Printing apparatus with job interrupt capabilities and control method thereof

A printing environment is provided, in which the user can obtain prints of special print jobs without stagnation of ordinary print jobs which otherwise might be caused by the loading of a special print job requiring manual sheet feed or sheet change. A controller for managing the print job schedule is operated in such a manner that print jobs J1 designating ordinary paper are routinely carried out in priority over print jobs J2 requiring special paper. Upon instruction from an operation input unit, at least one of the previously-loaded print jobs J2 requiring special paper is carried out in priority over the print jobs J1 designating ordinary paper.

BACKGROUND OF THE INVENTION
 This application is based on Japanese Patent Application No. 308424/1997
 filed on Nov. 11, 1997, the contents of which are incorporated herein by
 reference.
 1. Field of the Invention
 The present invention relates to a printing apparatus having a schedule
 management function accepting a plurality of print jobs from one or more
 external devices and a control method thereof applicable to a network
 printer or a print system including a print server and a printer.
 2. Description of the Prior Art
 Generally, a printer is capable of storing a plurality of sheets of paper
 and has an automatic paper feed function in which the paper sheets are
 taken out from the storage and fed for printing automatically. The printer
 also has what is called a manual paper feed port by way of which paper are
 supplied sheet by sheet manually. The manual paper feed port is used
 mainly for a comparatively small number of printing using a special paper
 sheet different from the paper sheets stored in the machine. The special
 paper includes those larger or smaller than the standard size, color
 printing paper, paper preprinted with a remark column or the like, and an
 0HP sheet. In loading a print job into the printer from an external device
 typically including a computer, the automatic paper feed or the manual
 paper feed is designated.
 A printer such as a network printer adapted to be shared by a plurality of
 external devices includes a buffer of a predetermined capacity and is
 capable of accepting a plurality of print jobs. In other words, the
 printer can accept a print job during the printing work as well as when
 waiting for a print job.
 The conventional printing apparatuses are configured so that print jobs are
 performed in the order in which they are loaded into the machine
 regardless of automatic or manual paper feed. On the other hand, a system
 configuration has been suggested in which the printing order of priority
 can be set, the actual printing order can be changed and the print jobs
 can be canceled as desired by the user operating an external device or the
 printing apparatus (JP-A-7-295767).
 In the prior art, as described above, the print jobs are carried out in the
 order in which they are loaded into the printer. In the case where a print
 job of manual paper feed is loaded, therefore, print jobs which may be
 loaded thereafter, regardless of automatic or manual paper feed, are not
 carried out until the previously-loaded print job of manual paper feed is
 complete. Assume, for example, that the user who has designated a print
 job of manual paper feed on an external device has forgotten to feed paper
 at the place of installation of the printer, the printer is left in a
 substantially inoperative state waiting for paper feed at the sacrifice of
 other users being troubled.
 Another problem is that the user who has come to the printer at the place
 of installation thereof to feed paper manually may have to wait for a long
 time until other print jobs of automatic paper feed are complete and his
 or her turn comes.
 SUMMARY OF THE INVENTION
 The object of the present invention is to provide a printing environment in
 which the user can obtain prints of a special print job requiring manual
 sheet feed or sheet change at any time without stagnation of ordinary
 print jobs.
 According to the present invention, there is provided a printing apparatus
 comprising a receiving section for receiving and accumulating a plurality
 of print jobs transmitted from one or more external devices, said print
 jobs including a first print job with specific attribute information added
 thereto and a second print job with no specific attribute information
 added thereto; an operation input unit for inputting an instruction to
 execute said first print job by operation of a user; and a controller for
 executing said second print job in the order of accumulation in said
 receiving section, and for, when the instruction is input through said
 operation input unit, suspending the execution of said second print job
 and executing said first print job; wherein said controller executes said
 first print job only when the instruction is input through said operation
 input unit.
 In carrying the present invention in one preferred mode, the controller
 manages a print job schedule in which print jobs designating ordinary
 paper rather than special paper are normally executed and upon an
 appropriate instruction from the operation input unit, at least one of the
 previously-loaded print jobs requiring special paper is executed in
 priority over those using ordinary paper.
 The operation input unit includes a manual button 32, for example, mounted
 in an operation panel of the printer or the like. When the user gives an
 instruction to the printer by way of the manual button 32, a list of print
 jobs (manual feed jobs J2) requiring special paper are displayed. The user
 designates one or more manual feed jobs J2 from among them. Then, a print
 job designating ordinary paper (ordinary job J1), which may be proceeding,
 is suspended and the designated manual feed job J2 is executed in
 priority. Upon completion of the printing designated as manual feed job
 J2, the ordinary job J1 that has thus far been suspended is resumed.
 According to the preferred mode of the present invention, the ordinary
 paper means the paper housed in a paper cassette in such a manner as to
 permit automatic feed, and the special paper means those paper of a size,
 a color or a quality different from ordinary paper and not normally housed
 in the paper cassette. Special paper are generally manually fed but may be
 automatically fed. For automatic feed, the special paper are housed in the
 paper cassette in place of ordinary paper or are housed in a paper
 cassette different from that of ordinary paper. Accordingly, the
 preprinted paper or color paper which can be normally housed to be fed
 automatically are "ordinary paper." A print job requiring special paper is
 the one in which the user is required to make an arrangement to feed the
 special paper (automatically or manually) after loading the particular
 print job.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 FIG. 1 is a diagram showing a network configuration according to the
 present invention.
 In FIG. 1, a computer network system 100 includes a plurality of computers
 41 to 44 connected by a network 50 like LAN for sharing a network printer
 1. The network printer 1 has built therein a network interface card (NIC)
 16 for connection with the network 50. With the computer network system
 100, the single computer 41 functions as a print server. It is also
 possible to employ a system in which the network printer 1 is connected to
 the computer 41 by use of a parallel port, though not shown, and thus is
 connected to the network 50 through the computer 41.
 FIG. 2 is a functional block diagram showing a network printer according to
 the present invention.
 In FIG. 2, the network printer 1 is a page printer configured in such a
 manner that printing by either automatic or manual paper feed is possible.
 The network printer 1 includes a controller 11 for control and data
 processing, a print engine 12 including a paper feed mechanism, an
 operation panel 13 for giving input instructions, a paper sensor 14 for
 detecting the presence or absence of the paper manually fed and the
 network interface card 16.
 The operation panel 13 includes a liquid crystal display (LCD) 31 for
 displaying a guide, and a manual button 32 for designating a print job
 requiring manual paper feed (manual feed job). The controller 11 includes
 a CPU 110 mainly constituted by a microprocessor and an image memory 120
 for storing print data in various processing stages. The CPU 110 processes
 data for command analysis and bit map development and controls the
 printing order of print jobs by a schedule management file 130 arranged in
 a work area.
 FIG. 3 is a model diagram showing an example of schedule management.
 As shown in FIG. 3, the network printer 1 is loaded with two types of print
 jobs from the computers 41 to 44 constituting external devices. One is
 ordinary jobs J1 designating automatic paper feed, and the other is manual
 feed jobs J2 designating manual paper feed.
 The schedule management file 130 includes a print queue 131 and an
 interrupt list 132. The CPU 110 identifies the paper feed designation
 information for a print job received through the NIC 16. The ordinary jobs
 J1 are registered in the order in which they are loaded in the print queue
 131, and the manual feed jobs J2 are registered in the interrupt list 132.
 The printing work is basically performed only for the ordinary jobs J1
 registered in the print queue 131 in the absence of an interrupt
 instruction by the manual button 32. Specifically, the ordinary job J1 at
 the head of the print queue 131 is determined as an object of printing.
 Any manual feed job J2 which may be loaded before the ordinary jobs J1 is
 held from the printing work and the ordinary jobs J1 are performed first.
 The ordinary jobs J1 for which the printing work is complete are deleted
 from the print queue 131, and the printing order of the registered
 ordinary jobs J1 is advanced. In this way, the job stagnation in the prior
 art (the state waiting for a manual paper feeding) can be avoided by
 giving priority normally to the ordinary job J1 over the manual feed job
 J2.
 Upon operating the manual button 32, on the other hand, the manual feed job
 J2 is given priority over the ordinary job J1 unlike during the normal
 time. In this case, the CPU 110 lists up the manual feed jobs J2
 registered in the interrupt list 132 on the LCD 31 and prompts the user to
 designate an object of printing. Then, the printing of the ordinary job J1
 , if proceeding, is suspended by page, for example, and the print engine
 12 is released for performing the manual feed job J2. Upon completion of
 the printing of the designated manual feed job J2, the particular manual
 feed job J2 is deleted from the interrupt list 132, and the operation
 returns to the state in which only the ordinary job J1 registered in the
 print queue 131 is performed.
 FIG. 4 is a diagram showing a manual feed job select screen.
 As shown in FIG. 4, the manual feed job select screen Q1 includes a list Z1
 having manual feed jobs arranged in the order of registration (loading) in
 the interrupt list 132 and a message Z2 prompting the user to input the
 number. The user name, the date and time of loading, the number of pages
 and other job identified information as well as the choice number are
 displayed in the list Z1. The user name may be the number of the external
 device or the title of the document (file name) to be printed as well as
 the name of the user himself or herself. The user desiring the printing by
 manual feed inputs the choice number corresponding to the desired manual
 feed job J2 by way of a predetermined button on the operation panel 13. In
 the shown case, the choice number "3" is input. In the presence of a paper
 sheet in the manual paper feed port, the manual feed job J2 begins as
 designated. Consequently,the user can produce the desired prints by
 setting the paper sheets equal to the number of pages one by one or
 collectively.
 FIG. 5 is a flowchart showing the printing steps on the part of an external
 device.
 In the flowchart of FIG. 5, when the user designates a printing according
 to an application program, the print driver is started, and it becomes
 possible to designate the printing conditions (#111). The user inputs a
 user name (#112), designates a paper feed mode (#113), and instructs a
 print job to be loaded (#114). In designating a paper feed mode, the user
 selects whether the ordinary paper cassette or the manual feed tray is to
 be used. As an alternative, the printer may be configured to permit the
 user to select whether the ordinary paper or the special paper is used. In
 this configuration, "whether or not special paper is used" is determined
 in step #122 described later.
 FIG. 6 is a flowchart showing the process of accepting jobs on the part of
 the printer.
 In the flowchart of FIG. 6, the print job received is taken in and the type
 of job is determined (#121, #122). The manual feed job J2, if any, is
 registered in the interrupt list 132 providing a queue dedicated to manual
 feed job J2 (#123). An ordinary job J1, on the other hand, is registered
 in the print queue 131 (#124).
 FIG. 7 is a flowchart of the schedule management executed by the CPU.
 In the flowchart of FIG. 7, on the other hand, if the manual button 32 is
 turned on (#131), it is determined whether the manual feed job J2 is
 registered in the interrupt list 132 or not (#132). When the manual feed
 job J2 is registered, the manual feed job select screen Q1 is displayed
 and the selected manual feed job J2 is designated as an object to print
 (#133, #134).
 During the normal operation when the manual feed button 32 is off or when
 the manual button 32 is turned on but the manual feed job J2 is not
 registered, it is determined whether the ordinary job J1 is registered in
 the print queue 131 or not (#135). When the ordinary job J1 is registered,
 the leading (highest-priority) ordinary job J1 is determined as an object
 to print (#136).
 FIG. 8 is a model diagram showing another example of schedule management.
 In the example shown in FIG. 8, the schedule management file 130b includes
 only a print queue 131b. Both the ordinary job J1 and the manual feed job
 J2 are registered in the print queue 131b. Nevertheless, only the ordinary
 jobs J1 are considered for determining the order of printing, while the
 printing of the manual feed job J2 is held during the normal operation as
 in the above-mentioned case. Also, the user can designate the ordinary job
 J1 for priority printing. The emergency ordinary job J1 designated for
 priority printing is printed in priority over the other ordinary jobs J1.
 When the manual feed button 32 is turned on, the manual feed jobs J2
 registered in the print queue 131b are displayed in a list, then the
 selected manual feed job J2 is printed.
 FIG. 9 is a flowchart showing a printing procedure on the part of an
 external device corresponding to FIG. 8.
 In the flowchart of FIG. 9, the user designates a printing according to an
 application program (#211), inputs the user name and attribute (#212,
 #213), and instructs a print job to be loaded (#214). The attributes
 include the paper feed mode (automatic or manual) and the requirement for
 priority printing.
 FIG. 10 is a flowchart for the process of accepting jobs on the part of the
 printer corresponding to FIG. 8.
 In the flowchart of FIG. 10, the CPU 110 fetches the received print job
 (#221) and registers it in the print queue 131b (#222).
 FIG. 11 is a flowchart of schedule management corresponding to FIG. 8.
 In the flowchart of FIG. 11, if the manual feed button 32 is turned on, it
 is determined whether the manual feed job J2 is registered in the print
 queue 131b or not (#232). When the manual feed job J2 is registered, the
 manual feed job select screen Q1 is displayed and the selected manual feed
 job J2 is determined as an object to print (#233, #234).
 During the normal operation when the manual feed button 32 is off or when
 the manual feed button 32 is turned on but the manual feed job J2 is not
 registered, the contents of the registration in the print queue 131b are
 checked (#235, #236). In the case where an emergency ordinary job J1 is
 registered, the highest-priority one of the ordinary jobs J1 is determined
 as an object to print (#237). In the case where the emergency ordinary job
 J1 is not registered but other ordinary jobs J1 are registered, then, the
 highest-priority one of them is determined as an object to print (#238).
 According to the above-mentioned embodiment, the manual feed job J2 can be
 designated for printing at any time regardless of the presence or absence
 of the ordinary job J1 and therefore there is not trouble of waiting for
 the end of the ordinary job J1 . Once the printing of the manual feed job
 J2 is over, the ordinary job J1 suspended or the ordinary job J1 waiting
 for printing is started. Therefore, the job stagnation can be minimized.
 In the embodiment described above, the printing of the ordinary job J1 is
 suspended in response to the turning on of the manual feed button 32. The
 printing of the ordinary job J1 , however, can alternatively be suspended
 in response to the selection of the manual feed job after the manual feed
 button 32 is turned on. Also, the print engine 12 can be released for the
 manual feed job J2 at the end of the ongoing printing of an ordinary job
 J1. It is also possible to designate a plurality of manual feed jobs J2
 collectively with the manual feed job select screen Q1 on display.
 The above-mentioned embodiment refers to the case in which the manual feed
 job select screen Q1 is displayed and a manual feed job is selected for
 printing. As an alternative, print jobs can be carried out simply on
 first-in first-out basis. Also, an arrangement can be made in which
 "manual feed" and "emergency" can be designated at the same time as a job
 attribute unlike in the above-mentioned case. In such a case, a manual
 feed job is carried out in steps #235, #236, #237 in that order in the
 flowchart of FIG. 11. As a result, the same situation of waiting for paper
 feed occurs as in the prior art. This situation of waiting for paper feed
 is allowed, however, in view of the emergency nature of the job.
 In the above-mentioned embodiment, the control system taking charge of
 schedule management can be provided separately from the print engine 12.
 The manual feed button 32 can be a switch, a keyboard or a touch panel
 having mechanical or electrical contacts. Also, an input can be made by
 way of the mouse or the like on the screen. The present invention is
 applicable to a printer-copier or a composite machine having an image
 reader and a printer integrated with each other.