JP3706657B2 - Printing apparatus and method for writing to buffer in printing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printing apparatus that can transmit data to a host computer or another device, and more particularly to a printing apparatus that is preferably implemented when performing bidirectional communication with a host computer or the like.
[0002]
[Prior art]
In the conventional printing apparatus, the communication between the printing apparatus and other devices such as the host computer has overwhelmingly more data transmission in one direction and very little data transmission in the opposite direction. In particular, data transmission from the printing apparatus to the host computer is hardly performed, and transmission of print data and control data from the host computer to the printing apparatus is mostly performed.
[0003]
However, the status information of the printing device is frequently sent to the host computer, so that the user operating the host computer can be notified of the status of the printing device, or remote operation of the printing device can be performed from the host computer. The ratio of the data amount of data communication with various device devices surrounding the printing apparatus is changing.
[0004]
Since conventional printers do not assume such bi-directional communication, all transmission data from the printer is transmitted in the same way as the host computer so that it is not missed. Even if data cannot be received, the data transmission from the printing apparatus is performed without giving up.
[0005]
[Problems to be solved by the invention]
However, in a printing apparatus that does not assume bidirectional communication as described above, for example, in an environment in which a plurality of host computers are connected to one printing apparatus in a network environment or the like, a certain host computer performs bidirectional communication. If a host computer does not have an application that supports bi-directional communication, copy the status request data used on the host computer that supports bi-directional communication. For example, transmission from a host computer that does not support bidirectional communication is highly conceivable. If the user frequently performs such use, the host computer does not receive the data transmitted from the printing apparatus, so that the transmission buffer of the printing apparatus becomes full and cannot be written to the transmission buffer. However, since the printing apparatus does not give up data transmission until transmission is possible, there is a problem that other processing such as further data reception and command analysis processing is interrupted.
[0006]
Even in a host computer equipped with an application that supports bi-directional communication, the host computer performs heavy processing such as file access for a long time, the input / output port is not controlled, and data from the printing device When reception cannot be performed, the printing apparatus tries to execute data transmission until data transmission is possible, and other processing is stopped.
[0007]
As mentioned in the above example, when bi-directional communication between the printing device and the device such as the host computer is not successful, there are two cases: physically impossible and temporarily unable to transmit / receive. It can be roughly divided. These environments can be in the states shown in FIGS. 4 (A) and 4 (B).
[0008]
In view of the above points, the object of the present invention is to connect to a device such as a host computer that cannot perform two-way communication, or even when the host computer cannot receive data temporarily. , Determine what is the appropriate operation for each situation, and do not interrupt the processing of the executable printing device, if it is not possible to bidirectionally, only the data transmission from the printing device is interrupted, printing It is an object of the present invention to provide a printing apparatus capable of smoothly executing the original printing process of the apparatus.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problem, the printing apparatus of the present invention provides:
A transmission buffer in which transmission data to be transmitted to an external device is written;
A discriminating means for discriminating whether or not writing to the transmission buffer has been completed;
If it is determined by the determining means that writing is not possible, it is determined whether a timeout has occurred, if it is determined that a timeout has occurred, the transmission data is discarded and the process is terminated. When a write request is made to the transmission buffer and the determination means determines that writing has been completed, the timeout time is reset, it is determined whether all writing has been completed, and it is determined that all writing has been completed. In this case, the processing unit is terminated, and when it is determined that all writing is impossible, there is a means for waiting for a predetermined time, making a write request to the transmission buffer, and causing the determination unit to determine.
Moreover, the printing apparatus of the present invention includes:
A transmission buffer in which transmission data to be transmitted to an external device is written;
A discriminating means for discriminating whether or not writing to the transmission buffer has been completed;
If it is determined by the determining means that writing is not possible, it is determined whether a timeout has occurred, if it is determined that a timeout has occurred, the transmission data is discarded and the process is terminated. When a write request is made to the transmission buffer and the determination means determines that writing has been completed, the timeout time is reset, it is determined whether all writing has been completed, and it is determined that all writing has been completed. If it is determined that all data cannot be written, the remaining number of write request data is calculated, the read position of the write data to the transmission buffer is shifted, and the next write preparation is performed, and a certain time is waited. A means for making a write request to the transmission buffer and causing the determination means to determine Characterized in that it.
Further, the writing method to the buffer in the printing apparatus of the present invention,
A method of writing to a buffer in a printing apparatus having a transmission buffer in which transmission data to be transmitted to an external device is written,
A determination step of determining whether or not writing to the transmission buffer was possible;
If it is determined in the determination step that writing cannot be performed, it is determined whether a time-out has occurred.If it is determined that a time-out has occurred, the transmission data is discarded and the process is terminated. , Make a write request to the transmission buffer, let the discrimination step discriminate, and if it is discriminated by the discrimination step that the write has been completed, reset the timeout time, determine whether all have been written, and determine that all have been written In this case, the process is terminated, and when it is determined that all the data cannot be written, there is a step of waiting for a certain time, making a write request to the transmission buffer, and causing the determination step to determine.
Further, the writing method to the buffer in the printing apparatus of the present invention,
A method of writing to a buffer in a printing apparatus having a transmission buffer in which transmission data to be transmitted to an external device is written,
A determination step of determining whether or not writing to the transmission buffer was possible;
If it is determined in the determination step that writing cannot be performed, it is determined whether a time-out has occurred.If it is determined that a time-out has occurred, the transmission data is discarded and the process is terminated. , Make a write request to the transmission buffer, let the discrimination step discriminate, and if it is discriminated by the discrimination step that the write has been completed, reset the timeout time, determine whether all have been written, and determine that all have been written If it is determined that all data cannot be written, the remaining number of write request data is calculated, the read position of the write data to the transmission buffer is shifted, and the next write preparation is performed, and a certain time is waited. Then, a write request is made to the transmission buffer, and the determination step is performed. And having a step of.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
(Example 1)
A first embodiment of the present invention will be described.
[0011]
FIG. 1 shows a system configuration including the printer of this embodiment. In FIG. 1, 101 is an external device such as a host computer, and 102 is a laser beam printer to which this embodiment is applied. A printer engine unit 105 forms a latent image on a photosensitive drum by a well-known electrophotographic process based on image data (binary or multi-valued data), transfers the image onto a sheet, and fixes and prints. 103 The printer engine unit 105 is connected to the printer engine unit 105, receives code data (ESC code, various PDLs, etc.) sent from an external device 101 such as a host computer, generates page information composed of dot data based on the code data, and generates the printer engine unit 105. A printer controller unit 104 that transmits image data by a predetermined interface means is a panel unit 104 that interfaces with a user (operator), and the user operates the panel unit 104 to operate the printer. 102 can instruct a predetermined operation
[0012]
FIG. 2 is a schematic diagram of the mechanism of the printer of this embodiment. In the figure, 201 is a printer housing and 202 is an operation panel. The operation panel 202 includes switches for operation, an LED display, and an LCD display. This is a physical aspect of the panel unit 104 shown in FIG. A control board storage unit 203 stores a control unit of the printer engine unit 105 that controls the printing process of the printer, and a printer controller unit 103 that controls the entire printer and analyzes data from the host computer and converts it into image data. is there. A paper cassette 210 holds paper and has a mechanism for electrically detecting the paper size by a partition plate (not shown). Reference numeral 211 denotes a cassette paper feed clutch, which separates only one uppermost paper sheet placed on the paper cassette 210 and transports the separated paper to the paper feed roller 212 by a driving means (not shown). The cam rotates intermittently for each paper feed, and feeds one sheet corresponding to one rotation. Reference numeral 214 denotes a registration shutter that presses the paper and stops paper feeding. The paper feed roller 212 conveys the leading edge of the paper to the registration shutter 214. 219 is a manual feed tray, and 215 is a manual paper feed clutch. The paper feed clutch 215 conveys the leading edge of the paper to the registration shutter 214. With the above configuration, it is possible to selectively feed paper from the paper cassette 210 and the manual paper feed tray 219.
[0013]
The printer engine unit 105 communicates with the printer controller unit 103 according to a predetermined communication protocol, determines a paper feeding unit from the cassette 210 or the manual feed tray 219 according to an instruction from the printer controller unit 103, and instructs to start printing. As described above, the sheet feeding is started and the sheet is conveyed to the registration shutter 214. A cartridge 204 has a photosensitive drum 205 and a toner holding unit (not shown). Reference numeral 206 denotes a laser driver, 207 denotes a rotating polygon mirror, 208 denotes a reflecting mirror, and 209 denotes a beam detector. When the sheet is conveyed to the registration shutter 214, a laser beam emitted from a semiconductor laser (not shown) that is driven on and off by a laser driver in accordance with image data sent from the printer controller unit 103 is mainly transmitted by a rotary polygon mirror 207. It scans in the scanning direction and is guided onto the photosensitive drum 205 through a reflection mirror to form an image, and scans in the main scanning direction to form a latent image on the main scanning line. In synchronization with the emission of the laser beam, the registration shutter 214 is driven upward, and the conveyance of the paper is synchronized with the sub-scanning of the laser beam. A beam detector 209 arranged at the start of scanning of the laser beam forms a synchronization signal for determining the image writing timing of main scanning by detecting the laser beam, and sends it to the printer controller unit 103. Thereafter, the sheet is conveyed by a conveying roller 213, the photosensitive drum is driven to rotate by a motor (not shown), and is visualized as a toner image by the developing device 220, and then transferred onto the sheet. The sheet onto which the toner image has been transferred is then heated and fixed by the fixing roller 216, passes through the transport roller 217, and is discharged onto the discharge tray of the printer housing by the discharge roller 218.
[0014]
FIG. 3 is a block diagram illustrating a configuration of the printer controller unit 103.
[0015]
In FIG. 3, reference numeral 302 denotes a host I / F unit that receives code data sent from the external device 101 and transmits data such as status to the external device 101. Data written in a transmission buffer, which will be described later, is transferred to the external device 101. Send to.
[0016]
A RAM 307 is used as an input buffer for received code data and a work memory for the page memory CPU 309. The received code data is temporarily stored in the input buffer, converted into an intermediate code by the CPU 309, and stored in the page memory.
[0017]
310 is an EEPROM, and external character data and form data created by the user are downloaded. A ROM 304 stores an operation program for the CPU 309, standard fonts, and the like.
[0018]
An image data generation unit 303 expands the intermediate code stored in the page memory in the RAM 307 into bitmap data and writes it into the image memory 305. The DMA control unit 308 sends the bitmap data in the image memory 305 to the printer engine unit 105 via the engine I / F unit 306.
[0019]
Further, the CPU 309 sends a status request command, a command for designating a sheet feeding unit, and the like to the printer engine unit via the engine I / F unit 306, and the printer engine unit 105 responds to these commands in response to these commands. Return status. Such status includes the type of error, designated paper feeding means, and the like.
[0020]
The printer controller unit 103 has a function of sending information regarding the status of the printer engine unit 105 obtained as described above, the internal font in the ROM 304, and the font downloaded to the EEPROM 310 to the external device 101 as a transmission status. .
[0021]
Hereinafter, the operation of the CPU 309 when transmitting such a transmission status will be described.
[0022]
FIG. 6 is a flowchart showing the contents of this embodiment assuming that there is one interface with the host computer for the sake of simplicity. When there is a status request from the host computer 101 or an event for transmitting data to the host computer 101 occurs in the printing apparatus, the transmission status is written into the transmission buffer in the host I / F unit 302 by the required number of bytes. A request is made (step S101). In the transmission buffer write in step S101, the state of the transmission buffer depends on the state of communication with the host computer 101 or the frequency of status transmission, etc., (A), (B), (C), (D) 4 shown in FIG. There are two patterns. If all the transmission data has been written in step S102 as shown in FIGS. 5A and 5B from the result of the write request in step S101 (state 1), step S201 in FIG. The time-out time during counting is reset (step S103). Here, the states of (A) and (B) in FIG. 5 will be described in detail. This state is when all the generated statuses can be written to the transmission buffer. The difference between (A) and (B) is that transmission is normal. The difference is whether the data can be written to the transmission buffer or the data cannot be transmitted, but the area writable in the transmission buffer is sufficiently free and writable.
[0023]
After performing the reset process in step S103, it is further determined in step S104 whether all the data for the number of bytes requested to be written have been written. If all the data for the number of bytes requested to be written can be written, all of the transmission data has been written to the transmission buffer, so the processing ends. On the other hand, if only a part can be written in step S104, transmission has not been completed. In step S105, the remaining number of write request bytes is calculated, and the read position of the write data to the transmission buffer is shifted to prepare for the next write. To do. Then, another task is activated once and waits for a predetermined time (step S106), and then a request for writing the remaining transmission data in the transmission buffer is made again (step S101). Normally, writing can often be performed once, but when a large amount of data is to be transmitted, this routine is used to write to the transmission buffer multiple times until all transmission data has been written. Repeat the process.
[0024]
In step S102, when writing to the transmission buffer is not possible, the time-out time counted in step S201 is referred to by the RAM 307 (step S107), and the time-out time has not yet elapsed to a certain threshold value that becomes the transmission time-out. In this case (step S108), the writing to the transmission buffer is not given up (state 2), and another task is started once and waits for a predetermined time (step S106), and then a request for writing the remaining transmission data to the transmission buffer is made again (step S106). Step S101). The state corresponding to state 2 is the state shown in FIG. 5C, and the transmission buffer has become full, but since the preset timeout period has not elapsed, it is temporarily incapable of transmission. And write to the transmission buffer is retried for a certain time. When the transmission state does not change and the state where writing to the transmission buffer cannot be continued continues, the above operation is repeated until the timeout time comes.
[0025]
In step S108, when the time-out time is reached (state 3), a time-out process is executed to discard the transmission data and end the process (step S109). In state 3 shown here, as shown in FIG. 5D, it is determined that transmission from the printing apparatus is impossible in the current environment because the state in which writing to the transmission buffer cannot be performed has reached a preset time. This is the case.
[0026]
In this way, when an event relating to data transmission occurs in the state where timeout has occurred, a write request to the transmission buffer is made only once, and if it still cannot be written, it gives up immediately and discards data (step) The process proceeds from step S108 to step S109 without going to step S106). Therefore, it is possible to operate as if transmission is being performed without interrupting other processing. When transmission becomes possible, transmission can be resumed immediately from either state 2 or state 3, so that it matches the communication state between the various device devices including the host computer and the printing apparatus. It is possible to determine the optimum operation and perform data transmission.
[0027]
(Example 2)
In the first embodiment, the number of interfaces is limited to one, but the above timeout determination may be performed for each of a plurality of interfaces. In a situation where the same transmission data is transmitted to a plurality of ports, a timeout occurrence state or the like is determined for each port. For example, when the serial port is not capable of bidirectional communication and the parallel port is capable of bidirectional communication, only the serial port that is not capable of bidirectional communication is shifted to the timeout state to enable bidirectional communication. Instead, the bidirectional communication may be performed only for the parallel port capable of bidirectional communication, and other processing may be performed smoothly.
[0028]
(Example 3)
In the first embodiment, the timeout process is terminated by discarding the transmission data, but writing to the transmission buffer may be enabled by clearing the transmission buffer. Further, instead of erasing all the contents of the transmission buffer, the old information may be erased so that only a necessary capacity is created.
[0029]
(Example 4)
In the first embodiment, when there is a write request after the occurrence of timeout, if the write is tried once in the transmission buffer and writing is still impossible, timeout processing is executed. May be set to retry for a certain time shorter than the normal timeout time.
[0030]
(Example 5)
In the first embodiment, it is desired to measure the time and execute the processing within a certain period of time. However, instead of the time, the number of retries may be set and the threshold value may be set to the number of times.
[0031]
【The invention's effect】
As described above, the printing apparatus according to the present invention is such that the printing apparatus is connected to a device device such as a host computer that cannot perform bidirectional communication, or the host computer cannot receive data temporarily. Even in such cases, it is determined what is the appropriate operation for each situation, and the processing of the executable printing device is not interrupted. If the bidirectional operation is impossible, only data transmission from the printing device is interrupted. Thus, it is possible to provide a printing apparatus that can smoothly execute the printing process inherent to the printing apparatus.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of a system including a printer to which the present invention is applied.
FIG. 2 is a schematic diagram of a printer mechanism to which the present invention is applied.
FIG. 3 is a block diagram showing an electrical configuration of a printer controller to which the present invention is applied.
FIG. 4 is a diagram illustrating the cause of the transmission buffer of the printing apparatus being in a writable state in the first embodiment.
FIG. 5 is a diagram illustrating a change in a writing method to a transmission buffer corresponding to a change in a communication state between a printing apparatus and a host computer in the first embodiment.
6 is a flowchart illustrating an example of a writing method to a transmission buffer corresponding to a change in a communication state between a printing apparatus and a host computer in Embodiment 1. FIG.
FIG. 7 is a flowchart illustrating an example of executing timeout time counting in the first embodiment.
[Explanation of symbols]
101 External device (host computer)
102 Laser beam printer 103 Printer controller unit 104 Panel unit 105 Printer engine unit 302 Host I / F unit 309 CPU

Claims (5)

A transmission buffer in which transmission data to be transmitted to an external device is written;
A discriminating means for discriminating whether or not writing to the transmission buffer has been completed;
If it is determined by the determining means that writing cannot be performed, it is determined whether a time-out has occurred. When a write request is made to the transmission buffer and the determination means determines that writing has been completed, the timeout time is reset, it is determined whether all writing has been completed, and it is determined that all writing has been completed. In this case, the printing apparatus includes: a unit that waits for a certain period of time when the process ends and it is determined that all writing is not possible, makes a write request to the transmission buffer, and causes the determination unit to determine. A transmission buffer in which transmission data to be transmitted to an external device is written;
A discriminating means for discriminating whether or not writing to the transmission buffer has been completed;
If it is determined by the determining means that writing is not possible, it is determined whether a timeout has occurred, if it is determined that a timeout has occurred, the transmission data is discarded and the process is terminated. When a write request is made to the transmission buffer and the determination means determines that writing has been completed, the timeout time is reset, it is determined whether all writing has been completed, and it is determined that all writing has been completed. If it is determined that all data cannot be written, the remaining number of write request data is calculated, the read position of the write data to the transmission buffer is shifted, and the next write preparation is performed, and a certain time is waited. A means for making a write request to the transmission buffer and causing the determination means to determine Printing apparatus characterized by.   The printing apparatus according to claim 1, further comprising a printing unit that performs printing based on data received from an external device. A method of writing to a buffer in a printing apparatus having a transmission buffer in which transmission data to be transmitted to an external device is written,
A determination step of determining whether or not writing to the transmission buffer was possible;
If it is determined in the determination step that writing cannot be performed, it is determined whether a time-out has occurred.If it is determined that a time-out has occurred, the transmission data is discarded and the process is terminated. , Make a write request to the transmission buffer, let the discrimination step discriminate, and if it is discriminated by the discrimination step that the write has been completed, reset the timeout time, determine whether all have been written, and determine that all have been written If it is determined that all the data cannot be written, the process waits for a certain period of time, makes a write request to the transmission buffer, and causes the determination step to make a determination. Writing method. A method of writing to a buffer in a printing apparatus having a transmission buffer in which transmission data to be transmitted to an external device is written,
A determination step of determining whether or not writing to the transmission buffer was possible;
If it is determined in the determination step that writing cannot be performed, it is determined whether a time-out has occurred.If it is determined that a time-out has occurred, the transmission data is discarded and the process is terminated. , Make a write request to the transmission buffer, let the discrimination step discriminate, and if it is discriminated by the discrimination step that the write has been completed, reset the timeout time, determine whether all have been written, and determine that all have been written If it is determined that all data cannot be written, the remaining number of write request data is calculated, the read position of the write data to the transmission buffer is shifted, and the next write preparation is performed, and a certain time is waited. Then, a write request is made to the transmission buffer, and the determination step is performed. How writing to the buffer in the printing apparatus characterized by comprising a step of.

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