JP2007326236A - Inkjet printer and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply improve a printing speed of a draft mode by a change of firmware of a printer without performing addition or change of commands of an existing device driver in an image forming apparatus such as an inkjet printer. <P>SOLUTION: When starting receiving of a printing data stream (S1), the inkjet printer stores the printing data stream one by one in a data buffer until it receives a printing setting information notifying command (S2). When receiving the printing setting information notifying command (YES in S3), the inkjet printer changes a paper feeding speed and a paper discharge speed on the basis of setting information on a printing resolution included in the printing setting information notifying command (S4). After changing of setting of the speeds, the inkjet printer sequentially executes commands in the printing data stream stored in the data buffer in the receiving order from the beginning (S5). Thus, the printing speed of the draft mode is simply improved, enabling printing processing to be carried out by the paper feeding speed and paper discharge speed conformed to setting of the printing resolution at all times. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as an ink jet printer having a plurality of print modes in which print quality and print speed are determined based on print resolution settings.

  In general, in an image forming apparatus such as an ink jet printer, a printing process is executed based on a print data string transmitted from a computer connected by a USB (Universal Serial Bus) interface or the like. The print data string includes operation control commands to the printer, print setting information notification commands, and print data such as characters and images to be printed on the paper. Each command and print data is analyzed by the printer control unit. And the printing process is performed based on these.

  When a print data sequence is sent from the computer, the printer extracts an operation control command and a print setting information notification command included in the received print data sequence, and, for example, a print head as a pre-printing process according to the extracted command. Is moved to the reference position, nozzle cleaning, paper feed processing, etc. are performed, and image data is read from memory based on the print setting information such as print resolution, paper size, and paper type sent together. A series of printing processes is performed by adjusting the speed, processing method, printing speed, paper feed speed, and the like.

  Conventionally, in the printing process of a printer, in addition to the image formation time for forming an image on paper, it takes time to analyze and convert the print data sequence received from the computer, and the entire printing process takes time. was there.

  As described above, since the print processing speed of the printer may be greatly influenced by the processing method of the received print data sequence and the printer control method based on the print data sequence, these data processing methods and control methods are different. Efforts are being made to improve and maximize the printing capability of printers and to perform printing processing at high quality and high speed.

The following are known examples of such efforts. For example, the invention of Patent Document 1 prints data at a high resolution without increasing the memory capacity by adjusting the process speed of the printing unit according to the complexity of the data stored in the page buffer. . In addition, the invention of Patent Document 2 manages the buffer information of the data buffer unit storing the image data in real time, performs multi-stage transport speed control according to the buffer amount, and enables printing with the minimum buffer amount. Printing can be started in a short time from the start of data reception. In addition, the invention of Patent Document 3 calculates the used capacity of the page memory from the resolution, paper size, etc. obtained from the received data, and determines whether the page memory has enough free capacity to load the drawing program. When there is free space in the page memory, the processing of the program is speeded up by loading the drawing program into the page memory and executing it.
Japanese Patent Laid-Open No. 10-114119 JP 2003-341184 A Japanese Patent Laid-Open No. 11-58857

  By using the invention as exemplified above, the memory resource mounted in the printer can be efficiently used to balance the processing speed of the image data to be printed and the printing speed, and the memory can be accessed at high speed. It is possible to increase the execution speed of the program by using the free space of the program. As a result, high-quality images can be formed at a high speed while ensuring economic efficiency without increasing the number of expensive memories.

  On the other hand, the speed of draft printing, where printing speed is more important, is an important item for practical use and evaluation of printer performance. Further speeding up of printing is desired. Further, speeding up the printing process is not only a newly developed one, but also a refreshing model for existing printers and improved products of existing printers, which is a very important issue.

  However, the improvement method for speeding up the printing process by changing the image data processing method as in the above example often requires a change of the device driver and the hardware of the printer. When there are restrictions on changes in software and hardware such as the refresh model, it may be difficult to use.

  The present invention has been made in view of the above points, and can easily improve the printing speed of the draft mode by changing the firmware of the printer without adding or changing the command of the device driver on the computer side. An object of the present invention is to provide an ink jet printer and an image forming apparatus.

  In order to achieve the above object, the invention of claim 1 provides a paper feed tray for loading paper, a pick roller for feeding the paper one by one from the paper feed tray, and the paper supplied by the pick roller. A printing unit that performs image formation; an eject roller that discharges the paper on which the image has been formed in the printing unit to a paper discharge tray; a USB interface for communicating with a computer; and firmware for controlling the entire device. ROM (Read Only Memory) for storing, RAM (Random Access Memory) used as a work area, and ASIC (Application Specific IC) having a CPU for executing the firmware, and a device installed in the computer A data buffer for storing a print data string received via a driver is configured on the RAM, and the print data string is configured by an operation control command of a device, a print setting information notification command, and print data, and the print setting The print setting information notified by the information notification command has print resolution setting information for dividing the print mode into a plurality of modes including a draft mode for performing draft printing. The ASIC includes the pick roller and the print roller. In the ink jet printer that controls the rotation speed of the eject roller to adjust the paper feed speed and the paper discharge speed, the ASIC sequentially processes the print data string received from the computer until the print resolution setting information is received. Stored in the data buffer and when the print resolution setting information is received, The print mode is determined based on the print resolution setting information, and when it is determined that the print mode is the draft mode as a result of the determination, the rotation speeds of the pick roller and the eject roller are set to other printing modes. After setting the rotation speed of the pick roller and the eject roller in the mode, the operation control command and the print setting information notification command stored in the data buffer are sequentially received in the order received from the beginning. This is executed to increase the paper feed speed and paper discharge speed in the draft mode.

  According to a second aspect of the present invention, there is provided a paper feed tray for loading paper, a paper feed mechanism for feeding the paper one by one from the paper feed tray, and a paper discharge mechanism for discharging the image-formed paper to a paper discharge tray. And an interface unit for communicating with the external device, a control unit for controlling the entire device, and a storage unit used as a work area, the print received from the external device via the interface unit A data buffer for storing a data string is configured on the storage unit, and the print data string includes an operation control command of the device, a print setting information notification command, and print data, and is notified by the print setting information notification command. The print setting information includes print resolution setting information, and the control unit controls the paper feed speeds of the paper feed mechanism and the paper discharge mechanism to control the paper feed speed. In the image forming apparatus that adjusts the paper discharge speed, the control unit sequentially stores the print data sequence received from the external device in the data buffer until the print resolution setting information is received, When the resolution setting information is received, the speed setting of either or both of the paper feed speed and the paper discharge speed is changed based on the print resolution setting information.

  According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, when the print resolution setting information received from the external device is a content meaning low resolution, the paper feed speed and the paper discharge The speed setting for both and / or one of the speeds is higher than that for other print resolution settings.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, based on the print resolution setting information received from the external device, both the paper feed speed and the paper discharge speed or After changing one of the speed settings, the operation control command and the print setting information notification command stored in the data buffer are sequentially executed in the order received from the beginning.

  According to the first aspect of the present invention, when the ink jet printer receives the print data string from the computer, the ink jet printer does not sequentially execute the commands included in the print data string as in the prior art, but instead executes the print resolution setting information. The print data sequence is sequentially stored in the data buffer until the print resolution is received, and when the print resolution setting information is received, the print mode is determined from the print resolution setting information, and based on this, the paper feed speed and paper discharge are determined. The speed setting is changed, and thereafter, the operation control command and the print setting information notification command in the print data sequence stored in the data buffer are sequentially executed from the beginning in the order of reception.

  Therefore, even if the print data string includes a paper feed command before the print setting information notification command including the print resolution setting information, the execution of the paper feed command is not a print setting information notification including the print resolution setting information. Since the command is received and the rotation speeds of the pick roller and eject roller are set, the paper feed speed and paper discharge always match the print resolution setting regardless of the order of each command in the print data sequence. The printing process can be performed by changing the speed.

  When the setting of the paper feed speed and the paper discharge speed is changed and the print mode is determined to be the draft mode from the received print resolution setting information, the rotation speeds of the pick roller and the eject roller are set. The rotation speed is set higher than that in the other printing modes such as the normal mode and the high resolution mode.

  Therefore, in the draft mode in which the printing speed is more important than the precision of printing, the paper feeding speed and the paper discharging speed can be set higher than those in other printing modes, and the printing speed of the printer can be increased to the maximum.

  In order to implement the present invention, it is not necessary to change the configuration of the computer and the device driver installed in the computer, and only a part of the firmware on the inkjet printer side needs to be changed. Therefore, it is suitable for improving the performance of the refresh model of the existing inkjet printer.

  According to the second aspect of the present invention, when the print data sequence is received from an external device such as a computer, the image forming apparatus does not sequentially execute the commands included in the print data sequence in the order received, Until the print resolution setting information is received, the print data sequence is sequentially stored in the data buffer. When the print resolution setting information is received, the paper feed speed and the paper discharge speed are based on the print resolution setting information. Change the speed setting for either or both.

  Therefore, even if the print data string includes a paper feed command before the print setting information notification command including the print resolution setting information, the execution of the paper feed command receives the print resolution setting information and Since it is performed after the speed and paper discharge speed settings have been changed, printing is always performed at the paper feed speed and paper discharge speed that are appropriate for each print resolution setting, regardless of the order of each command in the print data string. Processing can be performed.

  According to the third aspect of the present invention, when the print resolution setting information received from the external device is a content meaning low resolution, the speed setting of either or both of the paper feed speed and the paper discharge speed is set to the other speed setting. Make it faster than when setting the print resolution. Therefore, in the low-resolution printing process in which the printing speed is more important than the printing precision, the paper feeding speed and the paper discharging speed are increased and the printing processing speed of the image forming apparatus is increased as compared with the setting of other printing resolutions. be able to.

  According to the fourth aspect of the present invention, the speed setting of either or both of the paper feed speed and the paper discharge speed is changed based on the print resolution setting information received from the external device, and then stored in the data buffer. The operation control command and the print setting information notification command in the print data string are sequentially executed in the order received from the beginning. Therefore, in order to implement the present invention, it is not necessary to change the configuration of the external device and the device driver for controlling the image forming apparatus installed in the external device, and a part of the program on the image forming apparatus side is changed. Just do it. Therefore, it is suitable for improving the performance of a refresh model of an existing image forming apparatus.

  Hereinafter, the configuration of an ink jet printer according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. First, a schematic configuration of the entire inkjet printer will be described with reference to FIG. FIG. 1 shows the configuration of the main part of an inkjet printer.

  The ink jet printer 1 (image forming apparatus) performs main scanning by reciprocating a carrier 2 in which an ink cartridge 3 having a print head 3a for ejecting ink is mounted in a main scanning direction (indicated by an arrow A in the figure). An image is formed on a sheet P conveyed in a sub-scanning direction (indicated by an arrow B in the figure) orthogonal to the direction. The ink jet printer 1 is connected to, for example, an external personal computer (not shown) or the like, and forms an image on the paper P based on data and commands transmitted from the personal computer. The ink jet printer 1 has a paper feed tray 20 for holding the paper P to be printed at the upper rear of the chassis 10, and discharges the printed paper P below the front surface of the chassis 10. The paper discharge tray 30 is provided.

  Inside the chassis 10 of the ink jet printer 1 are a carrier 2, an ink cartridge 3 mounted on the carrier 2, a shaft 4 disposed on the back side of the carrier 2 so that the main scanning direction is the longitudinal direction, and paper A paper transport mechanism 5 that transports P, a carrier drive mechanism 6 that reciprocates by applying a driving force to the carrier 2, and a chassis 10 that detects the position of the carrier 2 in the main scanning direction. An encoder scale 7 disposed along the circuit board 8 and a circuit board 8 on which a control circuit for controlling various operations of the inkjet printer 1 is mounted.

  The carrier 2 supports the ink cartridge 3 so that it can be inserted and removed. In this embodiment, two ink cartridges 3 are mounted on the carrier 2, one filled with black ink and the other filled with three color inks of cyan, magenta, and yellow, for example. That is, the inkjet printer 1 is configured to be able to form a color image on the paper P. The configuration of the ink cartridge 3 mounted on the carrier 2 is not limited to this. For example, the black ink and the color ink are combined into one, or the color ink is separately sealed for each color. It may be. In addition, the ink jet printer 1 may be one in which only the ink cartridge 3 in which the black ink is sealed in the carrier 2 is mounted, and a gray scale image is formed.

  The carrier 2 is slidably fitted to the shaft 4 and is connected to a part of the belt 6a of the carrier driving mechanism 6 as will be described later, and is arranged to be movable in the main scanning direction while sliding with the shaft 4. ing. The carrier 2 is equipped with a photocoupler (not shown), and the photocoupler scans the encoder scale 7 having a predetermined resolution so that the position of the carrier 2 in the main scanning direction can be detected. It is configured.

  The carrier drive mechanism 6 includes, for example, an annular belt 6a disposed along the main scanning direction on the chassis 10 of the inkjet printer 1, and a DC motor 6b for rotating the belt 6a. is there. A part of the belt 6 a is connected to the carrier 2. The carrier driving mechanism 6 rotates the belt 6a by the DC motor 6b to apply a driving force to the carrier 2 to reciprocate in the main scanning direction. The carrier driving mechanism 6 is not limited to this configuration.

  The paper feed tray 20 is provided with a paper feed mechanism (not shown). The paper feed mechanism is provided with a pick roller 11 (see FIG. 2). When the pick roller 11 rotates, the paper P loaded in the paper feed tray 20 is fed out one by one in the paper feed direction. . The pick roller 11 is a roller made of a material having a high friction coefficient such as rubber that is rotated by a driving motor (not shown) such as a stepping motor via a driving force transmission means (not shown) such as a gear. The drive motor for driving the pick roller 11 is driven to rotate based on a command such as a rotation angle and a rotation speed from the control circuit.

  The paper transport mechanism 5 is provided with a feed roller (not shown). The feed roller is a pair of upper and lower rollers made of a material having a high coefficient of friction such as rubber that is rotated by a driving motor (not shown) such as a stepping motor via a driving force transmission means (not shown) such as a gear. is there. The drive motor for driving the feed roller is driven to rotate based on a command such as a rotation angle and a rotation speed from the control circuit. The feed roller conveys the paper P fed out from the pick roller 11 into the main body of the ink jet printer 1 and forms an image on the paper P. When the image is formed on the paper P, the printing unit 40 including the carrier driving mechanism 6 and the print head 3a. The paper is fed in synchronism with the ink ejection.

  The paper P on which an image is formed by the printing unit 40 is transported from the paper transport mechanism 5 to a paper discharge mechanism (not shown). The paper discharge mechanism is provided with an eject roller 12 (see FIG. 2). The eject roller 12 is a roller made of a material having a high friction coefficient such as rubber that is rotationally driven by a driving motor (not shown) such as a stepping motor via a driving force transmission means (not shown) such as a gear. The drive motor for driving the eject roller 12 is driven to rotate based on a command such as a rotation angle and a rotation speed from the control circuit. The eject roller 12 is applied to the paper P fed by the feed roller. By rotating in contact, the paper P is discharged to a paper discharge tray 30 outside the main body of the inkjet printer 1.

  The circuit board 8 is held on the back side of the chassis 10. The control circuit mounted on the circuit board 8 is controlled by software such as a device driver that operates on an external personal computer, for example, and includes a paper feed mechanism, a paper transport mechanism 5, a paper discharge mechanism, and a carrier drive mechanism 6. And the print head 3a and the like are controlled.

  Next, the configuration of the control system of the inkjet printer 1 will be described with reference to FIG. FIG. 2 shows the configuration of the control system of the inkjet printer 1 when connected to a computer. An ASIC (Application Specific IC) 13 (control unit) is provided on the circuit board 8 (see FIG. 1). The CPU 14 performs arithmetic processing, and the ROM (initial setting information and firmware 15 of the inkjet printer 1 is stored. A read only memory (RAM) 16 and a RAM (Random Access Memory) 17 (storage means) used as a work area for arithmetic processing or the like are included. Further, the inkjet printer 1 includes a USB (Universal Serial Bus) interface 18 (interface unit), and is connected to a computer 50 (external device) via the USB interface 18.

  The RAM 17 is provided with a data buffer 19 for storing the print data string 25. When printing, the print data string 25 received from the computer 50 via the USB interface 18 is sequentially stored in the data buffer 19. It has come to be.

  The CPU 14 executes the firmware 15 stored in the ROM 16 to perform operation control and status monitoring of the entire inkjet printer 1. Operation control commands and printing included in the print data string 25 from the connected computer 50 are printed on the CPU 14. Based on the setting information notification command and print data (characters and images to be printed), the pick roller 11 of the paper feed mechanism, the feed roller of the paper transport mechanism 5 (see FIG. 1), the eject roller 12 of the paper discharge mechanism, In addition, the rotation speed and rotation angle of each drive motor of the carrier drive mechanism 6 and various devices such as the print head 3a are controlled in an integrated manner to execute the printing process.

  A device driver 52 for controlling the ink jet printer 1 is installed in the HDD 51 built in the computer 50. When printing image data or the like stored in the computer 50 with the inkjet printer 1, the computer 50 transmits the print data string 25 including the image data to the inkjet printer 1 via the device driver 52, It is supposed to be printed.

  When the device driver 52 transmits print data such as image data to the inkjet printer 1, print setting information such as the paper size, paper type, and print resolution set by the computer 50 together with the printer operation control command and print data. Is sent as a print data string 25 to the inkjet printer 1. The inkjet printer 1 that has received these data performs an adjustment operation before printing, print data conversion processing, and the like based on the sent operation control command and print setting information of the print setting information notification command, and performs print processing. Execute.

  The print resolution set by the device driver 52 is determined by the user selecting an arbitrary print mode from among a plurality of print modes divided in advance such as a high image quality mode, a normal mode, a high speed mode, and a draft mode. A print resolution corresponding to the selected print mode is set. In addition, the print resolution may be set directly by the device driver 52, and the corresponding print mode may be selected based on the set print resolution.

  Next, the flow of printing processing in the draft mode by the inkjet printer 1 according to the above configuration will be described with reference to FIGS. FIG. 3 shows the flow of processing of the print data string 25 received from the computer 50 by the inkjet printer 1. FIG. 4 shows an example of the print data string 25 transmitted from the computer 50.

  When the computer 50 prints a document or image, the device driver 52 prints the print setting information notification command based on the print setting information set by the device driver 52 together with the document data and image data to be printed. The operation control commands are formed as a series of print data strings 25 and are sequentially transmitted to the inkjet printer 1 via the USB interface 18.

  In response to this, as shown in FIG. 3, the ASIC 13 starts receiving the print data string 25 (S1), and sequentially stores the received print data string 25 in the data buffer 19 configured on the RAM 17 ( S2). When storing the received print data string 25 in the data buffer 19, the ASIC 13 determines whether the print data string 25 being processed is a print setting information notification command including print resolution setting information (S3). When the received print data string 25 is not a print setting information notification command (NO in S3), the ASIC 13 returns to the process of S2 and stores the received print data string 25 in the data buffer 19 and receives the received print data string 25. Is a print setting information notification command (YES in S3), the paper feed speed and the paper discharge speed are determined based on the print resolution setting information included in the print setting information notification command (S4), and the data buffer 19 The operation control command and the print setting information notification command are called from the beginning in the order stored in the data buffer 19 from the print data string 25 stored in the first and sequentially executed (S5).

  In the present embodiment, the paper feed speed and paper discharge speed (rotational speeds of the drive motors of the pick roller 11 and the eject roller 12) determined by the process of S4 are described in the received print setting information notification command. When the print resolution setting included is a draft mode, a high-speed setting that is faster than the other print modes is used, and a normal setting is used in modes other than the draft mode.

  For example, when the inkjet printer 1 receives a print data string 25 as shown in FIG. 4 from the computer 50, data 1 to data 3 are sequentially stored in the data buffer 19 (S2), and print resolution setting information When the data 4 (print setting information notification command) including is received (YES in S3), the ASIC 13 determines the paper feed speed and the paper discharge speed based on the print resolution setting information of the data 4. Here, since the draft mode is set as the print resolution setting, the high speed setting is used for the paper feed speed and the paper discharge speed (S4). Then, after setting the paper feed speed and the paper discharge speed, the ASIC 13 stores the operation control command or the print setting information notification command in the data buffer 19 in the print data sequence 25 stored in the data buffer 19 (here, Data 1) is read out and executed in this order to perform the printing process. That is, data 1. Print head reference position movement command (command for moving the print head to the reference position), data2. 2. Print head cleaning command (command for cleaning nozzle), data 3. Paper feed command (command for executing paper feed processing), data 4. Print setting information notification command (command for acquiring / setting print setting information (excluding setting of paper feed speed and paper discharge speed based on print resolution setting information)), data 5. Return position information notification command (command for acquiring / setting print head return position information), data Swath data command (command for obtaining swath data (print image data for one scan of print head) length), data 7. Swath data (actual print data) is sequentially executed, and thereafter, processing of data 4 to data 7 is repeated to complete printing for one page.

  By configuring the ink jet printer 1 as described above, when the ink jet printer 1 receives the print data string 25 from the computer 50, the ink jet printer 1 sequentially executes the commands included in the print data string 25 as in the prior art. Instead, the print data string 25 is sequentially stored in the data buffer 19 until the print setting information notification command including the print resolution setting information is received, and the print setting information notification command including the print resolution setting information is received. In some cases, the print mode is determined from the print resolution setting information, the settings of the paper feed speed and the paper discharge speed are changed based on the print mode, and the print data string 25 stored in the data buffer 19 is stored. Are sequentially executed from the beginning in the order of reception.

  Therefore, as shown in FIG. 4, even if the print data string 25 includes a paper feed command before the print setting information notification command including the print resolution setting information, execution of the paper feed command This is performed after the print setting information notification command including the setting information is received and the rotation speeds of the pick roller 11 and the eject roller 12 are set. Regardless of the order of the commands in the print data string 25, the command is always set. Printing processing can be performed at a paper feed speed and a paper discharge speed according to the print resolution setting.

  Further, when it is determined that the print mode is the draft mode when the paper feed speed and the paper discharge speed are changed, the rotational speeds of the pick roller 11 and the eject roller 12 are set to the normal mode, the high resolution mode, or the like. The rotation speed was set higher than that in the other printing modes. Therefore, in the draft mode in which the printing speed is more important than the precision of printing, the paper feeding speed and the paper discharging speed can be increased more than in other modes, and the printing speed can be increased to the maximum.

  In order to implement the present invention, it is not necessary to change the configuration of the computer 50 and the device driver 52 installed in the computer 50, and only the firmware 15 on the inkjet printer 1 side needs to be changed. Therefore, it is suitable for improving the performance of a refresh model or the like of an existing inkjet printer that has restrictions on hardware improvement.

  The present invention is not limited to the configuration of each of the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, in this embodiment, when it is determined that the print mode is the draft mode, the rotational speeds of both the pick roller and the eject roller are set to a higher setting (high speed setting) than in the other printing modes (normal setting). However, the rotational speed of only one of the pick roller and the eject roller may be changed. In the above embodiment, only the normal setting and the high speed setting are used as the rotation speed settings of the pick roller and the eject roller. However, a plurality of settings may be used depending on the print resolution value for each print mode. Alternatively, the rotation speed of these rollers may be set to a variable rotation speed by using a function having information such as print resolution included in the print setting information as a variable. In addition, although the inkjet printing method is exemplified as the printer printing method, the printing method is not limited to the inkjet printing method, and is used for other image forming apparatuses such as a dot impact method, a thermal transfer method, and a laser beam method. However, the same effect can be obtained.

FIG. 3 is a perspective view illustrating a configuration of a main part of the ink jet printer. The block diagram of the control system of a printer same as the above. The flowchart of the process of the print data sequence of a printer same as the above. An example of a print data sequence received by the printer.

Explanation of symbols

1 Inkjet printer (image forming device)
5 Paper transport mechanism 6 Carrier drive mechanism 11 Pick roller 12 Eject roller 13 ASIC (control unit)
14 CPU
15 Firmware 18 USB interface (interface part)
19 Data buffer 25 Print data string 40 Printing unit 50 Computer (external device)
52 Device Driver

Claims (4)

A paper tray for loading paper,
A pick roller for feeding out the paper one by one from the paper feed tray;
A printing unit for forming an image on the paper supplied by the pick roller;
An eject roller for discharging the paper on which the image has been formed in the printing unit to a paper discharge tray;
A USB interface for communicating with a computer;
A ROM that stores firmware for controlling the entire device, a RAM that is used as a work area, and an ASIC that includes a CPU that executes the firmware;
A data buffer for storing a print data string received via a device driver installed in the computer is configured on the RAM,
The print data string is composed of device operation control commands, print setting information notification commands, and print data.
The print setting information notified by the print setting information notification command has print resolution setting information for dividing the print mode into a plurality of modes including a draft mode for performing the draft printing.
The ASIC is an inkjet printer that controls the rotation speed of the pick roller and the eject roller to adjust the paper feed speed and the paper discharge speed.
The ASIC is
The print data sequence received from the computer is sequentially stored in the data buffer until the print resolution setting information is received. When the print resolution setting information is received, printing is performed based on the print resolution setting information. Judgment of mode,
As a result of the determination, when it is determined that the print mode is the draft mode,
The setting of the rotation speed of the pick roller and the ejection roller is set higher than the setting of the rotation speed in other printing modes,
After setting the rotation speed of the pick roller and the eject roller, the operation control command and the print setting information notification command stored in the data buffer are sequentially executed in the order received from the beginning, and the paper feed speed and paper discharge in the draft mode are executed. Inkjet printer characterized by increased speed. A paper tray for loading paper,
A paper feed mechanism for feeding out the paper one by one from the paper feed tray;
A paper discharge mechanism for discharging the image-formed paper to a paper discharge tray;
An interface for communicating with an external device;
Control means for controlling the entire device;
Storage means used as a work area,
A data buffer for storing a print data string received from the external device via the interface unit is configured on the storage unit,
The print data string is composed of device operation control commands, print setting information notification commands, and print data.
The print setting information notified by the print setting information notification command has print resolution setting information,
In the image forming apparatus for adjusting the paper feed speed and the paper discharge speed by controlling the paper feed speed of the paper feed mechanism and the paper discharge mechanism,
The control unit sequentially stores the print data string received from the external device in the data buffer until the print resolution setting information is received, and when the print resolution setting information is received, The image forming apparatus is characterized in that the speed setting of either or both of the paper feed speed and the paper discharge speed is changed based on the setting information.   When the print resolution setting information received from the external device has a content that means low resolution, the speed setting of both or either of the paper feed speed and the paper discharge speed is set to another print resolution setting. The image forming apparatus according to claim 2, wherein the image forming apparatus is higher than the above.   Based on the print resolution setting information received from the external device, the operation control command stored in the data buffer after changing the speed setting of either or both of the paper feed speed and the paper discharge speed, and 4. The image forming apparatus according to claim 2, wherein the print setting information notification commands are sequentially executed in the order received from the beginning.

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