discharge destination to the second stacking section. Further comprising an image processing means for processing the image information from an external device,
The transmission unit further transmits an instruction to start image formation of the first page and the second page to the control unit according to a processing result of the image processing unit ;
The transmission unit, an image forming apparatus according to any one of claims 1 to 3, characterized in that transmitting the delay time after sending an instruction to start image formation of the first page. Image processing means for processing image information from an external device ;
The transmitting means further transmits image information of the first page and the second page generated by the image processing means to the control means,
The transmission unit, said when transmitting the image information of the second page, the image forming apparatus according to any one of claims 1 to 3, characterized in that also transmits the delay time. Image processing means for processing image information from an external device ;
The transmission unit further transmits an instruction to start image formation of the first page and the second page to the control unit according to a processing result of the image processing unit ;
The transmission unit, when transmitting the start instruction of image formation of the second page, the image forming according to any one of claims 1 to 3, characterized in that also transmits the delay time apparatus. The delay time, the image forming apparatus according to any one of claims 4 to 6, characterized in that it comprises a time to process the image information by the image processing means. 2. The control unit according to claim 1, wherein when the application of the AC voltage to the charging unit is temporarily stopped , the AC voltage application operation to the charging unit is started according to the delay time. The image forming apparatus according to claim 7 . The control means according to claim 8, characterized in that to start the application operation at the time the time difference between the delay time and the predetermined time from the start of image formation of the second page has elapsed Image forming apparatus.

Images