PRINTING SYSTEM, CONTROL METHOD THEREFOR, AND STORAGE MEDIUM

A method of controlling a printing system including a printing apparatus that prints an image on a sheet and a charge eliminating apparatus that performs a charge eliminating process on the sheet on which the image is printed includes measuring an amount of charge on the sheet that has undergone the charge eliminating process performed by the charge eliminating apparatus, and displaying a message prompting a user to change a setting for charge elimination to be performed by the charge eliminating apparatus in a case where the amount of charge on the sheet measured in the measuring does not fall within a predetermined range.

BACKGROUND

Field of the Disclosure

The present disclosure relates to a printing system, a method of controlling the printing system, and a storage medium.

Description of the Related Art

A recording medium (hereinafter, referred to as a “sheet”) used in printing operation is conveyed while being charged with static electricity as residual charge in an electrophotographic process or due to slight friction with conveying rollers or guides generated during sheet conveyance. The static electricity can cause some sheets to stick to each other. In addition, the static electricity causes dust and paper powder to adhere to a printed sheet, degrading the quality of the printed sheet.

Some kinds of sheets, such as plain paper, have low electrical resistance, with which the charge easily moves in the paper, the amount of charge itself is small, and thus the charge is quickly eliminated. However, other kinds of sheets made of synthetic resin (plastic), such as thick paper, synthetic paper, and coated paper, have high electrical resistance, with which movement of the charge is unlikely to occur in the paper. As a result, these kinds of sheets, such as synthetic paper and coated paper, are more likely to be charged and to have residual charges. It is generally known that these kinds of sheet are easily affected by the environment, particularly the humidity, and because of the influence of decrease in the amount of electric discharge into the air with low humidity in the environment, these kinds of sheet are easily charged with static electricity.

If sheets sticking to each other undergo a post-process, the sheets would affect an alignment process of sheets. This would not only degrade the quality in the post-process, but also cause a sheet feeding failure or a conveyance failure in the post-process, resulting in a jam, which could damage sheets or devices.

In order to avoid such a risk, it is desirable to eliminate static electricity on a sheet after a printing process before a post-process is performed. Japanese Patent Application Laid-Open No. 11-258881 discusses a technique of applying a voltage to a pair of conveying rollers located downstream in a sheet conveying direction to neutralize electric charges on sheets.

Charge elimination with a configuration in which a voltage is applied to a conveying roller (hereinafter, referred to as “charge eliminating roller”) involves giving a charge of the opposite polarity to a charge on a sheet via the charge eliminating roller to the sheet to neutralize the charge on the sheet. With this configuration, the amount of charge to be eliminated by the charge eliminating roller (application of a charge of the opposite polarity to the charge on the sheet to the charge eliminating roller) needs to be set in accordance with the amount of the charge on the sheet. In other words, there is an optimum charge adjustment value for charge elimination for each printing environment, such as humidity, and each type of sheet. The effect of charge elimination performed by the charge eliminating roller can vary depending on the condition, which requires that the user can check the effect of charge elimination of the printed sheet during the printing process. However, the user cannot determine whether the printed sheet with a sufficient effect of charge elimination is output during the printing process. As a result, some printed sheets with insufficient effects of charge elimination are output even though the printing apparatus includes the charge eliminating roller.

SUMMARY

Some embodiments of the present disclosure are directed to providing a printing system allowing charge elimination with an appropriate amount of charge in accordance with a printing environment and the type of a sheet.

According to an aspect of the present disclosure, a printing system including a printing apparatus that prints an image on a sheet and a charge eliminating apparatus that performs a charge eliminating process on the sheet on which the image is printed includes a measurement unit configured to measure an amount of charge on the sheet that has undergone the charge eliminating process performed by the charge eliminating apparatus, and a display unit configured to display a message for prompting a user to change a setting for charge elimination to be performed by the charge eliminating apparatus in a case where the amount of charge on the sheet measured in the measurement does not fall within a predetermined range.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, an exemplary embodiment for implementing the present disclosure will be described with reference to the drawings.

The following exemplary embodiment does not limit every embodiment according to the appended claims, and not all combinations of features described in the exemplary embodiment are used for the solving means of every embodiment.

Entire Configuration of System

FIG.1illustrates the entire configuration of a system according to the exemplary embodiment. The system includes a printing system1000and a client computer102(hereinafter, referred to as a “personal computer (PC)102”). These are connected to each other via a network101. The PC102can transmit page description language (PDL) code data as a print job to the printing system1000via the network101.

Hardware Configuration of Printing System

FIG.2is a hardware block diagram of the printing system1000. The printing system1000includes a printing apparatus100, which is surrounded by a dotted line inFIG.2, and a sheet processing apparatus200. A desired number of the sheet processing apparatuses200can be connected to the printing apparatus100. In the present exemplary embodiment, a multi-function peripheral (MFP) with a plurality of functions, such as a copy function and a printer function, will be described as an example of the printing apparatus100. Alternatively, the printing apparatus100may be a single-function printing apparatus with only a copy function or a printer function.

In the printing system1000, sheet processes can be performed on sheets printed by the printing apparatus100by the sheet processing apparatus200connected to the printing apparatus100. Alternatively, the printing apparatus100can constitute the printing system1000, with the sheet processing apparatus200disposed separately from the printing apparatus100.

The sheet processing apparatus200can communicate with the printing apparatus100, and perform a sheet process as described below in response to an instruction from the printing apparatus100.

A scanner unit201reads an image on a document, converts the image into image data, and transfers the image data to another unit.

An external interface (I/F)202performs data transmission and reception with external devices connected to the network101.

A printer unit203prints images based on input image data on sheets.

An operation unit204includes a touch panel unit401and a hard key input unit402as illustrated inFIG.4, and receives instructions from users via these units. The operation unit204performs various kinds of display on the touch panel unit401included in the operation unit204.

A control unit205integrally controls processes and operations performed by various units included in the printing system1000. In other words, these operations to be controlled include operations of the printing apparatus100and the sheet processing apparatus200connected to the printing apparatus100.

A read-only memory (ROM)207stores various computer programs executed by the control unit205.

For example, the ROM207stores a program for causing the control unit205to perform various processes of a flowchart described below and a display control program for displaying various setting screens described below. The ROM207also stores a program for causing the control unit205to interpret PDL code data received from the PC102and process the PDL code data into raster image data. In addition, the ROM207stores a boot sequence, font information, and thresholds for amounts of charge for determining the effect of charge elimination described below.

A random-access memory (RAM)208stores image data sent from the scanner unit201and PDL code data from the external I/F202, and various programs and setting information loaded from the ROM207. The RAM208also stores information about the sheet processing apparatus200(information about the type and functions of the sheet processing apparatus200connected to the printing apparatus100). The control unit205can use the information about the sheet processing apparatus200stored in the RAM208for control.

A hard-disk drive (HDD)209includes hard disks and a drive that reads and writes data from and to the hard disks. The HDD209is a large-capacity storage device for storing image data input from the scanner unit201and compressed by a compression/decompression unit210.

The control unit205can cause the printer unit203to print image data stored in the HDD209based on an instruction from a user. The HDD209is also used as a spooler, and the control unit205can manage PDL code data received from the PC102as a print job and store it in the HDD209. The control unit205can manage print jobs stored in the HDD209and also acquire the number of stored print jobs and setting information set in the print jobs.

The compression/decompression unit210performs compression/decompression operations on image data and other data stored in the RAM208and the HDD209by using various compression methods, such as Joint Bi-level Image Experts Group (JBIG) and Joint Photographic Experts Group (JPEG).

A hardware configuration of the printing system1000will now be described with reference toFIG.3.FIG.3is a sectional view of the printing apparatus100and the sheet processing apparatus200connected to the printing apparatus100. The sheet processing apparatus200includes a charge eliminating apparatus200-3aand a saddle-stitched bookbinding apparatus200-3b.

First, the printing apparatus100will be described. An automatic document feeder (ADF)301separates a bundle of documents set on the stacking surface of a document tray in order of pages from the first page of the documents, and conveys the documents onto a document table glass for the scanner302to scan the documents.

The scanner302reads images of the documents conveyed on the document table glass, and a charge-coupled device (CCD) converts the images into image data.

A rotary polygon mirror (polygon mirror or another type of mirror)303causes light beams, such as laser beams, modulated in accordance with image data to be incident on a photosensitive drum304as reflected scanning light via a reflection mirror.

The laser beams form a latent image on the photosensitive drum304, the latent image is developed with toner, and the toner image is transferred to a sheet attached on a transfer drum305. This image forming process is sequentially performed with toners of yellow (Y), magenta (M), cyan (C), and black (K), forming a full-color image. After the image forming process is performed four times, the sheet on which the full-color image is formed on the transfer drum305is separated by a stripper finger306, and is conveyed to a fixing device308by a pre-fixing conveying device307.

The fixing device308is formed with a combination of rollers and a belt, and includes a heat source inside, such as a halogen heater. The fixing device308melts and fixes the toner, which is the toner image transferred on the sheet, by heat and pressure.

A sheet ejecting flapper309is swingable about its swing shaft to define the direction of conveying sheets. With the sheet ejecting flapper309swung in the clockwise direction inFIG.3, the sheet is conveyed straight and ejected to the outside of the printing apparatus100by a sheet ejecting roller310. The control unit205controls the printing apparatus100to perform simplex printing through the above-described sequence.

On the other hand, to form images on both sides of a sheet, the sheet ejecting flapper309is swung in the counterclockwise direction inFIG.3, the path of the sheet is changed downward, and the sheet is sent to a duplex conveyance unit. The duplex conveyance unit includes a reversing flapper311, a reversing roller312, a reversing guide313, and a duplex tray314.

The reversing flapper311is swung about its swing shaft to define the direction of conveying sheets. To process a duplex print job, the control unit205performs control to swing the reversing flapper311in the counterclockwise direction inFIG.3and feed the sheet of which a first surface has been printed by the printer unit203to the reversing guide313via the reversing roller312. Then, the reversing roller312is temporarily stopped with the trailing end of the sheet nipped by the reversing roller312, and the reversing flapper311is subsequently swung in the clockwise direction inFIG.3. In addition, the reversing roller312is rotated in the reverse direction. This reverses and conveys the sheet, and the sheet is controlled to be guided to the duplex tray314with the trailing edge and the leading edge of the sheet being switched. The sheet is once put on the duplex tray314, and then the sheet is sent to a registration roller316again by a re-feeding roller315. At this time, the sheet has been fed with the surface opposite to the first surface of the sheet in the transfer process of the first surface facing the photosensitive drum304. Then, an image for a second surface is formed on the second surface of the sheet similarly to the above-described process. Then, the images are formed on both sides of the sheet, and the sheet undergoes the fixing process, and is ejected from the inside of the main body of the printing apparatus100via the sheet ejecting roller310to the outside of the printing apparatus100. The control unit205controls the printing apparatus100to perform the duplex printing process through the above-described sequence.

Charge Eliminating Apparatus

The charge eliminating apparatus200-3awill now be described.FIG.5is a system block diagram of the charge eliminating apparatus200-3a. The charge eliminating apparatus200-3aalso includes a control unit501, which is separate from the printing apparatus100. The control unit501integrally manages the entire charge eliminating apparatus200-3awhile communicating with the control unit205of the printing apparatus100inFIG.2via a bus (not illustrated).

An operation unit502is configured as illustrated inFIG.6, and the user can perform settings for the charge eliminating apparatus200-3avia the operation unit502.

A mode setting switch601inFIG.6switches whether to perform charge elimination by the charge eliminating apparatus200-3a(ON/OFF). The control unit501performs control to perform a charge eliminating process at a charge eliminating processing unit503described below only with the switch turned ON.

An adjustment dial602as a thumb rotary switch is used for adjusting the intensity of charge eliminating control performed with the mode setting switch601turned ON, and is controlled by the control unit501to be activated only with the mode setting switch601turned ON.

The charge eliminating processing unit503includes a charge eliminating roller322and an ionizer323, and a voltage application controller321for each of them, all of which will be described below, and is a unit that serves to perform the charge eliminating process on sheets conveyed in the charge eliminating processing unit503. The control unit501performs control of applying voltages to the charge eliminating roller322via the voltage application controller321and the ionizer323.

A ROM504stores a boot program for the charge eliminating apparatus200-3a, a control program for the operation unit502, a charge eliminating processing program for the charge eliminating processing unit503, and other kinds of program. The control unit501loads a relevant program from the ROM504to the RAM505as appropriate and executes the program.

The charge eliminating process performed by the charge eliminating processing unit503will now be described with reference toFIG.7.

FIG.7is a schematic diagram illustrating the charge eliminating process performed by the charge eliminating apparatus200-3aon a sheet that has undergone a printing process performed by the printing apparatus100. First, a sheet701is conveyed to a development and transfer portion including the photosensitive drum304and the transfer drum305via a conveying path704, and a charged toner702is placed on the sheet. The charged toner702on the sheet is negatively charged, and the sheet701to which the charged toner702is fixed by the fixing device308is conveyed to the charge eliminating apparatus200-3awith a printed surface703negatively charged. The charge eliminating apparatus200-3aincludes the charge eliminating roller322charged positively (+). The charge eliminating roller322applies a positive charge to the printed surface703charged negatively (−) by contact charge elimination to clear the charged state. Further, it is assumed that a negative charge that has not been eliminated through the charge eliminating process performed by the charge eliminating roller322or a positive charge that has been reversely charged remains on a sheet705that has passed the charge eliminating roller322. Thus, in the charge eliminating apparatus200-3aaccording to the present exemplary embodiment, the ionizer323is disposed downstream from the charge eliminating roller322. The ionizer323is a device that generates corona discharge by applying a voltage to an electrode needle provided in the device and eliminates a charge using ions generated by the corona discharge. In this way, the charge on the printed surface703is roughly eliminated by the charge eliminating roller322, and the residual charge is adjusted by the ionizer323, bringing the sheet707that has undergone the charge eliminating process and is ejected from the charge eliminating processing200-3ainto being in a state where the charge is eliminated. In the present exemplary embodiment, a charge amount measuring unit708that measures amounts of charge on a sheet after the printing process is further provided, and is connected so as to be able to notify measured numerical values.

Here, returning to the description using the sectional view ofFIG.3, the charge eliminating apparatus200-3aincludes the charge eliminating roller322and a roller paired with the charge eliminating roller322. A sheet conveyed to the charge eliminating apparatus200-3ais conveyed and subjected to the above-described rough charge elimination performed by the charge eliminating roller322while being sandwiched between the rollers. Thereafter, the sheet is conveyed to the outside of the charge eliminating apparatus200-3aby a conveying roller324, and the charge eliminating process for the residual charge on the sheet is performed by the ionizer323.

The saddle-stitched bookbinding apparatus200-3bwill now be described. The sheet processes performed by the saddle-stitched bookbinding apparatus200-3bincludes, for example, a saddle stitching process, a punching process, a cutting process, a shift sheet ejecting process, a folding process, and a stapling process. These jobs are referred to as “saddle-stitched bookbinding jobs”.

To process a saddle-stitched bookbinding job, first, the control unit205conveys the sheets of the job printed by the printing apparatus100to the saddle-stitched bookbinding apparatus200-3b, and then causes the saddle-stitched bookbinding apparatus200-3bto perform the sheet process(es) of the job. The control unit205causes a sheet ejecting destination Z of the saddle-stitched bookbinding apparatus200-3bto hold the printed sheets of the saddle-stitched bookbinding job, the printed sheets having undergone the sheet process(es) performed by the saddle-stitched bookbinding apparatus200-3b. The sheet ejecting destination Z includes a plurality of sheet ejecting destination candidates. These candidates are used when the saddle-stitched bookbinding apparatus200-3bcan perform a plurality of types of sheet process and a sheet ejecting destination is assigned to the corresponding sheet process of the sheet processes. In the present exemplary embodiment, a detailed description of a conveyance procedure of the saddle-stitched bookbinding job will be omitted.

Printing Process Procedure

A printing process executed by the printing system1000will now be described with reference to the flowchart ofFIG.8and using display examples of user interface (UI) screens of the touch panel unit401of the operation unit inFIGS.9,10,11, and12. This printing process is implemented by the control unit205, which is a central processing unit (CPU), loading programs stored in the ROM207and the HDD209into the RAM208and executing the programs.

This printing process is started when a print job is input to the printing system1000.

In step S801, the control unit205reads the threshold data for determining the effect of charge elimination of a printed sheet that is output from the ROM207, and stores the threshold data in the RAM208while the job is being executed. The charge threshold data in the present exemplary embodiment includes two values, i.e., an upper limit and a lower limit.

In step S802, the control unit205controls the printing apparatus100to performs a print process on the first page, and the charge eliminating apparatus200-3ato perform the charge eliminating process on the sheet707.

Subsequently, in step S803, the control unit205controls the charge amount measuring unit708to measure amounts of charge on the sheet707that has undergone the charge eliminating process performed by the charge eliminating apparatus200-3a. The control unit205receives a notification of measured numerical values as the amounts of charge.

In step S804, the control unit205compares the measured amounts of charge with the predetermined charge threshold data stored in the RAM208. In the comparison performed here, two determinations are made: whether the effect of charge elimination is sufficient because the numerical values as the amounts of charge on the sheet707are smaller than the threshold as the upper limit, and whether the charge elimination is excessive and the sheet is reversely charged because the numerical values as the amounts of charge on the sheet707are greater than the threshold as the lower limit. The determination results and the actually measured values are recorded in the HDD209, and are referred to in subsequent steps S805and S808.

In step S805, the control unit205refers to an upper limit and a lower limit of the amounts of charge of the actually measured values recorded in the HDD209in step S804, and determines whether both the upper limit and the lower limit fall within the range between the predetermined thresholds. If the actually measured values fall within the range between the thresholds (YES in step S805), the printing process proceeds to step S811and the printing process is continued. If the actually measured values do not fall within the range between the thresholds (NO in step S805), the printing process proceeds to step S806.

In step S811, it is determined whether the page is the last page. If the page is the last page (YES in step S811), the job is completed. If the page is not the last page (NO in step S811), the printing process returns to step S803, and the printing process is continued by repeating the procedure of step S803and subsequent steps up to the last page.

In step S806, the control unit205determines the sheet type of the sheet. If the sheet type is plain paper (YES in step S806), the printing process proceeds to step S811to continue the printing process. This is because even though the plain paper is charged, the charged state is quickly cleared. Thus, even if the plain paper is in the charged state in which a numerical value as an amount of charge of the plain paper exceeds a predetermined threshold, no treatment is required because the charged state does not cause the quality of the print output to be degraded. On the other hand, if the sheet type is a type other than the plain paper in step S806, for example, the sheet type is coated paper, in which amounts of charge can affect the quality of the printed sheet (NO in step S806), the control unit205advances the printing process to step S807.

In step S807, the control unit205sets the print job to a suspended state.

Subsequently, in step S808, the control unit205displays, on the touch panel unit401, a user UI screen for displaying a message for prompting the user to change a setting value for the amount of charge, as illustrated inFIG.9or11, based on the determination results of the thresholds for the amounts of charge recorded in step S804.FIG.9illustrates a UI screen for monitoring the numerical values measured by the charge amount measuring unit708and notified to the control unit205, and is an example of a display when a setting value for charge elimination produces a small effect and an amount of charge exceeding the threshold as the upper limit remains on the sheet707.FIG.11illustrates an example of a UI screen displayed when a setting value for charge elimination produces a large effect, and the sheet707is reversely charged and a numerical value as an amount of charge exceeds the lower limit as a charge threshold. An example of the UI screen ofFIG.9will be described. The control unit205notifies the user that the effect of charge elimination is insufficient and that a job resumption operation is performed after the setting value for charge elimination is reset on the operation unit502of the charge eliminating apparatus200-3ato produce a larger effect, in a message area of a field902, while displaying the current measurement value in a field901.

In step S809, the control unit205acquires the setting value for charge elimination to produce a larger effect reset by the user on the UI screen, and transmits the setting value for charge elimination to the charge eliminating apparatus200-3a.

When a “to job status screen” button903inFIG.9is pressed, the printing process proceeds to step S810.

In step S810, the control unit205displays a job status screen illustrated inFIG.10on the touch panel unit401. When a “Resume” button1010is further pressed for the suspended job, the suspended job is resumed with the newly set value for charge elimination, and the printing process proceeds to step S811. Thereafter, the above-described procedure is repeated up to the last page of the job.

In the determinations in step S805, if the setting value for charge elimination produces a too large effect and a value as an amount of charge exceeds the lower limit, it is necessary to prompt the user to reset the setting value for charge elimination to produce a smaller effect. In this case, the control unit205displays the screen and a message illustrated inFIG.11on the touch panel unit401. The subsequent procedure is the same as that in the case where the set value for charge elimination produces a small effect.

Further, the examples ofFIGS.9and11are display examples in the state where the user opens a charge elimination monitor screen. Alternatively, when a screen other than the charge elimination monitor screen is displayed, a message may be displayed on the entire screen of the touch panel unit401in order to notify the user of a situation.FIG.12illustrates an example of a UI screen for displaying a message in an entire-screen display. Similarly, methods for displaying on the touch panel unit401may be various methods, such as displaying a pop-up window and displaying a message line at the lower part of a screen.

Other Embodiments

This application claims priority to Japanese Patent Application No. 2023-031382, which was filed on Mar. 1, 2023, and No. 2024-016089, which was filed on filed Feb. 6, 2024, which are hereby incorporated by reference herein in its entirety.