A system is disclosed. The system comprises one or more print controllers to generate print interrupt instructions in response to receiving a web splice signal indicating that a web splice on a web print medium has been detected, wherein the print interrupt instructions indicate a first side sheet image and a second side sheet image within a print job to pause prior to stopping printing, wherein the print interrupt instructions comprise gap instructions to open a first printhead gap at the first print engine and to open a second printhead gap at the second print engine, control printing of the first side sheet image on a first side of a web at a first print engine based on the print interrupt instructions, control printing of the second side sheet image to a second side of the web at a second print engine based on the print interrupt instructions, wherein the print interrupt instructions are generated based on a determination of an interrupted first side sheet image to be paused prior to opening the first printhead gap and a determination of an interrupted second side sheet image to be paused prior to opening the second printhead gap.

Provided is a print data correction method that is executed by a printing device. The print data correction method includes: printing a first correction chart with a printer that performs printing; obtaining a first correction value based on the printed first correction chart; printing a second correction chart based on the first correction value with the printer; obtaining a second correction value based on the printed second correction chart; and correcting, based on the second correction value, print data to be printed by the printer.

Provided is a print data correction method that is executed by a printing device. The print data correction method includes: printing a first correction chart with a printer that performs printing; obtaining a first correction value based on the printed first correction chart; printing a second correction chart based on the first correction value with the printer; obtaining a second correction value based on the printed second correction chart; and correcting, based on the second correction value, print data to be printed by the printer.

An example image forming apparatus that detects an error of an image formed on a printing medium, the apparatus includes a print engine, an inline scanner located at an output end of the print engine, and a processor. The processor is to obtain information of print data of a received print job, form an image on a printing medium based on the print data by using the print engine, obtain information of a print image of the printing medium on which the image is formed by using the inline scanner, detect whether normal output is performed by comparing the information of the print data with the information of the print image, and, in a case where the normal output is not detected, detect an output error and perform re-output.

A printing system may include a printing module, a measurement device, and a correction device. The printing module performs printing processes on a substrate. The printing processes include a first printing process based on a first pulse number. The measurement device may obtain image data for the substrate before and after the first printing process. The correction device may use the image data to obtain information indicating a change in a separation between first and second reference marks on the substrate before and after the first printing process. The correction device may then determine a second pulse number based on the information and control the printing module to perform a second printing process that is based on the second pulse number.

A printing system may include a printing module, a measurement device, and a correction device. The printing module performs printing processes on a substrate. The printing processes include a first printing process based on a first pulse number. The measurement device may obtain image data for the substrate before and after the first printing process. The correction device may use the image data to obtain information indicating a change in a separation between first and second reference marks on the substrate before and after the first printing process. The correction device may then determine a second pulse number based on the information and control the printing module to perform a second printing process that is based on the second pulse number.