Image forming apparatus

Abstract

Reduce the time it takes to resume printing after it has been temporarily stopped. [Solution] When the voltage value of the power supplied from the power supply unit 102 to the control unit 101 falls below a first voltage value while the print data is stored in the volatile memory 201, the main control unit 200 stores the print data stored in the volatile memory 201 in the non-volatile memory 202. When the voltage value of the power supplied to the control unit 101 becomes greater than a second voltage value, the main control unit 200 transfers the print data stored in the non-volatile memory 202 to the volatile memory 201 and controls the print engine 103 to perform printing based on the print data transferred to the volatile memory 201.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] In the technology related to image forming apparatuses, a technique has been proposed to re - send print data from an information terminal to an image forming apparatus in order to resume printing after a trouble such as a power failure occurs (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology, it sometimes takes time to resume printing after power recovery, which is not satisfactory.

[0005] An object of the present invention is to shorten the time from temporarily stopping printing to resuming printing in order to solve the above problems.

Means for Solving the Problems

[0006] The image forming apparatus of the present invention includes a printing engine that performs printing, a control unit having a volatile memory in which print data, which is data for the printing, is stored, a non - volatile memory, and a main control unit that controls the printing engine, and a power supply unit that supplies power to the control unit. and is provided with When the print data is stored in the volatile memory, and the voltage value of the power supplied from the power supply unit to the control unit falls below the first voltage value, the main control unit stores the print data stored in the volatile memory in the non-volatile memory. When the voltage value of the power supplied to the control unit becomes greater than the second voltage value, the main control unit transfers the print data stored in the non-volatile memory to the volatile memory and controls the print engine to perform printing based on the print data transferred to the volatile memory. It is characterized by the following: [Effects of the Invention]

[0007] According to the present invention, the time required to resume printing after it has been temporarily stopped can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing a printer as an image forming apparatus. [Figure 2] Figure 1 is a block diagram illustrating the schematic configuration of the printer shown. [Figure 3] This is a flowchart showing the normal printing process in a printer. [Figure 4] This flowchart shows the printer's behavior when the power supply to the printer is interrupted during the printing process. [Figure 5] This flowchart shows the printer's operation when power is restored to the printer. [Figure 6] This is a sequence diagram showing the flow of print data when printing pages 1 through 4. [Modes for carrying out the invention]

[0009] Figure 1 is a schematic cross-sectional view showing the printer 100 as an image forming apparatus of the present invention. The printer 100 includes a control unit 101, a power supply unit 102 that supplies power to the control unit 101, and a printing engine 103 that performs printing.

[0010] The control unit 101 is, for example, a control board that controls the entire printer 100.

[0011] The power supply unit 102 is a power supply board that obtains power from the AC cable, converts the obtained power to DC (direct current), and supplies power to the entire printer 100. When the power supply unit 102 detects that the voltage supplied from the power supply has fallen below a first voltage value (for example, 20V), it sends a power outage signal to the main control unit 200 and the switch 206, which is a signal indicating that the power supply to the printer 100 has been cut off.

[0012] The printing engine 103 is a unit that receives print data from the control unit 101 and prints onto a medium using an electrophotographic process. For example, the printing engine 103 prints compressed bitmap data received from the control unit 101 while decompressing it.

[0013] Figure 2 is a block diagram schematically showing the configuration of the printer 100 shown in Figure 1. The control unit 101 includes a main control unit 200, a RAM 201, a ROM 202, an IF unit 203, and an input unit 204.

[0014] RAM201 is a volatile memory, such as DDR (Double Data Rate). RAM201 stores print data, which is data for printing.

[0015] The data for authenticated printing is data sent from an external terminal device (e.g., a PC) outside the printer 100 that is operated by the user, and is printing data before user authentication. The data for authenticated printing is converted into printing data to be sent to the printing engine 103 by the main control unit 200 after the user is authenticated. The data for authenticated printing and the data sent to the printing engine 103 may be collectively referred to as printing data.

[0016] The printing data generated by the main control unit 200 is data to be printed by the printing engine 103. The printing data generated by the control unit 101 is, for example, data of a general application converted into a bitmap image (for CMYK four colors) in which each pixel represents dot on / off with 1-bit data, and further subjected to compression processing.

[0017] The ROM 202 is a non-volatile memory such as an SSD (Solid State Drive), for example. The ROM 202 temporarily holds the data for authenticated printing and the printing data generated by the main control unit 200. A program for operating the main control unit 200 (e.g., a CPU (Central Processing Unit)) may be stored in the ROM 202. The transfer speed of the ROM 202 is, for example, 300 MB / s.

[0018] The IF unit 203 is an interface that receives the data for authenticated printing sent from a terminal device, such as a LAN, for example.

[0019] The input unit 204 is, for example, an operation panel. Designations such as designation of the data for authenticated printing to be printed or designation of printing start (printing instruction) are input to the input unit 204, for example.

[0020] The main control unit 200 controls the print engine 103. The main control unit 200 is composed of, for example, a CPU and its peripheral circuits. The main control unit 200 is realized by the CPU executing a program stored in the ROM 202. The main control unit 200 is connected to the bus 208 and accesses the RAM 201, ROM 202, and the print engine 103.

[0021] When the main control unit 200 receives a specification of authentication print data to be printed and a specification to start printing via the input unit 204 or IF unit 203, it stores the authentication print data for the target, which is stored in the ROM 202, in the RAM 201 and generates print data. When printing to a medium, the main control unit 200 transmits the generated print data to the print engine 103.

[0022] If the power supply to the printer 100 is interrupted, the main control unit 200 stores the print data stored in the RAM 201 in the ROM 202. For example, when print data is stored in the RAM 201, if the voltage value of the power supplied from the power supply unit 102 to the control unit 101 falls below a first voltage value (for example, 20V), the main control unit 200 stores the print data stored in the RAM 201 in the ROM 202.

[0023] When power is restored to the printer 100, the main control unit 200 stores the print data stored in the ROM 202 in the RAM 201 and controls the print engine 103 to print based on the print data. For example, when the voltage value of the power supplied to the control unit 101 becomes greater than a second voltage value, the main control unit 200 transfers the print data stored in the ROM 202 to the RAM 201 and controls the print engine 103 to print based on the print data transferred to the RAM 201.

[0024] The second voltage value may be the same as the first voltage value. The absolute value of the second voltage value may be less than the absolute value of the first voltage value.

[0025] The power supply unit 102 includes a power supply unit 205, a switch 206, and a voltage drop detection unit 207.

[0026] The power supply unit 205 is an AC-DC conversion unit. The power supply unit 205 converts, for example, AC 100V to DC 24V.

[0027] Switch 206 is a switch capable of electrically disconnecting the power supply from the load. When switch 206 receives a power outage signal from the voltage drop detection unit 207, it stops supplying power to the printing engine 103.

[0028] The voltage drop detection unit 207 is, for example, a power supply microcontroller. When the voltage drop detection unit 207 detects that the voltage supplied from the power supply has fallen below a first voltage value (for example, 20V), it sends a power outage signal to the main control unit 200 and the switch 206.

[0029] When the printing engine 103 receives print data from the control unit 101 (for example, the main control unit 200), it performs printing on the medium using an electrophotographic process.

[0030] Figure 3 is a flowchart showing the normal printing process in printer 100. In step S301, the authentication print data transmitted by the user using the terminal device is received by the IF unit 203 and stored in the ROM 202. Authentication print data being received is temporarily stored in the RAM 201. All authentication print data transmitted by the user using the terminal device is received by the IF unit 203 and then stored in the ROM 202. After being stored in the ROM 202, the authentication print data in the RAM 201 is erased.

[0031] In step S302, user authentication is performed in the printer 100 (for example, the main control unit 200), and the main control unit 200 receives the specification of authentication print data and a print command via the input unit 204 or the IF unit 203.

[0032] In step S303, print data is generated and printing is performed on the medium. For example, the main control unit 200 transfers the authentication print data for the print target stored in the ROM 202 to the RAM 201, generates print data, and controls the print engine 103 to perform printing based on the generated print data. The print engine 103 prints on the medium based on the control by the main control unit 200.

[0033] Figure 4 is a flowchart showing the operation of the printer 100 when the power supply to the printer 100 is interrupted during the printing process. In step S401, the power supply unit 102 (specifically, the voltage drop detection unit 207) detects a voltage drop. For example, when the voltage drop detection unit 207 detects that the voltage value of the power supplied from the power supply unit 205 to the control unit 101 has fallen below a first voltage value (for example, 20V), it sends a power outage signal to the main control unit 200 and the switch 206.

[0034] In step S402, the power supply to the print engine 103 is stopped. For example, the power supply unit 102 (specifically, switch 206) cuts off the power supply to the print engine 103 based on a power outage signal.

[0035] In step S403, all tasks performed by the CPU of the main control unit 200 are stopped. For example, the main control unit 200 stops all tasks that are being processed by the CPU and stops processing in peripheral circuits (including the IF unit 203 and the input unit 204), excluding RAM 201 and ROM 202.

[0036] If the CPU is multi-core, the main control unit 200 stops all but one core. This reduces the current flow by stopping the power supply to the printing engine 103, tasks in progress, and peripheral circuits, thereby extending the time until the voltage drops to a level that renders the system inoperable (e.g., 5V).

[0037] In step S404, the main control unit 200 transfers the print data from RAM 201 to ROM 202. For example, the data transfer from RAM 201 to ROM 202 is controlled by one CPU core that is not stopped. The data stored in ROM 202 from RAM 201 as a result of the processing in step S404 is called "avoidance data".

[0038] The avoidance data may include data other than print data. For example, the avoidance data may include print-related information such as page numbers and user information. Print-related information may include, for example, information to identify the data to be printed, information to identify the authenticated person, printed page numbers, and print data generation numbers (size approximately 1KB).

[0039] Figure 5 is a flowchart showing the operation of printer 100 when power supply to printer 100 is restored. In step S601, a recovery process is performed. For example, when power is restored to the printer 100, power is supplied to the control unit 101 and the print engine 103. When the voltage value of the power supplied to the control unit 101 becomes greater than the second voltage value, the recovery process is started, and the print engine 103 removes the medium in transit. The main control unit 200 makes the RAM 201, ROM 202, IF unit 203, and input unit 204 operational.

[0040] In step S602, user authentication is performed in the printer 100 (for example, the main control unit 200), and the main control unit 200 receives a print restart (print command) via the input unit 204 or the IF unit 203. If the power outage time is short, the process in step S602 may be omitted.

[0041] In step S603, the main control unit 200 transfers the avoidance data stored in the ROM 202 to the RAM 201. After transferring the data to the RAM 201, the main control unit 200 erases the avoidance data in the ROM 202.

[0042] In step S604, printing is resumed. For example, the main control unit 200 sends avoidance data (print data for the third page), which is print data that has not yet been printed, to the print engine 103. The print engine 103 prints to the medium based on the print data for the third page from the control unit 101. The main control unit 200 generates the print data for the fourth page and sends it to the print engine 103, and the print engine 103 finishes the printing process by printing to the medium based on the print data for the fourth page.

[0043] Figure 6 is a sequence diagram showing the flow of print data when printing pages 1 through 4. The pre-authentication print data (authentication print data) for pages 1 through 4, sent by the user using a terminal device, is temporarily stored in RAM 201 via IF unit 203. The authentication print data for pages 1 through 4 stored in RAM 201 is then sequentially stored in ROM 202. After being stored in ROM 202, the authentication print data in RAM 201 is erased. The example shown in Figure 6 illustrates the flow of authentication print data for page 4.

[0044] When user authentication is performed in the printer 100 (for example, the main control unit 200) and the main control unit 200 receives a print command, the process of generating print data begins. The main control unit 200 sets the initial values ​​of the printed page numbers and the generated print data page numbers to "0". This allows the number of printed pages and the number of generated print data pages to be counted.

[0045] As shown in Figure 6, print data for pages 1 through 3 is generated in RAM 201 and sent sequentially to the print engine 103. The main control unit 200 increments the page number for which print data has been generated each time a page is printed.

[0046] The print engine 103 performs printing whenever it receives print data, and notifies the main control unit 200 of the completion of printing each time printing is finished.

[0047] Each time the main control unit 200 receives notification that the printing process has finished, it increments the printed page number in RAM 201 and erases the print data for the first page in RAM 201.

[0048] As shown in Figure 6, if the power supply to the printer 100 is cut off after the second page has been printed and the print data for the third page has been generated in the RAM 201, the power supply unit 102 (specifically, the voltage drop detection unit 207) detects a voltage drop. As a result, the power supply unit 102 (specifically, the voltage drop detection unit 207) detects that the power supply to the printer 100 has been cut off. For example, a drop from 24V to 4V is detected 4ms after the power is cut off, and the power supply to the print engine 103 is stopped.

[0049] When a power outage occurs, the potential change ΔV / Δt per unit time is expressed by the following formula. ΔV / Δt=(Ia+Ib) / C=1[A] / 0.001[F]=1000[V / s] Ia: Current flowing through the printing engine 103 is 0.6[A] Ib: Current flowing through control unit 101 is 0.4[A] C: Capacitor located in power supply unit 205 In other words, the voltage drops by 1V in 1ms.

[0050] When the control unit 101 receives a power outage signal from the power supply unit 102 (specifically, the voltage drop detection unit 207), it reduces the current flowing through the control unit 101 from 0.4[A] to 0.25[A] by disabling functions other than data avoidance. As a result, the potential change ΔV / Δt per unit of time is expressed by the following formula. ΔV / Δt=(Ib) / C=0.25[A] / 0.001[F]=250[V / s] In other words, the voltage drops by 0.25V in 1ms. The time it takes for the voltage to drop from 20V to 5V (the point at which the device becomes inoperable) is 60ms.

[0051] The print data for page 3 generated in RAM201 and the pre-authentication print data for page 4 stored in RAM201 are transferred to ROM202. Once this data is stored in ROM202, a flag indicating the completion of the transfer is stored in ROM202.

[0052] The generated print data has a data size of 66MB under the conditions of A4 size and a resolution of 1200dpi. After compression, the generated print data becomes approximately 15MB. The transfer speed of ROM202 is 300MB / s, and the data being transferred is approximately 15MB, so the transfer from RAM201 to ROM202 can be completed in 50ms. Therefore, the transfer from RAM201 to ROM202 can be completed within the 60ms during which the printer 100 becomes inoperable.

[0053] When power is restored to the printer 100, the control unit 101 and the print engine 103 become operational, and the print engine 103 performs a recovery process. In the recovery process, for example, the print engine 103 ejects any media being transported out of the printer 100.

[0054] When the input unit 204 authenticates the user and receives a print restart command, the bypass data stored in ROM 202 (in the example shown in Figure 6, the print data for page 3 generated in RAM 201 and the pre-authentication print data for page 4 stored in RAM 201) is stored in RAM 201. Once the transfer of the bypass data from ROM 202 to RAM 201 is complete, the bypass data is erased from ROM 202.

[0055] The print data for the third page is sent to the print engine 103, and the print engine 103 prints it onto the medium. The main control unit 200 counts up the printed page number in the RAM 201 and erases the print data for the third page from the RAM 201.

[0056] Furthermore, the print data for the fourth page is generated in RAM 201, and the main control unit 200 increments the page number for which print data has been generated. The print data for the fourth page is sent to the print engine 103, and the print engine 103 prints it on the medium. The main control unit 200 increments the printed page number in RAM 201 and erases the print data for the fourth page in RAM 201.

[0057] As described above, according to this embodiment, when a power outage or other failure occurs and the power supply to the printer 100 is interrupted, workaround data is stored in the ROM 202, and printing is resumed using the workaround data in the ROM 202 after the power supply is restored. As a result, the print data does not need to be generated again, and the time from temporarily stopping printing to resuming printing can be shortened.

[0058] In this embodiment, an SSD is used as the ROM 202, but other non-volatile memory may be used. In this embodiment, one CPU of the main control unit 200 is used to control the transfer of avoidance data, but a sub-CPU with lower power consumption (current flowing to the printer 100) may be used to control the transfer of avoidance data. This makes it possible to extend the voltage drop time until the printer 100 stops functioning. In this embodiment, the print data is compressed, but printing may be performed using uncompressed print data.

[0059] The various aspects of this implementation are summarized below as an appendix. (Note 1) A printing engine that performs printing, A control unit having a volatile memory for storing print data, which is the data for printing, a non-volatile memory, and a main control unit for controlling the printing engine, A power supply unit that supplies power to the aforementioned control unit, Equipped with, When the print data is stored in the volatile memory, and the voltage value of the power supplied from the power supply unit to the control unit falls below the first voltage value, the main control unit stores the print data stored in the volatile memory in the non-volatile memory. When the voltage value of the power supplied to the control unit becomes greater than the second voltage value, the main control unit transfers the print data stored in the non-volatile memory to the volatile memory and controls the print engine to perform printing based on the print data transferred to the volatile memory. An image forming apparatus characterized by the following: (Note 2) The image forming apparatus according to Appendix 1, characterized in that when the voltage value of the power supplied to the control unit becomes greater than the second voltage value, the main control unit stores the print data stored in the non-volatile memory in the volatile memory without receiving the print data stored in the non-volatile memory again from an external terminal device of the image forming apparatus. (Note 3) The image forming apparatus according to Appendix 1 or 2, characterized in that the second voltage value is the same as the first voltage value. (Note 4) The image forming apparatus according to Appendix 1 or 2, characterized in that the absolute value of the second voltage value is smaller than the absolute value of the first voltage value. (Note 5) The image forming apparatus according to Appendix 1 or 2, characterized in that, while the print data is stored in the volatile memory, when the voltage value of the power supplied from the power supply unit to the control unit falls below the first voltage value, the power supply unit shuts off the power supply to the print engine. [Explanation of Symbols]

[0060] 100 Printer, 101 Control Unit, 102 Power Supply Unit, 103 Printing Engine, 200 Main Control Unit, 201 RAM (Volatile Memory), 202 ROM (Non-Volatile Memory), 203 IF Unit, 204 Input Unit, 205 Power Supply Unit, 206 Switch, 207 Voltage Drop Detection Unit, 208 Bus

Claims

1. A printing engine that performs printing, A control unit having a volatile memory for storing print data, which is the data for printing, a non-volatile memory, and a main control unit for controlling the printing engine, A power supply unit that supplies power to the aforementioned control unit, Equipped with, When the print data is stored in the volatile memory, and the voltage value of the power supplied from the power supply unit to the control unit falls below the first voltage value, the main control unit stores the print data stored in the volatile memory in the non-volatile memory. When the voltage value of the power supplied to the control unit becomes greater than the second voltage value, the main control unit transfers the print data stored in the non-volatile memory to the volatile memory and controls the print engine to perform printing based on the print data transferred to the volatile memory. An image forming apparatus characterized by the following:

2. The image forming apparatus according to claim 1, characterized in that when the voltage value of the power supplied to the control unit becomes greater than the second voltage value, the main control unit stores the print data stored in the non-volatile memory in the volatile memory without receiving the print data stored in the non-volatile memory again from an external terminal device of the image forming apparatus.

3. The image forming apparatus according to claim 1 or 2, characterized in that the second voltage value is the same as the first voltage value.

4. The image forming apparatus according to claim 1 or 2, characterized in that the absolute value of the second voltage value is smaller than the absolute value of the first voltage value.

5. The image forming apparatus according to claim 1 or 2, characterized in that, while the print data is stored in the volatile memory, when the voltage value of the power supplied from the power supply unit to the control unit falls below the first voltage value, the power supply unit shuts off the power supply to the print engine.

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