JPH0284371A - Double-side printer - Google Patents

Abstract

PURPOSE:To immediately restart reprinting of a jammed sheet by detecting the conveying malfunction of the sheet conveyed on the basis of stored dot data. CONSTITUTION:An input unit 1 inputs information for controlling a whole printer by a host computer or the like. A controller 2 controls the whole printer, analyzes input information, form a page in a memory 4, and feeds out dot data by pate unit to an engine 5. A data buffer 3 stores the page data of a plurality of pages input from the unit 1. The memory 4 develops the page data as printing image (dot data), stores the developed dot data of one page, and hold it until a sheet is completely discharged. A double-side printer 5 is of a laser printer for printing on both side surfaces of a recording sheet conveyed on the basis of the dot data fed from the memory 4, and has a sensor 5a for detecting the conveying malfunction (jam) of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a double-sided printing device that performs double-sided printing on a conveyed sheet based on page data such as input character codes.

[Conventional technology]

In recent years, various devices have been developed that temporarily store input page data such as character codes in a buffer, develop it into dot data (also called a print image), and print the data on recording paper. In such a printing apparatus, for example, in the case of A4 recording paper, approximately 1 megabyte of memory is required to develop one page's worth of input page data as a print image in memory. However, as memory chips have become larger in capacity and lower in price in recent years, it has become possible to use large capacity memories in printing devices.
It has become possible to develop a print image for one page in memory and then print it.

[Problem that the invention is trying to solve] However,
In the conventional example described above, when the amount of input page data is too large to store one page's worth of page data in the buffer, one page's worth of input page data is developed into dot data and stored in the memory. In this case, only one page can be stored in the device, so if a paper jam occurs in the duplex printing device, there is an inconvenience that the jammed paper cannot be immediately reprinted. It was happening.

The present invention has been made in view of the above-mentioned problems, and provides a double-sided printing device that can immediately resume reprinting of jammed sheets.

[Means and effects for solving the problem] According to the present invention, there is provided a first storage means for storing page data such as input character codes for a plurality of pages, and a first storage means for storing page data such as input character codes, which is expanded into dot data and stored. a second storage means for performing double-sided printing on a conveyed sheet based on the dot data stored in the second storage means; a detection means for detecting an abnormality in conveyance of the sheet; By providing a means for reprinting pages that could not be printed due to an abnormality in sheet conveyance, reprinting of jammed sheets can be immediately resumed.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing a double-sided printing apparatus of this embodiment. In the figure, 1 is an input device for inputting information to control the entire printing device from a host computer, etc., and 2 is an input device that controls the entire printing device and analyzes input information (control commands, character codes, etc.), which will be described later. 3 is a control device for creating pages on the storage device 4 to be used and sending dot data in units of pages to the engine section 5; 3 is page data for multiple pages input from the input device 1 (character code, number of copies, etc.); 4 is a data buffer that stores page data into a print image (dot data),
A storage device that can store one page's worth of developed dot data and hold it until the paper is ejected, and 5 a laser that prints on both sides of the recording paper being conveyed based on the dot data sent out from the storage device 4. It is a double-sided printing printer such as a printer. Incidentally, the double-sided printing printer 5 is equipped with a sensor 5a that detects a conveyance abnormality (jam) of recording paper.

FIG. 2 is a control flowchart of this embodiment, which is programmed and stored in the ROM in the control device 2.

In step S1, data from a host computer or the like is received using the input means 1, and page data is created on the data buffer 3. In this embodiment, it is assumed that all the page data on the front side can be developed onto the data buffer 3 at this time. Continuing to receive data on the back side, data buffer 3
Create page data on top. When the amount of this back page data is large or the capacity of the data buffer 3 is small, the page data on the back side is transferred to the data buffer 3 in step S2.
Detects that it cannot fit inside. In step s3, both the page data already created on the data buffer 3 and the back side data received after detecting that the data buffer 3 overflowed are developed into dot data (print image), and this is converted into a print image in the storage device 4. Store it in the deployment area. After the entire back surface is developed into a printed image in this way, data reception is temporarily stopped in step s4. Further, the front side is printed as a blank sheet without sending an image signal (dot data) to the printer 5, and the back side is printed using the printed image (dot data) that has been developed. In step s5, it is determined whether or not the ejection of the paper is completed. If the ejection is not completed, the process advances to step s6 and the printer 5
Checks for paper jams based on the output from If a paper jam has occurred, the process returns to step S4 and reprinting is performed using the dot data on the back side remaining in the print image development area in the storage device 4. If no paper jam has occurred, the process returns to step S5.

When the completion of paper ejection is confirmed in step s5, the process proceeds to step s7, and the print image development area in the storage device 4 is initialized in order to erase the print image after printing has been completed. In step S8, a print image is created from the page data in the data buffer 3 in order to print the surface that should have been printed in step s4 but could not be printed, and is developed in the print image development area. In step S9, the front side is printed using the developed print image, and the back side is printed as a blank sheet without sending an image signal to the printer 5.

In step SIO, it is determined whether or not paper ejection is completed. If the discharge is not completed, step Sll
Go to , and check to see if there is a paper jam.

If a paper jam has occurred, the process returns to step S9 and reprinting is performed based on the front side dot data stored in the print image development area. If no paper jam has occurred, the process returns to step S10. When the completion of paper ejection is confirmed in step SIO, the process proceeds to step S12, and the print image development area is initialized to erase the print image after printing has been completed.

In step S13, data reception is resumed and the next page data is created. As a result, the next page will be the front page, and page data will be printed on the desired side of the front and back pages.

[Other Examples]

FIG. 3 shows another example of a control flowchart executed by the control device 2. In step S1, data from a host computer or the like is received using the input means 1, and page data is created on the data buffer 3. When the amount of page data is large or when the capacity of the data buffer 3 is small, the front page data is transferred to the buffer 3 in step S2.
Detects that it cannot fit inside. In step S3, since the data buffer 3 can no longer be used, the received data is developed into a print image (dot data) and stored in the print image development area in the storage device 4.

In other words, all the page data on the front side is developed into dot data. In step S4, data input is temporarily stopped. Further, the front side is printed using the printed image (dot data) that has been developed, and the back side is printed as a blank sheet without sending an image signal (dot data) to the printer 5. In step S5, it is determined whether or not the ejection of the paper is completed. If the discharge is not completed, step S6
Then, based on the output from the printer 5, it is checked whether a paper jam has occurred. If a paper jam has occurred, the process returns to step S4 and reprinting is performed using the front side dot data remaining in the print image development area in the storage device 4. If no paper jam has occurred, the process returns to step S5. When the completion of paper ejection is confirmed in step s5, the process proceeds to step s7, and the print image development area is initialized to erase the print image that has been printed. In step S8, a page with no data is automatically created as the front page of one page in the data buffer 3, and then, in step S4, data input, which was temporarily stopped, is resumed. As a result, the next page to be received will be the back side of the blank paper, and thereafter page data will be printed on the desired side of the front and back sides.

Note that in this embodiment, both the front and back sides are printed and data reception is temporarily suspended while paper ejection is completed, but by providing a large capacity data reception buffer in the input device, data reception can be suspended. It is also possible to print without.

As explained above, even if the data buffer 3 of a duplex printing device does not contain enough data for two pages, reprinting is guaranteed in case of a paper jam, and the page data is printed on the desired side of the front/back side. can be printed.

〔effect〕

As described in detail above, according to the present invention, reprinting of a jammed sheet can be immediately resumed without retransmitting data from the host.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a double-sided printing apparatus in this embodiment, FIG. 2 is a control flowchart in this embodiment, and FIG. 3 is another example of the control flowchart. 1 is an input device, 2 is a control unit, 3 is a data buffer, 4 is a storage device, and 5 is a double-sided printing printer. Patent applicant: Canon Co., Ltd. Shifu Tomoe a

Claims (1)

[Claims] a first storage means for storing a plurality of pages of page data such as input character codes; a second storage means for storing the page data expanded into dot data;
printing means for performing double-sided printing on a conveyed sheet based on dot data stored in a storage means; a detection means for detecting an abnormality in conveyance of the sheet; and a detection means for detecting a page that could not be printed due to an abnormality in conveyance of the sheet. What is claimed is: 1. A double-sided printing device comprising means for printing again.